Body Fluids and Circulation Class 11 NCERT Solutions Study Material Free PDF
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About This Presentation
In the human body, a complex network of fluids and vessels works tirelessly to transport essential substances, ensuring the proper functioning of every cell and organ. This system, known as the circulatory system, plays a vital role in distributing oxygen, nutrients, hormones, and other crucial mole...
Slide Content
UNIT 1 - RESPIRATORY SYSTEM I
UNIT 2 - RESPIRATORY SYSTEM II
UNIT 3 - BODY FLUIDS
UNIT 4 - CARDIOVASCULAR SYSTEM
UNIT 5 - LYMPHATIC SYSTEM
HUMAN PHYSIOLOGY: BREATHING AND EXCHANGE
OF GASES, BODY FLUID AND CIRCULATION
UNIT 2 - RESPIRATORY SYSTEM II
UNIT 3 - BODY FLUIDS
UNIT 4 - CARDIOVASCULAR SYSTEM
UNIT 5 - LYMPHATIC SYSTEM
HUMAN PHYSIOLOGY: BREATHING AND EXCHANGE
OF GASES, BODY FLUID AND CIRCULATION
3
1
.1 INTRODUCTION
Respiration is the transport of oxygen from the air to the cell in the tissue, and the removal of
carbon dioxide in the opposite direction. The aerobic metabolic pathway of conversion of nutrients
to energy requires oxygen, for example:
C
6
H
12
O
6
+ O
2
CO
2
+ 6H
2
O + energy as ATP
Because the cells require a continuous supply of ATP, the body, in turn, needs a constant intake of oxygen and method for removal of carbon dioxide. Our respiratory system functions to accomplish
these necessary gas exchanges.
1.2 GROSS ANATOMY
1.2.1. Upper respiratory tract
A. Nose
The external portion of the nose begins at the base of the frontal bone and extends over the maxilla,
with the nasal bone providing the bridge of the nose. Extending from the nasal bone is a collection
of hyaline cartilages that make up the bulk of the nose. The medial region of the nose consists of
a central septal cartilage with two lateral processes. The tip of the nose contains the major alar
cartilage. Two minor alar cartilages are found at the sides and base of the lateral septal cartilages.
Dense fibrous connective tissue is found under the skin of the sides lateral aspects the nose, away
from the cartilage. Variations in the size of a person’s nose, or its form, are due to differences in the
various cartilages.
The openings to the nose, the nares, are lined with coarse hairs to aid in filtration of particulate
matter. The area immediately inside the nares, the vestibule, contains a large number of sebaceous
glands, sweat glands, and hair follicles. In rabbit, at the apex of nose, a pair of external-nares is
present. This is termed as Dirhynous condition.
The nasal cavity is divided into right and left sides by the nasal septum. This dividing wall’s anterior
portion is made of cartilage. Its floor, the palate, forms the roof of the mouth. It is separated into the
hard and soft palate. The anterior hard palate is formed from the maxillary process of the palatine
bone. The posterior soft palate does not contain bone and moves during swallowing to close off the
nasal cavity to prevent material from entering it from the mouth.
Extending from the nasal septum are three pairs of C-shaped structures called conchae/ turbinates.
The superior, middle, and inferior conchae extend the length of the nasal cavity. They are covered
by a mucus membrane. The conchae serve as baffles to increase the surface area of the nasal
cavity. The mucus glands and blood vessels aid in humidifying and warming the air coming into the
body.
There are two types of epithelial coverings in the nasal cavity: respiratory epithelium and olfactory
epithelium. The olfactory mucosa found in the roof of the cavity detects odors. The respiratory
UNIT 1 - RESPIRATORY SYSTEM I
1
.1 INTRODUCTION
Respiration is the transport of oxygen from the air to the cell in the tissue, and the removal of
carbon dioxide in the opposite direction. The aerobic metabolic pathway of conversion of nutrients
to energy requires oxygen, for example:
C
6
H
12
O
6
+ O
2
CO
2
+ 6H
2
O + energy as ATP
Because the cells require a continuous supply of ATP, the body, in turn, needs a constant intake of oxygen and method for removal of carbon dioxide. Our respiratory system functions to accomplish
these necessary gas exchanges.
1.2 GROSS ANATOMY
1.2.1. Upper respiratory tract
A. Nose
The external portion of the nose begins at the base of the frontal bone and extends over the maxilla,
with the nasal bone providing the bridge of the nose. Extending from the nasal bone is a collection
of hyaline cartilages that make up the bulk of the nose. The medial region of the nose consists of
a central septal cartilage with two lateral processes. The tip of the nose contains the major alar
cartilage. Two minor alar cartilages are found at the sides and base of the lateral septal cartilages.
Dense fibrous connective tissue is found under the skin of the sides lateral aspects the nose, away
from the cartilage. Variations in the size of a person’s nose, or its form, are due to differences in the
various cartilages.
The openings to the nose, the nares, are lined with coarse hairs to aid in filtration of particulate
matter. The area immediately inside the nares, the vestibule, contains a large number of sebaceous
glands, sweat glands, and hair follicles. In rabbit, at the apex of nose, a pair of external-nares is
present. This is termed as Dirhynous condition.
The nasal cavity is divided into right and left sides by the nasal septum. This dividing wall’s anterior
portion is made of cartilage. Its floor, the palate, forms the roof of the mouth. It is separated into the
hard and soft palate. The anterior hard palate is formed from the maxillary process of the palatine
bone. The posterior soft palate does not contain bone and moves during swallowing to close off the
nasal cavity to prevent material from entering it from the mouth.
Extending from the nasal septum are three pairs of C-shaped structures called conchae/ turbinates.
The superior, middle, and inferior conchae extend the length of the nasal cavity. They are covered
by a mucus membrane. The conchae serve as baffles to increase the surface area of the nasal
cavity. The mucus glands and blood vessels aid in humidifying and warming the air coming into the
body.
There are two types of epithelial coverings in the nasal cavity: respiratory epithelium and olfactory
epithelium. The olfactory mucosa found in the roof of the cavity detects odors. The respiratory
UNIT 1 - RESPIRATORY SYSTEM I
4
epithelium that covers the rest of the nasal cavity is also found through most of the respiratory tract
and is pseudostratified, ciliated, columnar epithelia. This is called pseudostratified columnar ciliated
glandular epithelium (PSCCGE).
Functional divisions of nasal passage:
Vestibular region: Skin, hairs, sebaceous glands.
Respiratory region: PSCCGE, Goblet cells.
Olfactory region: Schneiderian membrane or neuro sensory epithelium.
B. Paranasal sinuses
Within the bones surrounding the nasal cavity are paranasal sinuses (a sinus is a hollow area),
which function to make the skull lighter as well as moisten and warm incoming air. These sinuses
frequently become filled with excess fluid when a person has a head cold. Since the paranasal
sinuses serve as resonators for speech and sound it is not surprising that the sound of the voice
becomes altered when they are filled with fluid or swollen.
C. Pharynx
As the air passes posteriorly through the nasal cavity, it enters the pharynx which encompasses 3
distinct areas and connects the nasal passage to the larynx in the throat. It extends about 13 cm
from the base of the skull to the level of the 6
th
cervical vertebrae. The wall of all 3 portions contains
two layers of skeletal muscle: inner layer arranged in circular pattern and outer layer arranged
longitudinally.
Nasopharynx: The superior section of the pharynx, posterior to the nasal cavity and inferior to the
sphenoid bone. It acts only as a conduit for air and closes off during swallowing by raising the soft
palate. The paired pharyngeal tonsils, also known as the adenoids, lie in the posterior wall of the
nasopharynx.
Oropharynx: The opening from the oral cavity and the second portion of the pharynx, runs from the
soft palate to the epiglottis and is posterior to the oral cavity. In comparison to the nasopharynx,
which is lined with columnar epithelia, the oropharynx is covered by stratified squamous epithelia,
that are often found covering areas which are subject to a great deal of frictional wear.
Laryngopharynx: The third and shortest portion of the pharynx, runs inferiorly from epiglottis and
ends superior to the esophagus. It carries both air and food and is lined with stratified squamous
epithelia.
Pharynx is the only part where food and air passage mix together.
D. Larynx
It is a complex structure (about 5 cm (2 in.) long) extending from the laryngopharynx and the hyoid
bone to the trachea. It is in addition to providing a passageway for air, it directs air and food to their
appropriate tubes. The vocal cords, which are used in making sound and speech, can be found
epithelium that covers the rest of the nasal cavity is also found through most of the respiratory tract
and is pseudostratified, ciliated, columnar epithelia. This is called pseudostratified columnar ciliated
glandular epithelium (PSCCGE).
Functional divisions of nasal passage:
Vestibular region: Skin, hairs, sebaceous glands.
Respiratory region: PSCCGE, Goblet cells.
Olfactory region: Schneiderian membrane or neuro sensory epithelium.
B. Paranasal sinuses
Within the bones surrounding the nasal cavity are paranasal sinuses (a sinus is a hollow area),
which function to make the skull lighter as well as moisten and warm incoming air. These sinuses
frequently become filled with excess fluid when a person has a head cold. Since the paranasal
sinuses serve as resonators for speech and sound it is not surprising that the sound of the voice
becomes altered when they are filled with fluid or swollen.
C. Pharynx
As the air passes posteriorly through the nasal cavity, it enters the pharynx which encompasses 3
distinct areas and connects the nasal passage to the larynx in the throat. It extends about 13 cm
from the base of the skull to the level of the 6
th
cervical vertebrae. The wall of all 3 portions contains
two layers of skeletal muscle: inner layer arranged in circular pattern and outer layer arranged
longitudinally.
Nasopharynx: The superior section of the pharynx, posterior to the nasal cavity and inferior to the
sphenoid bone. It acts only as a conduit for air and closes off during swallowing by raising the soft
palate. The paired pharyngeal tonsils, also known as the adenoids, lie in the posterior wall of the
nasopharynx.
Oropharynx: The opening from the oral cavity and the second portion of the pharynx, runs from the
soft palate to the epiglottis and is posterior to the oral cavity. In comparison to the nasopharynx,
which is lined with columnar epithelia, the oropharynx is covered by stratified squamous epithelia,
that are often found covering areas which are subject to a great deal of frictional wear.
Laryngopharynx: The third and shortest portion of the pharynx, runs inferiorly from epiglottis and
ends superior to the esophagus. It carries both air and food and is lined with stratified squamous
epithelia.
Pharynx is the only part where food and air passage mix together.
D. Larynx
It is a complex structure (about 5 cm (2 in.) long) extending from the laryngopharynx and the hyoid
bone to the trachea. It is in addition to providing a passageway for air, it directs air and food to their
appropriate tubes. The vocal cords, which are used in making sound and speech, can be found
5
within the larynx. The epithelial lining of the
larynx exhibits two different arrangements.
Initially, stratified squamous epithelia lines
laryngopharynx to the vocal cords. Inferior to
the vocal cords, the epithelial lining shifts to
pseudostratified, ciliated, columnar epithelia.
The nine cartilage structures found in the
larynx provide key anatomical landmarks.
They function to maintain an open airway.
Eight of the cartilages are composed of
hyaline cartilage.
Epiglottis: It is made of elastic cartilage and
covered with stratified squamous epithelia. It
connects loosely to the tongue, the hyoid
bone, and the rim of the thyroid cartilage. The
epiglottis is normally open, allowing air to
freely flow into the rest of the larynx and the trachea. When a person swallows, the front of the
epiglottis is raised, and the posterior portion descends, covering the glottis, which is the opening to
the vocal cords and trachea. This movement directs food and water to the esophagus and prevents
it from entering the bottom portion of the larynx and the upper trachea.
Thyroid cartilage: The largest cartilage of the larynx and found at the front. This roughly triangularly
shaped cartilage contains the laryngeal prominence, commonly known as the “Adam’s apple” which
is more prominent in males (during puberty as the larynx widens, the voice deepens). The thyroid
cartilage connects to the hyoid bone by the thyrohyoid membrane or ligament.
Cricoid cartilage: Inferior to the thyroid cartilage, connects superiorly to the thyroid cartilage by the
cricothyroid ligament and inferiorly to the trachea by the cricotracheal ligament. When an occlusion
of the upper respiratory tract occurs and a tracheostomy is performed to facilitate breathing, the
cricothyroid ligament must be punctured.
Arytenoids cartilages, cuneiform cartilages, corniculate cartilages: The next six cartilages are
found in three pairs. Arytenoids cartilages anchor the true vocal cords. All pairs are found in lateral
and posterior walls of larynx. Except for the epiglottis, the arrangement of the cartilages of the
larynx ensures that the passages through the larynx remain open.
Vocal cords: Two pairs of folded tissue immediately inferior to the epiglottis: the false and true
vocal cords. The false vocal cords do not function in making sounds or speech but aid in closing the
glottis. The true vocal cords run from the arytenoids to the thyroid cartilage, are reinforced with
elastic fibers and vibrate when adequate air is forced through the gap between them, resulting in
sound. Pitch control is achieved by adjusting the tension on the cords. Lessening the tension lowers
the pitch.
Cricoid
cartilage
Hyoid bone
Epiglottis
Thyrohyoid
membrane
False vocal
cords
True vocal
cords
Thyroid
cartilage
Ventricle
Vocalis
muscle
Trachea
within the larynx. The epithelial lining of the
larynx exhibits two different arrangements.
Initially, stratified squamous epithelia lines
laryngopharynx to the vocal cords. Inferior to
the vocal cords, the epithelial lining shifts to
pseudostratified, ciliated, columnar epithelia.
The nine cartilage structures found in the
larynx provide key anatomical landmarks.
They function to maintain an open airway.
Eight of the cartilages are composed of
hyaline cartilage.
Epiglottis: It is made of elastic cartilage and
covered with stratified squamous epithelia. It
connects loosely to the tongue, the hyoid
bone, and the rim of the thyroid cartilage. The
epiglottis is normally open, allowing air to
freely flow into the rest of the larynx and the trachea. When a person swallows, the front of the
epiglottis is raised, and the posterior portion descends, covering the glottis, which is the opening to
the vocal cords and trachea. This movement directs food and water to the esophagus and prevents
it from entering the bottom portion of the larynx and the upper trachea.
Thyroid cartilage: The largest cartilage of the larynx and found at the front. This roughly triangularly
shaped cartilage contains the laryngeal prominence, commonly known as the “Adam’s apple” which
is more prominent in males (during puberty as the larynx widens, the voice deepens). The thyroid
cartilage connects to the hyoid bone by the thyrohyoid membrane or ligament.
Cricoid cartilage: Inferior to the thyroid cartilage, connects superiorly to the thyroid cartilage by the
cricothyroid ligament and inferiorly to the trachea by the cricotracheal ligament. When an occlusion
of the upper respiratory tract occurs and a tracheostomy is performed to facilitate breathing, the
cricothyroid ligament must be punctured.
Arytenoids cartilages, cuneiform cartilages, corniculate cartilages: The next six cartilages are
found in three pairs. Arytenoids cartilages anchor the true vocal cords. All pairs are found in lateral
and posterior walls of larynx. Except for the epiglottis, the arrangement of the cartilages of the
larynx ensures that the passages through the larynx remain open.
Vocal cords: Two pairs of folded tissue immediately inferior to the epiglottis: the false and true
vocal cords. The false vocal cords do not function in making sounds or speech but aid in closing the
glottis. The true vocal cords run from the arytenoids to the thyroid cartilage, are reinforced with
elastic fibers and vibrate when adequate air is forced through the gap between them, resulting in
sound. Pitch control is achieved by adjusting the tension on the cords. Lessening the tension lowers
the pitch.
Cricoid
cartilage
Hyoid bone
Epiglottis
Thyrohyoid
membrane
False vocal
cords
True vocal
cords
Thyroid
cartilage
Ventricle
Vocalis
muscle
Trachea
6
Actual speech is achieved with the coordination of muscles in the pharynx, face, tongue, soft palate,
a
nd lips.
1.2.2. Lower respiratory tract
A. Trachea
It is about 10 cm long and 2 cm wide, extends from the larynx to the level of the 5
th
thoracic vertebrae.
The presence of 16-20 C-shaped dorsally incomplete rings of hyaline cartilage located along the
trachea prevents this airway from collapsing.
The last cartilage in the trachea exhibits a projection called carina, from the anterior surface that
extends into the lumen. It is very sensitive to particulate material and causes coughing when
stimulated.
The openings of the C-shaped cartilages face the posterior of the trachea and contain the trachealis
smooth muscle which constricts when someone coughs, increasing the force of the cough. The
trachealis muscle also constricts during an asthmatic reaction, shrinking the airway and making it
harder to breathe.
Structurally, trachea consists of 3 concentric tissue layers:
Mucosa: Has 3 sublayers
•Epithelium - PSCCGE
•Lamina propria - Reticular fibrous connective tissue.
•Muscularis mucosa - Longitudinal and circular muscle fibers.
Submucosa: Areolar connective tissue.
Tunica adventia: White fibrous connective tissue.
B. Bronchi and Bronchioles
Branching of the trachea into the right and
left primary bronchi occurs after the last
cartilage in the trachea at the level of the 7
th
thoracic vertebrae. The right primary
bronchus is wider, shorter, and more vertical
than the left primary bronchus because the
left primary bronchus and lung must
accommodate the heart. The primary
bronchi branch to form the secondary or
lobar bronchi. There are three secondary
bronchi on the right and two on the left. The
secondary bronchi continue to branch into
the tertiary or segmented bronchi, which
also continue the branching pattern.
Tertiary
bronchus
Bronchiole
Terminal
bronchiole
Alveoli
Secondary
bronchus
Primary
bronchus
Alveoli enlarged
Actual speech is achieved with the coordination of muscles in the pharynx, face, tongue, soft palate,
a
nd lips.
1.2.2. Lower respiratory tract
A. Trachea
It is about 10 cm long and 2 cm wide, extends from the larynx to the level of the 5
th
thoracic vertebrae.
The presence of 16-20 C-shaped dorsally incomplete rings of hyaline cartilage located along the
trachea prevents this airway from collapsing.
The last cartilage in the trachea exhibits a projection called carina, from the anterior surface that
extends into the lumen. It is very sensitive to particulate material and causes coughing when
stimulated.
The openings of the C-shaped cartilages face the posterior of the trachea and contain the trachealis
smooth muscle which constricts when someone coughs, increasing the force of the cough. The
trachealis muscle also constricts during an asthmatic reaction, shrinking the airway and making it
harder to breathe.
Structurally, trachea consists of 3 concentric tissue layers:
Mucosa: Has 3 sublayers
•Epithelium - PSCCGE
•Lamina propria - Reticular fibrous connective tissue.
•Muscularis mucosa - Longitudinal and circular muscle fibers.
Submucosa: Areolar connective tissue.
Tunica adventia: White fibrous connective tissue.
B. Bronchi and Bronchioles
Branching of the trachea into the right and
left primary bronchi occurs after the last
cartilage in the trachea at the level of the 7
th
thoracic vertebrae. The right primary
bronchus is wider, shorter, and more vertical
than the left primary bronchus because the
left primary bronchus and lung must
accommodate the heart. The primary
bronchi branch to form the secondary or
lobar bronchi. There are three secondary
bronchi on the right and two on the left. The
secondary bronchi continue to branch into
the tertiary or segmented bronchi, which
also continue the branching pattern.
Tertiary
bronchus
Bronchiole
Terminal
bronchiole
Alveoli
Secondary
bronchus
Primary
bronchus
Alveoli enlarged
7
Approximately 23 successive branches lead to the bronchioles.
A
bronchiole is a tube with a diameter of less than 1 millimeter (mm). When the measurement
reaches less than 0.5 mm, a bronchiole is termed a terminal bronchiole. Plates of cartilage are
found in the walls of the bronchial tree, with the amount of cartilage and the number of plates
decreasing as the bronchi and bronchioles become smaller. The terminal bronchioles do not contain
cartilage plates, these tubes are small enough to stay open without cartilage. Smooth muscle is
found throughout the system, even into the respiratory zone.
C. Lungs
Along with the heart, the lungs take up nearly all of the space in the thorax, superior to the diaphragm.
As an organ, the lung is made up of airway tubes and alveoli, giving it little weight. Elastic connective
tissues in the stroma of the lungs allow them to expand with incoming air and recoil when expelling
air. The lungs contain a large amount of surface area in order to efficiently support the exchange of
oxygen and carbon dioxide.
The hilus (meaning depression of pit) of the lungs is an indentation on the medial side of the lungs
and the point of entry of blood vessels, primary bronchi, nerves, and lymphatics. This collection of
vessels and nerves makes up the root of the lung. The tip or apex of the lungs is a blunted point
found just above the clavicles. The posterior, lateral and anterior sides of the lungs are surrounded
by the ribs. These areas are called the costal surfaces of the lungs referring to the costal cartilage
surrounding them. The flat inferior surface of the lungs is found superior to the diaphragm and
referred to as the base of the lung. Since, the liver is found on the right side of the body and inferior
to the diaphragm, the insertion of the diaphragm is slightly raised on the right. Consequently the
right lung is usually slightly shorter than the left. The lungs extend from the first costal cartilage to
the tenth thoracic vertebrae.
The lungs consist of a right lung and a left lung. Even though the right lung is slightly shorter than the
left, the left lung has about 10% less mass than the right due to the cardiac notch on the medial side
of the left lung. The heart is tucked into this notch. The heart, the right lung, and the left lung are
each located in their own anatomical compartments in the upper thorax. The right lung is divided
into three lobes. A horizontal fissure separates the superior and middle lobes, and an oblique fissure
separates the middle and inferior lobes. The smaller left lung contains only two lobes. An oblique
fissure separates the superior and inferior lobes on this side.
Each lobe is divided into bronchopulmonary segments separated by connective tissue septa.
There are a total of 10 of these segments and each contains a tertiary bronchiole, a pulmonary and
bronchial artery, and a lymphatic branch. The presence of these segments aids in further isolating
parts of the lungs to prevent the spread of infection or disease. Connective tissue further divides the
segments into lung lobules, the smallest anatomical unit in the lungs. A lobule is hexagonal in shape
and less than a centimeter in diameter. Each lobule contains a terminal bronchiole and its associated
alveoli. The connective tissue associated with lobules may be blackened by tobacco smoke or
pollution from the environment.
Approximately 23 successive branches lead to the bronchioles.
A
bronchiole is a tube with a diameter of less than 1 millimeter (mm). When the measurement
reaches less than 0.5 mm, a bronchiole is termed a terminal bronchiole. Plates of cartilage are
found in the walls of the bronchial tree, with the amount of cartilage and the number of plates
decreasing as the bronchi and bronchioles become smaller. The terminal bronchioles do not contain
cartilage plates, these tubes are small enough to stay open without cartilage. Smooth muscle is
found throughout the system, even into the respiratory zone.
C. Lungs
Along with the heart, the lungs take up nearly all of the space in the thorax, superior to the diaphragm.
As an organ, the lung is made up of airway tubes and alveoli, giving it little weight. Elastic connective
tissues in the stroma of the lungs allow them to expand with incoming air and recoil when expelling
air. The lungs contain a large amount of surface area in order to efficiently support the exchange of
oxygen and carbon dioxide.
The hilus (meaning depression of pit) of the lungs is an indentation on the medial side of the lungs
and the point of entry of blood vessels, primary bronchi, nerves, and lymphatics. This collection of
vessels and nerves makes up the root of the lung. The tip or apex of the lungs is a blunted point
found just above the clavicles. The posterior, lateral and anterior sides of the lungs are surrounded
by the ribs. These areas are called the costal surfaces of the lungs referring to the costal cartilage
surrounding them. The flat inferior surface of the lungs is found superior to the diaphragm and
referred to as the base of the lung. Since, the liver is found on the right side of the body and inferior
to the diaphragm, the insertion of the diaphragm is slightly raised on the right. Consequently the
right lung is usually slightly shorter than the left. The lungs extend from the first costal cartilage to
the tenth thoracic vertebrae.
The lungs consist of a right lung and a left lung. Even though the right lung is slightly shorter than the
left, the left lung has about 10% less mass than the right due to the cardiac notch on the medial side
of the left lung. The heart is tucked into this notch. The heart, the right lung, and the left lung are
each located in their own anatomical compartments in the upper thorax. The right lung is divided
into three lobes. A horizontal fissure separates the superior and middle lobes, and an oblique fissure
separates the middle and inferior lobes. The smaller left lung contains only two lobes. An oblique
fissure separates the superior and inferior lobes on this side.
Each lobe is divided into bronchopulmonary segments separated by connective tissue septa.
There are a total of 10 of these segments and each contains a tertiary bronchiole, a pulmonary and
bronchial artery, and a lymphatic branch. The presence of these segments aids in further isolating
parts of the lungs to prevent the spread of infection or disease. Connective tissue further divides the
segments into lung lobules, the smallest anatomical unit in the lungs. A lobule is hexagonal in shape
and less than a centimeter in diameter. Each lobule contains a terminal bronchiole and its associated
alveoli. The connective tissue associated with lobules may be blackened by tobacco smoke or
pollution from the environment.
8
Each lobule is further divided into several air-sacs and in the end each air-sac is lastly divided into
3
or 4 alveoli, the structural and functional units of lungs. Approximately 300 million alveoli are
present in both lungs. Inner (alveolar) surface area of both lungs is approximately 100 m
2
. Wall of
alveoli consist of two layers: outer layer is composed of yellow fibrous CT while inner layer is composed
of simple squamous epithelium. Squamous cells are called as pneumocytes which help in gaseous
exchange (pneumocyte-I) while few pneumocytes (pneumocyte-II, larger in size) secrete lecithin
(phospholipid) that acts as surfactant preventing the alveoli from remaining collapse by reducing its
surface tension.
Alveoli internal surface, the respiratory surface is derived from the endoderm of the embryo. The
middle part of alveoli wall is made up of CT, richly supplied with a dense network of blood capillaries.
There are small pores, pores of Kohn, present in the walls of alveoli that make gas diffusion easy.
This is the characteristic feature of mammalian lungs, that there is no central cavity, mammalian
lungs are solid and spongy. Muscles are absent in the lungs of mammals. So the power of self-
contraction and self-expansion is absent in these lungs (sunken lungs).
Each lung is found in a pleural cavity bounded by the pleural membrane, a double sided membrane
that contains a thin layer of pleural fluid. The visceral pleural is a mucus membrane that covers the
lungs and folds over at the hilus. The folded membrane continues and becomes the parietal pleura,
which lines the inner wall of the thoracic cavity. The space between the two membranes is called the
pleural cavity or space. From 1 to 15 ml of pleural fluid is found on the facing surfaces of the
pleural membranes. This fluid helps to lubricate the membrane surfaces so that the movement of
the lungs during inhaling and exhaling does not cause frictional damage to the tissues. The fluid
also lightly holds the two membranes together so that they move together as the chest wall expands
and contracts.
The pleural sac extends below the lungs, to the level of the twelfth thoracic vertebrae. Samples of
the pleural fluid can be safely taken from this area. Normal pleural fluid is clear and pale yellow in
color. It has very few cells free in the fluid. The majority (75%) of these cells are macrophages.
About 23% of the cells are lymphocytes, with an assortment of cells making up the remaining 2%.
Sometimes due to bacterial infection the amount of pleural fluid increases and the organism feels
difficulty in breathing (dyspnoea), this is termed as pleural effusion disease.
Each lobule is further divided into several air-sacs and in the end each air-sac is lastly divided into
3
or 4 alveoli, the structural and functional units of lungs. Approximately 300 million alveoli are
present in both lungs. Inner (alveolar) surface area of both lungs is approximately 100 m
2
. Wall of
alveoli consist of two layers: outer layer is composed of yellow fibrous CT while inner layer is composed
of simple squamous epithelium. Squamous cells are called as pneumocytes which help in gaseous
exchange (pneumocyte-I) while few pneumocytes (pneumocyte-II, larger in size) secrete lecithin
(phospholipid) that acts as surfactant preventing the alveoli from remaining collapse by reducing its
surface tension.
Alveoli internal surface, the respiratory surface is derived from the endoderm of the embryo. The
middle part of alveoli wall is made up of CT, richly supplied with a dense network of blood capillaries.
There are small pores, pores of Kohn, present in the walls of alveoli that make gas diffusion easy.
This is the characteristic feature of mammalian lungs, that there is no central cavity, mammalian
lungs are solid and spongy. Muscles are absent in the lungs of mammals. So the power of self-
contraction and self-expansion is absent in these lungs (sunken lungs).
Each lung is found in a pleural cavity bounded by the pleural membrane, a double sided membrane
that contains a thin layer of pleural fluid. The visceral pleural is a mucus membrane that covers the
lungs and folds over at the hilus. The folded membrane continues and becomes the parietal pleura,
which lines the inner wall of the thoracic cavity. The space between the two membranes is called the
pleural cavity or space. From 1 to 15 ml of pleural fluid is found on the facing surfaces of the
pleural membranes. This fluid helps to lubricate the membrane surfaces so that the movement of
the lungs during inhaling and exhaling does not cause frictional damage to the tissues. The fluid
also lightly holds the two membranes together so that they move together as the chest wall expands
and contracts.
The pleural sac extends below the lungs, to the level of the twelfth thoracic vertebrae. Samples of
the pleural fluid can be safely taken from this area. Normal pleural fluid is clear and pale yellow in
color. It has very few cells free in the fluid. The majority (75%) of these cells are macrophages.
About 23% of the cells are lymphocytes, with an assortment of cells making up the remaining 2%.
Sometimes due to bacterial infection the amount of pleural fluid increases and the organism feels
difficulty in breathing (dyspnoea), this is termed as pleural effusion disease.
Trachea
Apex
Upper lobe
Oblique fissure
Upper lobe
Horizontal fissure
Oblique fissure
Lower lobe
Cardiac notch
Middle lobe
Lower lobe
Lung
Intercostal
muscle
Pleural sac
Trachea
Anterior azygous lobe
Bronchus
Left anterior lobe
Left posterior lobe
Posterior azygous lobe
Right posterior lobe
Rabbit
Right anterior
Terminal
bronchiole
Atria
Air saccules
Alveoli
Respiratory
bronchiole
Alveolar ducts
Man
D. Blood and nerve supply
The lungs have a dual blood supply. The pulmonary artery brings oxygen-poor blood from the
right ventricle of the heart. This blood passes through the pulmonary capillaries, where some
carbon
RABBIT HUMAN
Right lung Left lung Right lung (625 gm)Left lung (575 gm)
4 lobes 2 lobes 3 lobes 2 lobes
Anterior azygous Left anterior Anterior lobe Left anterior
Right anterior Left posterior Middle lobe Left posterior
Right posterior Posterior lobe
Posterior azygous
Apex
Upper lobe
Oblique fissure
Upper lobe
Horizontal fissure
Oblique fissure
Lower lobe
Cardiac notch
Middle lobe
Lower lobe
Lung
Intercostal
muscle
Pleural sac
Trachea
Anterior azygous lobe
Bronchus
Left anterior lobe
Left posterior lobe
Posterior azygous lobe
Right posterior lobe
Rabbit
Right anterior
Terminal
bronchiole
Atria
Air saccules
Alveoli
Respiratory
bronchiole
Alveolar ducts
Man
D. Blood and nerve supply
The lungs have a dual blood supply. The pulmonary artery brings oxygen-poor blood from the
right ventricle of the heart. This blood passes through the pulmonary capillaries, where some
carbon
RABBIT HUMAN
Right lung Left lung Right lung (625 gm)Left lung (575 gm)
4 lobes 2 lobes 3 lobes 2 lobes
Anterior azygous Left anterior Anterior lobe Left anterior
Right anterior Left posterior Middle lobe Left posterior
Right posterior Posterior lobe
Posterior azygous
10
dioxide will leave the blood and a large amount of oxygen will be acquired. The newly oxygenated
b
lood enters the pulmonary veins and returns back to the left side of the heart. The pulmonary
circulation holds about 500 milliliters (ml) of blood, or about 10% of the body’s supply. About 75 ml
of blood is in the pulmonary capillaries for gas exchange at any one time. The blood supply that
nourishes the tissues of the lungs arrives through the bronchial artery, which branches off of the
aorta and carries oxygen-rich blood to support the lung tissues. The bronchial supply anastomoses
with the pulmonary vessels, and a mixture of blood leaves through the bronchial and pulmonary
veins. Blood passes through the lungs at a rate equal to cardiac output, or about five liters per
minute.
Nerves from the pulmonary plexus enter the lungs at the hilus. These nerves contain a mixture of
visceral sensory and autonomic nerve fibers that follow the bronchial tree and blood vessels.
Parasympathetic nerve stimulation results in bronchoconstriction, constriction of the bronchioles,
while sympathetic nerve stimulation results in bronchodilation, dilation of the bronchioles.
E. Thoracic cage
Coverings of thoracic cavity makes thoracic cage.
Anterior surface: Clavicle bones, neck.
Posterior surface: Diaphragm.
Dorsal surface: Vertebral column and ribs.
Ventral surface: Sternum and ribs.
Lateral surface: Ribs.
F. Diaphragm
A muscular septum which is found only in mammals (and crocodile). Normal shape of it is dome like
which divides body cavity in two parts upper thoracic cavity and lower abdominal cavity. In central
region of diaphragm, central tendon is present. It is pierced by three structures:
(i) Oesophagus (ii) Aorta (iii) Posterior vena cava
Radial muscles are present in diaphragm. They originate from periphery and inserted in central
region of diaphragm. By the contraction in these muscles, diaphragm become flatten in shape, so,
volume of thoracic cavity increases. Therefore, diaphragm helps in inspiration.
G. Intercostal muscles (ICM)
Space between two ribs is called intercostal space in which 2 types of muscles are present: external
ICM (EICM) and internal ICM (IICM).
EICM: They originate from dorsal part of upper rib and insert on ventral part of lower rib. By the
contraction in these muscles, ribs and sternum shift upward and outward. So they help in inspiration.
IICM: They originate from dorsal part of lower rib and insert in ventral part of upper rib. By the
contraction in these muscles, ribs and sternum shift downward and inward respectively. So it helps
Inspiration
Sternum
Ribs
Vertebral
column
Expiration
Position of ribs
(Thoracic respiration)
dioxide will leave the blood and a large amount of oxygen will be acquired. The newly oxygenated
b
lood enters the pulmonary veins and returns back to the left side of the heart. The pulmonary
circulation holds about 500 milliliters (ml) of blood, or about 10% of the body’s supply. About 75 ml
of blood is in the pulmonary capillaries for gas exchange at any one time. The blood supply that
nourishes the tissues of the lungs arrives through the bronchial artery, which branches off of the
aorta and carries oxygen-rich blood to support the lung tissues. The bronchial supply anastomoses
with the pulmonary vessels, and a mixture of blood leaves through the bronchial and pulmonary
veins. Blood passes through the lungs at a rate equal to cardiac output, or about five liters per
minute.
Nerves from the pulmonary plexus enter the lungs at the hilus. These nerves contain a mixture of
visceral sensory and autonomic nerve fibers that follow the bronchial tree and blood vessels.
Parasympathetic nerve stimulation results in bronchoconstriction, constriction of the bronchioles,
while sympathetic nerve stimulation results in bronchodilation, dilation of the bronchioles.
E. Thoracic cage
Coverings of thoracic cavity makes thoracic cage.
Anterior surface: Clavicle bones, neck.
Posterior surface: Diaphragm.
Dorsal surface: Vertebral column and ribs.
Ventral surface: Sternum and ribs.
Lateral surface: Ribs.
F. Diaphragm
A muscular septum which is found only in mammals (and crocodile). Normal shape of it is dome like
which divides body cavity in two parts upper thoracic cavity and lower abdominal cavity. In central
region of diaphragm, central tendon is present. It is pierced by three structures:
(i) Oesophagus (ii) Aorta (iii) Posterior vena cava
Radial muscles are present in diaphragm. They originate from periphery and inserted in central
region of diaphragm. By the contraction in these muscles, diaphragm become flatten in shape, so,
volume of thoracic cavity increases. Therefore, diaphragm helps in inspiration.
G. Intercostal muscles (ICM)
Space between two ribs is called intercostal space in which 2 types of muscles are present: external
ICM (EICM) and internal ICM (IICM).
EICM: They originate from dorsal part of upper rib and insert on ventral part of lower rib. By the
contraction in these muscles, ribs and sternum shift upward and outward. So they help in inspiration.
IICM: They originate from dorsal part of lower rib and insert in ventral part of upper rib. By the
contraction in these muscles, ribs and sternum shift downward and inward respectively. So it helps
Inspiration
Sternum
Ribs
Vertebral
column
Expiration
Position of ribs
(Thoracic respiration)
11
in forceful expiration which is a voluntary activity. So contraction of IICM is under the control of
c
erebrum.
1.3 RESPIRATORY FUNCTIONS
1.3.1 Zones of respiratory system
A. Conducting zone
The conducting zone of the
respiratory system brings gases
into and out of the respiratory
system. In addition, the organs
and tissues along this path warm
the incoming air to approximately
body temperature, moisten the air
to about 100% humidity, and begin
filtering out any harmful
microorganisms or particles that
may be suspended in the inhaled
air.
If the air in the respiratory zone is
not near 100% humidity, the thin
walled alveoli can become
dehydrated and may deteriorate.
B. Respiratory zone
A transition occurs in the
composition of the epithelial lining
at the end of the terminal
bronchioles. The epithelial lining
changes to simple cuboidal cells
without any intermixed goblet
cells. The walls of the tubes at this
point become very thin and are
called respiratory bronchioles.
The loss of the goblet cells means
that no mucus is secreted into the
bronchioles at this point, but the
cilia are still present to sweep
away any mucus that should come
down into them. Some portions of
External nostrils
Vestibule
Nasal chamber
Internal nares
Nasopharynx
Pharynx
Glottis
Larynx
Trachea
Bronchial tree
Trachea
Primary bronchus
Secondary bronchusTertiary/Segmental bronchus
Total pulmonary bronchioles
Terminal bronchiole
Respiratory bronchiole
Alveolar duct
Atria
Alveolar sac
Alveoli
Conducting
zone
Exchange zone
Respiratory tree
Bronchial
tree
in forceful expiration which is a voluntary activity. So contraction of IICM is under the control of
c
erebrum.
1.3 RESPIRATORY FUNCTIONS
1.3.1 Zones of respiratory system
A. Conducting zone
The conducting zone of the
respiratory system brings gases
into and out of the respiratory
system. In addition, the organs
and tissues along this path warm
the incoming air to approximately
body temperature, moisten the air
to about 100% humidity, and begin
filtering out any harmful
microorganisms or particles that
may be suspended in the inhaled
air.
If the air in the respiratory zone is
not near 100% humidity, the thin
walled alveoli can become
dehydrated and may deteriorate.
B. Respiratory zone
A transition occurs in the
composition of the epithelial lining
at the end of the terminal
bronchioles. The epithelial lining
changes to simple cuboidal cells
without any intermixed goblet
cells. The walls of the tubes at this
point become very thin and are
called respiratory bronchioles.
The loss of the goblet cells means
that no mucus is secreted into the
bronchioles at this point, but the
cilia are still present to sweep
away any mucus that should come
down into them. Some portions of
External nostrils
Vestibule
Nasal chamber
Internal nares
Nasopharynx
Pharynx
Glottis
Larynx
Trachea
Bronchial tree
Trachea
Primary bronchus
Secondary bronchusTertiary/Segmental bronchus
Total pulmonary bronchioles
Terminal bronchiole
Respiratory bronchiole
Alveolar duct
Atria
Alveolar sac
Alveoli
Conducting
zone
Exchange zone
Respiratory tree
Bronchial
tree
12
the respiratory bronchioles are not completely covered by cilia, and a number of phagocytic
m
acrophages are found in this area to compensate for the loss of the cilia. Some gas exchange can
occur through the walls of the respiratory bronchioles.
Respiratory bronchioles lead into the alveolar ducts, which still have smooth muscle and some
elastic fibers in the walls. Alveolar sacs occur as clusters of alveoli (singular alveolus) sharing a
common chamber along the alveolar ducts.
1.3.2 Respiratory pulmonary ventilation
Pulmonary ventilation brings in air with a new supply of oxygen and a very small amount of carbon
dioxide from the atmosphere into the alveoli. This mixture then participates in external respiration,
the exchange of oxygen and carbon dioxide between the alveoli and pulmonary capillary blood
across the respiratory membrane. Internal respiration is the exchange of gases between the tissues
of the body and the blood, which provides oxygen for aerobic cellular respiration and removes
carbon dioxide. Aerobic cellular respiration refers to the intracellular use of oxygen and the
generation of carbon dioxide waste through metabolic pathways.
Inspiration
Inspiration occurs by increasing the volume of the thorax. This active process involves the use of
chest and neck muscles. Resting inspiration is achieved mostly by movement of the diaphragm.
The relaxed shape of the diaphragm resembles a shallow dome with the apex pointing towards the
lungs, similar to the shape of an open umbrella. When the diaphragm contracts, it tends to flatten
out, expanding the volume of the thorax in an inferior direction. Consequently, the intrapleural and
intrapulmonary pressures decrease below atmospheric pressure resulting in air being pulled through
the conducting zone and into the lungs. The external intercostal muscles work in conjunction with
the diaphragm. The normal orientation of the ribs is around the side of the thorax and angled inferiorly
to the sternum. When the external intercostal muscles contract, the ribs are pulled up, also expanding
the thoracic cavity in a horizontal direction. In adults, ventilation occurs about 12 times a minute and
moves roughly 500 ml of air during each breath. Normally it takes around 2 seconds.
Expiration
Resting expiration is a passive process. The muscles used during inspiration relax, and allow the
chest wall and the diaphragm to move back to their original position, thus decreasing the volume of
the thorax and forcing air from the lungs. The compression of the chest wall also aids in moving
blood and lymph through the vessels that drain the lungs. Expiration becomes an active process
when a more forceful exhale is required. The internal intercostal muscles pull the ribs down, helping
to compress the chest. The external and internal oblique and transverse abdominal muscles press
on the abdominal organs, which move them up against the diaphragm and force the diaphragm
higher than it would normally go on relaxation, further decreasing the volume of the thoracic cavity.
Normal breathing is also called abdominal breathing and it takes around 3 seconds.
the respiratory bronchioles are not completely covered by cilia, and a number of phagocytic
m
acrophages are found in this area to compensate for the loss of the cilia. Some gas exchange can
occur through the walls of the respiratory bronchioles.
Respiratory bronchioles lead into the alveolar ducts, which still have smooth muscle and some
elastic fibers in the walls. Alveolar sacs occur as clusters of alveoli (singular alveolus) sharing a
common chamber along the alveolar ducts.
1.3.2 Respiratory pulmonary ventilation
Pulmonary ventilation brings in air with a new supply of oxygen and a very small amount of carbon
dioxide from the atmosphere into the alveoli. This mixture then participates in external respiration,
the exchange of oxygen and carbon dioxide between the alveoli and pulmonary capillary blood
across the respiratory membrane. Internal respiration is the exchange of gases between the tissues
of the body and the blood, which provides oxygen for aerobic cellular respiration and removes
carbon dioxide. Aerobic cellular respiration refers to the intracellular use of oxygen and the
generation of carbon dioxide waste through metabolic pathways.
Inspiration
Inspiration occurs by increasing the volume of the thorax. This active process involves the use of
chest and neck muscles. Resting inspiration is achieved mostly by movement of the diaphragm.
The relaxed shape of the diaphragm resembles a shallow dome with the apex pointing towards the
lungs, similar to the shape of an open umbrella. When the diaphragm contracts, it tends to flatten
out, expanding the volume of the thorax in an inferior direction. Consequently, the intrapleural and
intrapulmonary pressures decrease below atmospheric pressure resulting in air being pulled through
the conducting zone and into the lungs. The external intercostal muscles work in conjunction with
the diaphragm. The normal orientation of the ribs is around the side of the thorax and angled inferiorly
to the sternum. When the external intercostal muscles contract, the ribs are pulled up, also expanding
the thoracic cavity in a horizontal direction. In adults, ventilation occurs about 12 times a minute and
moves roughly 500 ml of air during each breath. Normally it takes around 2 seconds.
Expiration
Resting expiration is a passive process. The muscles used during inspiration relax, and allow the
chest wall and the diaphragm to move back to their original position, thus decreasing the volume of
the thorax and forcing air from the lungs. The compression of the chest wall also aids in moving
blood and lymph through the vessels that drain the lungs. Expiration becomes an active process
when a more forceful exhale is required. The internal intercostal muscles pull the ribs down, helping
to compress the chest. The external and internal oblique and transverse abdominal muscles press
on the abdominal organs, which move them up against the diaphragm and force the diaphragm
higher than it would normally go on relaxation, further decreasing the volume of the thoracic cavity.
Normal breathing is also called abdominal breathing and it takes around 3 seconds.
13
Air enters
Ribcage moves
up and out
Lungs expand
Diaphragm
moves down
Inhalation
Air leaves
Ribcage moves
down and in
Lungs get
smaller
Diaphragm
moves up
Exhalation
1.3.3 Regulation of respiration
The respiratory rhythm is controlled by the nervous system. The rate of respiration can be enhanced
as per demand of the body during strenuous physical exercises. A number of groups of neurons
located bilaterally in the medulla oblongata control the respiration. These are called respiratory
centers. Three groups of respiratory centers have been identified, namely: dorsal respiratory group,
ventral respiratory group and pneumotaxic center.
The dorsal respiratory group is present in the dorsal portion of medulla oblongata. The signals
from these neurons generate the basic respiratory rhythm. The nervous signal released from this
group is transmitted to the diaphragm and EICM.
The ventral respiratory group of neurons are located anterolateral to the dorsal respiratory group.
During normal respiration, this remains inactive and even does not play any role.
In the enhanced respiratory drive, the respiratory signal of this group contributes to fulfill the demand
by regulating both inspiration and expiration. Few of the neurons of this group control inspiration,
while few other control expiration, thus regulating both. The pneumotaxic center is located dorsally
in the upper pons. It transmits signals to the inspiratory area. Primarily, it controls the switch off point
of inspiration. When this signal is strong (high frequency), the inspiration lasts for a shorter duration
and lungs are filled partially. During weak pneumotaxic signal, inspiration lasts for a longer duration
resulting into complete filling of lungs. The strong signal (high frequency) causes increased rate of
breathing, because duration of inspiration as well as expiration, is shortened. The concentration of
Air enters
Ribcage moves
up and out
Lungs expand
Diaphragm
moves down
Inhalation
Air leaves
Ribcage moves
down and in
Lungs get
smaller
Diaphragm
moves up
Exhalation
1.3.3 Regulation of respiration
The respiratory rhythm is controlled by the nervous system. The rate of respiration can be enhanced
as per demand of the body during strenuous physical exercises. A number of groups of neurons
located bilaterally in the medulla oblongata control the respiration. These are called respiratory
centers. Three groups of respiratory centers have been identified, namely: dorsal respiratory group,
ventral respiratory group and pneumotaxic center.
The dorsal respiratory group is present in the dorsal portion of medulla oblongata. The signals
from these neurons generate the basic respiratory rhythm. The nervous signal released from this
group is transmitted to the diaphragm and EICM.
The ventral respiratory group of neurons are located anterolateral to the dorsal respiratory group.
During normal respiration, this remains inactive and even does not play any role.
In the enhanced respiratory drive, the respiratory signal of this group contributes to fulfill the demand
by regulating both inspiration and expiration. Few of the neurons of this group control inspiration,
while few other control expiration, thus regulating both. The pneumotaxic center is located dorsally
in the upper pons. It transmits signals to the inspiratory area. Primarily, it controls the switch off point
of inspiration. When this signal is strong (high frequency), the inspiration lasts for a shorter duration
and lungs are filled partially. During weak pneumotaxic signal, inspiration lasts for a longer duration
resulting into complete filling of lungs. The strong signal (high frequency) causes increased rate of
breathing, because duration of inspiration as well as expiration, is shortened. The concentration of
14
CO
2
+
cause increased strength of inspiratory, as well as expiratory signal. However, oxygen
has no such direct effect.
Hering Breuer reflex arch
In the walls of terminal bronchioles and atria stretch receptors are present, which are normally
inactive but they become active when the lungs are excessively inflated due to failure of switch off
of inspiration. The Hering Breuer reflex arch now becomes activated and sends inhibitory signals to
the inspiratory center to switch off inspiration. This prevents the alveoli from over stretching and
bursting. Thus Hering Breuer reflex arch is a protective reflex which works only when normal
mechanism of switch off of inspiration does not work timely due to any reason.
1.3.4 Factors affecting breathing
A. Chemical factors
There are so many factors which affect the activity of respiratory center. Respiratory center is sensitive
to CO
2
concentration in the blood and pH of blood. Respiratory center is not sensitive for O
2
concentration in blood. Whenever, in the blood, CO
2
concentration is increased, or pH is decreased,
or acidity is increased, then respiratory center becomes more activated and increases the rate of
respiration. Normal breathing rate of rabbit is 36 to 38 per minute. For human it is 12 to 18 per
minute.
B. Physical factors
The activity of respiratory center is also affected by body temperature and blood pressure. Whenever
body temperature is increased or blood pressure goes high, respiratory center becomes more
activated and this increases the respiration rate.
C. Sensory factors
A sensory organ – carotid labyrinth is found in the walls of carotid arteries. This is sensitive for O
2
concentration in blood. Whenever O
2
concentration in the blood is reduced, this sensory organ
becomes activated and sends sensory impulse to respiratory center. As a result respiratory center,
becomes activated and this increases the rate of respiration. This center also can recognize changes
in CO
2
and H
+
concentration.
1.3.5 Respiratory volumes, capacities and function tests
Various lung volumes, capacities (capacities are combinations of lung volumes) and flow rates can
be evaluated through a process called spirometry. The patient breathes in and out under controlled
conditions, and the amount of air passing through the system, as well as the time it takes for air
passage is measured. The values for these measurements depend on lung function and the size of
the patient.
CO
2
+
cause increased strength of inspiratory, as well as expiratory signal. However, oxygen
has no such direct effect.
Hering Breuer reflex arch
In the walls of terminal bronchioles and atria stretch receptors are present, which are normally
inactive but they become active when the lungs are excessively inflated due to failure of switch off
of inspiration. The Hering Breuer reflex arch now becomes activated and sends inhibitory signals to
the inspiratory center to switch off inspiration. This prevents the alveoli from over stretching and
bursting. Thus Hering Breuer reflex arch is a protective reflex which works only when normal
mechanism of switch off of inspiration does not work timely due to any reason.
1.3.4 Factors affecting breathing
A. Chemical factors
There are so many factors which affect the activity of respiratory center. Respiratory center is sensitive
to CO
2
concentration in the blood and pH of blood. Respiratory center is not sensitive for O
2
concentration in blood. Whenever, in the blood, CO
2
concentration is increased, or pH is decreased,
or acidity is increased, then respiratory center becomes more activated and increases the rate of
respiration. Normal breathing rate of rabbit is 36 to 38 per minute. For human it is 12 to 18 per
minute.
B. Physical factors
The activity of respiratory center is also affected by body temperature and blood pressure. Whenever
body temperature is increased or blood pressure goes high, respiratory center becomes more
activated and this increases the respiration rate.
C. Sensory factors
A sensory organ – carotid labyrinth is found in the walls of carotid arteries. This is sensitive for O
2
concentration in blood. Whenever O
2
concentration in the blood is reduced, this sensory organ
becomes activated and sends sensory impulse to respiratory center. As a result respiratory center,
becomes activated and this increases the rate of respiration. This center also can recognize changes
in CO
2
and H
+
concentration.
1.3.5 Respiratory volumes, capacities and function tests
Various lung volumes, capacities (capacities are combinations of lung volumes) and flow rates can
be evaluated through a process called spirometry. The patient breathes in and out under controlled
conditions, and the amount of air passing through the system, as well as the time it takes for air
passage is measured. The values for these measurements depend on lung function and the size of
the patient.
15
Expiratory
reserve volume
Residual
volume
Expiration
Time
1000
2000
3000
4000
5000
6000
L
u
n
g
v
o
lu
m
e
(
m
l)
Functional
residual
capacity
Tidal
volume
Total lung
capacity
Vital
capacity
Inspiratory
capacity
Inspiratory
reserve
volume
Inspiration
Diagram showing respiratory excursions during normal breathing and during maximal
inspiration and maximal expiration
Several respiratory capacities can be calculated from the volumes listed above.
Inspiratory capacity: The amount of air (about 3500 milliliters) a person can breathe in,
beginning at the normal expiratory level and distending the lungs to the maximum amount.
Functional residual capacity: The amount of air that remains in the lungs at the end of
normal expiration (about 2300 milliliters).
Vital capacity: This is the maximum amount of air a person can expel from the lungs after
first filling the lungs to their maximum extent and then expiring to the maximum extent (about
4600 milliliters).
Respiratory volumes Description Normal adult values
Tidal Volume (TV) Volume of a resting breath 500 ml/breath
Inspiratory Reserve Maximum volume that can be inhaled after a 1900-3300 ml
Volume (IRV) normal inhale
Expiratory Reserve Maximum volume that can be exhaled after a 700-1200 ml
Volume (ERV) normal exhale
Residual Volume (RV) Air left in the lungs after exhaling completely 1200 ml
(i.e. after an ERV)
Dead Space Air inhaled during breathing that stays in the 150 ml
conducting zone
Expiratory
reserve volume
Residual
volume
Expiration
Time
1000
2000
3000
4000
5000
6000
L
u
n
g
v
o
lu
m
e
(
m
l)
Functional
residual
capacity
Tidal
volume
Total lung
capacity
Vital
capacity
Inspiratory
capacity
Inspiratory
reserve
volume
Inspiration
Diagram showing respiratory excursions during normal breathing and during maximal
inspiration and maximal expiration
Several respiratory capacities can be calculated from the volumes listed above.
Inspiratory capacity: The amount of air (about 3500 milliliters) a person can breathe in,
beginning at the normal expiratory level and distending the lungs to the maximum amount.
Functional residual capacity: The amount of air that remains in the lungs at the end of
normal expiration (about 2300 milliliters).
Vital capacity: This is the maximum amount of air a person can expel from the lungs after
first filling the lungs to their maximum extent and then expiring to the maximum extent (about
4600 milliliters).
Respiratory volumes Description Normal adult values
Tidal Volume (TV) Volume of a resting breath 500 ml/breath
Inspiratory Reserve Maximum volume that can be inhaled after a 1900-3300 ml
Volume (IRV) normal inhale
Expiratory Reserve Maximum volume that can be exhaled after a 700-1200 ml
Volume (ERV) normal exhale
Residual Volume (RV) Air left in the lungs after exhaling completely 1200 ml
(i.e. after an ERV)
Dead Space Air inhaled during breathing that stays in the 150 ml
conducting zone
16
Total lung capacity: The maximum volume to which the lungs can be expanded with the
greatest possible effort (about 5800 milliliters).
All pulmonary volumes and capacities are about 20-25% less in women than in men, and they are
greater in large and athletic people than in small and asthenic people.
Besides volumes and capacities, flow rates are often measured to assess a person’s lung function.
Flow rates are important because although changes in airway resistance will not usually change
volumes, they will affect the rate of air movement through the system. To assess flow rates, the
individual takes as deep a breath as possible (gets to VC) and then exhales maximally and as
quickly as possible. The time it takes to bring the lung volume down to RV provides information
about airway resistance. Flow rates are used to assess asthma and related conditions.
Lung volumes and flow rates can be used to differentiate between obstructive and restrictive
pulmonary diseases. Obstructive pulmonary disorders are those that increase the resistance to
airflow, thus increasing the time it takes to move air in and out of the lungs. Examples of obstructive
disorders include bronchitis and asthma. Restrictive pulmonary disorders are those that affect the
compliance of the lung or affect the ability of the chest wall to expand and relax normally. Such
disorders lead to lower lung volumes than would be expected based upon a person’s size. Examples
of restrictive pulmonary disorders include those that lead to structural or functional changes in the
lung tissue (tuberculosis, fibrosis) or those that impede normal muscular function (such as muscular
dystrophy) or function of motor nerves (such as multiple sclerosis and ALS).
TARGET POINTS
Spirometry is the measuring of breath and is one of the most common tests of pulmonary function.
These tests are collectively known as PFTs (pulmonary function tests) and are used to measure
and assess the ventilation of the lungs. Spirometry can measure the volume of air moving in and out
of lungs and the speed of airflow in and out of the lungs. The most common features measured in
spirometry are the vital capacity, the forced vital capacity, and forced expiratory volume.
Respiratory capacities Description Normal adult values
Inspiratory Capacity (IC) TV + IRV 2400 - 3800 ml
Functional Residual Capacity (FRC) RV + ERV 1800 - 2200 ml
Vital Capacity (VC) TV + IRV + ERV 3000 - 4600 ml
Total Lung Capacity (TLC) TV + IRV + ERV + RV 4200 - 6000 ml
Total lung capacity: The maximum volume to which the lungs can be expanded with the
greatest possible effort (about 5800 milliliters).
All pulmonary volumes and capacities are about 20-25% less in women than in men, and they are
greater in large and athletic people than in small and asthenic people.
Besides volumes and capacities, flow rates are often measured to assess a person’s lung function.
Flow rates are important because although changes in airway resistance will not usually change
volumes, they will affect the rate of air movement through the system. To assess flow rates, the
individual takes as deep a breath as possible (gets to VC) and then exhales maximally and as
quickly as possible. The time it takes to bring the lung volume down to RV provides information
about airway resistance. Flow rates are used to assess asthma and related conditions.
Lung volumes and flow rates can be used to differentiate between obstructive and restrictive
pulmonary diseases. Obstructive pulmonary disorders are those that increase the resistance to
airflow, thus increasing the time it takes to move air in and out of the lungs. Examples of obstructive
disorders include bronchitis and asthma. Restrictive pulmonary disorders are those that affect the
compliance of the lung or affect the ability of the chest wall to expand and relax normally. Such
disorders lead to lower lung volumes than would be expected based upon a person’s size. Examples
of restrictive pulmonary disorders include those that lead to structural or functional changes in the
lung tissue (tuberculosis, fibrosis) or those that impede normal muscular function (such as muscular
dystrophy) or function of motor nerves (such as multiple sclerosis and ALS).
TARGET POINTS
Spirometry is the measuring of breath and is one of the most common tests of pulmonary function.
These tests are collectively known as PFTs (pulmonary function tests) and are used to measure
and assess the ventilation of the lungs. Spirometry can measure the volume of air moving in and out
of lungs and the speed of airflow in and out of the lungs. The most common features measured in
spirometry are the vital capacity, the forced vital capacity, and forced expiratory volume.
Respiratory capacities Description Normal adult values
Inspiratory Capacity (IC) TV + IRV 2400 - 3800 ml
Functional Residual Capacity (FRC) RV + ERV 1800 - 2200 ml
Vital Capacity (VC) TV + IRV + ERV 3000 - 4600 ml
Total Lung Capacity (TLC) TV + IRV + ERV + RV 4200 - 6000 ml
17
1. The diagram shows organs associated with
breathing in humans
D
A
B
C
What are the numbered structures?
a) A- Bronchus, B - Bronchioles, C - Larynx,
D - Trachea
b) A- Bronchioles, B - Bronchus, C - Larynx,
D - Trachea
c) A- Larynx, B - Trachea, C - Bronchus,
D - Bronchiole
d) A- Trachea, B - Bronchus,
C - Bronchiole, D - Larynx
2. Which features distinguish bronchioles from
bronchi?
a) Bronchioles are less than 1 mm in
diameter
b) Bronchioles have cartilage in their walls
c) Larger bronchioles are supported by
connective tissue alone which extend
from the interlobular septa
d) Both (a) and (b)
3. By the contraction in diaphragm volume of
thoracic chamber increases in the
a) Dorso-ventral axis
b) Antero-posterior axis
c) Dorso-posterior axis
d) Antero-ventral axis
4. The most important muscular structure in
respiratory system of rabbit is
a) External intercostal muscle
b) Internal intercostal muscle
c) Diaphragm
d) Vertebral column
Simple Questions
5. A wall of alveoli is composed of
a) Simple squamous epithelium
b) Simple cuboidal epithelium
c) Pseudostratified epithelium
d) Simple columnar epithelium
6. Which of the following steps not involved in
respiration?
a) Diffusion of gases across alveolar
membrane
b) Transport of gases by the blood
c) Provide nutrients, O
2
to all the living cells
of body
d) Utilization of O
2
by the cells for catabolic
reactions and resultant release of CO
2
7. Which of the following is not a structural
feature of the left lung?
a) Superior lobe b) Cardiac notch
c) Inferior lobe d) Middle lobe
8. Very high number of alveoli present in a lung
is meant for
a) More space for increasing volume of
inspired air
b) More area for diffusion
c) Making the organ spongy
d) Increasing nerve supply
9. Life without air would be
a) Reductional
b) Free from oxidative damage
c) Impossible
d) Anaerobic
10. During normal respiration, without any effort,
the volume of air inspired or expired is called
a) Tidal volume b) Reserve volume
c) Residual volume d) None of these
11. After deep inspiration, capacity of maximum
expiration of lung is called
a) Total lung capacity
b) Functional residual capacity
c) Vital capacity
d) Inspiratory capacity
1. The diagram shows organs associated with
breathing in humans
D
A
B
C
What are the numbered structures?
a) A- Bronchus, B - Bronchioles, C - Larynx,
D - Trachea
b) A- Bronchioles, B - Bronchus, C - Larynx,
D - Trachea
c) A- Larynx, B - Trachea, C - Bronchus,
D - Bronchiole
d) A- Trachea, B - Bronchus,
C - Bronchiole, D - Larynx
2. Which features distinguish bronchioles from
bronchi?
a) Bronchioles are less than 1 mm in
diameter
b) Bronchioles have cartilage in their walls
c) Larger bronchioles are supported by
connective tissue alone which extend
from the interlobular septa
d) Both (a) and (b)
3. By the contraction in diaphragm volume of
thoracic chamber increases in the
a) Dorso-ventral axis
b) Antero-posterior axis
c) Dorso-posterior axis
d) Antero-ventral axis
4. The most important muscular structure in
respiratory system of rabbit is
a) External intercostal muscle
b) Internal intercostal muscle
c) Diaphragm
d) Vertebral column
Simple Questions
5. A wall of alveoli is composed of
a) Simple squamous epithelium
b) Simple cuboidal epithelium
c) Pseudostratified epithelium
d) Simple columnar epithelium
6. Which of the following steps not involved in
respiration?
a) Diffusion of gases across alveolar
membrane
b) Transport of gases by the blood
c) Provide nutrients, O
2
to all the living cells
of body
d) Utilization of O
2
by the cells for catabolic
reactions and resultant release of CO
2
7. Which of the following is not a structural
feature of the left lung?
a) Superior lobe b) Cardiac notch
c) Inferior lobe d) Middle lobe
8. Very high number of alveoli present in a lung
is meant for
a) More space for increasing volume of
inspired air
b) More area for diffusion
c) Making the organ spongy
d) Increasing nerve supply
9. Life without air would be
a) Reductional
b) Free from oxidative damage
c) Impossible
d) Anaerobic
10. During normal respiration, without any effort,
the volume of air inspired or expired is called
a) Tidal volume b) Reserve volume
c) Residual volume d) None of these
11. After deep inspiration, capacity of maximum
expiration of lung is called
a) Total lung capacity
b) Functional residual capacity
c) Vital capacity
d) Inspiratory capacity
18
12. The impulse for voluntary forced breathing
starts in
a) Medulla
b) Vagus
c) Cerebral hemisphere
d) Spinal cord
13. Inhibition of respiratory center is termed
a) Bradypnoea b) Apnoea
c) Anoxia d) Tachypnoea
14. Hiccough (hiccup) is due to activity of
a) Intercostal muscle
b) Food in air tract
c) Diaphragm
d) Inadequate oxygen in environment
15. During inspiration, the diaphragm
a) Expands
b) Shows no change
c) Contracts and flattens
d) Relaxes to become dome shaped
16. A person breathes in some volume of air by
forced inspiration after having a forced
expiration. This quantity of air taken in is
a) Total lung capacity
b) Tidal volume
c) Vital capacity
d) Inspiratory capacity
17. Which is not a structure of the respiratory
system?
a) The pharynx b) The bronchus
c) The larynx d) The hyoid
18. Lungs of rabbit and man are
a) Sunken lungs b) Pressure lungs
c) Aquatic lungs d) None
19. Cilia of trachea transfers
a) Mucous into pharynx
b) Mucous into lungs
c) Air into lungs
d) Air into pharynx
20. In lungs air is separated from venous blood
by
a) Squamous epithelium + tunica externa
of blood vessel
b) Squamous epithelium + endothelium of
blood vessel
c) Transitional epithelium + tunica media
of blood vessel
d) Columnar epithelium + 3 layered wall of
blood vessel
21. Which structure is not related to respiration
in frog?
a) Diaphragm b) Skin
c) Buccal cavity d) Lungs
22. Signet ring cartilage of larynx is
a) Cricoid b) Arytenoid
c) Thyroid d) All
23. Which one protects the lungs?
a) Rib b) Vertebral column
c) Sternum d) All above
24. Rate of breathing in rabbit
a) 12 / min b) 36 - 38 / min
c) 100 / min d) 300 / min
25. Lung recoil occurs because of elastic fibers
in the alveolar walls and
a) Barometric pressure
b) Pleural pressure
c) Surface tension of fluid that lines the
alveoli
d) Surfactant secretion in the alveoli
26. Surfactant
a) Reduces surface tension of the fluid
lining the alveoli
b) Increases pleural pressure
c) Decreases alveolar pressure
d) Makes inspiration more difficult
12. The impulse for voluntary forced breathing
starts in
a) Medulla
b) Vagus
c) Cerebral hemisphere
d) Spinal cord
13. Inhibition of respiratory center is termed
a) Bradypnoea b) Apnoea
c) Anoxia d) Tachypnoea
14. Hiccough (hiccup) is due to activity of
a) Intercostal muscle
b) Food in air tract
c) Diaphragm
d) Inadequate oxygen in environment
15. During inspiration, the diaphragm
a) Expands
b) Shows no change
c) Contracts and flattens
d) Relaxes to become dome shaped
16. A person breathes in some volume of air by
forced inspiration after having a forced
expiration. This quantity of air taken in is
a) Total lung capacity
b) Tidal volume
c) Vital capacity
d) Inspiratory capacity
17. Which is not a structure of the respiratory
system?
a) The pharynx b) The bronchus
c) The larynx d) The hyoid
18. Lungs of rabbit and man are
a) Sunken lungs b) Pressure lungs
c) Aquatic lungs d) None
19. Cilia of trachea transfers
a) Mucous into pharynx
b) Mucous into lungs
c) Air into lungs
d) Air into pharynx
20. In lungs air is separated from venous blood
by
a) Squamous epithelium + tunica externa
of blood vessel
b) Squamous epithelium + endothelium of
blood vessel
c) Transitional epithelium + tunica media
of blood vessel
d) Columnar epithelium + 3 layered wall of
blood vessel
21. Which structure is not related to respiration
in frog?
a) Diaphragm b) Skin
c) Buccal cavity d) Lungs
22. Signet ring cartilage of larynx is
a) Cricoid b) Arytenoid
c) Thyroid d) All
23. Which one protects the lungs?
a) Rib b) Vertebral column
c) Sternum d) All above
24. Rate of breathing in rabbit
a) 12 / min b) 36 - 38 / min
c) 100 / min d) 300 / min
25. Lung recoil occurs because of elastic fibers
in the alveolar walls and
a) Barometric pressure
b) Pleural pressure
c) Surface tension of fluid that lines the
alveoli
d) Surfactant secretion in the alveoli
26. Surfactant
a) Reduces surface tension of the fluid
lining the alveoli
b) Increases pleural pressure
c) Decreases alveolar pressure
d) Makes inspiration more difficult
19
27. I
and alveolar pressure become ____
barometric pressure
a) Equal to
b) Greater than
c) Lesser than
d) Cannot be determined
28. If compliance increases, lung expansion is
a) Easier b) More difficult
c) Unaffected d) None of these
29. If a person's vital capacity is 4000 ml, her
ERV is 1000 ml and her IRV is 2500 ml and
her TV is
a) 3500 ml b) 3000 ml
c) 500 ml d) 1500 ml
30. If the total pressure of a gas is 700 mmHg
and its composition is 20% O
2
, 0.03% CO
2
,
75% N
2
, and 5% water vapor, the partial
pressure of O
2
(pO
2
)
a) 140 mmHg b) 105 mmHg
c) 20 mmHg d) 1600 mmHg
Difficult Questions
1. Match the following columns
Codes
A B C D E
a) 3 4 2 1 5
b) 3 1 2 5 4
c) 3 1 4 5 4
d) 5 4 2 1 2
2. The air that enters our lungs is characterized
that
I) It is warm
II) It is filtered
III) Some oxygen is extracted from it
IV) Some carbon dioxide is added to it
The correct answer is
a) I, II, III and IV b) I and II
c) II and IV d) III and IV
Column I Column II
A. Tidal volume 1. 2500 to 3000 mL of air
B. Inspiratory reserve 2. 1000 mL of air
volume
C. Expiratory reserve 3. 500 mL of air
volume
D. Residual volume 4. 3400 to 4800 mL of air
E. Vital capacity 5. 1200 mL of air
3. The following diagram shows a section of
an alveolus in a human lung
Air flowAlveolus
Blood flow
Blood capillary
Which conditions would result in the
maximum rate of diffusion of oxygen from
the alveolus into the blood capillary?
Amount of Amount of Rate of
oxygen in oxygen blood
alveolar air in blood flow
a) Small Large Fast
b) Small Large Slow
c) Large Small Fast
d) Large Small Slow
27. I
and alveolar pressure become ____
barometric pressure
a) Equal to
b) Greater than
c) Lesser than
d) Cannot be determined
28. If compliance increases, lung expansion is
a) Easier b) More difficult
c) Unaffected d) None of these
29. If a person's vital capacity is 4000 ml, her
ERV is 1000 ml and her IRV is 2500 ml and
her TV is
a) 3500 ml b) 3000 ml
c) 500 ml d) 1500 ml
30. If the total pressure of a gas is 700 mmHg
and its composition is 20% O
2
, 0.03% CO
2
,
75% N
2
, and 5% water vapor, the partial
pressure of O
2
(pO
2
)
a) 140 mmHg b) 105 mmHg
c) 20 mmHg d) 1600 mmHg
Difficult Questions
1. Match the following columns
Codes
A B C D E
a) 3 4 2 1 5
b) 3 1 2 5 4
c) 3 1 4 5 4
d) 5 4 2 1 2
2. The air that enters our lungs is characterized
that
I) It is warm
II) It is filtered
III) Some oxygen is extracted from it
IV) Some carbon dioxide is added to it
The correct answer is
a) I, II, III and IV b) I and II
c) II and IV d) III and IV
Column I Column II
A. Tidal volume 1. 2500 to 3000 mL of air
B. Inspiratory reserve 2. 1000 mL of air
volume
C. Expiratory reserve 3. 500 mL of air
volume
D. Residual volume 4. 3400 to 4800 mL of air
E. Vital capacity 5. 1200 mL of air
3. The following diagram shows a section of
an alveolus in a human lung
Air flowAlveolus
Blood flow
Blood capillary
Which conditions would result in the
maximum rate of diffusion of oxygen from
the alveolus into the blood capillary?
Amount of Amount of Rate of
oxygen in oxygen blood
alveolar air in blood flow
a) Small Large Fast
b) Small Large Slow
c) Large Small Fast
d) Large Small Slow
20
4. Which is correct?
a) Respiratory centers are not affected by
CO
2
.
b) In humans vital capacity is just double
the expiratory volume.
c) A human lung has 10
3
alveoli.
d) During inspiration the lungs act as
suction pump.
5. Which one of the following statement is
correct?
a) Chest expands because air enters into
the lungs
b) Air enters into the lungs because chest
expands
c) The muscles of the diaphragm contacts
because air enters into the lungs
d) All of the above statements are correct
6. Which part of thyroid cartilage in larynx is
closed?
a) Dorsal b) Ventral
c) Anterior d) Posterior
7. Neither the trachea nor the bronchi contain
a) Hyaline cartilage
b) Ciliated columnar epithelium
c) Goblet cells
d) Simple squamous epithelium
8. In man, the structure which functions similar
to spiracles of cockroach are
a) Lungs b) Alveoli
c) Bronchioles d) Nostrils
9. Among mammals, the efficiency of
ventilation of lungs as compared to reptiles
and birds is better developed by the
presence of
a) Ribs and costal muscles
b) Only ribs
c) Only costal muscles
d) Diaphragm
10. Listed below are four respiratory capacities
(a-d) and four jumbled respiratory volumes
of a normal human adult
Respiratory Respiratory
capacities volumes
A) Residual volume 2500 ml
B) Vital capacity 3500 ml
C) Inspiratory reserve 1200 ml
volume
D) Inspiratory capacity 4500 ml
Which one of the following is the correct
matching of two capacities and volumes?
a) A) 4500 ml B) 3500 ml
b) B) 2500 ml C) 4500 ml
c) C) 1200 ml D) 2500 ml
d) D) 3500 ml A) 1200 ml
11. If the thoracic wall but not the lungs are
punctured
a) The lungs get inflated
b) The man dies as the lungs get collapsed
c) The breathing rate decreases
d) The breathing rate increases
12. One of the following is a difference between
pulmonary respiration of frog and human
a) Diaphragm and ribs play role in breathing
b) Lungs are respiratory organs
c) Respiration occurs due to pressure
gradient
d) None of the above
13. A person met with an accident and died
instantly without any injury to heart, brain,
stomach and kidney. One of the following
is a reason for his death
a) Intestine got twisted
b) RBCs became coagulated
c) Stomach stopped digestion
d) Diaphragm got punctured
4. Which is correct?
a) Respiratory centers are not affected by
CO
2
.
b) In humans vital capacity is just double
the expiratory volume.
c) A human lung has 10
3
alveoli.
d) During inspiration the lungs act as
suction pump.
5. Which one of the following statement is
correct?
a) Chest expands because air enters into
the lungs
b) Air enters into the lungs because chest
expands
c) The muscles of the diaphragm contacts
because air enters into the lungs
d) All of the above statements are correct
6. Which part of thyroid cartilage in larynx is
closed?
a) Dorsal b) Ventral
c) Anterior d) Posterior
7. Neither the trachea nor the bronchi contain
a) Hyaline cartilage
b) Ciliated columnar epithelium
c) Goblet cells
d) Simple squamous epithelium
8. In man, the structure which functions similar
to spiracles of cockroach are
a) Lungs b) Alveoli
c) Bronchioles d) Nostrils
9. Among mammals, the efficiency of
ventilation of lungs as compared to reptiles
and birds is better developed by the
presence of
a) Ribs and costal muscles
b) Only ribs
c) Only costal muscles
d) Diaphragm
10. Listed below are four respiratory capacities
(a-d) and four jumbled respiratory volumes
of a normal human adult
Respiratory Respiratory
capacities volumes
A) Residual volume 2500 ml
B) Vital capacity 3500 ml
C) Inspiratory reserve 1200 ml
volume
D) Inspiratory capacity 4500 ml
Which one of the following is the correct
matching of two capacities and volumes?
a) A) 4500 ml B) 3500 ml
b) B) 2500 ml C) 4500 ml
c) C) 1200 ml D) 2500 ml
d) D) 3500 ml A) 1200 ml
11. If the thoracic wall but not the lungs are
punctured
a) The lungs get inflated
b) The man dies as the lungs get collapsed
c) The breathing rate decreases
d) The breathing rate increases
12. One of the following is a difference between
pulmonary respiration of frog and human
a) Diaphragm and ribs play role in breathing
b) Lungs are respiratory organs
c) Respiration occurs due to pressure
gradient
d) None of the above
13. A person met with an accident and died
instantly without any injury to heart, brain,
stomach and kidney. One of the following
is a reason for his death
a) Intestine got twisted
b) RBCs became coagulated
c) Stomach stopped digestion
d) Diaphragm got punctured
21
14. Division of mammalian lungs into a very
large number of tiny alveoli around alveolar
ducts opening into bronchioles is
a) An inefficient system of ventilation of
alveoli through with very little residual air
b) An inefficient system of ventilation of
alveoli resulting in very high percentage
of residual air in the lungs
c) A very efficient system of ventilation of
alveoli with no residual air
d) An efficient system of ventilation of
alveoli with little or no residual air
15. Which of the following factor can affect the
rate of diffusion of gases?
a) Thickness of the membranes involved
in diffusion
b) Solubility of the gases
c) Pressure of the gases
d) All of these
16. Residual air mostly occurs in
a) Alveoli b) Bronchus
c) Nostrils d) Trachea
17. When there is no air in initial bronchioles,
they does not collapse. It is due to
a) Presence of lecithin
b) Presence of incomplete cartilaginous
rings
c) Presence of complete cartilaginous
rings
d) Presence of mucous
18. Breathing differs from respiration by
a) Both are same and there is no
difference
b) Breathing refers to respiration in human
beings whereas respiration occurs in rest
of the animals and plants
c) Breathing refers to chest movements
due to inhalation of oxygen and
exhalation of carbon dioxide, whereas
respiration refers to gaseous exchanges.
d) None of the above
19. Adam's apple represents
a) Arytenoid cartilage of larynx
b) Cricoid cartilage of larynx
c) Thyroid cartilage of larynx
d) All of the above
20. Common factor in the trachea of mammals
and insects is
a) Ciliated inner lining
b) Non-collapsible wall
c) Paired nature
d) Origin from head region
21. The impulse for voluntary muscles for
forced breathing starts in
a) Medulla oblongata
b) Vagus nerve
c) Cerebellum
d) Cerebrum
22. The function of tracheal cilia is to
a) Pass mucus out b) Pass mucus in
c) Pass air out d) Pass air in
23. Expiration involves
a) Relaxation of diaphragm and intercostal
muscles
b) Contraction of diaphragm and intercostal
muscles
c) Contraction of diaphragm muscles
d) Contraction of intercostal muscles
24. If expiratory reserve volume is 1100 ml,
residual volume is 1200 ml and tidal volume
is 500 ml, what shall be the functional
residual capacity?
a) 1600 ml b) 2800 ml
c) 2300 ml d) 1200 ml
25. Which is not a function of the paranasal
sinuses?
a) Warm inhaled air
b) Responsible for sound resonance
c) Gas exchange
d) Humidify inhaled air
14. Division of mammalian lungs into a very
large number of tiny alveoli around alveolar
ducts opening into bronchioles is
a) An inefficient system of ventilation of
alveoli through with very little residual air
b) An inefficient system of ventilation of
alveoli resulting in very high percentage
of residual air in the lungs
c) A very efficient system of ventilation of
alveoli with no residual air
d) An efficient system of ventilation of
alveoli with little or no residual air
15. Which of the following factor can affect the
rate of diffusion of gases?
a) Thickness of the membranes involved
in diffusion
b) Solubility of the gases
c) Pressure of the gases
d) All of these
16. Residual air mostly occurs in
a) Alveoli b) Bronchus
c) Nostrils d) Trachea
17. When there is no air in initial bronchioles,
they does not collapse. It is due to
a) Presence of lecithin
b) Presence of incomplete cartilaginous
rings
c) Presence of complete cartilaginous
rings
d) Presence of mucous
18. Breathing differs from respiration by
a) Both are same and there is no
difference
b) Breathing refers to respiration in human
beings whereas respiration occurs in rest
of the animals and plants
c) Breathing refers to chest movements
due to inhalation of oxygen and
exhalation of carbon dioxide, whereas
respiration refers to gaseous exchanges.
d) None of the above
19. Adam's apple represents
a) Arytenoid cartilage of larynx
b) Cricoid cartilage of larynx
c) Thyroid cartilage of larynx
d) All of the above
20. Common factor in the trachea of mammals
and insects is
a) Ciliated inner lining
b) Non-collapsible wall
c) Paired nature
d) Origin from head region
21. The impulse for voluntary muscles for
forced breathing starts in
a) Medulla oblongata
b) Vagus nerve
c) Cerebellum
d) Cerebrum
22. The function of tracheal cilia is to
a) Pass mucus out b) Pass mucus in
c) Pass air out d) Pass air in
23. Expiration involves
a) Relaxation of diaphragm and intercostal
muscles
b) Contraction of diaphragm and intercostal
muscles
c) Contraction of diaphragm muscles
d) Contraction of intercostal muscles
24. If expiratory reserve volume is 1100 ml,
residual volume is 1200 ml and tidal volume
is 500 ml, what shall be the functional
residual capacity?
a) 1600 ml b) 2800 ml
c) 2300 ml d) 1200 ml
25. Which is not a function of the paranasal
sinuses?
a) Warm inhaled air
b) Responsible for sound resonance
c) Gas exchange
d) Humidify inhaled air
22
26. T
cardiovascular and lymphatic systems in
a) Regulating blood volume
b) Regulating blood pressure
c) Controlling body fluid pH
d) All of the above
27. Which one of the following does not
accurately characterize the epithelial lining
of the respiratory tract?
a) It is mostly pseudostratified ciliated
columnar epithelium with numerous
goblet cells.
b) Cilia in the larger passageways sweep
trapped debris towards the pharynx,
where it is swallowed.
c) It changes from simple columnar to
simple cuboidal epithelium within
progressively smaller bronchioles.
d) Goblet cells and mucous glands in the
lamina propria secrete a watery,
lubricating fluid
28. Which paranasal sinuses are located
deepest within the skull, or farthest posterior
to the face?
a) Ethmoidal b) Frontal
c) Sphenoid d) Maxillary
29. Even if all the defenses in the conducting
portion of the respiratory tract fail, ______
may still destroy pathogens before they can
enter the body fluids
a) Macrophages in the pulmonary lymph
nodes
b) NK cells in the elastic tissues of the
lungs
c) Cytotoxic T- lymphocytes
d) Alveolar macrophages
30. Autonomic stimulation via the vagus nerves
causes what response within the lungs?
a) Deeper inhalation
b) Forced exhalation
c) Bronchodilation
d) Bronchoconstriction
31. Babies that sleep on their stomachs are now
known to be at greater risk of
a) Asphyxiation
b) SIDS (crib death)
c) Developmental delays
d) All of the above
32. Ultimately, the harmful effects of cystic
fibrosis are attributable to _____ caused by
a defective gene
a) Excessive, dilute mucus in the lungs
b) Hyposecretion of pancreatic enzymes
c) Hypersecretion of sodium chloride
d) Osmotic imbalance in gland cells
33. In prematurely born infants, hyaline
membrane disease is associated with
inadequate production of _______ by
_______ cells
a) Lysozyme: Mucus glands
b) Mucin: Goblet
c) Glycoproteins: Alveolar type I
d) Surfactant: Alveolar type II
34. According to Boyle's law, intrapulmonary
pressure should ____ when the diaphragm
or external intercostal muscle contract
a) Increase
b) Decrease
c) Remain constant
d) Equal atmospheric pressure
26. T
cardiovascular and lymphatic systems in
a) Regulating blood volume
b) Regulating blood pressure
c) Controlling body fluid pH
d) All of the above
27. Which one of the following does not
accurately characterize the epithelial lining
of the respiratory tract?
a) It is mostly pseudostratified ciliated
columnar epithelium with numerous
goblet cells.
b) Cilia in the larger passageways sweep
trapped debris towards the pharynx,
where it is swallowed.
c) It changes from simple columnar to
simple cuboidal epithelium within
progressively smaller bronchioles.
d) Goblet cells and mucous glands in the
lamina propria secrete a watery,
lubricating fluid
28. Which paranasal sinuses are located
deepest within the skull, or farthest posterior
to the face?
a) Ethmoidal b) Frontal
c) Sphenoid d) Maxillary
29. Even if all the defenses in the conducting
portion of the respiratory tract fail, ______
may still destroy pathogens before they can
enter the body fluids
a) Macrophages in the pulmonary lymph
nodes
b) NK cells in the elastic tissues of the
lungs
c) Cytotoxic T- lymphocytes
d) Alveolar macrophages
30. Autonomic stimulation via the vagus nerves
causes what response within the lungs?
a) Deeper inhalation
b) Forced exhalation
c) Bronchodilation
d) Bronchoconstriction
31. Babies that sleep on their stomachs are now
known to be at greater risk of
a) Asphyxiation
b) SIDS (crib death)
c) Developmental delays
d) All of the above
32. Ultimately, the harmful effects of cystic
fibrosis are attributable to _____ caused by
a defective gene
a) Excessive, dilute mucus in the lungs
b) Hyposecretion of pancreatic enzymes
c) Hypersecretion of sodium chloride
d) Osmotic imbalance in gland cells
33. In prematurely born infants, hyaline
membrane disease is associated with
inadequate production of _______ by
_______ cells
a) Lysozyme: Mucus glands
b) Mucin: Goblet
c) Glycoproteins: Alveolar type I
d) Surfactant: Alveolar type II
34. According to Boyle's law, intrapulmonary
pressure should ____ when the diaphragm
or external intercostal muscle contract
a) Increase
b) Decrease
c) Remain constant
d) Equal atmospheric pressure
23
ANSWER KEYS
S
imple Questions
1.d 2.d 3.b 4.c 5.a 6.c 7.d 8.b 9.d 10.a 11.c 12.c
13.b 14.c 15.c 16.a 17.d 18.a 19.a 20.b 21.a 22.a 23.d 24.b
25.c 26.a 27.a 28.a 29.c 30.a
Difficult Questions
1.b 2.a 3.c 4.d 5.b 6.b 7.d 8.d 9.d 10.d 11.b 12.a
13.d 14.d 15.d 16.a 17.b 18.c 19.c 20.b 21.d 22.a 23.a 24.c
25.c 26.d 27.d 28.c 29.d 30.d 31.b 32.d 33.d 34.b
ANSWER KEYS
S
imple Questions
1.d 2.d 3.b 4.c 5.a 6.c 7.d 8.b 9.d 10.a 11.c 12.c
13.b 14.c 15.c 16.a 17.d 18.a 19.a 20.b 21.a 22.a 23.d 24.b
25.c 26.a 27.a 28.a 29.c 30.a
Difficult Questions
1.b 2.a 3.c 4.d 5.b 6.b 7.d 8.d 9.d 10.d 11.b 12.a
13.d 14.d 15.d 16.a 17.b 18.c 19.c 20.b 21.d 22.a 23.a 24.c
25.c 26.d 27.d 28.c 29.d 30.d 31.b 32.d 33.d 34.b
24
1. D
a) Amount of air remaining in the alveoli
b) Amount of air left behind in lungs at the
end of deep expiration
c) Amount of air taken in and out
d) Air left in the bronchial tree
2. Vital capacity of lung is
a) Inspiratory Reserve Volume (IRV) +
Expiratory Reserve Volume (ERV) + Tidal
Volume (TV) + Residual Volume (RV).
b) IRV + ERV + TV
c) IRV + ERV
d) IRV + ERV + TV-RV
3. Whether a child died after normal birth or
died before birth can be confirmed by
measuring
a) Tidal volume of air
b) Residual volume of air
c) The weight of the child
d) The dead space air
4. Respiratory rhythm center is present in
a) Pons region b) Aortic arch
c) Medulla region d) Carotid artery
5. The function of conducting part in
respiratory system of human is
a) Clear foreign particles
b) Humidifies atmospheric air
c) Brings the air to body temperature
d) All of the above
DPP - 1
6. Arrange the following in the order of
increasing volume
I) Tidal volume
II) Residual volume
III) Expiratory reserve volume
IV) Vital capacity
a) I < II < III < IV b) I < III < II < IV
c) I < IV < III < II d) I < IV < II < III
7. Respiratory center in brain occurs in
a) Medulla oblongata
b) Cerebellum
c) Hypothalamus
d) Pericardium
8. Vital capacity of lungs of an average human
is
a) 3000 to 4500 ml b) 1500 to 1800 ml
c) 2000 to 2500 ml d) 500 to 1000 ml
9. During hibernation period, frog's respiration
is
a) Cutaneous
b) Pulmonary
c) Pharyngeal
d) Buccopharyngeal
10. Type of cartilage seen in tracheal wall is
a) Hyaline cartilage
b) Fibrocartilage
c) Elastic cartilage
d) None of these
1. D
a) Amount of air remaining in the alveoli
b) Amount of air left behind in lungs at the
end of deep expiration
c) Amount of air taken in and out
d) Air left in the bronchial tree
2. Vital capacity of lung is
a) Inspiratory Reserve Volume (IRV) +
Expiratory Reserve Volume (ERV) + Tidal
Volume (TV) + Residual Volume (RV).
b) IRV + ERV + TV
c) IRV + ERV
d) IRV + ERV + TV-RV
3. Whether a child died after normal birth or
died before birth can be confirmed by
measuring
a) Tidal volume of air
b) Residual volume of air
c) The weight of the child
d) The dead space air
4. Respiratory rhythm center is present in
a) Pons region b) Aortic arch
c) Medulla region d) Carotid artery
5. The function of conducting part in
respiratory system of human is
a) Clear foreign particles
b) Humidifies atmospheric air
c) Brings the air to body temperature
d) All of the above
DPP - 1
6. Arrange the following in the order of
increasing volume
I) Tidal volume
II) Residual volume
III) Expiratory reserve volume
IV) Vital capacity
a) I < II < III < IV b) I < III < II < IV
c) I < IV < III < II d) I < IV < II < III
7. Respiratory center in brain occurs in
a) Medulla oblongata
b) Cerebellum
c) Hypothalamus
d) Pericardium
8. Vital capacity of lungs of an average human
is
a) 3000 to 4500 ml b) 1500 to 1800 ml
c) 2000 to 2500 ml d) 500 to 1000 ml
9. During hibernation period, frog's respiration
is
a) Cutaneous
b) Pulmonary
c) Pharyngeal
d) Buccopharyngeal
10. Type of cartilage seen in tracheal wall is
a) Hyaline cartilage
b) Fibrocartilage
c) Elastic cartilage
d) None of these
2.1 RESPIRATORY LEVELS OF ORGANIZATION
Chemical level - oxygen, carbon dioxide, bicarbonate and hydrogen ions.
Macromolecular level - hemoglobin, mucus and surfactant.
Cellular level - ciliated cells, goblet cells, alveolar cells, and macrophages.
Tissue level - Stratified to pseudostratified to simple squamous epithelium.
Organ level - Upper respiratory tract, bronchial tree and lungs.
Organ system level - integration of organs for gas exchange.
2.2 HOW GASES EXCHANGE
The respiratory system brings in oxygen and exchanges it for carbon dioxide. Oxygen makes up
21% of the air we breathe while carbon dioxide is found at very low levels (0.039%). The diffusion of
gases across membranes follows the same principles as the diffusion of solutes in solution across
membranes, basically molecules move down a gradient. The difference is that gases in solution are
measured in terms of partial pressure.
Partial pressure is the pressure that a given gas in a mixture contributes to the total pressure
inside the container or in the atmosphere. The partial pressure is equal to the total pressure times
the fraction of the gas.
Table of partial pressures and percentage concentrations (in brackets) of gases in various airs
Thus partial pressure of O
2
in pure blood pO
2
= 104 mmHg and pCO
2
= 40 mmHg.
Pure blood goes to tissues from heart. Inspirated air contains 19.6% oxygen and expirated air has
15.7% O
2
. So, approximately 4% oxygen goes to blood from air. In the same way inspirated air contains
0.04% CO
2
and expirated air has 3.6% CO
2
so approximately 3.56% CO
2
goes to air from blood.
Henry's Law, explains that the amount of dissolved gas found in liquid is proportionate to the gas
phase partial pressure as well as the molecules solubility in a specific liquid. For example,
considering
UNIT 2 - RESPIRATORY SYSTEM II
Gas Atmospheric air Functional residual Expired air
alveolar air
O
2
159.0 (20.84%) 104.0 (13.6%) 120.0 (15.7%)
CO
2
0.3 (0.04%) 40.0 (5.3%) 27.0 (3.6%)
Partial Pulmonary Pulmonary Tissue fluid Inside of cell
Pressure Arterial Blood Venous Blood
(Deoxygenated blood) (Oxygenated blood)
pO
2
40 mmHg 95-104 mmHg 40 mmHg 20 mmHg
pO
2
45-46 mmHg 40 mmHg 45 mmHg 50 mmHg
Chemical level - oxygen, carbon dioxide, bicarbonate and hydrogen ions.
Macromolecular level - hemoglobin, mucus and surfactant.
Cellular level - ciliated cells, goblet cells, alveolar cells, and macrophages.
Tissue level - Stratified to pseudostratified to simple squamous epithelium.
Organ level - Upper respiratory tract, bronchial tree and lungs.
Organ system level - integration of organs for gas exchange.
2.2 HOW GASES EXCHANGE
The respiratory system brings in oxygen and exchanges it for carbon dioxide. Oxygen makes up
21% of the air we breathe while carbon dioxide is found at very low levels (0.039%). The diffusion of
gases across membranes follows the same principles as the diffusion of solutes in solution across
membranes, basically molecules move down a gradient. The difference is that gases in solution are
measured in terms of partial pressure.
Partial pressure is the pressure that a given gas in a mixture contributes to the total pressure
inside the container or in the atmosphere. The partial pressure is equal to the total pressure times
the fraction of the gas.
Table of partial pressures and percentage concentrations (in brackets) of gases in various airs
Thus partial pressure of O
2
in pure blood pO
2
= 104 mmHg and pCO
2
= 40 mmHg.
Pure blood goes to tissues from heart. Inspirated air contains 19.6% oxygen and expirated air has
15.7% O
2
. So, approximately 4% oxygen goes to blood from air. In the same way inspirated air contains
0.04% CO
2
and expirated air has 3.6% CO
2
so approximately 3.56% CO
2
goes to air from blood.
Henry's Law, explains that the amount of dissolved gas found in liquid is proportionate to the gas
phase partial pressure as well as the molecules solubility in a specific liquid. For example,
considering
UNIT 2 - RESPIRATORY SYSTEM II
Gas Atmospheric air Functional residual Expired air
alveolar air
O
2
159.0 (20.84%) 104.0 (13.6%) 120.0 (15.7%)
CO
2
0.3 (0.04%) 40.0 (5.3%) 27.0 (3.6%)
Partial Pulmonary Pulmonary Tissue fluid Inside of cell
Pressure Arterial Blood Venous Blood
(Deoxygenated blood) (Oxygenated blood)
pO
2
40 mmHg 95-104 mmHg 40 mmHg 20 mmHg
pO
2
45-46 mmHg 40 mmHg 45 mmHg 50 mmHg
26
partial pressures alone it would be expected that oxygen would readily diffuse from the alveoli
b
ecause there is a high partial pressure gradient between alveoli and blood. However, oxygen has
very low solubility in plasma, so even with the large gradient between the two very little of oxygen
leaves the alveoli and dissolves directly into the plasma. Instead most of the dissolved oxygen
found in the blood is attached to the hemoglobin molecules found inside the red blood cells. On the
other hand carbon dioxide is very soluble in plasma (over 20 times more soluble than oxygen), so
significant amounts can be found directly in
dissolved form. Because of its high solubility, large
amounts of carbon dioxide can move between air
and liquid compartments even with small partial
pressure gradients.
Diffusing capacity: Volume of gas diffusing
through the membrane per minute for a difference
or 1 mmHg. It is 21 ml/mt/mmHg for O
2
.
At high altitudes, the fraction of oxygen in the
atmosphere is the same (21%), but the total
atmospheric pressure is less. This causes the
partial pressure of the oxygen we breathe in to be
significantly less than that at sea level, making it
much harder to move oxygen from the air into our
plasma.
Respiratory membrane (0.2 mm thick): Alveolar
epithelium + Epithelial basement membrane + thin
interstitial spaces + capillary basement membrane
+ capillary endothelial membrane.
2.2.1 External respiration
The partial pressure of oxygen in the alveoli is slightly lower than the partial pressure of oxygen
found in the atmosphere. Air taken into the lungs (tidal volume minus the volume of the conduction
zone) mixes with air that is already in the lungs (functional residual volume). Because gas exchange
is constantly occurring (even between breaths, when we hold our breath, etc), the air making up the
functional residual volume has had some oxygen removed from it and some carbon dioxide added
to it. When a new tidal volume of air is inhaled, the portion of this air that enters the alveoli mixes
with the functional residual volume and effectively lowers the fraction of oxygen in this alveolar air.
Inhaled air at sea level typically has a partial pressure of oxygen near 160 mmHg. In the alveoli, the
partial pressure of oxygen would vary with our ventilation pattern, but typically equilibrates at about
105 mmHg. It is the difference between alveolar oxygen partial pressure and the plasma oxygen
partial pressure that drives external respiration across the alveolar membrane. Blood coming through
the pulmonary arterial circulation is lower in oxygen, with a typical partial pressure of 40 mmHg. The
Interstitial
space
Epithelial basement membrane
Alveolar epithelial wall
Alveolus Capillary
Diffusion
of O
2
Diffusion
of CO
2
Capillary basement membrane
Capillary
endothelium
partial pressures alone it would be expected that oxygen would readily diffuse from the alveoli
b
ecause there is a high partial pressure gradient between alveoli and blood. However, oxygen has
very low solubility in plasma, so even with the large gradient between the two very little of oxygen
leaves the alveoli and dissolves directly into the plasma. Instead most of the dissolved oxygen
found in the blood is attached to the hemoglobin molecules found inside the red blood cells. On the
other hand carbon dioxide is very soluble in plasma (over 20 times more soluble than oxygen), so
significant amounts can be found directly in
dissolved form. Because of its high solubility, large
amounts of carbon dioxide can move between air
and liquid compartments even with small partial
pressure gradients.
Diffusing capacity: Volume of gas diffusing
through the membrane per minute for a difference
or 1 mmHg. It is 21 ml/mt/mmHg for O
2
.
At high altitudes, the fraction of oxygen in the
atmosphere is the same (21%), but the total
atmospheric pressure is less. This causes the
partial pressure of the oxygen we breathe in to be
significantly less than that at sea level, making it
much harder to move oxygen from the air into our
plasma.
Respiratory membrane (0.2 mm thick): Alveolar
epithelium + Epithelial basement membrane + thin
interstitial spaces + capillary basement membrane
+ capillary endothelial membrane.
2.2.1 External respiration
The partial pressure of oxygen in the alveoli is slightly lower than the partial pressure of oxygen
found in the atmosphere. Air taken into the lungs (tidal volume minus the volume of the conduction
zone) mixes with air that is already in the lungs (functional residual volume). Because gas exchange
is constantly occurring (even between breaths, when we hold our breath, etc), the air making up the
functional residual volume has had some oxygen removed from it and some carbon dioxide added
to it. When a new tidal volume of air is inhaled, the portion of this air that enters the alveoli mixes
with the functional residual volume and effectively lowers the fraction of oxygen in this alveolar air.
Inhaled air at sea level typically has a partial pressure of oxygen near 160 mmHg. In the alveoli, the
partial pressure of oxygen would vary with our ventilation pattern, but typically equilibrates at about
105 mmHg. It is the difference between alveolar oxygen partial pressure and the plasma oxygen
partial pressure that drives external respiration across the alveolar membrane. Blood coming through
the pulmonary arterial circulation is lower in oxygen, with a typical partial pressure of 40 mmHg. The
Interstitial
space
Epithelial basement membrane
Alveolar epithelial wall
Alveolus Capillary
Diffusion
of O
2
Diffusion
of CO
2
Capillary basement membrane
Capillary
endothelium
27
differential concentration gradient for oxygen to move from the alveolar air into the capillary blood
s
tarts at about 65 mmHg (105 mmHg in the alveoli minus 40 mmHg in blood), providing enough of
a difference in partial pressures for oxygen to diffuse from the alveoli into the capillary. Diffusion will
occur along the length of the pulmonary capillary until the partial pressures come into equilibrium
near 105 mmHg.
The functioning of the pressure gradient for carbon dioxide works in reverse of that for oxygen, with
the carbon dioxide partial pressure being higher in the pulmonary arterial blood than in the alveoli.
Even with a much smaller gradient for carbon dioxide than for oxygen, nearly as much carbon
dioxide diffuses from the blood to the alveoli as oxygen diffuses from the alveoli to the blood because
of the much higher solubility of carbon dioxide in the plasma.
Alveolus wall
Capillary wall
Deoxygenated
blood cell
Oxygenated
blood cell
Carbon dioxide
Oxygen
2.2.2 Internal respiration
Internal respiration occurs between the blood and systemic tissues of the body. The systemic arteries
carry essentially the same concentration of oxygen and carbon dioxide as the pulmonary veins.
Oxygen is continually being used by the tissues, and the partial pressure of oxygen in active cells
remains below 40 mmHg. Oxygen circulating in the systemic arterial blood readily diffuses across
the membranes of the blood vessels into the tissues, replenishing the supply of oxygen in the cells.
The final concentration of oxygen and carbon dioxide in the systemic veins is essentially the same
as it is in the pulmonary arteries.
Just as the tissues are continually using up the oxygen, they are continually producing carbon dioxide.
The partial pressure of carbon dioxide in tissues is always greater than 45 mmHg. This accounts for
the diffusion of carbon dioxide into the systemic capillaries, raising the pressure to 45 mmHg.
Blood
Cells
CO
2
O
2
External respiration: pulmonary pO
2
pCO
2
Pulmonary arteries leading to 40 45
capillaries
Alveoli 105 40
Pulmonary veins 100 40
Internal respiration: tissues pO
2
pCO
2
Systemic arteries leading to capillaries 100 40
Metabolically active tissues < 40 > 45
Systemic veins 40 45
differential concentration gradient for oxygen to move from the alveolar air into the capillary blood
s
tarts at about 65 mmHg (105 mmHg in the alveoli minus 40 mmHg in blood), providing enough of
a difference in partial pressures for oxygen to diffuse from the alveoli into the capillary. Diffusion will
occur along the length of the pulmonary capillary until the partial pressures come into equilibrium
near 105 mmHg.
The functioning of the pressure gradient for carbon dioxide works in reverse of that for oxygen, with
the carbon dioxide partial pressure being higher in the pulmonary arterial blood than in the alveoli.
Even with a much smaller gradient for carbon dioxide than for oxygen, nearly as much carbon
dioxide diffuses from the blood to the alveoli as oxygen diffuses from the alveoli to the blood because
of the much higher solubility of carbon dioxide in the plasma.
Alveolus wall
Capillary wall
Deoxygenated
blood cell
Oxygenated
blood cell
Carbon dioxide
Oxygen
2.2.2 Internal respiration
Internal respiration occurs between the blood and systemic tissues of the body. The systemic arteries
carry essentially the same concentration of oxygen and carbon dioxide as the pulmonary veins.
Oxygen is continually being used by the tissues, and the partial pressure of oxygen in active cells
remains below 40 mmHg. Oxygen circulating in the systemic arterial blood readily diffuses across
the membranes of the blood vessels into the tissues, replenishing the supply of oxygen in the cells.
The final concentration of oxygen and carbon dioxide in the systemic veins is essentially the same
as it is in the pulmonary arteries.
Just as the tissues are continually using up the oxygen, they are continually producing carbon dioxide.
The partial pressure of carbon dioxide in tissues is always greater than 45 mmHg. This accounts for
the diffusion of carbon dioxide into the systemic capillaries, raising the pressure to 45 mmHg.
Blood
Cells
CO
2
O
2
External respiration: pulmonary pO
2
pCO
2
Pulmonary arteries leading to 40 45
capillaries
Alveoli 105 40
Pulmonary veins 100 40
Internal respiration: tissues pO
2
pCO
2
Systemic arteries leading to capillaries 100 40
Metabolically active tissues < 40 > 45
Systemic veins 40 45
28
2.3 TRANSPORT OF GASES
H
ere are a few of symbols you will see:
Deoxyhemoglobin (HHb): A hemoglobin molecule that has been reduced and does not
have a full complement of oxygen molecules attached to it.
Oxygen (O
2
): A gas that is required for converting nutrients into cellular energy.
Oxyhemoglobin (HbO
2
): A hemoglobin molecule that has been oxidized and is bound to
four oxygen molecules.
Carbon dioxide (CO
2
): A gas that is released as a waste product during the breakdown of
glucose to release energy.
2,3 bisphosphoglycerate (BPG): It is a molecule found in red blood cells that can bind to
hemoglobin and decrease its affinity for oxygen.
Carbonic acid (H
2
CO
3
): It is formed as an intermediate step in the transportation of carbon
dioxide. Carbonic anhydrase is an enzyme that will speed up the formation of carbonic acid
from water and carbon dioxide.
Bicarbonate (HCO
3
–
): Carbonic acid can quickly convert to bicarbonate and a hydrogen ion.
Bicarbonate plays a huge role in transporting carbon dioxide and maintaining blood pH.
2.3.1 Transport of oxygen
As much oxygen comes in the blood from air, it is approximately 3% dissolved in the blood plasma.
Remaining 97% oxygen combines with hemoglobin to form Oxyhemoglobin. One molecule of
hemoglobin combines with 4 molecules of oxygen. Hemoglobin is made up of 4 units. Every unit of
it, reacts with one molecule of oxygen. 1 gm hemoglobin transports 1.34 ml oxygen. 100 ml (1 dL) of
blood contains normally 15 gm of hemoglobin. So, 100 ml blood transports approximately 20 ml
oxygen. Oxygen does not oxidise hemoglobin. Formation of oxyhemoglobin is a process of
oxygenation. The valency of iron is 2 in oxyhemoglobin. Some gases (eg. ozone) oxidise hemoglobin.
This oxidized hemoglobin is called methemoglobin. This is a colorless compound. This types of
gases are environmental pollutant. At the time, oxyhemoglobin reaches upto the tissues it dissociates.
O
2
freed from it goes into the tissue fluid from blood.
In a conducting cycle blood gives its 25% O
2
to tissues. Dissociation of oxyhemoglobin is affected
by so many factors
Low partial pressure of oxygen: Combination of oxygen with hemoglobin is a reversible
reaction. Low partial pressure of O
2
activates dissociation of oxyhemoglobin.
High concentration of CO
2
: High concentration of CO
2
also activates the dissociation of
oxyhemoglobin. The effect of CO
2
concentration on dissociation of oxyhemoglobin is called
Bohr's effect.
Low pH value of tissue fluid: Acidity activates dissociation of oxyhemoglobin. The effect of
pH on dissociation of oxyhemoglobin is called Root effect.
2.3 TRANSPORT OF GASES
H
ere are a few of symbols you will see:
Deoxyhemoglobin (HHb): A hemoglobin molecule that has been reduced and does not
have a full complement of oxygen molecules attached to it.
Oxygen (O
2
): A gas that is required for converting nutrients into cellular energy.
Oxyhemoglobin (HbO
2
): A hemoglobin molecule that has been oxidized and is bound to
four oxygen molecules.
Carbon dioxide (CO
2
): A gas that is released as a waste product during the breakdown of
glucose to release energy.
2,3 bisphosphoglycerate (BPG): It is a molecule found in red blood cells that can bind to
hemoglobin and decrease its affinity for oxygen.
Carbonic acid (H
2
CO
3
): It is formed as an intermediate step in the transportation of carbon
dioxide. Carbonic anhydrase is an enzyme that will speed up the formation of carbonic acid
from water and carbon dioxide.
Bicarbonate (HCO
3
–
): Carbonic acid can quickly convert to bicarbonate and a hydrogen ion.
Bicarbonate plays a huge role in transporting carbon dioxide and maintaining blood pH.
2.3.1 Transport of oxygen
As much oxygen comes in the blood from air, it is approximately 3% dissolved in the blood plasma.
Remaining 97% oxygen combines with hemoglobin to form Oxyhemoglobin. One molecule of
hemoglobin combines with 4 molecules of oxygen. Hemoglobin is made up of 4 units. Every unit of
it, reacts with one molecule of oxygen. 1 gm hemoglobin transports 1.34 ml oxygen. 100 ml (1 dL) of
blood contains normally 15 gm of hemoglobin. So, 100 ml blood transports approximately 20 ml
oxygen. Oxygen does not oxidise hemoglobin. Formation of oxyhemoglobin is a process of
oxygenation. The valency of iron is 2 in oxyhemoglobin. Some gases (eg. ozone) oxidise hemoglobin.
This oxidized hemoglobin is called methemoglobin. This is a colorless compound. This types of
gases are environmental pollutant. At the time, oxyhemoglobin reaches upto the tissues it dissociates.
O
2
freed from it goes into the tissue fluid from blood.
In a conducting cycle blood gives its 25% O
2
to tissues. Dissociation of oxyhemoglobin is affected
by so many factors
Low partial pressure of oxygen: Combination of oxygen with hemoglobin is a reversible
reaction. Low partial pressure of O
2
activates dissociation of oxyhemoglobin.
High concentration of CO
2
: High concentration of CO
2
also activates the dissociation of
oxyhemoglobin. The effect of CO
2
concentration on dissociation of oxyhemoglobin is called
Bohr's effect.
Low pH value of tissue fluid: Acidity activates dissociation of oxyhemoglobin. The effect of
pH on dissociation of oxyhemoglobin is called Root effect.
29
A graph is plotted between O
2
concentration and percentage saturation of hemoglobin with oxygen
(we get a sigmoid curve), this curve is called dissociation curve. As the concentration of CO
2
increases, saturation of hemoglobin with oxygen decreases. At higher CO
2
concentration, dissociation
curve shifts towards right. This effect is called Bohr's effect.
The meaning of right side shifting of dissociation curve is that, O
2
is readily dissociating from
oxyhemoglobin.
Shift to left means increase in
affinity between O
2
and Hb (which
may be due to
pH, temperature,
CO
2
).
Shift to right means decrease in
affinity between O
2
and Hb. (which
may be due to pH, temperature,
CO
2
).
Hb cannot take up O
2
beyond a
saturation level of 97%. Hb is 50%
saturated with O
2
at 30 mm Hg.
P
50
value - pO
2
at which the Hb is
50% saturated with O
2
. Higher the
P
50
lower is the affinity of Hb for O
2
.
2, 3 diphosphoglycerate (2, 3 DPG)
- a substance formed during
glycolysis.
2,3 DPG will cause shiftt
to right.
Transport of O
2
during strenuous exercise
Normally: 5 ml O
2
/ 100 ml is delivered.
During heavy exercise: Muscle cells
use O
2
at a rapid rate. Interstitial fluid
pO
2
falls as low as 15 mmHg.
Only 4.4 ml O
2
remains bound to Hb.
19.4 - 4.4 = 15 ml O
2
/ 100 ml blood is
delivered to muscle. Also cardiac output
can reach maximum 7 times the (normal) value. Therefore O
2
delivery maximum limit which we can
achieve is 20 - 21 times the normal.
100
90
80
70
60
50
40
30
20
10
0
10 20 30 40 50 60 70 80 90 100
pO (mmHg)
2
O
x
y
h
e
m
o
g
lo
b
in
(
%
s
a
t
u
r
a
t
io
n
)
Decreased temp
Decreased 2-3 DPG
Decreased [H
CO
+
]
Right shift
(reduced affinity)
Increased temp
Increased 2-3 DPG
Increased [H
+
]
HbO dissociation curve
2
19.4 ml O /100 ml
2
Saturation of Hb
with oxygen is 97%
(Artery)
14.4 ml O /100 ml
2
(Vein)
Organ
Saturation of Hb
with oxygen is 75%
A graph is plotted between O
2
concentration and percentage saturation of hemoglobin with oxygen
(we get a sigmoid curve), this curve is called dissociation curve. As the concentration of CO
2
increases, saturation of hemoglobin with oxygen decreases. At higher CO
2
concentration, dissociation
curve shifts towards right. This effect is called Bohr's effect.
The meaning of right side shifting of dissociation curve is that, O
2
is readily dissociating from
oxyhemoglobin.
Shift to left means increase in
affinity between O
2
and Hb (which
may be due to
pH, temperature,
CO
2
).
Shift to right means decrease in
affinity between O
2
and Hb. (which
may be due to pH, temperature,
CO
2
).
Hb cannot take up O
2
beyond a
saturation level of 97%. Hb is 50%
saturated with O
2
at 30 mm Hg.
P
50
value - pO
2
at which the Hb is
50% saturated with O
2
. Higher the
P
50
lower is the affinity of Hb for O
2
.
2, 3 diphosphoglycerate (2, 3 DPG)
- a substance formed during
glycolysis.
2,3 DPG will cause shiftt
to right.
Transport of O
2
during strenuous exercise
Normally: 5 ml O
2
/ 100 ml is delivered.
During heavy exercise: Muscle cells
use O
2
at a rapid rate. Interstitial fluid
pO
2
falls as low as 15 mmHg.
Only 4.4 ml O
2
remains bound to Hb.
19.4 - 4.4 = 15 ml O
2
/ 100 ml blood is
delivered to muscle. Also cardiac output
can reach maximum 7 times the (normal) value. Therefore O
2
delivery maximum limit which we can
achieve is 20 - 21 times the normal.
100
90
80
70
60
50
40
30
20
10
0
10 20 30 40 50 60 70 80 90 100
pO (mmHg)
2
O
x
y
h
e
m
o
g
lo
b
in
(
%
s
a
t
u
r
a
t
io
n
)
Decreased temp
Decreased 2-3 DPG
Decreased [H
CO
+
]
Right shift
(reduced affinity)
Increased temp
Increased 2-3 DPG
Increased [H
+
]
HbO dissociation curve
2
19.4 ml O /100 ml
2
Saturation of Hb
with oxygen is 97%
(Artery)
14.4 ml O /100 ml
2
(Vein)
Organ
Saturation of Hb
with oxygen is 75%
30
2.3.2 Transport of carbon dioxide
C
arbon dioxide is carried in the blood in three forms: dissolved, attached to hemoglobin, and converted
to bicarbonate ions. Dissolved CO
2
accounts for 7 to 10% of the carbon dioxide carried in the blood.
This is also the only form of carbon dioxide that diffuses from the tissues into the blood and from the
blood into the alveoli for expulsion from the body.
Carbaminohemoglobin
Carbon dioxide can bind to any protein and form a carbamate compound. 20 to 23% of the CO
2
carried in the blood is bound to hemoglobin in the form of Carbaminohemoglobin. In the capillaries
of the systemic tissues, CO
2
molecules attach to the terminal amino acids of the alpha and beta
chains of the hemoglobin molecule. Deoxygenated hemoglobin such as that found in metabolically
active tissues, binds CO
2
easily. In the capillaries of the lungs, the elevated levels of oxygen found
in alveoli force the carbon dioxide off the hemoglobin molecule and oxidize the protein, freeing up
hydrogen ions. Although some carbon dioxide is transported as Carbaminohemoglobin, the majority,
about 70%, is dissolved in the blood as bicarbonate ions that arise from the reversible reactions.
Bicarbonate
Carbon dioxide in the presence of water can be reversibly converted to carbonic acid. Carbonic acid is
not very stable and readily dissociates into a hydrogen ion and a bicarbonate ion. Red blood cells
contain an enzyme called carbonic anhydrase (CA), which is capable of facilitating one million reactions
per second per enzyme molecule. Because of the enzyme, most of the CO
2
dissolved in the blood is
quickly converted to carbonic acid which breaks down to form, hydrogen ions, and bicarbonate ions.
77% CO
2
CO
2
7% CO is carried
dissolved in plasma
2
23% CO
2
Tissue
level
70% diffuses inside RBC
CO + H O
2 2 H CO
2 3
C.A.
H CO
2 3
H + HCO
+ –
3
KHbO
2 KHb + O
2
KHb K + Hb
+
H + Hb
+
H.Hb
CO + HHb, NH
2 2 H.Hb.NHCOOH
K + Cl
+ –
KCl
HCO
3
Cl
–
NaCl Na + Cl
+ –
HCO + Na
3
– + NaHCO
3
CO H H HCO
2 2 2 3 3
+ –
(in the presence of CA) + O CO H +
The oxyhemoglobin (HbO
2
) of the erythrocytes is weekly acidic and remains in association with K
+
ions as KHbO
2
. The hydrogen ions (H
+
) released from carbonic acid combine with hemoglobin after
its dissociation from the potassium ions.
2.3.2 Transport of carbon dioxide
C
arbon dioxide is carried in the blood in three forms: dissolved, attached to hemoglobin, and converted
to bicarbonate ions. Dissolved CO
2
accounts for 7 to 10% of the carbon dioxide carried in the blood.
This is also the only form of carbon dioxide that diffuses from the tissues into the blood and from the
blood into the alveoli for expulsion from the body.
Carbaminohemoglobin
Carbon dioxide can bind to any protein and form a carbamate compound. 20 to 23% of the CO
2
carried in the blood is bound to hemoglobin in the form of Carbaminohemoglobin. In the capillaries
of the systemic tissues, CO
2
molecules attach to the terminal amino acids of the alpha and beta
chains of the hemoglobin molecule. Deoxygenated hemoglobin such as that found in metabolically
active tissues, binds CO
2
easily. In the capillaries of the lungs, the elevated levels of oxygen found
in alveoli force the carbon dioxide off the hemoglobin molecule and oxidize the protein, freeing up
hydrogen ions. Although some carbon dioxide is transported as Carbaminohemoglobin, the majority,
about 70%, is dissolved in the blood as bicarbonate ions that arise from the reversible reactions.
Bicarbonate
Carbon dioxide in the presence of water can be reversibly converted to carbonic acid. Carbonic acid is
not very stable and readily dissociates into a hydrogen ion and a bicarbonate ion. Red blood cells
contain an enzyme called carbonic anhydrase (CA), which is capable of facilitating one million reactions
per second per enzyme molecule. Because of the enzyme, most of the CO
2
dissolved in the blood is
quickly converted to carbonic acid which breaks down to form, hydrogen ions, and bicarbonate ions.
77% CO
2
CO
2
7% CO is carried
dissolved in plasma
2
23% CO
2
Tissue
level
70% diffuses inside RBC
CO + H O
2 2 H CO
2 3
C.A.
H CO
2 3
H + HCO
+ –
3
KHbO
2 KHb + O
2
KHb K + Hb
+
H + Hb
+
H.Hb
CO + HHb, NH
2 2 H.Hb.NHCOOH
K + Cl
+ –
KCl
HCO
3
Cl
–
NaCl Na + Cl
+ –
HCO + Na
3
– + NaHCO
3
CO H H HCO
2 2 2 3 3
+ –
(in the presence of CA) + O CO H +
The oxyhemoglobin (HbO
2
) of the erythrocytes is weekly acidic and remains in association with K
+
ions as KHbO
2
. The hydrogen ions (H
+
) released from carbonic acid combine with hemoglobin after
its dissociation from the potassium ions.
31
The majority of bicarbonate ions (HCO
3
–
)
formed within the erythrocytes diffuses out into the plasma
along a concentration gradient. H
+
combine with hemoglobin to form the hemoglobinic acid (H.Hb)
In response, chloride ions (Cl
–
) diffuse from plasma into the erythrocytes to maintain the ionic balance.
Thus, electrochemical neutrality is maintained. This is called Chloride shift or Hamburger
phenomenon. The chloride ions (Cl
–
) inside RBC combine with potassium ions (K
+
) to form potassium
chloride (KCl). Whereas hydrogen carbonate ions (HCO
3
–
) in the plasma combine with Na
+
to form
sodium bicarbonate (NaHCO
3
). Nearly 70% of carbon dioxide is transported from tissues to the
lungs in this form.
Release of carbon dioxide in the alveoli of lung: When the deoxygenated blood reaches the
alveoli of the lung, It contains carbon dioxide as dissolved in plasma, as carbaminohemoglobin, and
as bicarbonate ions in the pulmonary capillaries. The carbon dioxide dissolved in plasma diffuses
into alveoli. Carbaminohemoglobin also splits into carbon dioxide and hemoglobin. For the release
of carbon dioxide from the bicarbonate, a small series of reverse reactions takes place. When the
hemoglobin in the pulmonary blood takes up oxygen, the H
+
is released from it. Then the Cl
–
and
HCO
3
–
ions are released from KCl in RBC, and NaHCO
3
in the plasma, respectively. Then HCO
3
–
reacts with H
+
to form H
2
CO
3
, ultimately, then splits into carbon dioxide and water in the presence of
carbonic anhydrase enzyme and carbon dioxide is released into lungs.
When bicarbonates and carbamino compounds reach in the lungs, then they dissociate. Thus CO
2
is formed. This dissociation is stimulated by oxyhemoglobin. This CO
2
freed from blood goes into
atmosphere. The effect of oxyhemoglobin on the dissociation of these compounds is known as
Haldane-effect. In this reaction oxyhemoglobin acts like a strong acid i.e. it frees H
+
in the medium.
These H
+
combine with bicarbonates and thus their dissociation is stimulated, in this way transportation
of CO
2
is completed.
2.4 RESPIRATORY DISORDERS
A. Bronchial asthma: This is characterized by the spasm of the smooth muscles present in the walls
of the bronchiole. It is generally caused due to the hypersensitivity of the bronchiole to the foreign
substances present in the air passing through it. The symptoms of the disease may be coughing or
difficulty in breathing mainly during expiration. The mucous membranes on the walls of the air passage
start secreting excess amount of mucous, which may clog the bronchi, as well as bronchiole.
B. Bronchitis: It is the inflammation of the bronchi, which is characterized by hypertrophy and hyperplasia
of seromucous gland and goblet cells lining the bronchi. The symptom is regular coughing, with thick
greenish yellow sputum that indicates the underlying infection, resulting into excessive secretion of
mucous. It may also be caused by cigarette smoking and exposure to air pollutants like carbon monoxide.
C. Emphysema: It is an inflation or abnormal distension of the bronchiole or alveolar sac, which
results into the loss of elasticity of these parts. As a result the alveolar sac remains filled with air
even after expiration and ultimately, the lung size increases. The reason for such a condition can be
assigned to cigarette smoking and chronic bronchitis.
The majority of bicarbonate ions (HCO
3
–
)
formed within the erythrocytes diffuses out into the plasma
along a concentration gradient. H
+
combine with hemoglobin to form the hemoglobinic acid (H.Hb)
In response, chloride ions (Cl
–
) diffuse from plasma into the erythrocytes to maintain the ionic balance.
Thus, electrochemical neutrality is maintained. This is called Chloride shift or Hamburger
phenomenon. The chloride ions (Cl
–
) inside RBC combine with potassium ions (K
+
) to form potassium
chloride (KCl). Whereas hydrogen carbonate ions (HCO
3
–
) in the plasma combine with Na
+
to form
sodium bicarbonate (NaHCO
3
). Nearly 70% of carbon dioxide is transported from tissues to the
lungs in this form.
Release of carbon dioxide in the alveoli of lung: When the deoxygenated blood reaches the
alveoli of the lung, It contains carbon dioxide as dissolved in plasma, as carbaminohemoglobin, and
as bicarbonate ions in the pulmonary capillaries. The carbon dioxide dissolved in plasma diffuses
into alveoli. Carbaminohemoglobin also splits into carbon dioxide and hemoglobin. For the release
of carbon dioxide from the bicarbonate, a small series of reverse reactions takes place. When the
hemoglobin in the pulmonary blood takes up oxygen, the H
+
is released from it. Then the Cl
–
and
HCO
3
–
ions are released from KCl in RBC, and NaHCO
3
in the plasma, respectively. Then HCO
3
–
reacts with H
+
to form H
2
CO
3
, ultimately, then splits into carbon dioxide and water in the presence of
carbonic anhydrase enzyme and carbon dioxide is released into lungs.
When bicarbonates and carbamino compounds reach in the lungs, then they dissociate. Thus CO
2
is formed. This dissociation is stimulated by oxyhemoglobin. This CO
2
freed from blood goes into
atmosphere. The effect of oxyhemoglobin on the dissociation of these compounds is known as
Haldane-effect. In this reaction oxyhemoglobin acts like a strong acid i.e. it frees H
+
in the medium.
These H
+
combine with bicarbonates and thus their dissociation is stimulated, in this way transportation
of CO
2
is completed.
2.4 RESPIRATORY DISORDERS
A. Bronchial asthma: This is characterized by the spasm of the smooth muscles present in the walls
of the bronchiole. It is generally caused due to the hypersensitivity of the bronchiole to the foreign
substances present in the air passing through it. The symptoms of the disease may be coughing or
difficulty in breathing mainly during expiration. The mucous membranes on the walls of the air passage
start secreting excess amount of mucous, which may clog the bronchi, as well as bronchiole.
B. Bronchitis: It is the inflammation of the bronchi, which is characterized by hypertrophy and hyperplasia
of seromucous gland and goblet cells lining the bronchi. The symptom is regular coughing, with thick
greenish yellow sputum that indicates the underlying infection, resulting into excessive secretion of
mucous. It may also be caused by cigarette smoking and exposure to air pollutants like carbon monoxide.
C. Emphysema: It is an inflation or abnormal distension of the bronchiole or alveolar sac, which
results into the loss of elasticity of these parts. As a result the alveolar sac remains filled with air
even after expiration and ultimately, the lung size increases. The reason for such a condition can be
assigned to cigarette smoking and chronic bronchitis.
32
D. Chronic Obstructive Pulmonary Disease (COPD): C
hronic obstructive pulmonary disease
(COPD) is a chronic, debilitating disease. COPD is a set of symptoms that can develop as a result
of either chronic bronchitis or emphysema. People with chronic bronchitis constantly produce mucus
in the conducting division in response to inhaled irritants or mild infections emphysema which is
permanent results from the progressive destruction of lung tissue. It is typically a more severe form
of COPD than bronchitis, and may lead to death. The leading cause of both conditions is tobacco
smoke, inhaled as either firsthand or secondhand smoke. Occasionally, emphysema can develop
as a result of exposure to gases or fumes in the workplace. There is a low incidence of COPD
resulting from a deficiency of the protein alpha-1-antitrypsin.
The symptoms of COPD include a cough with or without mucus, fatigue, frequent respiratory
infections, shortness of breath (dyspnea), the inability to catch one’s breath, and wheezing. As the
disease progresses, patients may have more symptoms which can progress in severity. Evaluating
lung sounds and x rays are not necessarily useful in establishing a diagnosis for COPD. Spirometry
and the examination of arterial blood gases to determine the blood concentrations of oxygen and
carbon dioxide provide much better diagnostic tools.
As COPD worsens, blood oxygen levels decrease and blood carbon dioxide level increase. The
decreased oxygen leads to the fatigue, dizziness and decreased activity tolerance these people
often experience. The increase in carbon dioxide can lead to respiratory acidosis, ultimately
contributing to dysfunction in many of the body’s metabolic pathways.
There is no cure for COPD, but medications can help alleviate its effects. Inhalers that cause
bronchodilation and contain steroids to reduce inflammation and mucus secretion are effective in
many cases. Other anti – inflammatory may also help. If the conditions become severe, steroids
can be administered orally or by intravenous methods. Oxygen may be needed, and mechanical
breathing assistance may be used.
E. Occupational lung disease: It is caused because of the exposure to potentially harmful
substances, such as gas, fumes of dusts present in the environment where a person works, silicosis
and asbestosis are the common examples which occur due to chronic exposure of silica and asbestos
dust in the mining industry. It is characterized by fibrosis (proliferation of fibrous connective tissue)
of upper part of lung, causing inflammation.
F. Decompression sickness: During deep sea diving the diver inhales gases at an increased
pressure in depth, as a result the nitrogen also gets dissolved in the blood. When the diver comes
back to the surface, where the pressure has again decreased, the dissolved nitrogen start getting
released from blood in the form of bubbles which cause a number of problems, example air embolism
infarction due to blocked vessel etc.
G. Altitude sickness: Also called acute mountain sickness, can strike people climbing to elevations
above 8000 feet. At elevations high above sea level, there is much less atmospheric pressure which
lowers the partial pressure of the oxygen being inhaled so less oxygen enters the body. If the body
does not adapt well, a person can experience altitude sickness ranging from mild to severe forms.
D. Chronic Obstructive Pulmonary Disease (COPD): C
hronic obstructive pulmonary disease
(COPD) is a chronic, debilitating disease. COPD is a set of symptoms that can develop as a result
of either chronic bronchitis or emphysema. People with chronic bronchitis constantly produce mucus
in the conducting division in response to inhaled irritants or mild infections emphysema which is
permanent results from the progressive destruction of lung tissue. It is typically a more severe form
of COPD than bronchitis, and may lead to death. The leading cause of both conditions is tobacco
smoke, inhaled as either firsthand or secondhand smoke. Occasionally, emphysema can develop
as a result of exposure to gases or fumes in the workplace. There is a low incidence of COPD
resulting from a deficiency of the protein alpha-1-antitrypsin.
The symptoms of COPD include a cough with or without mucus, fatigue, frequent respiratory
infections, shortness of breath (dyspnea), the inability to catch one’s breath, and wheezing. As the
disease progresses, patients may have more symptoms which can progress in severity. Evaluating
lung sounds and x rays are not necessarily useful in establishing a diagnosis for COPD. Spirometry
and the examination of arterial blood gases to determine the blood concentrations of oxygen and
carbon dioxide provide much better diagnostic tools.
As COPD worsens, blood oxygen levels decrease and blood carbon dioxide level increase. The
decreased oxygen leads to the fatigue, dizziness and decreased activity tolerance these people
often experience. The increase in carbon dioxide can lead to respiratory acidosis, ultimately
contributing to dysfunction in many of the body’s metabolic pathways.
There is no cure for COPD, but medications can help alleviate its effects. Inhalers that cause
bronchodilation and contain steroids to reduce inflammation and mucus secretion are effective in
many cases. Other anti – inflammatory may also help. If the conditions become severe, steroids
can be administered orally or by intravenous methods. Oxygen may be needed, and mechanical
breathing assistance may be used.
E. Occupational lung disease: It is caused because of the exposure to potentially harmful
substances, such as gas, fumes of dusts present in the environment where a person works, silicosis
and asbestosis are the common examples which occur due to chronic exposure of silica and asbestos
dust in the mining industry. It is characterized by fibrosis (proliferation of fibrous connective tissue)
of upper part of lung, causing inflammation.
F. Decompression sickness: During deep sea diving the diver inhales gases at an increased
pressure in depth, as a result the nitrogen also gets dissolved in the blood. When the diver comes
back to the surface, where the pressure has again decreased, the dissolved nitrogen start getting
released from blood in the form of bubbles which cause a number of problems, example air embolism
infarction due to blocked vessel etc.
G. Altitude sickness: Also called acute mountain sickness, can strike people climbing to elevations
above 8000 feet. At elevations high above sea level, there is much less atmospheric pressure which
lowers the partial pressure of the oxygen being inhaled so less oxygen enters the body. If the body
does not adapt well, a person can experience altitude sickness ranging from mild to severe forms.
33
TARGET NOTES
Eupnoea: It is the state of normal breathing. In humans, rate of normal breathing is 12 to 16 per
minute. In infants rate of breathing is 44 per minute. Rate of breathing is slowest while sleeping.
Bradypnoea or hyponoea: It is the state of slow breathing.
Tachypnoea or hypernoea: It is the state of fast breathing.
Apnoea: It is the state of stoppage of breathing temporarily.
Dyspnoea: It is the state of discomfort due to difficulty in breathing.
Asphyxia: It is the state of suffocation due to high CO
2
concentration or low O
2
concentration.
Anoxia: It is the absence of O
2
supply to tissues.
Hypocapnoea: It is the state of reduced CO
2
concentration in blood.
Hypercapnoea: It is the state of increased CO
2
concentration in blood
Pathological dead space: If due to disease of circulatory origin the air is filling in the alveolis but
the blood circulation or perfusion in the capillaries of wall of alveoli is absent or low then this air
also gets wasted as there is no blood present to whom it may oxygenate. This amount of air is
pathological dead space. in a normal person this is zero.
Total dead space = Anatomical dead space + pathological dead space.
Alveolar perfusion: The amount of blood that enters the wall of the alveoli via capillaries to
participate in exchange of gases. This is denoted as ‘Q’.
Physiological shunt: Not entire amount of blood which enters the lungs via pulmonary arteries
actually reaches the walls of alveoli. 2% of the total blood actually never passes through the
walls, instead it enters the venule side from arteriole side via the conduction zone in lungs. So
this blood never gets oxygenated. This is shunted blood (2% of total). This means that only 98%
blood which enters the lungs actually gets oxygenated. This phenomenon of bypass of alveoli by
2% of total blood is called as physiological shunt. It is normally present in all human beings.
Pathological shunt: If due to presence of some respiratory disease, alveoli do not get filled up
with air and remain collapse, then blood which passes through the walls of these alveoli does not
get oxygenated. This portion of blood is called pathological shunt. So greater is the pathological
shunt, greater will be the amount of a blood which falls to get oxygenated as it passes through
lungs. The pathological shunt is zero in lungs of normal human beings.
Total shunt = physiological shunt + pathological shunt.
•One molecule of hemoglobin combines with four molecules of carbon monoxide to form
carboxyhemoglobin. Its color is cherry red.
•One molecule of hemoglobin has 4 Fe
++
ions metal. Only one ion of iron metal is present in
myoglobin.
•In normal conditions – frogs show 35% - cutaneous respiration, 9% - buccopharyngeal
respiration and 56% pulmonary respiration.
In frog, sternohyal and mylohyal (petrohyal) muscles are related with the process of respiration.
TARGET NOTES
Eupnoea: It is the state of normal breathing. In humans, rate of normal breathing is 12 to 16 per
minute. In infants rate of breathing is 44 per minute. Rate of breathing is slowest while sleeping.
Bradypnoea or hyponoea: It is the state of slow breathing.
Tachypnoea or hypernoea: It is the state of fast breathing.
Apnoea: It is the state of stoppage of breathing temporarily.
Dyspnoea: It is the state of discomfort due to difficulty in breathing.
Asphyxia: It is the state of suffocation due to high CO
2
concentration or low O
2
concentration.
Anoxia: It is the absence of O
2
supply to tissues.
Hypocapnoea: It is the state of reduced CO
2
concentration in blood.
Hypercapnoea: It is the state of increased CO
2
concentration in blood
Pathological dead space: If due to disease of circulatory origin the air is filling in the alveolis but
the blood circulation or perfusion in the capillaries of wall of alveoli is absent or low then this air
also gets wasted as there is no blood present to whom it may oxygenate. This amount of air is
pathological dead space. in a normal person this is zero.
Total dead space = Anatomical dead space + pathological dead space.
Alveolar perfusion: The amount of blood that enters the wall of the alveoli via capillaries to
participate in exchange of gases. This is denoted as ‘Q’.
Physiological shunt: Not entire amount of blood which enters the lungs via pulmonary arteries
actually reaches the walls of alveoli. 2% of the total blood actually never passes through the
walls, instead it enters the venule side from arteriole side via the conduction zone in lungs. So
this blood never gets oxygenated. This is shunted blood (2% of total). This means that only 98%
blood which enters the lungs actually gets oxygenated. This phenomenon of bypass of alveoli by
2% of total blood is called as physiological shunt. It is normally present in all human beings.
Pathological shunt: If due to presence of some respiratory disease, alveoli do not get filled up
with air and remain collapse, then blood which passes through the walls of these alveoli does not
get oxygenated. This portion of blood is called pathological shunt. So greater is the pathological
shunt, greater will be the amount of a blood which falls to get oxygenated as it passes through
lungs. The pathological shunt is zero in lungs of normal human beings.
Total shunt = physiological shunt + pathological shunt.
•One molecule of hemoglobin combines with four molecules of carbon monoxide to form
carboxyhemoglobin. Its color is cherry red.
•One molecule of hemoglobin has 4 Fe
++
ions metal. Only one ion of iron metal is present in
myoglobin.
•In normal conditions – frogs show 35% - cutaneous respiration, 9% - buccopharyngeal
respiration and 56% pulmonary respiration.
In frog, sternohyal and mylohyal (petrohyal) muscles are related with the process of respiration.
34
1. Oxygen hemoglobin dissociation curve will
shift to right on decrease of
a) Acidity
b) Carbon dioxide concentration
c) Both (a) and (b)
d) pH
2. “ Emphysema” is a condition in which
a) Respiratory center is inhibited
b) Lot of fluid is in the lungs
c) The walls separating the alveoli breaks
d) Lungs have more oxygen
3. Respiratory centre of brain is stimulated by
a) Carbon dioxide content in venous blood
b) Carbon dioxide content in arterial blood
c) Oxygen content in venous blood
d) Oxygen content in arterial blood
4. Which of the following changes (I-IV) usually
tend to occur in the plain dwellers when they
move to high altitudes (3,500 m or more)?
I) Increase in red blood cell size
II) Increase in red blood cell production
III) Increased breathing rate
IV) Increase in thrombocyte count
Changes occurring are
a) II and III b) III and IV
c) I and IV d) I and II
5. Determination of oxygen carried by
hemoglobin is done by
a) pH
b) Partial pressure of oxygen
c) Partial pressure of carbon dioxide
d) All the above
6. What is true about RBCs in humans?
a) They do not carry CO
2
at all
b) They carry about 20 to 25% of CO
2
c) They transport 99.5% of O
2
d) They transport about 80% oxygen only
and the rest 20% of it is transported in
dissolved state in blood plasma
Simple Questions
7. Amount of oxygen present in one gram if
hemoglobin is
a) 20 ml
b) 1.34 ml
c) 13.4 ml
d) None of these
8. During transport of CO
2
blood does not
become acidic due to
a) Neutralisation of H
2
CO
3
by Na
2
CO
3
b) Absorption of leukocytes
c) Blood buffers
d) Non-accumulation
9. If a man from sea coast goes to Everest
mountain peak, his
a) Breathing and heart beat will increase
b) Breathing and heart beat will decrease
c) Respiratory rate will decrease
d) Heart beat will decrease
10. If a reduced oxygen supply weakens the
heart cells but does not actually kill them,
the condition is called
a) Myocardial infarction
b) Tachycardia
c) Bradycardia
d) Ischemia
11. Which of the following statement correctly
defines Bohr’s effect?
a) Rise in P
50
with a decrease in CO
2
concentration
b) Rise in P
50
with a decrease in pH
c) Rise in P
50
with increase in pH
d) Fall in P
50
with a decrease in pH
12. A stage when lung collapsed, especially the
alveoli are
a) Atelectasis
b) Poliomyelitis
c) Asthma
d) Epistaxis
1. Oxygen hemoglobin dissociation curve will
shift to right on decrease of
a) Acidity
b) Carbon dioxide concentration
c) Both (a) and (b)
d) pH
2. “ Emphysema” is a condition in which
a) Respiratory center is inhibited
b) Lot of fluid is in the lungs
c) The walls separating the alveoli breaks
d) Lungs have more oxygen
3. Respiratory centre of brain is stimulated by
a) Carbon dioxide content in venous blood
b) Carbon dioxide content in arterial blood
c) Oxygen content in venous blood
d) Oxygen content in arterial blood
4. Which of the following changes (I-IV) usually
tend to occur in the plain dwellers when they
move to high altitudes (3,500 m or more)?
I) Increase in red blood cell size
II) Increase in red blood cell production
III) Increased breathing rate
IV) Increase in thrombocyte count
Changes occurring are
a) II and III b) III and IV
c) I and IV d) I and II
5. Determination of oxygen carried by
hemoglobin is done by
a) pH
b) Partial pressure of oxygen
c) Partial pressure of carbon dioxide
d) All the above
6. What is true about RBCs in humans?
a) They do not carry CO
2
at all
b) They carry about 20 to 25% of CO
2
c) They transport 99.5% of O
2
d) They transport about 80% oxygen only
and the rest 20% of it is transported in
dissolved state in blood plasma
Simple Questions
7. Amount of oxygen present in one gram if
hemoglobin is
a) 20 ml
b) 1.34 ml
c) 13.4 ml
d) None of these
8. During transport of CO
2
blood does not
become acidic due to
a) Neutralisation of H
2
CO
3
by Na
2
CO
3
b) Absorption of leukocytes
c) Blood buffers
d) Non-accumulation
9. If a man from sea coast goes to Everest
mountain peak, his
a) Breathing and heart beat will increase
b) Breathing and heart beat will decrease
c) Respiratory rate will decrease
d) Heart beat will decrease
10. If a reduced oxygen supply weakens the
heart cells but does not actually kill them,
the condition is called
a) Myocardial infarction
b) Tachycardia
c) Bradycardia
d) Ischemia
11. Which of the following statement correctly
defines Bohr’s effect?
a) Rise in P
50
with a decrease in CO
2
concentration
b) Rise in P
50
with a decrease in pH
c) Rise in P
50
with increase in pH
d) Fall in P
50
with a decrease in pH
12. A stage when lung collapsed, especially the
alveoli are
a) Atelectasis
b) Poliomyelitis
c) Asthma
d) Epistaxis
35
13. Body tissues obtain O
2
from hemoglobin
because of its dissociation in tissues caused
by
a) Low oxygen concentration and high CO
2
concentration
b) High O
2
concentration
c) Low CO
2
concentration
d) High CO
2
concentration
14. Hering Breuer reflex is related to
a) Effect of pH on respiratory center
b) Effect of CO
2
on respiratory center
c) Effect of nerves on respiratory center
d) Effect of temperature on respiratory
center
15. Effect of CO
2
concentration on dissociation
of oxyhemoglobin is called
a) Bohr’s effect
b) Haldane effect
c) Hamburger effect
d) Gaudi Kov’s effect
16. The state, during which the respiratory
center is inhibited, is termed as
a) Asphyxia b) Choking
c) Anoxia d) Suffocation
17. In the process of transport of CO
2
which
phenomenon occurs between RBCs and
plasma
a) Osmosis b) Adsorption
c) Chloride shift d) Absorption
18. Carbonic anhydrase is found in
a) WBC b) RBC
c) Blood plasma d) All
19. The chloride shift is movement of Cl
–
a) From plasma to RBC
b) From WBC to plasma
c) Both
d) None
20. W hen temperature decreases oxy-
hemoglobin curve will become
a) More steep b) Straight
c) Parabola d) None of the above
21. Inflammation of the lung covering causing
severe chest pain in
a) Emphysema b) Pleurisy
c) Asphyxia d) Hypoxia
22. Partial pressure of oxygen in the inspired
and expired air is respectively
a) 158 and 116 mmHg
b) 158 and 40 mmHg
c) 100 and 95 mmHg
d) 40 and 95 mmHg
23. Hamburger’s phenomenon is also called
a) HCO
3
shift b) Chloride shift
c) Hydrogen shift d) None of these
24. After taking a long deep breath, we do not
respire for some seconds due to
a) More CO
2
in blood
b) More O
2
in blood
c) Less CO
2
in blood
d) Less O
2
in blood
25. Increased asthmatic attacks in certain
seasons are related to
a) Hot and humid environment
b) Eating fruits preserved in tin containers
c) Inhalation of seasonal pollen
d) Low temperature
26. All are the disease of lungs except
a) Asthma b) Bronchitis
c) Encephalitis d) Pneumonia
27. When carbon dioxide concentration in blood
increases, breathing becomes
a) Shallower and slow.
b) There is no effect on breathing
c) Slow and deep
d) Faster and deeper
13. Body tissues obtain O
2
from hemoglobin
because of its dissociation in tissues caused
by
a) Low oxygen concentration and high CO
2
concentration
b) High O
2
concentration
c) Low CO
2
concentration
d) High CO
2
concentration
14. Hering Breuer reflex is related to
a) Effect of pH on respiratory center
b) Effect of CO
2
on respiratory center
c) Effect of nerves on respiratory center
d) Effect of temperature on respiratory
center
15. Effect of CO
2
concentration on dissociation
of oxyhemoglobin is called
a) Bohr’s effect
b) Haldane effect
c) Hamburger effect
d) Gaudi Kov’s effect
16. The state, during which the respiratory
center is inhibited, is termed as
a) Asphyxia b) Choking
c) Anoxia d) Suffocation
17. In the process of transport of CO
2
which
phenomenon occurs between RBCs and
plasma
a) Osmosis b) Adsorption
c) Chloride shift d) Absorption
18. Carbonic anhydrase is found in
a) WBC b) RBC
c) Blood plasma d) All
19. The chloride shift is movement of Cl
–
a) From plasma to RBC
b) From WBC to plasma
c) Both
d) None
20. W hen temperature decreases oxy-
hemoglobin curve will become
a) More steep b) Straight
c) Parabola d) None of the above
21. Inflammation of the lung covering causing
severe chest pain in
a) Emphysema b) Pleurisy
c) Asphyxia d) Hypoxia
22. Partial pressure of oxygen in the inspired
and expired air is respectively
a) 158 and 116 mmHg
b) 158 and 40 mmHg
c) 100 and 95 mmHg
d) 40 and 95 mmHg
23. Hamburger’s phenomenon is also called
a) HCO
3
shift b) Chloride shift
c) Hydrogen shift d) None of these
24. After taking a long deep breath, we do not
respire for some seconds due to
a) More CO
2
in blood
b) More O
2
in blood
c) Less CO
2
in blood
d) Less O
2
in blood
25. Increased asthmatic attacks in certain
seasons are related to
a) Hot and humid environment
b) Eating fruits preserved in tin containers
c) Inhalation of seasonal pollen
d) Low temperature
26. All are the disease of lungs except
a) Asthma b) Bronchitis
c) Encephalitis d) Pneumonia
27. When carbon dioxide concentration in blood
increases, breathing becomes
a) Shallower and slow.
b) There is no effect on breathing
c) Slow and deep
d) Faster and deeper
36
28. B
unusually high quantity of
carboxyhemoglobin content. Which of the
following conclusions is most likely to be
correct? The patient has been inhaling
polluted air containing usually high content
of
a) Carbon disulphide
b) Chloroform
c) Carbon dioxide
d) Carbon monoxide
29. Carbon monoxide prevents transport of
oxygen by
a) Forming stable compound with
hemoglobin
b) Destroying hemoglobin
c) Forming carbon dioxide with oxygen
d) Destroying RBCs
30. CO
2
is carried in blood in physical solution,
in the form of carbaminohemoglobin and in
the form of HCO
3
–
, the proportion of CO
2
in
different forms respectively is
a) 5%, 10%, 85% b) 5%, 85%, 10%
c) 85%, 5%, 10% d) 10%, 85%, 5%
31. In rabbit respiration takes place in
a) Cells lining the lungs cavity
b) Cells found in blood
c) All living cells of the body
d) Only RBC
32. Asthma is a respiratory disease caused due
to
a) Infection of trachea
b) Infection of lungs
c) Bleeding into pleural cavity
d) Spasm in bronchial muscles
33. Low O
2
concentration causes
a) Emphysema
b) Pleurisy
c) Asphyxia
d) Hypoxia
34. In fever breathing rate
a) Increases
b) Decreases
c) Stop
d) None
Difficult Questions
1. What is true about hemoglobin?
a) It is a dipeptide and present in red blood
corpuscles in blood warm.
b) It is present in the dissolved state in
blood plasma in earthworm.
c) It is a dipeptide in mammals and
localized in red blood corpuscles.
d) It is present in dissolved state in blood
plasma in scorpions.
2. Which one of the following is the correct
statement for respiration in humans?
a) Cigarette smoking may lead to
inflammation of bronchi.
b) Neural signals from penumotoxic center
in pons region of brain can increase the
duration of inspiration.
c) Workers in grinding and stone breaking
industries may suffer, from lung fibrosis.
d) About 90% of CO
2
is carried
by hemoglobin as Carbamino-
hemoglobin.
28. B
unusually high quantity of
carboxyhemoglobin content. Which of the
following conclusions is most likely to be
correct? The patient has been inhaling
polluted air containing usually high content
of
a) Carbon disulphide
b) Chloroform
c) Carbon dioxide
d) Carbon monoxide
29. Carbon monoxide prevents transport of
oxygen by
a) Forming stable compound with
hemoglobin
b) Destroying hemoglobin
c) Forming carbon dioxide with oxygen
d) Destroying RBCs
30. CO
2
is carried in blood in physical solution,
in the form of carbaminohemoglobin and in
the form of HCO
3
–
, the proportion of CO
2
in
different forms respectively is
a) 5%, 10%, 85% b) 5%, 85%, 10%
c) 85%, 5%, 10% d) 10%, 85%, 5%
31. In rabbit respiration takes place in
a) Cells lining the lungs cavity
b) Cells found in blood
c) All living cells of the body
d) Only RBC
32. Asthma is a respiratory disease caused due
to
a) Infection of trachea
b) Infection of lungs
c) Bleeding into pleural cavity
d) Spasm in bronchial muscles
33. Low O
2
concentration causes
a) Emphysema
b) Pleurisy
c) Asphyxia
d) Hypoxia
34. In fever breathing rate
a) Increases
b) Decreases
c) Stop
d) None
Difficult Questions
1. What is true about hemoglobin?
a) It is a dipeptide and present in red blood
corpuscles in blood warm.
b) It is present in the dissolved state in
blood plasma in earthworm.
c) It is a dipeptide in mammals and
localized in red blood corpuscles.
d) It is present in dissolved state in blood
plasma in scorpions.
2. Which one of the following is the correct
statement for respiration in humans?
a) Cigarette smoking may lead to
inflammation of bronchi.
b) Neural signals from penumotoxic center
in pons region of brain can increase the
duration of inspiration.
c) Workers in grinding and stone breaking
industries may suffer, from lung fibrosis.
d) About 90% of CO
2
is carried
by hemoglobin as Carbamino-
hemoglobin.
37
3. The apparatus shown is used to investigate
gas exchange during breathing:
M
T
Limewater
solution
X Y
Which one of the following would occur
when a person blows through tube M?
a) The solution in X and Y both turns cloudy
b) The solution in X remains clear, but that
in Y turns cloudy
c) The solution in X turns cloudy, but that
in Y remains clear
d) The solution in X is forced out through
the tube T
4. During strenuous exercise, which of the
following change occurs?
a) Glucose is converted into glycogen
b) Glucose is converted into pyruvic acid
c) Starch is converted into glucose
d) Pyruvic acid is converted into lactic acid
5. Complete bronchus obstruction results in
a) Collapse of the portion of the lung
supplied by the bronchus
b) A rise in intrapleural pressure on the
affected side
c) An increase in physiological dead space.
d) Vasodilation of alveoli supplied by the
bronchus
6. The compound soluble in water but does
not impede the oxygen transportation is
a) SO
3
b) SO
2
c) NO d) CO
7. For proper transport of O
2
and CO
2
blood
should be
a) Slightly acidic b) Strongly acidic
c) Strongly alkaline d) Slightly alkaline
8. What would happen when blood is acidic?
a) Binding of oxygen with hemoglobin
increases
b) Red blood corpuscles are formed in
higher number
c) Binding of oxygen with hemoglobin
decreases
d) There is no change in oxygen binding
nor number of RBC
9. Intra-aortic balloon pump is inflated by
a) Hydrogen b) Oxygen
c) Helium d) Chlorine
10. The ‘blue baby’ syndrome results from
a) Excess of dissolved oxygen
b) Excess of TDS (total dissolved solids)
c) Excess of chloride
d) Methemoglobin
11. Which of the following statement is / are
correct?
1) A high concentration of carbonic
anhydrase is present in RBC
2) Minute quantities of carbonic anhydrase
are present in plasma.
3) Every 100 ml blood deliv ers
approximately 4 ml of CO
2
to the alveoli.
4) 20 to 25% CO
2
is carried by hemoglobin
as carbaminohemoglobin.
a) 1, 3 and 4 b) 1 and 4
c) 1, 2, 3 and 4 d) Only 1
12. W hich of the following can cause
atelectasis?
a) Blockage of small bronchi with mucus.
b) Obstruction of major bronchus.
c) Lack of surfactant in fluids lining the
alveoli
d) All of the above
3. The apparatus shown is used to investigate
gas exchange during breathing:
M
T
Limewater
solution
X Y
Which one of the following would occur
when a person blows through tube M?
a) The solution in X and Y both turns cloudy
b) The solution in X remains clear, but that
in Y turns cloudy
c) The solution in X turns cloudy, but that
in Y remains clear
d) The solution in X is forced out through
the tube T
4. During strenuous exercise, which of the
following change occurs?
a) Glucose is converted into glycogen
b) Glucose is converted into pyruvic acid
c) Starch is converted into glucose
d) Pyruvic acid is converted into lactic acid
5. Complete bronchus obstruction results in
a) Collapse of the portion of the lung
supplied by the bronchus
b) A rise in intrapleural pressure on the
affected side
c) An increase in physiological dead space.
d) Vasodilation of alveoli supplied by the
bronchus
6. The compound soluble in water but does
not impede the oxygen transportation is
a) SO
3
b) SO
2
c) NO d) CO
7. For proper transport of O
2
and CO
2
blood
should be
a) Slightly acidic b) Strongly acidic
c) Strongly alkaline d) Slightly alkaline
8. What would happen when blood is acidic?
a) Binding of oxygen with hemoglobin
increases
b) Red blood corpuscles are formed in
higher number
c) Binding of oxygen with hemoglobin
decreases
d) There is no change in oxygen binding
nor number of RBC
9. Intra-aortic balloon pump is inflated by
a) Hydrogen b) Oxygen
c) Helium d) Chlorine
10. The ‘blue baby’ syndrome results from
a) Excess of dissolved oxygen
b) Excess of TDS (total dissolved solids)
c) Excess of chloride
d) Methemoglobin
11. Which of the following statement is / are
correct?
1) A high concentration of carbonic
anhydrase is present in RBC
2) Minute quantities of carbonic anhydrase
are present in plasma.
3) Every 100 ml blood deliv ers
approximately 4 ml of CO
2
to the alveoli.
4) 20 to 25% CO
2
is carried by hemoglobin
as carbaminohemoglobin.
a) 1, 3 and 4 b) 1 and 4
c) 1, 2, 3 and 4 d) Only 1
12. W hich of the following can cause
atelectasis?
a) Blockage of small bronchi with mucus.
b) Obstruction of major bronchus.
c) Lack of surfactant in fluids lining the
alveoli
d) All of the above
38
13. At what pCO
2
death may occur?
a) 50 mm Hg
b) 100 to 150 mm Hg
c) > 500 mm Hg
d) Does not occur at any pCO
2
14. Mark the incorrect statement
a) Respiratory centers are found in medulla
oblongata
b) Near lungs Cl
-
moves out of the RBC
c) RBC of deoxygenated blood are slightly
bigger than that of oxygenated blood
d) None of the above
15. A large proportion of oxygen is left unused
in the human blood even after its uptake by
the body tissues. This O
2
a) Raises the pCO
2
of blood to 75 mm of
Hg
b) Is enough to keep oxyhemoglobin
c) Helps in releasing more O
2
to the
epithelial tissues
d) Acts as a reserve during muscular
exercises
16. The decompression sickness is
a) Respiration under depression
b) Sickness develops after coming over the
sea surface from a great depth
c) Sickness develops after attaining a high
altitude
d) Sickness develops after coming on earth
surface from the mines
17. Combination of hemoglobin with oxygen in
lungs can be promoted by
a) Increasing carbon dioxide concentration
in blood
b) Increasing oxygen concentration in
blood
c) Decreasing oxygen concentration in
blood
d) Introducing carbon monoxide in blood
18. After fast running, man has fast heart beat,
slow pulse and shallow breathing, in such
conditions, he has
a) Oxygen debt
b) Poisoning due to lactic acid
c) No pulmonary pressure
d) Weak heart
19. Oxyhemoglobin dissociates into oxygen and
deoxyhemoglobin at
a) Low oxygen pressure in tissues
b) High oxygen pressure in tissue
c) Equal oxygen pressure inside and
outside tissue
d) All times irrespective of oxygen pressure
20. When blood CO
2
level rises
a) Only the rate of breathing decreases
b) Respiratory acidosis may occur
c) Peripheral pressure receptors respond
d) Both the rate and depth of breathing
decrease
21. What is incorrect about oxygen binding with
hemoglobin?
a) The bond between oxygen and
hemoglobin is very loose
b) Oxygen becomes ionic when it binds to
hemoglobin
c) Hb and oxygen is readily reversible
combinations
d) None of the above
22. Minimum concentration and pressure of CO
in alveoli of lungs that would be dangerous
to man
a) 1%, 0 – 7 mm Hg
b) 0 – 4%, 0 – 7 mm Hg
c) 2 – 7%, 0 – 4 mm Hg
d) 0 – 3%, 0 – 4 mm Hg
13. At what pCO
2
death may occur?
a) 50 mm Hg
b) 100 to 150 mm Hg
c) > 500 mm Hg
d) Does not occur at any pCO
2
14. Mark the incorrect statement
a) Respiratory centers are found in medulla
oblongata
b) Near lungs Cl
-
moves out of the RBC
c) RBC of deoxygenated blood are slightly
bigger than that of oxygenated blood
d) None of the above
15. A large proportion of oxygen is left unused
in the human blood even after its uptake by
the body tissues. This O
2
a) Raises the pCO
2
of blood to 75 mm of
Hg
b) Is enough to keep oxyhemoglobin
c) Helps in releasing more O
2
to the
epithelial tissues
d) Acts as a reserve during muscular
exercises
16. The decompression sickness is
a) Respiration under depression
b) Sickness develops after coming over the
sea surface from a great depth
c) Sickness develops after attaining a high
altitude
d) Sickness develops after coming on earth
surface from the mines
17. Combination of hemoglobin with oxygen in
lungs can be promoted by
a) Increasing carbon dioxide concentration
in blood
b) Increasing oxygen concentration in
blood
c) Decreasing oxygen concentration in
blood
d) Introducing carbon monoxide in blood
18. After fast running, man has fast heart beat,
slow pulse and shallow breathing, in such
conditions, he has
a) Oxygen debt
b) Poisoning due to lactic acid
c) No pulmonary pressure
d) Weak heart
19. Oxyhemoglobin dissociates into oxygen and
deoxyhemoglobin at
a) Low oxygen pressure in tissues
b) High oxygen pressure in tissue
c) Equal oxygen pressure inside and
outside tissue
d) All times irrespective of oxygen pressure
20. When blood CO
2
level rises
a) Only the rate of breathing decreases
b) Respiratory acidosis may occur
c) Peripheral pressure receptors respond
d) Both the rate and depth of breathing
decrease
21. What is incorrect about oxygen binding with
hemoglobin?
a) The bond between oxygen and
hemoglobin is very loose
b) Oxygen becomes ionic when it binds to
hemoglobin
c) Hb and oxygen is readily reversible
combinations
d) None of the above
22. Minimum concentration and pressure of CO
in alveoli of lungs that would be dangerous
to man
a) 1%, 0 – 7 mm Hg
b) 0 – 4%, 0 – 7 mm Hg
c) 2 – 7%, 0 – 4 mm Hg
d) 0 – 3%, 0 – 4 mm Hg
39
23. If a large number of people are enclosed in
a room, then
a) Oxygen decreases and carbon dioxide
increases
b) Oxygen increases and carbon dioxide
decreases
c) Both oxygen and carbon dioxide
decreases
d) Both Oxygen and carbon dioxide
increases
24. Rate of respiration is directly affected by
a) CO
2
concentration
b) O
2
in trachea
c) Concentration of O
2
d) Diaphragm expansion
25. Diffusion of gases along the respiratory
surface occurs because
a) pCO
2
is more in alveoli than blood
b) pO
2
is more in alveoli than blood
c) pCO
2
is more in blood than in tissues
d) pO
2
is more in blood than in tissues
26. Ratio of oxyhemoglobin and hemoglobin in
blood is based upon
a) Oxygen tension
b) Carbon dioxide tension
c) Carbonate tension
d) Bicarbonate tension
27. Artificial respiration at the rate of 10 to 15
times per minute is being given to a man
saved from drowning. This is because
a) The water in the respiratory passage is
cleared fast at this rate
b) It is the normal rate of breathing
c) Choking is least at this rate
d) The lungs are ventilated best at this rate
28. W hich f orms stable compound with
hemoglobin?
a) O
2
b) CO
2
c) CO
d) All
29. Iron free compound of hemoglobin is
a) Hemotoxin
b) Bilirubin
c) Haematin
d) Globin
30. The diabetic patient shows
a) High respiratory quotient
b) Low respiratory quotient
c) Zero respiratory quotient
d) None of the above
ANSWER KEYS
Simple Questions
1.d 2.c 3.b 4.a 5.d 6.b 7.b 8.c 9.a 10.d 11.a 12.a
13.a 14.c 15.a 16.c 17.c 18.b 19.a 20.a 21.b 22.a 23.b 24.c
25.c 26.c 27.d 28.d 29.a 30.a 31.c 32.d 33.c 34.a
Difficult Questions
1.c 2.c 3.b 4.d 5.a 6.b 7.d 8.c 9.c 10.d 11.c 12.d
13.b 14.d 15.d 16.b 17.c 18.a 19.a 20.b 21.b 22.a 23.a 24.a
25.b 26.a 27.a 28.c 29.d 30.b
23. If a large number of people are enclosed in
a room, then
a) Oxygen decreases and carbon dioxide
increases
b) Oxygen increases and carbon dioxide
decreases
c) Both oxygen and carbon dioxide
decreases
d) Both Oxygen and carbon dioxide
increases
24. Rate of respiration is directly affected by
a) CO
2
concentration
b) O
2
in trachea
c) Concentration of O
2
d) Diaphragm expansion
25. Diffusion of gases along the respiratory
surface occurs because
a) pCO
2
is more in alveoli than blood
b) pO
2
is more in alveoli than blood
c) pCO
2
is more in blood than in tissues
d) pO
2
is more in blood than in tissues
26. Ratio of oxyhemoglobin and hemoglobin in
blood is based upon
a) Oxygen tension
b) Carbon dioxide tension
c) Carbonate tension
d) Bicarbonate tension
27. Artificial respiration at the rate of 10 to 15
times per minute is being given to a man
saved from drowning. This is because
a) The water in the respiratory passage is
cleared fast at this rate
b) It is the normal rate of breathing
c) Choking is least at this rate
d) The lungs are ventilated best at this rate
28. W hich f orms stable compound with
hemoglobin?
a) O
2
b) CO
2
c) CO
d) All
29. Iron free compound of hemoglobin is
a) Hemotoxin
b) Bilirubin
c) Haematin
d) Globin
30. The diabetic patient shows
a) High respiratory quotient
b) Low respiratory quotient
c) Zero respiratory quotient
d) None of the above
ANSWER KEYS
Simple Questions
1.d 2.c 3.b 4.a 5.d 6.b 7.b 8.c 9.a 10.d 11.a 12.a
13.a 14.c 15.a 16.c 17.c 18.b 19.a 20.a 21.b 22.a 23.b 24.c
25.c 26.c 27.d 28.d 29.a 30.a 31.c 32.d 33.c 34.a
Difficult Questions
1.c 2.c 3.b 4.d 5.a 6.b 7.d 8.c 9.c 10.d 11.c 12.d
13.b 14.d 15.d 16.b 17.c 18.a 19.a 20.b 21.b 22.a 23.a 24.a
25.b 26.a 27.a 28.c 29.d 30.b
40
1. A
arterial blood while passing through the
tissues is
a) 0.4 to 0.6 ml b) 4 to 6 ml
c) 14 to 15 ml d) 19 to 20 ml
2. Which of the following is correct in mmHg?
Alveoli Deoxyge- Tissue
nated blood
a) pO
2
= 159 pCO
2
= 40 pCO
2
= 20
b) pCO
2
= 40 pO
2
= 95 pO
2
= 40
c) pO
2
= 104 pCO
2
= 45 pCO
2
= 45
d) pO
2
= 40 pO
2
= 40 pCO
2
= 45
3. During rest, the metabolic needs of the body
are at their minimum. Which of the following
is indicative of this situation?
a) Rate of breathing
b) Pulse rate
c) O
2
intake and CO
2
output
d) All of these
4. Which of the following factors raise the P
50
value and shifts the HbO
2
dissociation curve
to right and vice versa?
1) Rise in pCO
2
2) Fall in temperature
3) Raise in H
+
(fall in pH)
4) Fall in diphosphoglyceric acid
a) 1 and 2 are correct
b) 2 and 4 are correct
c) 1 and 3 are correct
d) 1, 2 and 3 are correct
5. If O
2
concentration in tissues was almost
as high as at the respiratory surface then
a) Oxyhemoglobin would dissociate to
supply to the tissue
b) Hemoglobin would combine with more
O
2
at respiratory surface
c) Oxyhemoglobin would not dissociate to
supply O
2
to the tissue
d) CO
2
will interfere the O
2
transport
DPP - 2
6. People living at sea level have around 5
million RBCs per cubic millimeter of their
blood, whereas those living at an altitude of
5400 m have around 8 million. This is
because at high altitude
a) People get pollution free air to breath and
more oxygen available
b) Atmospheric oxygen level is less and
hence, more RBCs are needed to
absorb the required amount of O
2
to
survive
c) There is more UV radiation, which
enhances RBC production
d) People eat more nutritive food, therefore,
more RBCs are formed
7. People who have migrated from the planes
to an area adjoining Rohtang pass about
six months back
a) Have more RBCs and their Hb has a
lower binding affinity to O
2
b) Are not physically fit to play games like
football
c) Suffer from altitude sickness with
symptoms like nausea, fatigue etc
d) Have the usual RBC count, but their Hb
has very high binding affinity to O
2
8. Ratio of oxyhemoglobin and hemoglobin in
the blood is based upon
a) Bicarbonate tension
b) Carbon dioxide tension
c) Carbonate tension
d) Oxygen tension
9. A chemosensitive area is situated adjacent
to respiratory rhythm center. Which is highly
sensitive to _____ and ______ ions?
a) O
2
, H
+
b) CO
2
, OH
-
c) CO
2
, H
+
d) CO
2
, O
2
10. O
2
dissociation curve is
a) Sigmoid b) Parabolic
c) Hyperbolic d) Straight line
1. A
arterial blood while passing through the
tissues is
a) 0.4 to 0.6 ml b) 4 to 6 ml
c) 14 to 15 ml d) 19 to 20 ml
2. Which of the following is correct in mmHg?
Alveoli Deoxyge- Tissue
nated blood
a) pO
2
= 159 pCO
2
= 40 pCO
2
= 20
b) pCO
2
= 40 pO
2
= 95 pO
2
= 40
c) pO
2
= 104 pCO
2
= 45 pCO
2
= 45
d) pO
2
= 40 pO
2
= 40 pCO
2
= 45
3. During rest, the metabolic needs of the body
are at their minimum. Which of the following
is indicative of this situation?
a) Rate of breathing
b) Pulse rate
c) O
2
intake and CO
2
output
d) All of these
4. Which of the following factors raise the P
50
value and shifts the HbO
2
dissociation curve
to right and vice versa?
1) Rise in pCO
2
2) Fall in temperature
3) Raise in H
+
(fall in pH)
4) Fall in diphosphoglyceric acid
a) 1 and 2 are correct
b) 2 and 4 are correct
c) 1 and 3 are correct
d) 1, 2 and 3 are correct
5. If O
2
concentration in tissues was almost
as high as at the respiratory surface then
a) Oxyhemoglobin would dissociate to
supply to the tissue
b) Hemoglobin would combine with more
O
2
at respiratory surface
c) Oxyhemoglobin would not dissociate to
supply O
2
to the tissue
d) CO
2
will interfere the O
2
transport
DPP - 2
6. People living at sea level have around 5
million RBCs per cubic millimeter of their
blood, whereas those living at an altitude of
5400 m have around 8 million. This is
because at high altitude
a) People get pollution free air to breath and
more oxygen available
b) Atmospheric oxygen level is less and
hence, more RBCs are needed to
absorb the required amount of O
2
to
survive
c) There is more UV radiation, which
enhances RBC production
d) People eat more nutritive food, therefore,
more RBCs are formed
7. People who have migrated from the planes
to an area adjoining Rohtang pass about
six months back
a) Have more RBCs and their Hb has a
lower binding affinity to O
2
b) Are not physically fit to play games like
football
c) Suffer from altitude sickness with
symptoms like nausea, fatigue etc
d) Have the usual RBC count, but their Hb
has very high binding affinity to O
2
8. Ratio of oxyhemoglobin and hemoglobin in
the blood is based upon
a) Bicarbonate tension
b) Carbon dioxide tension
c) Carbonate tension
d) Oxygen tension
9. A chemosensitive area is situated adjacent
to respiratory rhythm center. Which is highly
sensitive to _____ and ______ ions?
a) O
2
, H
+
b) CO
2
, OH
-
c) CO
2
, H
+
d) CO
2
, O
2
10. O
2
dissociation curve is
a) Sigmoid b) Parabolic
c) Hyperbolic d) Straight line
41
3.1 BODY FLUIDS AND CELL’S ENVIRONMENT
C
ell, tissue and organs are
immersed in body fluids which
make sure that all the cells has
the right assortment of
nutrients, ions, etc.
Body keep both cells and the
fluid surrounding the cells in a
dynamically stable environment
via a process called
homeostasis.
3.2 WATER
About 60% of the body is water.
– Blood is 83% water.
– Muscle is 75% water.
– Brain is 74% water.
– Bone is 22% water.
Total body water depend on amount of
fat in the body.
– Obese animal can have as low as 45%
TBF.
– Lean animal can have as high as 70%
TBF.
2/3 of total body water (i.e. 40% of TBW)
is found within cells so we refer to it as
intracellular fluid (ICF).
The other 1/3 (i.e. 20% of TBW) is
outside cells so we call it extracellular
fluid (ECF).
The 3 main types of ECF are:
i) The fluid that surrounds the cells –
the tissue fluid or interstitial fluid
(ISF) (~ 15% of TBW).
UNIT 3 - BODY FLUIDS
Regulates body
temperature
Lubricates joints
Lessens the burden on the kidneys and liver by flushing out waste products
Carries nutrients and oxygen to cells
Moistens tissues such as those in the mouth,
eyes and nose
Protects body organs
and tissues
Helps prevent constipation
Helps dissolve minerals and other nutrients to make them accessible to the body
Function of body fluid
Composition of human body
Substance Male Female
Water 62 59
Protein 18 15
Lipid 14 20
Carbohydrates 1 1
Other (electrolytes, 5 5
nucleic acids)
IVF ISF ICF
Water
Proteins
Capillary wall Cell membrane
WaterWater
Urea UreaUrea
GlucoseGlucose
Na
+
Na
+
3.1 BODY FLUIDS AND CELL’S ENVIRONMENT
C
ell, tissue and organs are
immersed in body fluids which
make sure that all the cells has
the right assortment of
nutrients, ions, etc.
Body keep both cells and the
fluid surrounding the cells in a
dynamically stable environment
via a process called
homeostasis.
3.2 WATER
About 60% of the body is water.
– Blood is 83% water.
– Muscle is 75% water.
– Brain is 74% water.
– Bone is 22% water.
Total body water depend on amount of
fat in the body.
– Obese animal can have as low as 45%
TBF.
– Lean animal can have as high as 70%
TBF.
2/3 of total body water (i.e. 40% of TBW)
is found within cells so we refer to it as
intracellular fluid (ICF).
The other 1/3 (i.e. 20% of TBW) is
outside cells so we call it extracellular
fluid (ECF).
The 3 main types of ECF are:
i) The fluid that surrounds the cells –
the tissue fluid or interstitial fluid
(ISF) (~ 15% of TBW).
UNIT 3 - BODY FLUIDS
Regulates body
temperature
Lubricates joints
Lessens the burden on the kidneys and liver by flushing out waste products
Carries nutrients and oxygen to cells
Moistens tissues such as those in the mouth,
eyes and nose
Protects body organs
and tissues
Helps prevent constipation
Helps dissolve minerals and other nutrients to make them accessible to the body
Function of body fluid
Composition of human body
Substance Male Female
Water 62 59
Protein 18 15
Lipid 14 20
Carbohydrates 1 1
Other (electrolytes, 5 5
nucleic acids)
IVF ISF ICF
Water
Proteins
Capillary wall Cell membrane
WaterWater
Urea UreaUrea
GlucoseGlucose
Na
+
Na
+
42
ii) T
intravascular fluid (IVF) (~5% of TBW).
iii) The fluid in body cavities – the transcellular fluid (TCF) (<1% of TBW).
– Cerebrospinal fluid (CSF)
– Intraocular fluid.
– Fluid in digestive tract.
Ion compositon of body fluids
Interstitium
Cations Anions Cations
Cytosol
Anions
Na
+
CI
–
Ca , Mg
2+ 2+
HCO
3
–
K
+
Proteins, phosphates,
etc.
K
+
Proteins
–
Ca , Mg
2+ 2+
Na
+
Misc
HCO
3 –
Inorganic
phospate
Water balance: Body must gain water to balance the lost water.
Water turnover: Amount of water gained by body to balance that which is lost.
Water requirement depend on: Caloric expenditure, basal metabolism condition, body surface
area.
mval/L (mmol/L)
Ion Plasma Serum Interstitium Cytosol
Na
+
142 153 145 ca. 12
K
+
4.3 4.6 4.4 ca. 140
Free Ca
2+
2.6 (1.3*) 2.8 (1.3) 2.5 (1.5) <0.001
Free Mg
2+
1.0 (0.5**) 1.0 (0.5) 0.9 (0.45) 1.6
Sum 150 162 153 ca. 152
CI
–
104 112 117 ca. 3
HCO
3
–
24 36 27 10
Inorganic phosphate 2 2.2 2.3 ca. 30
Proteins 14 15 0.4 ca. 54
Misc. 5.9 6.3 6.2 ca. 54
Sum 150 162 153 ca. 152
*) Total plasma Ca: 2.5 mmol/L; **) Total plasma Mg: 0.9 mmol/L
AnionsCations
ii) T
intravascular fluid (IVF) (~5% of TBW).
iii) The fluid in body cavities – the transcellular fluid (TCF) (<1% of TBW).
– Cerebrospinal fluid (CSF)
– Intraocular fluid.
– Fluid in digestive tract.
Ion compositon of body fluids
Interstitium
Cations Anions Cations
Cytosol
Anions
Na
+
CI
–
Ca , Mg
2+ 2+
HCO
3
–
K
+
Proteins, phosphates,
etc.
K
+
Proteins
–
Ca , Mg
2+ 2+
Na
+
Misc
HCO
3 –
Inorganic
phospate
Water balance: Body must gain water to balance the lost water.
Water turnover: Amount of water gained by body to balance that which is lost.
Water requirement depend on: Caloric expenditure, basal metabolism condition, body surface
area.
mval/L (mmol/L)
Ion Plasma Serum Interstitium Cytosol
Na
+
142 153 145 ca. 12
K
+
4.3 4.6 4.4 ca. 140
Free Ca
2+
2.6 (1.3*) 2.8 (1.3) 2.5 (1.5) <0.001
Free Mg
2+
1.0 (0.5**) 1.0 (0.5) 0.9 (0.45) 1.6
Sum 150 162 153 ca. 152
CI
–
104 112 117 ca. 3
HCO
3
–
24 36 27 10
Inorganic phosphate 2 2.2 2.3 ca. 30
Proteins 14 15 0.4 ca. 54
Misc. 5.9 6.3 6.2 ca. 54
Sum 150 162 153 ca. 152
*) Total plasma Ca: 2.5 mmol/L; **) Total plasma Mg: 0.9 mmol/L
AnionsCations
43
Metabolic water: Water derived from metabolic reactions in cell. 100 g of protein, carbohydrate
and fat yield 40, 60 and 110 ml of water
Failure of water balance
Dehydration:
– Occur when water losses exceed water gain.
– Mild – thirst mechanism re-establish the water balance.
– Moderate to severe (>10% of body weight) – therapy required.
During dehydration
– Immediate source of water – ECF.
– Kidney also excrete electrolyte and ions to maintain the osmolarity.
– So, rehydration requires not only water but also electrolytes.
Kinds of electrolytes
Acid: Carbonic acid, hydrochloric acid, acetic acid, phosphoric acid.
Base: Sodium hydroxide, potassium hydroxide, magnesium hydroxide, aluminum hydroxide.
Salt: Sodium chloride, aluminum chloride, magnesium sulphate.
TARGET POINTS
It is because of the more limited reserves (e.g. ECF) associated with their relatively higher needs
that young baby become distressed more quickly in conditions of uncontrolled water loss (e.g.
Diarrhea).
Adaptation to water lack
Camel, sheep, donkey etc.
– Can endure dehydration ~ 30% of their body weight (other animal ~ 10%).
– Can drink ~ 25% of their body weight at one time without any harmful effect.
– Excrete dry feces and concentrated urine.
– Metabolic water from stored fat.
Metabolic water: Water derived from metabolic reactions in cell. 100 g of protein, carbohydrate
and fat yield 40, 60 and 110 ml of water
Failure of water balance
Dehydration:
– Occur when water losses exceed water gain.
– Mild – thirst mechanism re-establish the water balance.
– Moderate to severe (>10% of body weight) – therapy required.
During dehydration
– Immediate source of water – ECF.
– Kidney also excrete electrolyte and ions to maintain the osmolarity.
– So, rehydration requires not only water but also electrolytes.
Kinds of electrolytes
Acid: Carbonic acid, hydrochloric acid, acetic acid, phosphoric acid.
Base: Sodium hydroxide, potassium hydroxide, magnesium hydroxide, aluminum hydroxide.
Salt: Sodium chloride, aluminum chloride, magnesium sulphate.
TARGET POINTS
It is because of the more limited reserves (e.g. ECF) associated with their relatively higher needs
that young baby become distressed more quickly in conditions of uncontrolled water loss (e.g.
Diarrhea).
Adaptation to water lack
Camel, sheep, donkey etc.
– Can endure dehydration ~ 30% of their body weight (other animal ~ 10%).
– Can drink ~ 25% of their body weight at one time without any harmful effect.
– Excrete dry feces and concentrated urine.
– Metabolic water from stored fat.
44
3.3 BLOOD
Along with lymph, blood is a vascular connective tissue whose matrix is liquid and fiber free.
Blood
Blood cells Blood platelets Plasma
Erythrocytes Leukocytes
Granulocytes Agranulocytes
Neutrophils Eosinophils Basophils Monocytes Lymphocytes
3.3.1 Salient features
Color: red
pH: 7.4 (slightly alkaline)
By weight: 7 to 8% of body weight
By volume: 5 to 6 liters in male and 4 to 5 liters in
female.
Blood is a false CT because: – Cells of blood have no power of division. – Fibers are completely absent in blood.
– Matrix of blood is produced and synthesized by
liver and lymphoid organs.
Composition:
Liquid part – matrix – plasma 55%
Solid part – blood corpuscles – 45% (RBC, WBC and platelets) [formed elements]
TARGET POINTS
Study of blood – haematology.
Haemopoiesis: Process of blood formation.
Packed cell volume – (PVC)% volume or total number of blood corpuscles is blood.
Haematocrit volume: %volume or only number of RBC in blood.
PVC ~ HV because 99% of packed cell volume is completed by RBC and in rest 1% WBC and
platelets are present.
Plasma
(55% of total blood)
Buffy coat
leukocytes and platelets
(<1% of total blood)
Erythrocytes
(45% of total blood)
3.3 BLOOD
Along with lymph, blood is a vascular connective tissue whose matrix is liquid and fiber free.
Blood
Blood cells Blood platelets Plasma
Erythrocytes Leukocytes
Granulocytes Agranulocytes
Neutrophils Eosinophils Basophils Monocytes Lymphocytes
3.3.1 Salient features
Color: red
pH: 7.4 (slightly alkaline)
By weight: 7 to 8% of body weight
By volume: 5 to 6 liters in male and 4 to 5 liters in
female.
Blood is a false CT because: – Cells of blood have no power of division. – Fibers are completely absent in blood.
– Matrix of blood is produced and synthesized by
liver and lymphoid organs.
Composition:
Liquid part – matrix – plasma 55%
Solid part – blood corpuscles – 45% (RBC, WBC and platelets) [formed elements]
TARGET POINTS
Study of blood – haematology.
Haemopoiesis: Process of blood formation.
Packed cell volume – (PVC)% volume or total number of blood corpuscles is blood.
Haematocrit volume: %volume or only number of RBC in blood.
PVC ~ HV because 99% of packed cell volume is completed by RBC and in rest 1% WBC and
platelets are present.
Plasma
(55% of total blood)
Buffy coat
leukocytes and platelets
(<1% of total blood)
Erythrocytes
(45% of total blood)
45
3.3.2 Plasma (blood matrix)
Reabsorb in blood
Gives colour to plasma
Dead
RBC
Haem
Globin Iron
Porphyrin
Bilirubin (Yellow)
Biliverdin (Green)
Bile
juice
Stercobilinogen
Gives colour
to stool
Urobilinogen
Pale yellow in color due to urobilinogen (bilirubin).
Composition: Water (90 – 92%), solid part (8 – 10%) contains inorganic and organic compounds
Inorganic components (0.9%):
1. Ions – Na
+
, K
+
, Ca
++
, Cl
–
, HCO
3
–
, SO
4
2–
, PO
4
3–
, Cl
–
> Na
+
.
2. Salts – NaCl, KCl, NaHCO
3
, KHCO
3
, [maximum: NaCl (also called as common salt).]
3. Gases – O
2
, CO
2
, N
2
, [each100 ml of plasma contains 0.29% O
2
, 0.5% N
2
, 5% CO
2
present
in dissolved form.]
Organic compounds (7 – 9%):
A. Proteins (6-7% maximum): albumin, globulin, prothrombin, fibrinogen.
B. Digested nutrients:
Amino acid
Glucose
Fatty acid
Glycerol
Cholesterol
Vitamins
If exceeds 180 mg/100ml
= Appears in urine = Glucosuria
70 - 110 m/dI = Fasting Glucose
110 - 140 mg/dI = Glucose PP
(Blood cholesterol level - 80 - 180 mg/100ml)
(Blood Glucose level - 80 - 100 mg %)
C. Waste products: Urea, uric acid, creatine, creatinine.
Normal blood urea level 17 – 30 mg%. If blood urea becomes more than 40 mg this condition
is called uremia in which RBC becomes irregular in shape called burr cell which are
destroyed in spleen so uremia is a type of anaemia.
D. Anticoagulant: Heparin (a mucopolysaccharide that prevents clotting of blood in blood
vessels.)
E. Protective compounds: Lysozyme (an enzyme which dissolves the cell wall of bacteria
and destroy them) and properdin (large protein molecules, destroy toxins synthesized by
bacteria or viruses).
3.3.2 Plasma (blood matrix)
Reabsorb in blood
Gives colour to plasma
Dead
RBC
Haem
Globin Iron
Porphyrin
Bilirubin (Yellow)
Biliverdin (Green)
Bile
juice
Stercobilinogen
Gives colour
to stool
Urobilinogen
Pale yellow in color due to urobilinogen (bilirubin).
Composition: Water (90 – 92%), solid part (8 – 10%) contains inorganic and organic compounds
Inorganic components (0.9%):
1. Ions – Na
+
, K
+
, Ca
++
, Cl
–
, HCO
3
–
, SO
4
2–
, PO
4
3–
, Cl
–
> Na
+
.
2. Salts – NaCl, KCl, NaHCO
3
, KHCO
3
, [maximum: NaCl (also called as common salt).]
3. Gases – O
2
, CO
2
, N
2
, [each100 ml of plasma contains 0.29% O
2
, 0.5% N
2
, 5% CO
2
present
in dissolved form.]
Organic compounds (7 – 9%):
A. Proteins (6-7% maximum): albumin, globulin, prothrombin, fibrinogen.
B. Digested nutrients:
Amino acid
Glucose
Fatty acid
Glycerol
Cholesterol
Vitamins
If exceeds 180 mg/100ml
= Appears in urine = Glucosuria
70 - 110 m/dI = Fasting Glucose
110 - 140 mg/dI = Glucose PP
(Blood cholesterol level - 80 - 180 mg/100ml)
(Blood Glucose level - 80 - 100 mg %)
C. Waste products: Urea, uric acid, creatine, creatinine.
Normal blood urea level 17 – 30 mg%. If blood urea becomes more than 40 mg this condition
is called uremia in which RBC becomes irregular in shape called burr cell which are
destroyed in spleen so uremia is a type of anaemia.
D. Anticoagulant: Heparin (a mucopolysaccharide that prevents clotting of blood in blood
vessels.)
E. Protective compounds: Lysozyme (an enzyme which dissolves the cell wall of bacteria
and destroy them) and properdin (large protein molecules, destroy toxins synthesized by
bacteria or viruses).
46
F. H
Secreted by endocrine glands which are transported by blood plasma.
Proteins of plasma:
A. Albumin (4% maximum):
Produced and synthesized by liver.
Smallest plasma protein.
Responsible to maintain BCOP (28 – 32 mmHg).
B. Globulin (2 – 2.5%):
Ratio of albumin and globulin is 2:1.
Produce and secreted by liver and lymphoid organs.
Transport or carry substance in body.
Destroy bacteria virus and toxic substances.
In blood 3 types of globulins are present.
i)-Globulin: Produced by liver. e.g. Ceruloplasmin – Cu carrying protein.
ii)-Globulin: Produced by liver. e.g. Transferin – Fe carrying protein.
iii)-Globulin: Produced by lymphoid organs. Present in the form of antibodies which
destroy bacteria, virus and toxic substance. Also called immunoglobulins. These
are of 5 types.
a) IgG (-immunoglobulin)- (75%): Maximum in quantity and smallest in size, molecular
weight 1,46,000 dalton, single antibody to cross placenta which mother gives to child
during embryonic life.
b) IgA (- immunoglobulin) – (10 – 15%): Molecular weight 1,70,000 dalton, secretory
antibody because it is present in glandular secretions like milk or intestinal secretion.
After birth mother gives to child immunoglobulin A.
Colostrum – 1
st
milk after parturition in which more IgA is present.
c) IgM (- immunoglobulin) (5 – 10%): Molecular weight 9,60,000 dalton, produced
and synthesized at the time of recent infection of bacteria and viruses, largest, heaviest
and oldest antibody.
d) IgD (- immunoglobulin) (1- 3%): Molecular weight 1,84,000 dalton, surface antibody.
Present on the surface of B lymphocyte.
e) IgE (-Immunoglobulin) (0.005%): Molecular weight 1,88,000 dalton, produced at
time of severe allergy.
C. Prothrombin (0.3%): Produced by liver.
D. Fibrinogen (0.3%): Produced by liver, it is the largest plasma protein and helps in blood
clotting.
F. H
Secreted by endocrine glands which are transported by blood plasma.
Proteins of plasma:
A. Albumin (4% maximum):
Produced and synthesized by liver.
Smallest plasma protein.
Responsible to maintain BCOP (28 – 32 mmHg).
B. Globulin (2 – 2.5%):
Ratio of albumin and globulin is 2:1.
Produce and secreted by liver and lymphoid organs.
Transport or carry substance in body.
Destroy bacteria virus and toxic substances.
In blood 3 types of globulins are present.
i)-Globulin: Produced by liver. e.g. Ceruloplasmin – Cu carrying protein.
ii)-Globulin: Produced by liver. e.g. Transferin – Fe carrying protein.
iii)-Globulin: Produced by lymphoid organs. Present in the form of antibodies which
destroy bacteria, virus and toxic substance. Also called immunoglobulins. These
are of 5 types.
a) IgG (-immunoglobulin)- (75%): Maximum in quantity and smallest in size, molecular
weight 1,46,000 dalton, single antibody to cross placenta which mother gives to child
during embryonic life.
b) IgA (- immunoglobulin) – (10 – 15%): Molecular weight 1,70,000 dalton, secretory
antibody because it is present in glandular secretions like milk or intestinal secretion.
After birth mother gives to child immunoglobulin A.
Colostrum – 1
st
milk after parturition in which more IgA is present.
c) IgM (- immunoglobulin) (5 – 10%): Molecular weight 9,60,000 dalton, produced
and synthesized at the time of recent infection of bacteria and viruses, largest, heaviest
and oldest antibody.
d) IgD (- immunoglobulin) (1- 3%): Molecular weight 1,84,000 dalton, surface antibody.
Present on the surface of B lymphocyte.
e) IgE (-Immunoglobulin) (0.005%): Molecular weight 1,88,000 dalton, produced at
time of severe allergy.
C. Prothrombin (0.3%): Produced by liver.
D. Fibrinogen (0.3%): Produced by liver, it is the largest plasma protein and helps in blood
clotting.
47
BLOOD CORPUSCLES
Red blood cellPlateletWhite blood cell
Multipotential hematopoietic
stem cell (Hemocytoblast)
Common myeloid progenitor Common lymphoid progenitor
Erythrocyte Mast cell Myeloblast
Megakaryocyte
Thrombocytes
Basophil Neutrophil Eosinophil Monocyte
Macrophage
Plasma cell
B lymphocyteT lymphocyte
Small lymphocyte
Natural killer cell
(Large granular lymphocyte)
Hematopoiesis and stem cells
During embryonic development the formation of blood cells occurs in the liver, spleen, and yolk sac.
However, after birth, the infant’s liver and spleen become the locations for destroying blood cells. All
blood cells, whether they end up in the myeloid or lymphoid family, begin as hemocytoblasts, stem
cells that develop from embryonic mesenchyme.
3.3.3 Red blood cells (RBCs) or erythrocytes
Size
– Human – 7.5 Rabbit – 6.9 Frog – 35
BLOOD CORPUSCLES
Red blood cellPlateletWhite blood cell
Multipotential hematopoietic
stem cell (Hemocytoblast)
Common myeloid progenitor Common lymphoid progenitor
Erythrocyte Mast cell Myeloblast
Megakaryocyte
Thrombocytes
Basophil Neutrophil Eosinophil Monocyte
Macrophage
Plasma cell
B lymphocyteT lymphocyte
Small lymphocyte
Natural killer cell
(Large granular lymphocyte)
Hematopoiesis and stem cells
During embryonic development the formation of blood cells occurs in the liver, spleen, and yolk sac.
However, after birth, the infant’s liver and spleen become the locations for destroying blood cells. All
blood cells, whether they end up in the myeloid or lymphoid family, begin as hemocytoblasts, stem
cells that develop from embryonic mesenchyme.
3.3.3 Red blood cells (RBCs) or erythrocytes
Size
– Human – 7.5 Rabbit – 6.9 Frog – 35
48
– Largest RBC – Amphiuma, 75 – 80 (class: amphibia).
– Smallest RBC – Musk deer, 2.5(class: mammalia).
– Largest RBC among all mammals is elephant, 9 – 11
– Change in the size of RBC is called as anisocytosis.
1. Due to Vitamin B
12
deficiency RBC becomes larger in size called as macrocytes. These
are immature RBCs which are destroyed in spleen. In these RBCs amount of hemoglobin
is normal.
2. Due to Fe deficiency RBCs become smaller in size called as microcytes. They are also
destroyed in spleen. In these RBCs amount of hemoglobin is less.
Shape:
– Biconcave.
– Change in the shape of RBC is called as poikilocytosis.
–Uremia – RBC becomes irregular in shape.
–Sickle cell anaemia – RBC becomes sickle shaped.
– If RBC is kept in hypertonic solution it will shrink (crenation).
– In hypotonic solution it will burst.
– 0.8 – 1% NaCl solution is isotonic for RBC (0.9% of NaCl).
– 80 – 100 mg% of glucose is also isotonic.
Mammalian RBC’s are biconcave, circular and non-nucleated. At the time of origin, nucleus
is present in RBCs but it degenerates during maturation. Biconcave shape increases the
surface area. Absence of nucleus and biconcavity allow more hemoglobin to be filled in RBC.
Exception: Camel and Lamma are mammals with biconvex, oval shaped.
Endoplasmic reticulum is absent; endoskeleton is composed of structural protein, fats and
cholesterol in the form of network called stromatin which is a spongy cytoskeleton. Plasma
membrane of RBC is called Donnan’s membrane. It is highly permeable to some ions like
Cl
–
and HCO
3
–
and impermeable to Na
+
and K
+
. This is called Donnan’s phenomenon. Due
to presence of stromatin spongy cytoskeleton and flexible plasma membrane, RBC (7.5 m)
can pass through less diameter blood capillaries (5 m).
Higher cell organelles like mitochondria and Golgi complex are absent and thus, anaerobic
respiration takes place in RBC. Enzymes of glycolysis are present while enzymes of Kreb’s
cycle are absent. Carbonic anhydrase enzyme is present which increases the rate of formation
and dissociation of carbonic acid by 5000 times (fastest catalyst (with zinc)).
Antigen of blood group is present on the surface of RBC. If Rh antigen is present then it is
also found on the surface.
Single RBC is pale yellow while groups of RBCs appear red.
– Largest RBC – Amphiuma, 75 – 80 (class: amphibia).
– Smallest RBC – Musk deer, 2.5(class: mammalia).
– Largest RBC among all mammals is elephant, 9 – 11
– Change in the size of RBC is called as anisocytosis.
1. Due to Vitamin B
12
deficiency RBC becomes larger in size called as macrocytes. These
are immature RBCs which are destroyed in spleen. In these RBCs amount of hemoglobin
is normal.
2. Due to Fe deficiency RBCs become smaller in size called as microcytes. They are also
destroyed in spleen. In these RBCs amount of hemoglobin is less.
Shape:
– Biconcave.
– Change in the shape of RBC is called as poikilocytosis.
–Uremia – RBC becomes irregular in shape.
–Sickle cell anaemia – RBC becomes sickle shaped.
– If RBC is kept in hypertonic solution it will shrink (crenation).
– In hypotonic solution it will burst.
– 0.8 – 1% NaCl solution is isotonic for RBC (0.9% of NaCl).
– 80 – 100 mg% of glucose is also isotonic.
Mammalian RBC’s are biconcave, circular and non-nucleated. At the time of origin, nucleus
is present in RBCs but it degenerates during maturation. Biconcave shape increases the
surface area. Absence of nucleus and biconcavity allow more hemoglobin to be filled in RBC.
Exception: Camel and Lamma are mammals with biconvex, oval shaped.
Endoplasmic reticulum is absent; endoskeleton is composed of structural protein, fats and
cholesterol in the form of network called stromatin which is a spongy cytoskeleton. Plasma
membrane of RBC is called Donnan’s membrane. It is highly permeable to some ions like
Cl
–
and HCO
3
–
and impermeable to Na
+
and K
+
. This is called Donnan’s phenomenon. Due
to presence of stromatin spongy cytoskeleton and flexible plasma membrane, RBC (7.5 m)
can pass through less diameter blood capillaries (5 m).
Higher cell organelles like mitochondria and Golgi complex are absent and thus, anaerobic
respiration takes place in RBC. Enzymes of glycolysis are present while enzymes of Kreb’s
cycle are absent. Carbonic anhydrase enzyme is present which increases the rate of formation
and dissociation of carbonic acid by 5000 times (fastest catalyst (with zinc)).
Antigen of blood group is present on the surface of RBC. If Rh antigen is present then it is
also found on the surface.
Single RBC is pale yellow while groups of RBCs appear red.
49
In each RBC, 26.5 crores molecules of hemoglobin (mol. wt. 67, 200 Da) are present.
Composition: Water (60%), solid part (40%). Only Hb constitutes 36% of total weight of
RBC and 90% on dry weight.
Hemoglobin: Haem (5%) and Globin (95% protein part)
A. Haem (iron and porphyrin):
– Iron present in the form of Fe
+2
– While in muscles, myoglobin is present where iron is present in the form of Fe
+3
.
– Porphyrin is composed of acetic acid and glycine amino acid.
– Each molecule of Hb carries 4 molecules of O
2
, 1 gm Hb carries 1.34 ml of O
2
, 100 ml
blood contain 15 gm Hb, 100 ml blood transport 20 ml O
2
.
B. Globin:
– Each molecule of globin protein is composed of 4 polypeptide chains. Polypeptide chains
are of 4 types:
i)polypeptide chain having 141 amino acids.
ii)polypeptide chain having 146 amino acids.
iii) polypeptide chain having 146 amino acids.
iv) polypeptide chain having 146 amino acids.
On the basis of these polypeptide chains 3 types of Hb are formed in human.
– HbA (adult Hb) – 2 + 2
– HbA
2
(adult-2) – 2 + 2
– HbF (foetal Hb) – 2 + 2
(oxygen binding capacity of foetal Hb is more than
adult Hb)
RBCs formation:
– RBC formation is erythropoiesis and the producing organs are called erythropoietic
organs. Hormone which stimulates erythropoiesis is erythropoietin synthesized by the
kidney.
– 1st RBC is produced by yolk sac. During embryonic life, RBCs are produced by liver,
spleen, placenta and thymus gland. In adult stage, red bone marrow (filled in trabeculae of
spongy bones) produce RBCs. Kidney is an erythropoietic organ in frog.
– 1% RBCs are destroyed daily but in same number new RBCs enter in the blood. Destruction
occurs in spleen (the graveyard of RBC). Spleen also stores excess blood corpuscles,
also called as ‘the blood bank of body’.
Chain
Heme
Fe
2+
Chain
In each RBC, 26.5 crores molecules of hemoglobin (mol. wt. 67, 200 Da) are present.
Composition: Water (60%), solid part (40%). Only Hb constitutes 36% of total weight of
RBC and 90% on dry weight.
Hemoglobin: Haem (5%) and Globin (95% protein part)
A. Haem (iron and porphyrin):
– Iron present in the form of Fe
+2
– While in muscles, myoglobin is present where iron is present in the form of Fe
+3
.
– Porphyrin is composed of acetic acid and glycine amino acid.
– Each molecule of Hb carries 4 molecules of O
2
, 1 gm Hb carries 1.34 ml of O
2
, 100 ml
blood contain 15 gm Hb, 100 ml blood transport 20 ml O
2
.
B. Globin:
– Each molecule of globin protein is composed of 4 polypeptide chains. Polypeptide chains
are of 4 types:
i)polypeptide chain having 141 amino acids.
ii)polypeptide chain having 146 amino acids.
iii) polypeptide chain having 146 amino acids.
iv) polypeptide chain having 146 amino acids.
On the basis of these polypeptide chains 3 types of Hb are formed in human.
– HbA (adult Hb) – 2 + 2
– HbA
2
(adult-2) – 2 + 2
– HbF (foetal Hb) – 2 + 2
(oxygen binding capacity of foetal Hb is more than
adult Hb)
RBCs formation:
– RBC formation is erythropoiesis and the producing organs are called erythropoietic
organs. Hormone which stimulates erythropoiesis is erythropoietin synthesized by the
kidney.
– 1st RBC is produced by yolk sac. During embryonic life, RBCs are produced by liver,
spleen, placenta and thymus gland. In adult stage, red bone marrow (filled in trabeculae of
spongy bones) produce RBCs. Kidney is an erythropoietic organ in frog.
– 1% RBCs are destroyed daily but in same number new RBCs enter in the blood. Destruction
occurs in spleen (the graveyard of RBC). Spleen also stores excess blood corpuscles,
also called as ‘the blood bank of body’.
Chain
Heme
Fe
2+
Chain
50
– In resting and slow flowing blood, RBCs form piles called Roulaux by adhering together
due to surface tension.
–Haemoconia: Minute bits of disintegrated RBCs.
– Ghost of RBC is made up of its plasma membrane.
Stem cell Committed cell Developmental pathway
Phase 3
Ejection of nucleus
Hemocytoblast Proerythroblast
Early
erythroblast
Late
erythroblastNormoblast
Reticulocyte Erythrocyte
Erythropoiesis/RBC production
Life span of RBCs:
Average life span of RBC in all mammals: 120 – 127 days.
Radioactive chromium method is used to estimate life span of RBC.
RBCs count:
– Number of RBC in per cubic mm of blood is called RBC count.
Human (male)
Human (female)
Newly born baby
Rabbit
Frog
15.5 ± 2.5 g / dl5.5 million
14.0 ± 2.5 g / dl4.5 million
0.4 million
16.5 ± 3.0 g / dl7 million
6.8 million
– Increase in the RBC count condition is called polycythemia. This occurs at hill station.
– Decrease in RBC count condition is called anaemia.
1. Macrocytic normochromic anaemia: Due to vitamin B
12
deficiency macrocytes are
formed which are destroyed in spleen. In macrocytes % of Hb is normal.
2. Microcytic hypochromic anaemia: Due to Fe deficiency microcytes are formed.
3. Normocytic, normochromic anaemia: Excess blood loss.
Rabbit 80 days
Frog 100 days
Human 120 days
New born baby 100 days
– In resting and slow flowing blood, RBCs form piles called Roulaux by adhering together
due to surface tension.
–Haemoconia: Minute bits of disintegrated RBCs.
– Ghost of RBC is made up of its plasma membrane.
Stem cell Committed cell Developmental pathway
Phase 3
Ejection of nucleus
Hemocytoblast Proerythroblast
Early
erythroblast
Late
erythroblastNormoblast
Reticulocyte Erythrocyte
Erythropoiesis/RBC production
Life span of RBCs:
Average life span of RBC in all mammals: 120 – 127 days.
Radioactive chromium method is used to estimate life span of RBC.
RBCs count:
– Number of RBC in per cubic mm of blood is called RBC count.
Human (male)
Human (female)
Newly born baby
Rabbit
Frog
15.5 ± 2.5 g / dl5.5 million
14.0 ± 2.5 g / dl4.5 million
0.4 million
16.5 ± 3.0 g / dl7 million
6.8 million
– Increase in the RBC count condition is called polycythemia. This occurs at hill station.
– Decrease in RBC count condition is called anaemia.
1. Macrocytic normochromic anaemia: Due to vitamin B
12
deficiency macrocytes are
formed which are destroyed in spleen. In macrocytes % of Hb is normal.
2. Microcytic hypochromic anaemia: Due to Fe deficiency microcytes are formed.
3. Normocytic, normochromic anaemia: Excess blood loss.
Rabbit 80 days
Frog 100 days
Human 120 days
New born baby 100 days
51
Circulation for about
120 days
Amino
acids
Reused for
protein synthesis
12
3
4
9
2
1 10
13
11
7
Fe
3+
+
Globin
+
Vitamin B
+
Erythopoietin
12
8Erythropoiesis in
red bone marrow
Urobilinogen
Red blood cell death and phagocytosis
Macrophage in spleen, liver, or
red bone marrow
Urobilin
Kidney
Bilirubin
Biliverdin
Heme
Globin
Fe
3+
6
Transferrin
Ferritin and hemosiderin
Bilirubin
Liver
Small
intestine
Bacteria
Bilirubin
Large
intestine
14
Stercobilin
Feces
Urine
Fe
3+
Transferrin
5
Life cycle of RBCs
3.3.4 White blood corpuscles (WBCs) / leukocytes
WBC (white blood corpuscles) is also called as leukocytes because they are colorless. TLC = Total
leukocyte count. Number of WBC / mm
3
8000 – 11000/mm
3
.
Leukocytosis: Increase in TLC. This condition occurs in bacterial and viral infection.
Leukocytopenia: Decrease in TLC. Normally TLC increases in bacterial and viral infection but in
typhoid and AIDS, TLC decreases. Leukemia: Abnormal increase in TLC (more than 1 lakh), it is called as blood cancer.
On the basis of nucleus and nature of cytoplasm, leukocyte are of 2 types:
Granulocytes – In their cytoplasm, granules are present which can be stained by specific dye.
– Nucleus is multilobed and lobes are interconnected by protoplasmic strand.
– Due to presence of lobed nucleus they are called as polymorphonuclear WBC.
– Produced in bone marrow
– They are acidophils, basophils and neutrophils.
Agranulocytes
– Cytoplasm is clear and granular.
– Nucleus do not divide in lobes so called as mononuclear WBC.
– Produced in bone marrow.
Circulation for about
120 days
Amino
acids
Reused for
protein synthesis
12
3
4
9
2
1 10
13
11
7
Fe
3+
+
Globin
+
Vitamin B
+
Erythopoietin
12
8Erythropoiesis in
red bone marrow
Urobilinogen
Red blood cell death and phagocytosis
Macrophage in spleen, liver, or
red bone marrow
Urobilin
Kidney
Bilirubin
Biliverdin
Heme
Globin
Fe
3+
6
Transferrin
Ferritin and hemosiderin
Bilirubin
Liver
Small
intestine
Bacteria
Bilirubin
Large
intestine
14
Stercobilin
Feces
Urine
Fe
3+
Transferrin
5
Life cycle of RBCs
3.3.4 White blood corpuscles (WBCs) / leukocytes
WBC (white blood corpuscles) is also called as leukocytes because they are colorless. TLC = Total
leukocyte count. Number of WBC / mm
3
8000 – 11000/mm
3
.
Leukocytosis: Increase in TLC. This condition occurs in bacterial and viral infection.
Leukocytopenia: Decrease in TLC. Normally TLC increases in bacterial and viral infection but in
typhoid and AIDS, TLC decreases. Leukemia: Abnormal increase in TLC (more than 1 lakh), it is called as blood cancer.
On the basis of nucleus and nature of cytoplasm, leukocyte are of 2 types:
Granulocytes – In their cytoplasm, granules are present which can be stained by specific dye.
– Nucleus is multilobed and lobes are interconnected by protoplasmic strand.
– Due to presence of lobed nucleus they are called as polymorphonuclear WBC.
– Produced in bone marrow
– They are acidophils, basophils and neutrophils.
Agranulocytes
– Cytoplasm is clear and granular.
– Nucleus do not divide in lobes so called as mononuclear WBC.
– Produced in bone marrow.
52
– They are of two types – monocytes and lymphocytes.
DLC (Differential leukocyte count): number / % of different type of leukocyte in per cubic mm.
of blood.
Acidophils – 4% of TLC
Basophils – 0.5 – 1% TLC
Neutrophils – 65 – 70% TLC
Monocytes – 4 to 8% TLC
Lymphocytes – 25 to 30% TLC
A. Eosinophils / acidophils
Amoeboid shape of 10 -14 m; bilobed nucleus.
Life span: 4-8 hrs in blood
Cytoplasm contains acidiophilic granules that can be stained by acidic dye Eosin.
They protect body against allergy and parasitic infection. In allergy they synthesize histamine
while in parasitic infection they act as lysosome. They attach with the surface or body wall of
parasite and synthesize enzymes which dissolve body wall of parasite and destroy them.
Increase in number of acidophils condition is eosinophilia which occurs in Taeniasis, Ascariasis
(parasitic infection), Hay fever (allergy).
B. Basophils
Minimum in number, amoeboid shape of 8 -10 m, the smallest granulocytes.
Life span: 10 hrs.
Cytoplasm contains basophilic granules that can be stained with basic dye methylene blue.
Nucleus is divided in 2 or 3 lobes, ‘S’ shaped.
Main function is to secrete and transport heparin, histamine and serotonin which are produced
in liver.
C. Neutrophils / heterophils
Maximum in number, amoeboid shape of 10 -12 m
Life span: 12 hrs.
Cytoplasm granules can be stained by any dye (acidic, neutral, basic).
Nucleus is divided in 3 - 5 or more lobes, maximum lobed nucleus is in neutrophils. Counting
of lobes is called Arneth count.
They are active and motile WBC. They can squeeze and come out from the wall of blood
capillaries in tissue, phenomenon called Diapedesis.
Destroy bacteria and viruses by phagocytosis. Due to their smaller size and phagocytic nature
they are called micropoliceman.
– They are of two types – monocytes and lymphocytes.
DLC (Differential leukocyte count): number / % of different type of leukocyte in per cubic mm.
of blood.
Acidophils – 4% of TLC
Basophils – 0.5 – 1% TLC
Neutrophils – 65 – 70% TLC
Monocytes – 4 to 8% TLC
Lymphocytes – 25 to 30% TLC
A. Eosinophils / acidophils
Amoeboid shape of 10 -14 m; bilobed nucleus.
Life span: 4-8 hrs in blood
Cytoplasm contains acidiophilic granules that can be stained by acidic dye Eosin.
They protect body against allergy and parasitic infection. In allergy they synthesize histamine
while in parasitic infection they act as lysosome. They attach with the surface or body wall of
parasite and synthesize enzymes which dissolve body wall of parasite and destroy them.
Increase in number of acidophils condition is eosinophilia which occurs in Taeniasis, Ascariasis
(parasitic infection), Hay fever (allergy).
B. Basophils
Minimum in number, amoeboid shape of 8 -10 m, the smallest granulocytes.
Life span: 10 hrs.
Cytoplasm contains basophilic granules that can be stained with basic dye methylene blue.
Nucleus is divided in 2 or 3 lobes, ‘S’ shaped.
Main function is to secrete and transport heparin, histamine and serotonin which are produced
in liver.
C. Neutrophils / heterophils
Maximum in number, amoeboid shape of 10 -12 m
Life span: 12 hrs.
Cytoplasm granules can be stained by any dye (acidic, neutral, basic).
Nucleus is divided in 3 - 5 or more lobes, maximum lobed nucleus is in neutrophils. Counting
of lobes is called Arneth count.
They are active and motile WBC. They can squeeze and come out from the wall of blood
capillaries in tissue, phenomenon called Diapedesis.
Destroy bacteria and viruses by phagocytosis. Due to their smaller size and phagocytic nature
they are called micropoliceman.
53
Help in sex detection. In females, neutrophil barr body is attached with the lobe of nucleus
which is formed by the modification of x chromosomes. Barr body is absent in males.
D. Monocytes
Largest blood corpuscles, 12 - 20 m
Life span: In blood less than 24 hrs but in connective tissue it may be weeks/months.
Nucleus is kidney/bean shaped
Active motile WBC, shows diapedesis
Destroy bacteria and viruses by phagocytosis, also called macropoliceman.
Also called scavenger of blood because they engulf damaged or dead and minute bits of
blood corpuscles.
E. Lymphocytes
Amoeboid shape of 6 - 16 m (smallest WBC).
Life span: 5-7 days or less than 10 days in blood but in connective tissue it may be month/
year/whole life.
Large nucleus is present pushing the cytoplasm to the periphery.
Lymphocytes are of two types:
T – Lymphocytes: Produced in bone marrow but mature in thymus gland. On the basis of
function, these are of 3 types:
i) T-Killer/Cytotoxic: Directly kill bacteria or viruses
ii) T-Helper: Stimulates B–lymphocytes to produce antibodies
iii) T-Suppressor: Suppresses T-Killer and protects the immune system.
B – Lymphocytes: Produced and mature in bone marrow. Its function is to produce, synthesize
and transport antibodies.
Eosinophil Basophil Neutrophil Monocyte Lymphocyte
Help in sex detection. In females, neutrophil barr body is attached with the lobe of nucleus
which is formed by the modification of x chromosomes. Barr body is absent in males.
D. Monocytes
Largest blood corpuscles, 12 - 20 m
Life span: In blood less than 24 hrs but in connective tissue it may be weeks/months.
Nucleus is kidney/bean shaped
Active motile WBC, shows diapedesis
Destroy bacteria and viruses by phagocytosis, also called macropoliceman.
Also called scavenger of blood because they engulf damaged or dead and minute bits of
blood corpuscles.
E. Lymphocytes
Amoeboid shape of 6 - 16 m (smallest WBC).
Life span: 5-7 days or less than 10 days in blood but in connective tissue it may be month/
year/whole life.
Large nucleus is present pushing the cytoplasm to the periphery.
Lymphocytes are of two types:
T – Lymphocytes: Produced in bone marrow but mature in thymus gland. On the basis of
function, these are of 3 types:
i) T-Killer/Cytotoxic: Directly kill bacteria or viruses
ii) T-Helper: Stimulates B–lymphocytes to produce antibodies
iii) T-Suppressor: Suppresses T-Killer and protects the immune system.
B – Lymphocytes: Produced and mature in bone marrow. Its function is to produce, synthesize
and transport antibodies.
Eosinophil Basophil Neutrophil Monocyte Lymphocyte
54
Stem cells Hematopoietic stem cell
(hemocytoblast)
Myeloid stem cell Lymphoid stem cell
Myeloblast Myeloblast Myeloblast Monoblast B Iymphocyte
precursor
T Iymphocyte
precursor
Committed
cells
Developmental
pathway
Promyelocyte Promyelocyte Promyelocyte Promyelocyte
Eosinophilic
myelocyte
Basophilic
myelocyte
Neutrophilic
myelocyte
Eosinophilic
band cells
Basophilic
band cells
Neutrophilic
band cells
Granular
leukocytes
Eosinophils Basophils Neutrophils Monocytes B Iymphocytes T Iymphocytes
Agranular
leukocytes
Some
become
Some
become
Some
become
Macrophages (tissues) Plasma cells Effector T cells
Leukopoiesis/WBC production
3.3.5 Platelets / thrombocytes
Found only in mammals while in other vertebrates, spindle corpuscles are present which
perform the same function.
Stem cells Hematopoietic stem cell
(hemocytoblast)
Myeloid stem cell Lymphoid stem cell
Myeloblast Myeloblast Myeloblast Monoblast B Iymphocyte
precursor
T Iymphocyte
precursor
Committed
cells
Developmental
pathway
Promyelocyte Promyelocyte Promyelocyte Promyelocyte
Eosinophilic
myelocyte
Basophilic
myelocyte
Neutrophilic
myelocyte
Eosinophilic
band cells
Basophilic
band cells
Neutrophilic
band cells
Granular
leukocytes
Eosinophils Basophils Neutrophils Monocytes B Iymphocytes T Iymphocytes
Agranular
leukocytes
Some
become
Some
become
Some
become
Macrophages (tissues) Plasma cells Effector T cells
Leukopoiesis/WBC production
3.3.5 Platelets / thrombocytes
Found only in mammals while in other vertebrates, spindle corpuscles are present which
perform the same function.
55
N
Shape: Disc like, oval or biconvex. While spindle corpuscles are spindle in shape with a
rounded nucleus in the center.
Size: 2-3 m
Life span: 2 - 4/5 days
Cytoplasm contains basophilic granules that can be stained by methylene blue. Maximum
part of cytoplasm is composed of the contractile protein Thrombosthenin.
Count: 1.5 - 4.5 lakh/mm
3
. Decrease in number is called Thrombocytopenia. Critical count
of thrombocytes is 40,000/mm
3
. If number is less than the critical count, red spot or rashes
appear on the skin, Purpura disease.
Functions:
– Repair endothelium of blood vascular
system by the formation of platelet plug
because they have the tendency to attach
on gelatinous or mucilaginous surface.
– Synthesize thromboplastin that helps in
blood clotting.
– Synthesize serotonin.
Stem cell Developmental pathway
Hemocytoblast Megakaryoblast Promegakaryocyte Megakaryocyte Platelets
Thrombopoiesis/Platelet production
3.3.6 Blood clotting
Blood flows from cut or wound but after sometimes it stops automatically. It is called clotting of
blood.
Bleeding time is 1 – 3 minutes.
Clotting time is 2 – 8 minutes.
Sometimes clots are also formed in intact blood vessels which are of 2 types.
a) Thrombus clot
– Static clots which grow bigger and ultimately block the blood vessels.
Platelet
Megakaryocyte
N
Shape: Disc like, oval or biconvex. While spindle corpuscles are spindle in shape with a
rounded nucleus in the center.
Size: 2-3 m
Life span: 2 - 4/5 days
Cytoplasm contains basophilic granules that can be stained by methylene blue. Maximum
part of cytoplasm is composed of the contractile protein Thrombosthenin.
Count: 1.5 - 4.5 lakh/mm
3
. Decrease in number is called Thrombocytopenia. Critical count
of thrombocytes is 40,000/mm
3
. If number is less than the critical count, red spot or rashes
appear on the skin, Purpura disease.
Functions:
– Repair endothelium of blood vascular
system by the formation of platelet plug
because they have the tendency to attach
on gelatinous or mucilaginous surface.
– Synthesize thromboplastin that helps in
blood clotting.
– Synthesize serotonin.
Stem cell Developmental pathway
Hemocytoblast Megakaryoblast Promegakaryocyte Megakaryocyte Platelets
Thrombopoiesis/Platelet production
3.3.6 Blood clotting
Blood flows from cut or wound but after sometimes it stops automatically. It is called clotting of
blood.
Bleeding time is 1 – 3 minutes.
Clotting time is 2 – 8 minutes.
Sometimes clots are also formed in intact blood vessels which are of 2 types.
a) Thrombus clot
– Static clots which grow bigger and ultimately block the blood vessels.
Platelet
Megakaryocyte
56
– I
coronary thrombosis which
can cause heart attack.
– If form in brain, then called as cephalic thrombus causes paralysis.
b) Embolus clot
– Moving clots which flow with blood and ultimately dissolve in blood.
– More harmful due to their moving nature.
Hemostasis
Set of process that stops bleeding and promotes healing of damaged blood vessel wall.
3 processes:
1. Vascular spasm: Squeeze the vessel.
2. Platelet plug formation: Temporary patch.
3. Coagulation: Long lasting patch.
Coagulation
A multi-step process that results in the formation of blood clot.
Require several clotting factors that are present in the blood and can act in a cascade, clotting
cascade.
Two pathways – extrinsic and intrinsic.
Mechanism of blood clotting (enzyme cascade theory): Proposed by Macfarlane and coworkers.
Releasing of thromboplastin: Injured tissue synthesizes exothromboplastin and platelets
synthesize endothromboplastin. Both these thromboplastin react with plasma proteins in the
presence of Ca
++
ions to form the prothrombinase enzymes (thrombokinase). These enzymes
inactivate heparin (antiheparin).
Conversion of prothrombin into thrombin: Prothrombinase enzymes convert inactive
prothrombin into active thrombin in the presence of Ca
++
ion.
Conversion of fibrinogen into fibrin: Fibrinogen is soluble protein of plasma. Thrombin
proteins polymerize monomers of fibrinogen to form insoluble fibrous protein fibrin. Fibrin
fibers form networks on cut or wound in which blood corpuscles get trapped. This form the
blood clot.
After clotting a pale yellow liquid oozes called serum in which antibodies are found.
Blood – Corpuscles = Plasma
Plasma – Fibrinogen and large proteins = Serum
– I
coronary thrombosis which
can cause heart attack.
– If form in brain, then called as cephalic thrombus causes paralysis.
b) Embolus clot
– Moving clots which flow with blood and ultimately dissolve in blood.
– More harmful due to their moving nature.
Hemostasis
Set of process that stops bleeding and promotes healing of damaged blood vessel wall.
3 processes:
1. Vascular spasm: Squeeze the vessel.
2. Platelet plug formation: Temporary patch.
3. Coagulation: Long lasting patch.
Coagulation
A multi-step process that results in the formation of blood clot.
Require several clotting factors that are present in the blood and can act in a cascade, clotting
cascade.
Two pathways – extrinsic and intrinsic.
Mechanism of blood clotting (enzyme cascade theory): Proposed by Macfarlane and coworkers.
Releasing of thromboplastin: Injured tissue synthesizes exothromboplastin and platelets
synthesize endothromboplastin. Both these thromboplastin react with plasma proteins in the
presence of Ca
++
ions to form the prothrombinase enzymes (thrombokinase). These enzymes
inactivate heparin (antiheparin).
Conversion of prothrombin into thrombin: Prothrombinase enzymes convert inactive
prothrombin into active thrombin in the presence of Ca
++
ion.
Conversion of fibrinogen into fibrin: Fibrinogen is soluble protein of plasma. Thrombin
proteins polymerize monomers of fibrinogen to form insoluble fibrous protein fibrin. Fibrin
fibers form networks on cut or wound in which blood corpuscles get trapped. This form the
blood clot.
After clotting a pale yellow liquid oozes called serum in which antibodies are found.
Blood – Corpuscles = Plasma
Plasma – Fibrinogen and large proteins = Serum
57
Trauma
INTRINSIC PATHWAY
Damaged surface
Kininogen
kallikrein
XII
XII
a
XI
XI
a
IX
IX
a
VIII
a
X
X
a
V
a
VIIVII
a
EXTRINSIC PATHWAY
Tissue
factor
Trauma
Prothrombin
(II)
Thrombin
(II )
a
Fibrinogen
(I)
Fibrin
(I )
a
XIII
a
Cross-linked
fibrin clot
FINAL COMMON
PATHWAY
Clotting cascade
X
Clotting factors
13 factors help in blood clotting. These are mainly produced in liver and require vitamin K for their
synthesis. These factors are:
I – Fibrinogen
II – Prothrombin
III – Thromboplastin
IV – Ca
++
(cofactor in each step of blood clotting)
V – Proaccelerin
VI – Accelerin (rejected)
VII– Proconvertein
VII – AHG (antihemophilic globin), absent in
hemophilia-A)
IX – Christmas factor
X – Stuart factor
XI – PTA (plasma thromboplastin antecedent)
XII – Hagman factor (become active by friction)
XIII– FSF factor (Fibrin stabilizing factor)(Laki
Lorand factor)
Trauma
INTRINSIC PATHWAY
Damaged surface
Kininogen
kallikrein
XII
XII
a
XI
XI
a
IX
IX
a
VIII
a
X
X
a
V
a
VIIVII
a
EXTRINSIC PATHWAY
Tissue
factor
Trauma
Prothrombin
(II)
Thrombin
(II )
a
Fibrinogen
(I)
Fibrin
(I )
a
XIII
a
Cross-linked
fibrin clot
FINAL COMMON
PATHWAY
Clotting cascade
X
Clotting factors
13 factors help in blood clotting. These are mainly produced in liver and require vitamin K for their
synthesis. These factors are:
I – Fibrinogen
II – Prothrombin
III – Thromboplastin
IV – Ca
++
(cofactor in each step of blood clotting)
V – Proaccelerin
VI – Accelerin (rejected)
VII– Proconvertein
VII – AHG (antihemophilic globin), absent in
hemophilia-A)
IX – Christmas factor
X – Stuart factor
XI – PTA (plasma thromboplastin antecedent)
XII – Hagman factor (become active by friction)
XIII– FSF factor (Fibrin stabilizing factor)(Laki
Lorand factor)
58
3.3.7 Blood groups
An
tigen of blood groups is present on the surface of RBC also called as agglutinogen.
Antibody for blood group antigen is present in serum (plasma) called agglutinin.
Antigen and antibody are special type of glycoproteins.
Blood groups are of 4 types A, B, AB, O. A, B, O discovered by Landsteiner. AB discovered
by Decastello and Sturli.
Blood group O is universal donor and blood group is AB is universal acceptor.
Blood groups are examples of multiple alleles. For gene of blood groups 3 alternatives are
present. Gene A and B are dominant gene. They can give their expression in homozygous
and heterozygous condition so blood groups A and B are due to dominant gene A and B.
I I
A O
I I
A A
A
I I
B O
I I
B B
B
Gene O is a recessive gene which gives its expression in homozygous condition. Blood group
O is due to recessive gene.
I I
O O
O
Blood group AB is an example of codominance in which both dominant gene A and B are
present.
I I
A B
AB
Rh Factor
Discovered by Landsteiner and Weiner in Rhesus monkey. Rh antigen is due to dominant
gene. If one of the gametes possess gene of Rh factor, its offspring will be always Rh +ve.
Rh
+
: Antigen is present, antibody is absent
Rh
–
: Antigen is absent, antibody is absent
In India, % ratio of Rh is – Rh
+
- 97%, Rh
–
- 3%
In World, % ratio of Rh is – Rh
+
- 80%, Rh
–
- 20%
If Rh
+
blood is transfused to Rh
–
then 1
st
blood transfusion is complete successfully but during
1
st
blood transfusion Rh antibodies are formed in receiver’s blood so in next blood transfusion,
agglutination of blood takes place.
If mother is Rh
–
and father is Rh
+
then offspring is also Rh
+
. In this case 1
st
pregnancy is
completely successful but at the time of 1
st
delivery Rh antibody is formed in mother’s blood
due to damaged blood vessel so in next pregnancy death of fetus will occur in the earlier
stage due to agglutination of blood called erythroblastosis fetalis.
To destroy Rh antibody medicines are used like Rhogam, Rholin, Anti D.
Blood groups Antigen Antibody Receive Donate
A A b A, O A, AB
B B a B, O B, AB
AB A, B - A, B, AB, O AB
O - ab O A, B, AB, O
3.3.7 Blood groups
An
tigen of blood groups is present on the surface of RBC also called as agglutinogen.
Antibody for blood group antigen is present in serum (plasma) called agglutinin.
Antigen and antibody are special type of glycoproteins.
Blood groups are of 4 types A, B, AB, O. A, B, O discovered by Landsteiner. AB discovered
by Decastello and Sturli.
Blood group O is universal donor and blood group is AB is universal acceptor.
Blood groups are examples of multiple alleles. For gene of blood groups 3 alternatives are
present. Gene A and B are dominant gene. They can give their expression in homozygous
and heterozygous condition so blood groups A and B are due to dominant gene A and B.
I I
A O
I I
A A
A
I I
B O
I I
B B
B
Gene O is a recessive gene which gives its expression in homozygous condition. Blood group
O is due to recessive gene.
I I
O O
O
Blood group AB is an example of codominance in which both dominant gene A and B are
present.
I I
A B
AB
Rh Factor
Discovered by Landsteiner and Weiner in Rhesus monkey. Rh antigen is due to dominant
gene. If one of the gametes possess gene of Rh factor, its offspring will be always Rh +ve.
Rh
+
: Antigen is present, antibody is absent
Rh
–
: Antigen is absent, antibody is absent
In India, % ratio of Rh is – Rh
+
- 97%, Rh
–
- 3%
In World, % ratio of Rh is – Rh
+
- 80%, Rh
–
- 20%
If Rh
+
blood is transfused to Rh
–
then 1
st
blood transfusion is complete successfully but during
1
st
blood transfusion Rh antibodies are formed in receiver’s blood so in next blood transfusion,
agglutination of blood takes place.
If mother is Rh
–
and father is Rh
+
then offspring is also Rh
+
. In this case 1
st
pregnancy is
completely successful but at the time of 1
st
delivery Rh antibody is formed in mother’s blood
due to damaged blood vessel so in next pregnancy death of fetus will occur in the earlier
stage due to agglutination of blood called erythroblastosis fetalis.
To destroy Rh antibody medicines are used like Rhogam, Rholin, Anti D.
Blood groups Antigen Antibody Receive Donate
A A b A, O A, AB
B B a B, O B, AB
AB A, B - A, B, AB, O AB
O - ab O A, B, AB, O
59
1. W hen dissolv ed in body fluids, the
antibodies produced by plasma cells are
called
a) Immunoglobulins.
b) Lymphokines
c) Agglutinins
d) Cytokines
2. Which type of lymphatic cell is responsible
for producing antibodies?
a) Macrophages
b) Helper T lymphocytes
c) Plasma cell
d) NK cell
3. A person with blood type A has
a) Anti-B antibodies in her blood plasma
b) Anti-A antibodies in her blood plasma
c) Both anti A and anti B antibodies in her
blood plasma
d) No antibodies in her blood plasma
4. The hematocrit is a measure of
a) Water concentration in the plasma
b) The percentage of erythrocytes in the
blood
c) The number of platelets in the blood
d) Antibody concentration in the plasma
5. T lymphocytes mature in the _____, while
B lymphocytes mature in the ____:
a) Yellow bone marrow; red bone marrow
b) Thyroid follicles; bone marrow
c) Bone marrow; thymus
d) Thymus; bone marrow
6. In the adult, the stem cells for leukocytes
reside in the
a) Blood stream b) Red bone marrow
c) Liver d) Muscle
7. Which type of leukocyte increases during
allergic reactions and parasitic worm
infections?
a) Basophil b) Eosinophil
c) Lymphocyte. d) Neutrophil
Simple Questions
8. Immature erythrocytes that still have nuclei
and are actively synthesizing hemoglobin
are called
a) Normoblasts b) Progenitor cells
c) Erythroblasts d) Reticulocytes
9. As the final step in the maturation process,
_____ lose their remaining ribosomes to
become erythrocytes
a) Reticulocytes b) Normoblasts
c) Erythroblasts d) Proerythroblasts
10. This cell forms platelets in the red bone
marrow
a) Lymphocyte b) Megakaryocyte
c) Eosinophil d) Reticulocyte
11. Which of the following is not a function of
blood?
a) Prevention of fluid loss
b) Nutrient and waste transport
c) Maintenance of constant pH levels
d) Production of hormones
12. Salts and protein molecules in blood help
prevent excess fluid loss from the plasma
by maintaining the proper ____; this is
necessary because water and solutes must
be able to “leak” across capillary walls to
complete another major function of blood,
____.
a) Osmotic balance; transportation
b) Filtration rate; thermoregulation
c) Water tension; chemoregulation
d) Hydrostatic pressure; immune protection
13. All types of blood cells arise indirectly from:
a) Myeloid cells
b) Lymphatic stem cells
c) Progenitor cells
d) Hemocytoblasts
14. The types of _____ are named for their
specific affinities to chemical stains
a) Erythrocytes b) Lymphocytes
c) Agranulocytes d) Granulocytes
1. W hen dissolv ed in body fluids, the
antibodies produced by plasma cells are
called
a) Immunoglobulins.
b) Lymphokines
c) Agglutinins
d) Cytokines
2. Which type of lymphatic cell is responsible
for producing antibodies?
a) Macrophages
b) Helper T lymphocytes
c) Plasma cell
d) NK cell
3. A person with blood type A has
a) Anti-B antibodies in her blood plasma
b) Anti-A antibodies in her blood plasma
c) Both anti A and anti B antibodies in her
blood plasma
d) No antibodies in her blood plasma
4. The hematocrit is a measure of
a) Water concentration in the plasma
b) The percentage of erythrocytes in the
blood
c) The number of platelets in the blood
d) Antibody concentration in the plasma
5. T lymphocytes mature in the _____, while
B lymphocytes mature in the ____:
a) Yellow bone marrow; red bone marrow
b) Thyroid follicles; bone marrow
c) Bone marrow; thymus
d) Thymus; bone marrow
6. In the adult, the stem cells for leukocytes
reside in the
a) Blood stream b) Red bone marrow
c) Liver d) Muscle
7. Which type of leukocyte increases during
allergic reactions and parasitic worm
infections?
a) Basophil b) Eosinophil
c) Lymphocyte. d) Neutrophil
Simple Questions
8. Immature erythrocytes that still have nuclei
and are actively synthesizing hemoglobin
are called
a) Normoblasts b) Progenitor cells
c) Erythroblasts d) Reticulocytes
9. As the final step in the maturation process,
_____ lose their remaining ribosomes to
become erythrocytes
a) Reticulocytes b) Normoblasts
c) Erythroblasts d) Proerythroblasts
10. This cell forms platelets in the red bone
marrow
a) Lymphocyte b) Megakaryocyte
c) Eosinophil d) Reticulocyte
11. Which of the following is not a function of
blood?
a) Prevention of fluid loss
b) Nutrient and waste transport
c) Maintenance of constant pH levels
d) Production of hormones
12. Salts and protein molecules in blood help
prevent excess fluid loss from the plasma
by maintaining the proper ____; this is
necessary because water and solutes must
be able to “leak” across capillary walls to
complete another major function of blood,
____.
a) Osmotic balance; transportation
b) Filtration rate; thermoregulation
c) Water tension; chemoregulation
d) Hydrostatic pressure; immune protection
13. All types of blood cells arise indirectly from:
a) Myeloid cells
b) Lymphatic stem cells
c) Progenitor cells
d) Hemocytoblasts
14. The types of _____ are named for their
specific affinities to chemical stains
a) Erythrocytes b) Lymphocytes
c) Agranulocytes d) Granulocytes
60
15. The most abundant type of circulating
leukocyte, which has a multilobed nucleus
and cytoplasm packed with pale staining
granules, is the
a) Eosinophil b) Neutrophil
c) Basophil d) Lymphocyte
16. Which leukocyte lacks specific granules, is
up to three times the diameter of an
erythrocyte, and has a large kidney shaped
or C shaped nucleus?
a) Monocyte b) Lymphocyte
c) Basophil d) Neutrophil
17. Persons with Rh ____ blood never exhibit
Rh____.
a) Negative; incompatibility
b) Negative; antibodies
c) Positive; surface antigens
d) Positive; antibodies
18. All the plasma proteins are synthesized in
liver gamma globulin which is synthesized
in
a) Kidney b) Lungs
c) Lymphoid organ d) All
19. Blood clotting requires
a) Na
+
+ K
+
b) Na
+
+ prothrombin
c) Na
+
+ thromboplastin
d) Ca
++
+ thromboplastin
20. Mark the pair of substances among the
following which is essential for coagulation
of blood?
a) Heparin and calcium ions
b) Calcium ions and platelet factors
c) Oxalates and citrates
d) Platelet factors and heparin
21. RBCs are nucleated in
a) Man b) Rabbit
c) Rat d) Frog
22. Content of hemoglobin / 100 ml of blood
a) 15 gm b) 20 gm
c) 10 gm d) 5 gm
23. Haemoconia is
a) Minute bits of disintegrated blood cells
b) Minute bits of disintegrated WBC
c) Minute bits of disintegrated RBC
d) Minute bits of disintegrated platelets
24. Blood colloidal osmotic pressure is mainly
maintained by which plasma protein?
a) Globulin
b) Albumin
c) Fibrinogen
d) Prothombin
25. Which one of the following plasma proteins
is involved in the coagulation of blood?
a) Serum amylase b) A globulin
c) Fibrinogen d) An albumin
26. Serum is
a) Blood without fibrinogen
b) Lymph without corpuscles
c) Blood without corpuscles and fibrinogen
d) Lymph
27. ABO blood grouping is based on
a) Surface antibodies on RBC
b) Surface antigen on WBC
c) Surface antigen on RBC
d) Plasma antigens
28. Which one is the main graveyard of RBC?
a) Bone marrow b) Spleen
c) Liver d) Kidney
29. Which of the following is lack of blood
supply?
a) Bone b) Cartilage
c) Connective tissue d) None
30. One is more in lymph than blood
a) RBC b) Nutrients
c) Lipids d) Oxygen
15. The most abundant type of circulating
leukocyte, which has a multilobed nucleus
and cytoplasm packed with pale staining
granules, is the
a) Eosinophil b) Neutrophil
c) Basophil d) Lymphocyte
16. Which leukocyte lacks specific granules, is
up to three times the diameter of an
erythrocyte, and has a large kidney shaped
or C shaped nucleus?
a) Monocyte b) Lymphocyte
c) Basophil d) Neutrophil
17. Persons with Rh ____ blood never exhibit
Rh____.
a) Negative; incompatibility
b) Negative; antibodies
c) Positive; surface antigens
d) Positive; antibodies
18. All the plasma proteins are synthesized in
liver gamma globulin which is synthesized
in
a) Kidney b) Lungs
c) Lymphoid organ d) All
19. Blood clotting requires
a) Na
+
+ K
+
b) Na
+
+ prothrombin
c) Na
+
+ thromboplastin
d) Ca
++
+ thromboplastin
20. Mark the pair of substances among the
following which is essential for coagulation
of blood?
a) Heparin and calcium ions
b) Calcium ions and platelet factors
c) Oxalates and citrates
d) Platelet factors and heparin
21. RBCs are nucleated in
a) Man b) Rabbit
c) Rat d) Frog
22. Content of hemoglobin / 100 ml of blood
a) 15 gm b) 20 gm
c) 10 gm d) 5 gm
23. Haemoconia is
a) Minute bits of disintegrated blood cells
b) Minute bits of disintegrated WBC
c) Minute bits of disintegrated RBC
d) Minute bits of disintegrated platelets
24. Blood colloidal osmotic pressure is mainly
maintained by which plasma protein?
a) Globulin
b) Albumin
c) Fibrinogen
d) Prothombin
25. Which one of the following plasma proteins
is involved in the coagulation of blood?
a) Serum amylase b) A globulin
c) Fibrinogen d) An albumin
26. Serum is
a) Blood without fibrinogen
b) Lymph without corpuscles
c) Blood without corpuscles and fibrinogen
d) Lymph
27. ABO blood grouping is based on
a) Surface antibodies on RBC
b) Surface antigen on WBC
c) Surface antigen on RBC
d) Plasma antigens
28. Which one is the main graveyard of RBC?
a) Bone marrow b) Spleen
c) Liver d) Kidney
29. Which of the following is lack of blood
supply?
a) Bone b) Cartilage
c) Connective tissue d) None
30. One is more in lymph than blood
a) RBC b) Nutrients
c) Lipids d) Oxygen
61
31. T
a) Rabbit
b) Camel
c) Monkey
d) Rat
32. Blood clot is mainly due to
a) Fibrin + corpuscles
b) Heparin + corpuscles
c) Plasma + thrombocytes
d) Plasma + RBC
Difficult Questions
1. Regarding the distribution and life span of
lymphocytes, which statement is false?
a) They are not evenly distributed in the
blood and bone marrow
b) B – lymphocytes are seldom found in the
thymus
c) They have a relatively uniform life span
of about 120 days
d) T lymphocytes may outnumber B
lymphocytes by more than 5 to 1
2. How does the production of T lymphocytes
change their puberty?
a) Some mature in the red bone marrow
before puberty but not afterward
b) In adults, they are produced only by
division of existing T lymphocytes
c) The thymus assumes a greater role in T
lymphocytes differentiation in adults
d) T lymphocytes production shifts from the
thymus to the spleen after puberty
3. Lymphocytes may respond to which of the
following?
a) Invading organisms, such as viruses
b) Abnormal body cells, such as cancer cells
c) Foreign proteins, such as toxins
released by bacteria
d) All of the above
4. During the recycling of components
following the normal destruction of
erythrocytes, globin is broken down, and its
components are
a) Used to synthesize new proteins
b) Stored as iron in the liver
c) Eliminated from the body in the bile
d) Removed in the urine
5. Myeloid stem cells give rise to three
separate lineages of _____ that differentiate
into erythrocytes, megakaryocytes, and
_____
a) Lymphoid stem cells; lymphocytes and
NK cells
b) Progenitor cells; granulocytes and
monocytes
c) Hemocytoblasts; leukocytes
d) Pluripotent cells; agranulocytes
6. W hich pair correctly matches a
lymphocyte’s function with its typical
coreceptor?
a) Turns off the immune response; CD4
b) Kills cells containing a specific antigen;
CD4
c) Initiates and overseas the immune
response; CD8
d) Kills a wide variety of infected or
cancerous cells; CD16
7. Which two of the following are typically
necessary to stimulate a B lymphocyte to
divide and differentiate?
a) A plasma cell and an antibody
b) A helper T lymphocyte and an antigen
c) A cytokine and an immunoglobulin
d) A memory T lymphocyte and a cytokine
8. An elevated count of neutrophils in the blood
would most likely indicate
a) An acute viral infection
b) A parasitic infection
c) A chronic bacterial infection
d) An allergic reaction
31. T
a) Rabbit
b) Camel
c) Monkey
d) Rat
32. Blood clot is mainly due to
a) Fibrin + corpuscles
b) Heparin + corpuscles
c) Plasma + thrombocytes
d) Plasma + RBC
Difficult Questions
1. Regarding the distribution and life span of
lymphocytes, which statement is false?
a) They are not evenly distributed in the
blood and bone marrow
b) B – lymphocytes are seldom found in the
thymus
c) They have a relatively uniform life span
of about 120 days
d) T lymphocytes may outnumber B
lymphocytes by more than 5 to 1
2. How does the production of T lymphocytes
change their puberty?
a) Some mature in the red bone marrow
before puberty but not afterward
b) In adults, they are produced only by
division of existing T lymphocytes
c) The thymus assumes a greater role in T
lymphocytes differentiation in adults
d) T lymphocytes production shifts from the
thymus to the spleen after puberty
3. Lymphocytes may respond to which of the
following?
a) Invading organisms, such as viruses
b) Abnormal body cells, such as cancer cells
c) Foreign proteins, such as toxins
released by bacteria
d) All of the above
4. During the recycling of components
following the normal destruction of
erythrocytes, globin is broken down, and its
components are
a) Used to synthesize new proteins
b) Stored as iron in the liver
c) Eliminated from the body in the bile
d) Removed in the urine
5. Myeloid stem cells give rise to three
separate lineages of _____ that differentiate
into erythrocytes, megakaryocytes, and
_____
a) Lymphoid stem cells; lymphocytes and
NK cells
b) Progenitor cells; granulocytes and
monocytes
c) Hemocytoblasts; leukocytes
d) Pluripotent cells; agranulocytes
6. W hich pair correctly matches a
lymphocyte’s function with its typical
coreceptor?
a) Turns off the immune response; CD4
b) Kills cells containing a specific antigen;
CD4
c) Initiates and overseas the immune
response; CD8
d) Kills a wide variety of infected or
cancerous cells; CD16
7. Which two of the following are typically
necessary to stimulate a B lymphocyte to
divide and differentiate?
a) A plasma cell and an antibody
b) A helper T lymphocyte and an antigen
c) A cytokine and an immunoglobulin
d) A memory T lymphocyte and a cytokine
8. An elevated count of neutrophils in the blood
would most likely indicate
a) An acute viral infection
b) A parasitic infection
c) A chronic bacterial infection
d) An allergic reaction
62
9. Which two types of cells release histamine
(to dilate blood vessels) and heparin (to
inhibit clotting)?
a) Basophils and eosinophils
b) Neutrophils and lymphocytes
c) Monocytes and macrophages
d) Mast cells and basophils
10. In contrast to vaccination, injection of
immunoglobulins
a) Stimulates activity by helper T
lymphocytes and eventually by plasma
cells
b) Provides antibodies directly without
training the body how to produce them
c) Is rarely effective against antigens
already present in the body
d) Protects the recipient against a specific
illness for a much longer time
11. A general shortage of the only formed
elements that retain all of their organelles
is called
a) Leukopenia b) Anaemia
c) Hemophilia d) Leukemia
12. When a leukocyte squeezes between
endothelial cells in pursuit of pathogens, its
____ has triggered its____
a) Random movement; entrapment
b) Phagocytosis; autolysis
c) Chemotaxis; diapedesis
d) Hemolysis; differentiation
13. Given that the liver synthesizes most of the
plasma proteins, severe liver disorders can
be expected to cause
a) Decreased osmotic pressure of the
blood plasma
b) Less efficient transport of iron ions and
lipids
c) Diminished clotting ability
d) All of the above
14. The type of leukocyte that produces
antibodies is a (an)
a) Eosinophil b) Basophil
c) T-lymphocyte d) B lymphocyte
15. Which of the following is not a characteristic
of a mature erythrocyte?
a) It has a biconcave disc shape
b) It lacks organelles
c) Its usual life span is about 12 months
d) It is filled with hemoglobin
16. How can Rh antibodies, the very molecules
that cause hemolytic disease of the
newborn, prevent this disease when
administered to an Rh negative woman who
is pregnant with an Rh positive fetus?
a) The antibodies cross the placenta early
in development and desensitizes the
fetus’s blood
b) Presence of the antibodies transforms
the fetus into an Rh negative individual
c) The antibodies destroy any Rh antigens
from the fetus before the mother is
sensitized
d) None of the above; an Rh negative
woman cannot have an Rh positive child
17. According to Best and Taylor’s theory, which
of the following does not play any role in
blood clotting?
a) Calcium ions b) Prothrombin
c) Fibrinogen d) Platelets
18. In the blood bank, donor’s blood is treated
with_____ chemical to prevent clotting
a) Heparin
b) Sodium citrate
c) Sodium glycocholate
d) Sodium taurocholate
19. A blood group has agglutinogen on / in
a) Serum b) RBC
c) Plasma d) Hemoglobin
9. Which two types of cells release histamine
(to dilate blood vessels) and heparin (to
inhibit clotting)?
a) Basophils and eosinophils
b) Neutrophils and lymphocytes
c) Monocytes and macrophages
d) Mast cells and basophils
10. In contrast to vaccination, injection of
immunoglobulins
a) Stimulates activity by helper T
lymphocytes and eventually by plasma
cells
b) Provides antibodies directly without
training the body how to produce them
c) Is rarely effective against antigens
already present in the body
d) Protects the recipient against a specific
illness for a much longer time
11. A general shortage of the only formed
elements that retain all of their organelles
is called
a) Leukopenia b) Anaemia
c) Hemophilia d) Leukemia
12. When a leukocyte squeezes between
endothelial cells in pursuit of pathogens, its
____ has triggered its____
a) Random movement; entrapment
b) Phagocytosis; autolysis
c) Chemotaxis; diapedesis
d) Hemolysis; differentiation
13. Given that the liver synthesizes most of the
plasma proteins, severe liver disorders can
be expected to cause
a) Decreased osmotic pressure of the
blood plasma
b) Less efficient transport of iron ions and
lipids
c) Diminished clotting ability
d) All of the above
14. The type of leukocyte that produces
antibodies is a (an)
a) Eosinophil b) Basophil
c) T-lymphocyte d) B lymphocyte
15. Which of the following is not a characteristic
of a mature erythrocyte?
a) It has a biconcave disc shape
b) It lacks organelles
c) Its usual life span is about 12 months
d) It is filled with hemoglobin
16. How can Rh antibodies, the very molecules
that cause hemolytic disease of the
newborn, prevent this disease when
administered to an Rh negative woman who
is pregnant with an Rh positive fetus?
a) The antibodies cross the placenta early
in development and desensitizes the
fetus’s blood
b) Presence of the antibodies transforms
the fetus into an Rh negative individual
c) The antibodies destroy any Rh antigens
from the fetus before the mother is
sensitized
d) None of the above; an Rh negative
woman cannot have an Rh positive child
17. According to Best and Taylor’s theory, which
of the following does not play any role in
blood clotting?
a) Calcium ions b) Prothrombin
c) Fibrinogen d) Platelets
18. In the blood bank, donor’s blood is treated
with_____ chemical to prevent clotting
a) Heparin
b) Sodium citrate
c) Sodium glycocholate
d) Sodium taurocholate
19. A blood group has agglutinogen on / in
a) Serum b) RBC
c) Plasma d) Hemoglobin
63
20. B
heart is rich in
a) Bile b) Urea
c) Ammonia d) Oxygen
21. Diapedesis is
a) A type of ameboid movement
b) Movement of some WBC to tissue
through the wall of blood capillary to
destroy harmful bacteria
c) A type of movement in hydra
d) Filtration process of urea in kidney
22. Feature of pernicious anaemia is
a) Increased size of RBC
b) Deficiency of vitamin B in body
c) Delay in maturation of erythroblasts
d) All
23. Ratio WBC/RBC in human blood
a) 1: 100 b) 1: 200
c) 500: 1 d) 1: 500
24. Heparin in synthesized in
a) Liver b) Kidney
c) Saliva d) Pancreas
25. pH of blood is
a) More in arteries than in veins
b) More in veins than in arteries
c) Same in arteries and veins
d) Variable
26. HbF (foetal Hb) has chain
a) 2 , 2 b) 2 , 2
c) 2 , 2 d) 4
27. Sex chromatin present in
a) Drum stick like in lobe of neutrophil
b) Drum stick like in lobe of basophil
c) Drum stick like in lobe of eosinophil
d) Drum stick like in lobe of lymphocyte
28. Which of the following is the anticoagulant
used in blood cell counting?
a) Acetic acid b) Formaldehyde
c) EDTA d) Benzene
29. In leukemia (blood cancer) leukocyte count
a) > 1 lac b) < 10,000
c) 10 – 20,000 d) None
30. Eosinophilia is caused by
a) Teniasis b) Ascariasis
c) Hay fever d) All of the above
ANSWER KEYS
Simple Questions
1.a 2.c 3.a 4.b 5.d 6.b 7.b 8.a 9.a 10.b 11.d 12.a
13.d 14.d 15.b 16.a 17.d 18.c 19.d 20.b 21.d 22.a 23.c 24.b
25.c 26.c 27.c 28.b 29.b 30.c 31.b 32.a
Difficult Questions
1.c 2.b 3.d 4.a 5.b 6.d 7.b 8.c 9.d 10.b 11.a 12.c
13.d 14.d 15.c 16.c 17.d 18.b 19.b 20.b 21.b 22.d 23.d 24.a
25.b 26.b 27.a 28.c 29.a 30.d
20. B
heart is rich in
a) Bile b) Urea
c) Ammonia d) Oxygen
21. Diapedesis is
a) A type of ameboid movement
b) Movement of some WBC to tissue
through the wall of blood capillary to
destroy harmful bacteria
c) A type of movement in hydra
d) Filtration process of urea in kidney
22. Feature of pernicious anaemia is
a) Increased size of RBC
b) Deficiency of vitamin B in body
c) Delay in maturation of erythroblasts
d) All
23. Ratio WBC/RBC in human blood
a) 1: 100 b) 1: 200
c) 500: 1 d) 1: 500
24. Heparin in synthesized in
a) Liver b) Kidney
c) Saliva d) Pancreas
25. pH of blood is
a) More in arteries than in veins
b) More in veins than in arteries
c) Same in arteries and veins
d) Variable
26. HbF (foetal Hb) has chain
a) 2 , 2 b) 2 , 2
c) 2 , 2 d) 4
27. Sex chromatin present in
a) Drum stick like in lobe of neutrophil
b) Drum stick like in lobe of basophil
c) Drum stick like in lobe of eosinophil
d) Drum stick like in lobe of lymphocyte
28. Which of the following is the anticoagulant
used in blood cell counting?
a) Acetic acid b) Formaldehyde
c) EDTA d) Benzene
29. In leukemia (blood cancer) leukocyte count
a) > 1 lac b) < 10,000
c) 10 – 20,000 d) None
30. Eosinophilia is caused by
a) Teniasis b) Ascariasis
c) Hay fever d) All of the above
ANSWER KEYS
Simple Questions
1.a 2.c 3.a 4.b 5.d 6.b 7.b 8.a 9.a 10.b 11.d 12.a
13.d 14.d 15.b 16.a 17.d 18.c 19.d 20.b 21.d 22.a 23.c 24.b
25.c 26.c 27.c 28.b 29.b 30.c 31.b 32.a
Difficult Questions
1.c 2.b 3.d 4.a 5.b 6.d 7.b 8.c 9.d 10.b 11.a 12.c
13.d 14.d 15.c 16.c 17.d 18.b 19.b 20.b 21.b 22.d 23.d 24.a
25.b 26.b 27.a 28.c 29.a 30.d
64
1. W
a) Kupffer’s cells b) Bone cells
c) Mast cells d) None
2. You are required to draw blood from a
patient and to keep it in a test tube for the
analysis of blood corpuscles and plasma.
You are also provided with the following four
types of test tubes. Which of them will you
not use for the purpose?
a) Test tube containing calcium bicarbonate.
b) Chilled test tube
c) Test tube containing heparin
d) Test tube containing sodium oxalate
3. Life span of platelets is
a) 4 days b) 9 to 12 days
c) 20 to 30 days d) 90 days
4. Human blood maintains homeostasis in the
internal environment of the body by
a) Replenishment of oxygen and
elimination of CO
2
b) Replenishment of nutrients and oxygen
and elimination of metabolic wastes from
the extracellular fluid
c) Maintenance of ion concentration in the
blood and body fluids by eliminating
nitrogenous wastes
d) Maintenance of blood sugar level and
conversion of amino acids into urea and
destruction of worn out RBCs
DPP - 3
5. Coloring agent of plasma is
a) Billiverdin b) Stercobilinogen
c) Urobilinogen d) Urochrome
6. Blood protein which initiates blood
coagulation is
a) Prothrombin
b) Thrombin
c) Fibrinogen
d) Fibrin
7. The organs yolk sac, kidney, spleen, liver
and bone marrow are
a) Erythropoietic
b) Red organs
c) Both (a) and (b)
d) Diapedic
8. Thrombocytopenic purpura is a
hemorrhagic disorder. This is because of
a) Very high platelet count
b) Very low platelet count
c) Low concentration of fibrinogen
d) Absence of vitamin K
9. Blood cells are produced by bone marrow
in
a) All bones b) Some bones
c) Most of the bones d) None
10. First site of hemopoiesis is
a) Bone marrow b) Spleen
c) Liver d) Yolk sac
1. W
a) Kupffer’s cells b) Bone cells
c) Mast cells d) None
2. You are required to draw blood from a
patient and to keep it in a test tube for the
analysis of blood corpuscles and plasma.
You are also provided with the following four
types of test tubes. Which of them will you
not use for the purpose?
a) Test tube containing calcium bicarbonate.
b) Chilled test tube
c) Test tube containing heparin
d) Test tube containing sodium oxalate
3. Life span of platelets is
a) 4 days b) 9 to 12 days
c) 20 to 30 days d) 90 days
4. Human blood maintains homeostasis in the
internal environment of the body by
a) Replenishment of oxygen and
elimination of CO
2
b) Replenishment of nutrients and oxygen
and elimination of metabolic wastes from
the extracellular fluid
c) Maintenance of ion concentration in the
blood and body fluids by eliminating
nitrogenous wastes
d) Maintenance of blood sugar level and
conversion of amino acids into urea and
destruction of worn out RBCs
DPP - 3
5. Coloring agent of plasma is
a) Billiverdin b) Stercobilinogen
c) Urobilinogen d) Urochrome
6. Blood protein which initiates blood
coagulation is
a) Prothrombin
b) Thrombin
c) Fibrinogen
d) Fibrin
7. The organs yolk sac, kidney, spleen, liver
and bone marrow are
a) Erythropoietic
b) Red organs
c) Both (a) and (b)
d) Diapedic
8. Thrombocytopenic purpura is a
hemorrhagic disorder. This is because of
a) Very high platelet count
b) Very low platelet count
c) Low concentration of fibrinogen
d) Absence of vitamin K
9. Blood cells are produced by bone marrow
in
a) All bones b) Some bones
c) Most of the bones d) None
10. First site of hemopoiesis is
a) Bone marrow b) Spleen
c) Liver d) Yolk sac
65
4.1 INTRODUCTION
A
ll metabolic processes in the body require nutrients and oxygen and produce waste products.
Nutrients are absorbed through the digestive system and oxygen is acquired through the respiratory
system. The cardiovascular system is responsible for moving material through the body. The heart
pumps blood throughout the blood vessels.
The whole circulatory system in human is formed by the mesoderm of embryo, except the inner
lining of blood vessels and heart which are of endodermal origin.
Types of circulatory system based on complexity and evolution:
In humans (on the basis of circulating fluid) two types of circulatory system are observed.
Blood circulatory system: It consist of – blood, blood vessels, heart.
Lymphatic system: It consists of lymph, lymph capillaries, lymph vessels, lymph nodes,
lymphoid tissues / organs.
The study of blood vascular system or circulatory system is called angiology.
William Harvey is known as father of angiology. He called heart as the “pumping station of body”.
Blood circulation
Single Circuit: Eg. fishes
HEART
CO
2
Gills
O
2
Body Parts
CO
2
Double Circuit: Eg. man, rabbit
LUNGS
Smaller Circuit
(1) Pulmonary circuit
ORGANS
Greater Circuit
(2) Systemic circuit
HEART
RA LA
LVRV
O
2
CO
2
CO
2
O
2
UNIT 4 - CARDIOVASCULAR SYSTEM
Open type Closed type
Blood is filled in coelomic channel and sinus Blood circulates in closed vessels coelom is called haemocoel. Fluid is called
haemolymph.
Tissues are in direct contact with circulating Tissues are not in direct contact with circulating
fluid fluid
eg. Arthropods, non cephalopod molluscs eg. Annelids, cephalopod molluscs, chordates
4.1 INTRODUCTION
A
ll metabolic processes in the body require nutrients and oxygen and produce waste products.
Nutrients are absorbed through the digestive system and oxygen is acquired through the respiratory
system. The cardiovascular system is responsible for moving material through the body. The heart
pumps blood throughout the blood vessels.
The whole circulatory system in human is formed by the mesoderm of embryo, except the inner
lining of blood vessels and heart which are of endodermal origin.
Types of circulatory system based on complexity and evolution:
In humans (on the basis of circulating fluid) two types of circulatory system are observed.
Blood circulatory system: It consist of – blood, blood vessels, heart.
Lymphatic system: It consists of lymph, lymph capillaries, lymph vessels, lymph nodes,
lymphoid tissues / organs.
The study of blood vascular system or circulatory system is called angiology.
William Harvey is known as father of angiology. He called heart as the “pumping station of body”.
Blood circulation
Single Circuit: Eg. fishes
HEART
CO
2
Gills
O
2
Body Parts
CO
2
Double Circuit: Eg. man, rabbit
LUNGS
Smaller Circuit
(1) Pulmonary circuit
ORGANS
Greater Circuit
(2) Systemic circuit
HEART
RA LA
LVRV
O
2
CO
2
CO
2
O
2
UNIT 4 - CARDIOVASCULAR SYSTEM
Open type Closed type
Blood is filled in coelomic channel and sinus Blood circulates in closed vessels coelom is called haemocoel. Fluid is called
haemolymph.
Tissues are in direct contact with circulating Tissues are not in direct contact with circulating
fluid fluid
eg. Arthropods, non cephalopod molluscs eg. Annelids, cephalopod molluscs, chordates
66
Transitional type circuit: Two circuits are not completely separate. E.g. Frog – blood mixes in ventricles.
Evolutionary sequence is present in vertebrates
Fishes have a tubular “venous heart”. In their heart, deoxygenated blood enters from one
side and from the other side enters inside the gills for purification. This is called the “single
heart circuit”.
In amphibians (like frog) and reptiles the
auricles are divided into right and left.
Right auricle gets impure and left auricle
gets pure blood from the body. But only 1
ventricle is present or is incompletely
divided so after coming here the pure and
impure blood mix up.
In some reptiles (Crocodile, Gavialis and
Alligator) and in all birds and mammals the heart
is divided into 2 auricles and 2 ventricles so while
circulating inside the heart the pure and impure
blood remain separated. The right portion of the
heart collects impure blood from the body and
sends it to the lungs for purification, while the
left portion takes pure blood from the lungs and
distributes it to the whole body.
The right portion of the heart is called as the
“pulmonary heart” and the left portion is termed
as the “systemic heart”. This is termed as “double circulation of heart”, because the blood has to
pass through the heart twice before being delivered to systemic organs.
Types of heart on the basis of type of blood which it receives:
Venous / Branchial (fishes)
Arterial (prawn)
Arterio venous (lung fishes, tetrapods)
4.2 HEART
The heart pumps continuously to provide tissues and organs with needed oxygen and remove
cellular waste materials. On average, the heart pumps 70 to 72 beats per minute, every minute of
every day. It is able to pump close to the entire volume of blood in your body every minute. This
means that on a daily basis, almost 7200 liters of blood are pumped by the heart. This amount
increases when you exercise.
Pulmonary circuit
Systemic circuit
Key:
= Oxygen poor,
CO
2
-rich blood
Path of blood in double circuit (man) - first
discovered by William Harvey
Transitional type circuit: Two circuits are not completely separate. E.g. Frog – blood mixes in ventricles.
Evolutionary sequence is present in vertebrates
Fishes have a tubular “venous heart”. In their heart, deoxygenated blood enters from one
side and from the other side enters inside the gills for purification. This is called the “single
heart circuit”.
In amphibians (like frog) and reptiles the
auricles are divided into right and left.
Right auricle gets impure and left auricle
gets pure blood from the body. But only 1
ventricle is present or is incompletely
divided so after coming here the pure and
impure blood mix up.
In some reptiles (Crocodile, Gavialis and
Alligator) and in all birds and mammals the heart
is divided into 2 auricles and 2 ventricles so while
circulating inside the heart the pure and impure
blood remain separated. The right portion of the
heart collects impure blood from the body and
sends it to the lungs for purification, while the
left portion takes pure blood from the lungs and
distributes it to the whole body.
The right portion of the heart is called as the
“pulmonary heart” and the left portion is termed
as the “systemic heart”. This is termed as “double circulation of heart”, because the blood has to
pass through the heart twice before being delivered to systemic organs.
Types of heart on the basis of type of blood which it receives:
Venous / Branchial (fishes)
Arterial (prawn)
Arterio venous (lung fishes, tetrapods)
4.2 HEART
The heart pumps continuously to provide tissues and organs with needed oxygen and remove
cellular waste materials. On average, the heart pumps 70 to 72 beats per minute, every minute of
every day. It is able to pump close to the entire volume of blood in your body every minute. This
means that on a daily basis, almost 7200 liters of blood are pumped by the heart. This amount
increases when you exercise.
Pulmonary circuit
Systemic circuit
Key:
= Oxygen poor,
CO
2
-rich blood
Path of blood in double circuit (man) - first
discovered by William Harvey
67
4.2.1 A
A. External structure
Heart is situated at the ventral side of mediastinal space of thoracic cavity in between the lungs. Left
lung has cardiac notch, heart is 5 – 3.5 inches in size, weight 300 gm. It is enclosed in coelomic
epithelium. Its triangular superior broad portion is tilted slightly towards right (dorsal) side. Its lower
narrow portion is tilted towards left side. Covering of heart is called pericardium which consists of
two layers.
Outer: Parietal pericardium in which two sub layers are present:
a) Outer: fibrous connective tissue layer.
b) Inner: Simple squamous epithelium (serous membrane).
Inner: Visceral pericardium or epicardium made up of simple squamous epithelium (Serous
membrane).
The narrow space in between these two membranes is called pericardial cavity.
A serous fluid present in the cavity is called pericardial fluid. It is secreted by the pericardium.
Pericardial cavity is a true coelom (as it lies between two layers of mesoderm).
Functions of pericardial fluid:
It prevents the heart from external jerks.
It provides moisture to heart. It prevents the two membranes from collapsing.
It prevents the heart from the bad effect of friction at the time of contraction.
B. Heart wall
Just deep to the pericardium is the myocardium, which is the muscle layer of the heart. It comprises
99% of the mass of the heart. The endocardium is the innermost layer of the heart tissue that lines
the heart chambers and is continuous with the endothelium lining blood vessels.
Layers of the heart wall
Pericardial cavity
Fibrous
layer
Parietal
pericardium
Visceral
pericardium
Myocardium
Endocardium
Layer Characteristics Function
Epicardium Serous membrane Serves as
(visceral layer including blood capillaries, lubricative
of serous lymph capillaries, and outer covering
pericardium) nerve fibers
Myocardium Cardiac muscle tissue Provides muscular
separated by connective contractions that
tissues and including eject blood
blood capillaries, lymph from the
capillaries, and nerve fibers heart chambers
Endocardium Endothelial tissue and a Serves as
thick subendothelial protective inner
layer of elastic and lining of the
collagenous fibers chambers and
valves
4.2.1 A
A. External structure
Heart is situated at the ventral side of mediastinal space of thoracic cavity in between the lungs. Left
lung has cardiac notch, heart is 5 – 3.5 inches in size, weight 300 gm. It is enclosed in coelomic
epithelium. Its triangular superior broad portion is tilted slightly towards right (dorsal) side. Its lower
narrow portion is tilted towards left side. Covering of heart is called pericardium which consists of
two layers.
Outer: Parietal pericardium in which two sub layers are present:
a) Outer: fibrous connective tissue layer.
b) Inner: Simple squamous epithelium (serous membrane).
Inner: Visceral pericardium or epicardium made up of simple squamous epithelium (Serous
membrane).
The narrow space in between these two membranes is called pericardial cavity.
A serous fluid present in the cavity is called pericardial fluid. It is secreted by the pericardium.
Pericardial cavity is a true coelom (as it lies between two layers of mesoderm).
Functions of pericardial fluid:
It prevents the heart from external jerks.
It provides moisture to heart. It prevents the two membranes from collapsing.
It prevents the heart from the bad effect of friction at the time of contraction.
B. Heart wall
Just deep to the pericardium is the myocardium, which is the muscle layer of the heart. It comprises
99% of the mass of the heart. The endocardium is the innermost layer of the heart tissue that lines
the heart chambers and is continuous with the endothelium lining blood vessels.
Layers of the heart wall
Pericardial cavity
Fibrous
layer
Parietal
pericardium
Visceral
pericardium
Myocardium
Endocardium
Layer Characteristics Function
Epicardium Serous membrane Serves as
(visceral layer including blood capillaries, lubricative
of serous lymph capillaries, and outer covering
pericardium) nerve fibers
Myocardium Cardiac muscle tissue Provides muscular
separated by connective contractions that
tissues and including eject blood
blood capillaries, lymph from the
capillaries, and nerve fibers heart chambers
Endocardium Endothelial tissue and a Serves as
thick subendothelial protective inner
layer of elastic and lining of the
collagenous fibers chambers and
valves
68
C. Heart Chambers
H
uman heart is four chambered with 2 auricles and 2 ventricles. It is pinkish in color and conical in
shape. Broad upper part is the auricular part or base and lower conical part is the ventricular part (its
tip is called apex). In between the auricles and ventricles, a clear groove is present, which is known
as coronary sulcus. This groove is more towards auricles; by the effect of this the auricular surface
is smaller than ventricles.
Brachiocephalic artery
Left common carotid artery
Left subclavian artery
Aorta
Left pulmonary arteries
Pulmonary trunk
Left Pulmonary veins
Left atrium
Semilunar valves
Atrioventricular
(mitral valve)
Myocardium
Left ventricle
Endocardium
Septum
Superior
vena cava
Right
pulmonary
arteries
Right
pulmonary
veins
Right atrium
Atrioventricular
(tricuspid) valve
Chordae tendineae
Papillary muscles
Right ventricle
Inferior vena cava
Structure of Heart
Auricles: Auricular part of heart is smaller and of dark color. Its walls are thin. It is divided into right
and left auricles by fissure called interauricular sulcus, which is shifted slightly towards left. Therefore
out of these two, right auricular surface is bigger than left auricle.
Each auricle forms a bulbous structure called auricular appendages. It covers a small part of ventricle
of its side.
Ventricles: Ventricular part is broad, muscular and of light color. Ventricles have thicker walls than
auricles. The grooves which divide the two ventricles are termed as inter ventricular groove or
sulcus. It is oblique or tilted towards right. It does not reach till the tip or apex of the heart, so the
right ventricle is smaller than the left ventricle. Left ventricle is more muscular and thick walled than
right because it has to pump blood into those arteries which take blood throughout the body while
right ventricle has to pump blood only to the lungs.
C. Heart Chambers
H
uman heart is four chambered with 2 auricles and 2 ventricles. It is pinkish in color and conical in
shape. Broad upper part is the auricular part or base and lower conical part is the ventricular part (its
tip is called apex). In between the auricles and ventricles, a clear groove is present, which is known
as coronary sulcus. This groove is more towards auricles; by the effect of this the auricular surface
is smaller than ventricles.
Brachiocephalic artery
Left common carotid artery
Left subclavian artery
Aorta
Left pulmonary arteries
Pulmonary trunk
Left Pulmonary veins
Left atrium
Semilunar valves
Atrioventricular
(mitral valve)
Myocardium
Left ventricle
Endocardium
Septum
Superior
vena cava
Right
pulmonary
arteries
Right
pulmonary
veins
Right atrium
Atrioventricular
(tricuspid) valve
Chordae tendineae
Papillary muscles
Right ventricle
Inferior vena cava
Structure of Heart
Auricles: Auricular part of heart is smaller and of dark color. Its walls are thin. It is divided into right
and left auricles by fissure called interauricular sulcus, which is shifted slightly towards left. Therefore
out of these two, right auricular surface is bigger than left auricle.
Each auricle forms a bulbous structure called auricular appendages. It covers a small part of ventricle
of its side.
Ventricles: Ventricular part is broad, muscular and of light color. Ventricles have thicker walls than
auricles. The grooves which divide the two ventricles are termed as inter ventricular groove or
sulcus. It is oblique or tilted towards right. It does not reach till the tip or apex of the heart, so the
right ventricle is smaller than the left ventricle. Left ventricle is more muscular and thick walled than
right because it has to pump blood into those arteries which take blood throughout the body while
right ventricle has to pump blood only to the lungs.
69
The four chambers of the mammalian heart:
D. Walls in heart chambers
E. Heart valves
Right auricle or atriumInlets: It receives one SVC, one IVC and one opening of coronary sinus
in man. In rabbit, it receives two SVC (right and left). The SVC and IVC
bring impure blood from the upper and lower body parts respectively.
The coronary sinus receives impure blood from the right and left
coronary veins and drains it in the right auricle.
Outlets: This impure blood drains through the right AV foramen into the
right ventricle.
Right ventricle Inlets: Receives impure blood through right AV foramen from right auricle.
Outlets: Drains the impure blood into pulmonary artery through which it
reaches lungs for oxygenation.
Left auricle Inlets: Receives oxygenated blood from lungs via pulmonary vein.
Outlets: This pure blood is drained into left ventricle through left AV foramen.
Left ventricle Inlets: Receives pure blood through left AV foramen from left auricle.
Outlets: Drains pure blood into the aorta from where it is supplied to
systemic organs.
Auricles The inner wall surface here presents a series of transverse muscular ridges called musculi pectinati. They run forward and downward towards AV foramen, giving
appearance of the teeth of a comb (combed muscles).
VentriclesThe inner wall is rough due to presence of muscular ridges trabeculae carnae or
columnae carnae. These continue as papillary muscles, whose one end is attached
to the ventricular wall and the other end connected to the cusps of AV valves by Chordae tendinae. These chorda tendinae are collagenous and inelastic chords
one end of which is inserted in the papillary muscles and other end is connected to the flaps of AV valves. These are meant for preventing the pushing of flaps into
atrium during ventricular contraction
Right atrium All its inlets are guarded with valves to prevent backflow of the blood. The
SVC opening is said to be guarded by Haversian valve. The IVC which opens
below this has its opening guarded by a valve called Eustachian valve (during
embryonic life the valve guides the inferior vena caval blood to the left auricle
through foramen ovale). The opening of coronary sinus in right atrium is
guarded by Thebesian valve.
Left atrium At its inlet in pulmonary vein (four veins in man and two in rabbit), these have
no guarding valve.
The four chambers of the mammalian heart:
D. Walls in heart chambers
E. Heart valves
Right auricle or atriumInlets: It receives one SVC, one IVC and one opening of coronary sinus
in man. In rabbit, it receives two SVC (right and left). The SVC and IVC
bring impure blood from the upper and lower body parts respectively.
The coronary sinus receives impure blood from the right and left
coronary veins and drains it in the right auricle.
Outlets: This impure blood drains through the right AV foramen into the
right ventricle.
Right ventricle Inlets: Receives impure blood through right AV foramen from right auricle.
Outlets: Drains the impure blood into pulmonary artery through which it
reaches lungs for oxygenation.
Left auricle Inlets: Receives oxygenated blood from lungs via pulmonary vein.
Outlets: This pure blood is drained into left ventricle through left AV foramen.
Left ventricle Inlets: Receives pure blood through left AV foramen from left auricle.
Outlets: Drains pure blood into the aorta from where it is supplied to
systemic organs.
Auricles The inner wall surface here presents a series of transverse muscular ridges called musculi pectinati. They run forward and downward towards AV foramen, giving
appearance of the teeth of a comb (combed muscles).
VentriclesThe inner wall is rough due to presence of muscular ridges trabeculae carnae or
columnae carnae. These continue as papillary muscles, whose one end is attached
to the ventricular wall and the other end connected to the cusps of AV valves by Chordae tendinae. These chorda tendinae are collagenous and inelastic chords
one end of which is inserted in the papillary muscles and other end is connected to the flaps of AV valves. These are meant for preventing the pushing of flaps into
atrium during ventricular contraction
Right atrium All its inlets are guarded with valves to prevent backflow of the blood. The
SVC opening is said to be guarded by Haversian valve. The IVC which opens
below this has its opening guarded by a valve called Eustachian valve (during
embryonic life the valve guides the inferior vena caval blood to the left auricle
through foramen ovale). The opening of coronary sinus in right atrium is
guarded by Thebesian valve.
Left atrium At its inlet in pulmonary vein (four veins in man and two in rabbit), these have
no guarding valve.
70
From the two ventricles the pulmonary artery and systemic aorta arise out in the form of arches
(
called as pulmonary and systemic arches). These arches cross each other and at the point of
crossing they are attached by ligamentum arteriosum. Ligamentum arteriosum is the remainant of
ductus arteriosus. Ductus arteriosus is a small channel connecting the lumen of the two arches
which closes at the time of birth.
Side view
cross-section
Tricuspid valve
Pulmonary valve
Aortic valve
Mitral valve
Tricuspid
valve
Top view enlarged
cross-section
Mitral valve
Coronary
sinus
Pulmonary
valve
Left
coronary
artery
Aortic valve
Right
coronary
artery
F. Septum
Interauricular septum – It is a partition between the left and right auricles. It is shifted slightly
towards left, so the right auricle is slightly bigger than left. An oval depression (fossa ovalis) is
present on its posterior part. It is remainant of foramen ovale present in foetal stage which closes at
birth. In foetal circulation the lungs are non functional and by-passed so the blood directly reaches
the left atrium from right atrium through foramen ovale.
AV foramen The right AV foramen has a unidirectional valve called tricuspid valve (made
of three flaps or cusps) which allows entry of blood from right atrium to right
ventricle and prevents its backflow. The unidirectional valve present on left AV
foramen is made of two cusps only hence called bicuspid valve (also called
as the Mitral valve).
Right ventricleIts outlet is in the pulmonary artery. It is guarded by a pulmonary semilunar
valve.
Left ventricleIts outlet is in the systemic aorta. This opening is guarded by an aortic semilunar
valve. Both these semilunar valves are made of three cusps each and are
unidirectional in nature.
From the two ventricles the pulmonary artery and systemic aorta arise out in the form of arches
(
called as pulmonary and systemic arches). These arches cross each other and at the point of
crossing they are attached by ligamentum arteriosum. Ligamentum arteriosum is the remainant of
ductus arteriosus. Ductus arteriosus is a small channel connecting the lumen of the two arches
which closes at the time of birth.
Side view
cross-section
Tricuspid valve
Pulmonary valve
Aortic valve
Mitral valve
Tricuspid
valve
Top view enlarged
cross-section
Mitral valve
Coronary
sinus
Pulmonary
valve
Left
coronary
artery
Aortic valve
Right
coronary
artery
F. Septum
Interauricular septum – It is a partition between the left and right auricles. It is shifted slightly
towards left, so the right auricle is slightly bigger than left. An oval depression (fossa ovalis) is
present on its posterior part. It is remainant of foramen ovale present in foetal stage which closes at
birth. In foetal circulation the lungs are non functional and by-passed so the blood directly reaches
the left atrium from right atrium through foramen ovale.
AV foramen The right AV foramen has a unidirectional valve called tricuspid valve (made
of three flaps or cusps) which allows entry of blood from right atrium to right
ventricle and prevents its backflow. The unidirectional valve present on left AV
foramen is made of two cusps only hence called bicuspid valve (also called
as the Mitral valve).
Right ventricleIts outlet is in the pulmonary artery. It is guarded by a pulmonary semilunar
valve.
Left ventricleIts outlet is in the systemic aorta. This opening is guarded by an aortic semilunar
valve. Both these semilunar valves are made of three cusps each and are
unidirectional in nature.
71
Interventricular septum – It is a partition dividing the right and left ventricles. It is shifted towards
right. So the left ventricle is bigger than right.
Auriculoventricular septum – It separates the two auricles from the two ventricles. It is shifted
upwards towards auricles. Therefore auricles are smaller than ventricles.
TARGET POINTS
Systemic heart – Left part of the heart (i.e. left auricle and left ventricle) contain the blood which
is to be pumped into the systemic circulation. The main purpose of such a circulation is to
transport oxygen as well as nutrients to the body tissues, and to remove carbon dioxide and
other harmful nitrogenous waste from them.
Pulmonary heart – Right part of the heart (i.e. right auricle and right ventricle) contain the blood
which is to be pumped in pulmonary circulation for oxygenation. The pulmonary circulation is
responsible for regular oxygenation of the impure deoxygenated blood which is received by the
right auricle.
Blood supply of heart (coronary circulation) – The oxygenated blood is supplied to the heart
musculature for its consumption with the help of two coronary arteries, left and right. These
arteries arise from the common origin at arch of aorta. The left and right coronary arteries then
further subdivided into number of branches carrying blood to different regions of heart. The
impure blood from heart walls return back via coronary veins which drain into the coronary sinus.
The coronary sinus opens in the right atrium.
4.2.2 Heart conduction
Autorhythmic cells are located in 5 main groups that form the conduction system of the heart
Left atrium
Left ventricle
Anterior view of frontal section
Purkinje fibers
Right ventricle
Right and left bundle branches
Atrioventricular (AV) bundle (bundle of his)
Atrioventricular (AV) node
Sinoatrial (SA) node
Right atrium
Interventricular septum – It is a partition dividing the right and left ventricles. It is shifted towards
right. So the left ventricle is bigger than right.
Auriculoventricular septum – It separates the two auricles from the two ventricles. It is shifted
upwards towards auricles. Therefore auricles are smaller than ventricles.
TARGET POINTS
Systemic heart – Left part of the heart (i.e. left auricle and left ventricle) contain the blood which
is to be pumped into the systemic circulation. The main purpose of such a circulation is to
transport oxygen as well as nutrients to the body tissues, and to remove carbon dioxide and
other harmful nitrogenous waste from them.
Pulmonary heart – Right part of the heart (i.e. right auricle and right ventricle) contain the blood
which is to be pumped in pulmonary circulation for oxygenation. The pulmonary circulation is
responsible for regular oxygenation of the impure deoxygenated blood which is received by the
right auricle.
Blood supply of heart (coronary circulation) – The oxygenated blood is supplied to the heart
musculature for its consumption with the help of two coronary arteries, left and right. These
arteries arise from the common origin at arch of aorta. The left and right coronary arteries then
further subdivided into number of branches carrying blood to different regions of heart. The
impure blood from heart walls return back via coronary veins which drain into the coronary sinus.
The coronary sinus opens in the right atrium.
4.2.2 Heart conduction
Autorhythmic cells are located in 5 main groups that form the conduction system of the heart
Left atrium
Left ventricle
Anterior view of frontal section
Purkinje fibers
Right ventricle
Right and left bundle branches
Atrioventricular (AV) bundle (bundle of his)
Atrioventricular (AV) node
Sinoatrial (SA) node
Right atrium
72
Heart tissues:
T
he bulk of the myocardium consists of cardiac muscle cells.
There are two types of cardiac muscle cells.
– Contractile cells – 99%
– Autorhythmic cells – 1%
The conducting system has the following parts:
SA node (pacemaker)
Internodal pathway
AV node
Bundle of His
Purkinje fibers (right and left)
Rate of conduction is fastest in Purkinje fibers and slowest in AV node.
Sinoatrial node (SA node): It is known as the “pacemaker” of the heart. It is present in right upper
corner of the right atrium. It generates impulses at the rate of about 72 per minute and initiates
heartbeat. It was discovered by Keith and Fack.
Although impulse is produced by the entire neuromuscular pathway, the frequency of impulse
generation is maximum in case of SA node in comparison to other parts of pathway. Hence it guides
the rhythm of heartbeat and is called the pacemaker of the heart. The AV node on the other hand
just conducts the impulse forward.
Internodal pathway – It is the network of neuromuscular pathway that connects the SA node to the
AV node.
Atrioventricular node (AV node) – It is smaller than SA node and is situated in the lower left corner
of the right atrium close to the atrioventricular septum. It is capable of generating impulse at rate of
about 40/min. It was discovered by Kent.
Bundle of His (AV bundle) – It is the connection between the atrial and ventricular musculature. It
begins at the AV node and then divides into left and right branches as it descends down towards
ventricles.
The left branch of the AV bundle descends on the left side of the interventricular septum and is
distributed to the left ventricle after dividing into Purkinje fibers.
The Purkinje fibers - These are distributed through the endocardium of the ventricles and propagate
the impulse in the entire ventricle musculature (18 to 25 per minute)
Heart tissues:
T
he bulk of the myocardium consists of cardiac muscle cells.
There are two types of cardiac muscle cells.
– Contractile cells – 99%
– Autorhythmic cells – 1%
The conducting system has the following parts:
SA node (pacemaker)
Internodal pathway
AV node
Bundle of His
Purkinje fibers (right and left)
Rate of conduction is fastest in Purkinje fibers and slowest in AV node.
Sinoatrial node (SA node): It is known as the “pacemaker” of the heart. It is present in right upper
corner of the right atrium. It generates impulses at the rate of about 72 per minute and initiates
heartbeat. It was discovered by Keith and Fack.
Although impulse is produced by the entire neuromuscular pathway, the frequency of impulse
generation is maximum in case of SA node in comparison to other parts of pathway. Hence it guides
the rhythm of heartbeat and is called the pacemaker of the heart. The AV node on the other hand
just conducts the impulse forward.
Internodal pathway – It is the network of neuromuscular pathway that connects the SA node to the
AV node.
Atrioventricular node (AV node) – It is smaller than SA node and is situated in the lower left corner
of the right atrium close to the atrioventricular septum. It is capable of generating impulse at rate of
about 40/min. It was discovered by Kent.
Bundle of His (AV bundle) – It is the connection between the atrial and ventricular musculature. It
begins at the AV node and then divides into left and right branches as it descends down towards
ventricles.
The left branch of the AV bundle descends on the left side of the interventricular septum and is
distributed to the left ventricle after dividing into Purkinje fibers.
The Purkinje fibers - These are distributed through the endocardium of the ventricles and propagate
the impulse in the entire ventricle musculature (18 to 25 per minute)
73
4.2.3 Heartbeat
Rhythmic contraction and relaxation of heart is called heart beat. Actually contraction and relaxation
occur separately in atria and ventricles. However, ventricular movements are quite prominent and
forceful. Therefore, heartbeat is synonym with ventricular or apex beat. The rate of heartbeat in an
adult male is on the average 72 per minute. It is higher in women, children and infants and lower in
aged persons. It increases temporarily with activity and disease. In animals, heart beat is connected
with size. In mammals, smaller animals have higher heartbeat.
Heartbeat is entirely controlled by nervous supply in arthropods and some annelids. It is called
neurogenic heartbeat and the heart is called neurogenic heart. In molluscs and vertebrates heart
beat originates from a special muscular tissue. Such a heartbeat is called myogenic heartbeat and
the heart is called myogenic heart. Human heart is myogenic.
Difference between neurogenic and myogenic hearts
Regulation of heartbeat
A. Nervous control
The “cardiac center” (neural center) which regulates heartbeat is found in medulla oblongata of the
brain, it can moderate the cardiac function through ANS. This cardiac center has two units:
i) Cardio-accelerator center.
ii) Cardio-inhibitory center.
From the cardio-acceleratory center, a pair of sympathetic nerves go into the SA node. This center
increases the rate of heartbeat.
While the cardio-inhibitory center sends impulses to the SA node through cardiac branch of vagus
nerve. This center reduces the rate of heartbeat.
Adult human – 72 per minute Blue whale – 25 per minute Rabbit – 210 per minute
Foetus – 140-160 per minute Elephant – 28 per minute Rat – 400 – 600 per minute
New born – 120-140 per minute Sparrow – 500 per minute Shrew – 600 – 800 per minute
Child – 100 per minute Canary bird – 1000 per minute
Neurogenic heart Myogenic heart
Impulse of heartbeat comes from outside heart The impulse of heartbeat develops within the heart
Impulse is generated by nervous system. Impulse is generated by a special muscular
tissue.
Nerve fibers are spread over the heart to There are special conducting muscle fibers for
bring about contraction and relaxation. spreading the impulse.
Heart will stop beating if removed from the body It will continue to beat for some time, if detached
heart is supplied with proper nourishment and
favorable conditions.
4.2.3 Heartbeat
Rhythmic contraction and relaxation of heart is called heart beat. Actually contraction and relaxation
occur separately in atria and ventricles. However, ventricular movements are quite prominent and
forceful. Therefore, heartbeat is synonym with ventricular or apex beat. The rate of heartbeat in an
adult male is on the average 72 per minute. It is higher in women, children and infants and lower in
aged persons. It increases temporarily with activity and disease. In animals, heart beat is connected
with size. In mammals, smaller animals have higher heartbeat.
Heartbeat is entirely controlled by nervous supply in arthropods and some annelids. It is called
neurogenic heartbeat and the heart is called neurogenic heart. In molluscs and vertebrates heart
beat originates from a special muscular tissue. Such a heartbeat is called myogenic heartbeat and
the heart is called myogenic heart. Human heart is myogenic.
Difference between neurogenic and myogenic hearts
Regulation of heartbeat
A. Nervous control
The “cardiac center” (neural center) which regulates heartbeat is found in medulla oblongata of the
brain, it can moderate the cardiac function through ANS. This cardiac center has two units:
i) Cardio-accelerator center.
ii) Cardio-inhibitory center.
From the cardio-acceleratory center, a pair of sympathetic nerves go into the SA node. This center
increases the rate of heartbeat.
While the cardio-inhibitory center sends impulses to the SA node through cardiac branch of vagus
nerve. This center reduces the rate of heartbeat.
Adult human – 72 per minute Blue whale – 25 per minute Rabbit – 210 per minute
Foetus – 140-160 per minute Elephant – 28 per minute Rat – 400 – 600 per minute
New born – 120-140 per minute Sparrow – 500 per minute Shrew – 600 – 800 per minute
Child – 100 per minute Canary bird – 1000 per minute
Neurogenic heart Myogenic heart
Impulse of heartbeat comes from outside heart The impulse of heartbeat develops within the heart
Impulse is generated by nervous system. Impulse is generated by a special muscular
tissue.
Nerve fibers are spread over the heart to There are special conducting muscle fibers for
bring about contraction and relaxation. spreading the impulse.
Heart will stop beating if removed from the body It will continue to beat for some time, if detached
heart is supplied with proper nourishment and
favorable conditions.
74
B. Hormonal control
Fr
om the sympathetic nerve fibers a hormone sympathins or nor-adrenaline is secreted which
increases the heartbeat. From the parasympathetic nerve fibers hormone acetyl-choline is secreted
which decreases the heartbeat. The adrenaline hormone and thyroxin hormone secreted by adrenal
medulla and thyroid respectively also increases heartbeat.
Heart conditions
A. Tachycardia: It is the condition where heart rate exceeds 90 per minute for an average adult.
Common causes:
Temperature: Rate of heartbeat increases. Fever causes tachycardia because increased
body temperature increases the rate of metabolism of the sinus node, which in turn directly
increases its excitability and rhythm.
Stimulation by sympathetic nerves: Stimulation of the sympathetic nerves releases the
hormone norepinephrine at the sympathetic nerve endings. Therefore this leads to increase
in the heart rate.
Weak condition of the heart: Weakening of the myocardium usually increases the heart
rate because the weakened heart does not pump blood into the arterial tree to a normal
extent, and this causes sympathetic reflexes to increase heart rate.
Shock / loss of blood: When a patient loses blood and passes into a state of shock or semi
shock, reflex stimulation of heart occurs which increases the frequency of heartbeat to
compensate for less delivery.
Exercise: Physical exertion cause an increased consumption of oxygen by tissues. In order
to meet the increased demand the heart has to work faster.
Sinus tachycardia: Increased frequency of impulse discharges from the SA node will in turn
increase the heart rate.
B. Bradycardia: It is the condition where the heart rate falls below 60 per minute in an average adult.
Common causes:
Temperature: Fall in body temperature leads to fall in the rate of SA node metabolism, which
in turn reduces its excitability and rhythm.
Stimulation by parasympathetic vagus: Parasympathetic stimulation of acetylcholine
secreted by vagus has an inhibitory effect on the SA node. (Opposite phenomenon of
sympathetic stimulation occurs here).
Hormonal control Adrenaline –
Rate
Nor adrenaline – Rate
Vagal stimulation releases acetyl choline – Rate
Autonomic nervous system Sympathetic – Rate
Parasympathetic – Rate
B. Hormonal control
Fr
om the sympathetic nerve fibers a hormone sympathins or nor-adrenaline is secreted which
increases the heartbeat. From the parasympathetic nerve fibers hormone acetyl-choline is secreted
which decreases the heartbeat. The adrenaline hormone and thyroxin hormone secreted by adrenal
medulla and thyroid respectively also increases heartbeat.
Heart conditions
A. Tachycardia: It is the condition where heart rate exceeds 90 per minute for an average adult.
Common causes:
Temperature: Rate of heartbeat increases. Fever causes tachycardia because increased
body temperature increases the rate of metabolism of the sinus node, which in turn directly
increases its excitability and rhythm.
Stimulation by sympathetic nerves: Stimulation of the sympathetic nerves releases the
hormone norepinephrine at the sympathetic nerve endings. Therefore this leads to increase
in the heart rate.
Weak condition of the heart: Weakening of the myocardium usually increases the heart
rate because the weakened heart does not pump blood into the arterial tree to a normal
extent, and this causes sympathetic reflexes to increase heart rate.
Shock / loss of blood: When a patient loses blood and passes into a state of shock or semi
shock, reflex stimulation of heart occurs which increases the frequency of heartbeat to
compensate for less delivery.
Exercise: Physical exertion cause an increased consumption of oxygen by tissues. In order
to meet the increased demand the heart has to work faster.
Sinus tachycardia: Increased frequency of impulse discharges from the SA node will in turn
increase the heart rate.
B. Bradycardia: It is the condition where the heart rate falls below 60 per minute in an average adult.
Common causes:
Temperature: Fall in body temperature leads to fall in the rate of SA node metabolism, which
in turn reduces its excitability and rhythm.
Stimulation by parasympathetic vagus: Parasympathetic stimulation of acetylcholine
secreted by vagus has an inhibitory effect on the SA node. (Opposite phenomenon of
sympathetic stimulation occurs here).
Hormonal control Adrenaline –
Rate
Nor adrenaline – Rate
Vagal stimulation releases acetyl choline – Rate
Autonomic nervous system Sympathetic – Rate
Parasympathetic – Rate
75
S
The athlete’s heart is considered stronger than that of a
normal person. This allows it to pump greater stroke volume output per heartbeat. When the
athlete is at rest, this excessive quantity of pumped blood causes a negative feedback response
resulting in bradycardia.
Rest: When at rest or sleeping, the oxygen demand of body is lesser this gives a negative
feedback resulting in fall in heart rate.
Sinus bradycardia: Reduced frequency of impulse discharge from SA node will reduce the
heart rate.
The ratio of heart rate to respiratory rate in an average adult under normal circumstances is 4:1.
4.2.4 Cardiac cycle
The process of heartbeat begins from the time of embryonal development. Once the heartbeat
starts, it continues throughout the life (inherent capacity). In resting stage of man in 1 minute the
heart beats around 72 times and during this 1 minute, 5 liters of blood is pumped to different parts of
the body through heart through left ventricle.
Ventricles relaxed Ventricles contracted Ventricles contracted Ventricles relaxed Ventricles relaxed
Atrial systole
atria: contract
ventricles are relaxed
valves: AV open,
semilunar closed
Early ventricular systole
atria: relax
ventricles: contract
valves: AV close,
semilunar closed
Late ventricular systole
atria: relax
ventricles: contract
valves: AV close,
semilunar open
Early ventricular diastole
atria: relax and fill
ventricles: relax
valves: AV closed,
semilunar close
Late ventricular diastole
atria: relax and fill
ventricles: relax
valves: AV open,
semilunar closed
AV
valves
open
All
valves
closed
AV
valves
closed
All
valves
closed
AV
valves
open
Atria contracted Atria relaxed Atria relaxed Atria relaxed Atria relaxed
Semilunar
valves
open
Semilunar
valves
closed
1 2 3 4 5
The serial wise or sequential changes which take place in the heart are called cardiac cycle.
The Cardiac cycle can be divided into two distinct phases, diastole and systole. During diastole,
the muscles are relaxed and the chambers fill passively with blood. Although there is both an atrial
and a ventricular diastole, which differ slightly in their timing, the word diastole is commonly used in
Phase
Atrial systole
Early ventricular
Late ventricular Early ventricular
Late ventricular
Structure
systole systole diastole diastole
Atria Contract Relax Relax
Ventricles Relax Contract Relax
AV valves Open Closed Open
Semilunar Closed Open Closed
valves
S
The athlete’s heart is considered stronger than that of a
normal person. This allows it to pump greater stroke volume output per heartbeat. When the
athlete is at rest, this excessive quantity of pumped blood causes a negative feedback response
resulting in bradycardia.
Rest: When at rest or sleeping, the oxygen demand of body is lesser this gives a negative
feedback resulting in fall in heart rate.
Sinus bradycardia: Reduced frequency of impulse discharge from SA node will reduce the
heart rate.
The ratio of heart rate to respiratory rate in an average adult under normal circumstances is 4:1.
4.2.4 Cardiac cycle
The process of heartbeat begins from the time of embryonal development. Once the heartbeat
starts, it continues throughout the life (inherent capacity). In resting stage of man in 1 minute the
heart beats around 72 times and during this 1 minute, 5 liters of blood is pumped to different parts of
the body through heart through left ventricle.
Ventricles relaxed Ventricles contracted Ventricles contracted Ventricles relaxed Ventricles relaxed
Atrial systole
atria: contract
ventricles are relaxed
valves: AV open,
semilunar closed
Early ventricular systole
atria: relax
ventricles: contract
valves: AV close,
semilunar closed
Late ventricular systole
atria: relax
ventricles: contract
valves: AV close,
semilunar open
Early ventricular diastole
atria: relax and fill
ventricles: relax
valves: AV closed,
semilunar close
Late ventricular diastole
atria: relax and fill
ventricles: relax
valves: AV open,
semilunar closed
AV
valves
open
All
valves
closed
AV
valves
closed
All
valves
closed
AV
valves
open
Atria contracted Atria relaxed Atria relaxed Atria relaxed Atria relaxed
Semilunar
valves
open
Semilunar
valves
closed
1 2 3 4 5
The serial wise or sequential changes which take place in the heart are called cardiac cycle.
The Cardiac cycle can be divided into two distinct phases, diastole and systole. During diastole,
the muscles are relaxed and the chambers fill passively with blood. Although there is both an atrial
and a ventricular diastole, which differ slightly in their timing, the word diastole is commonly used in
Phase
Atrial systole
Early ventricular
Late ventricular Early ventricular
Late ventricular
Structure
systole systole diastole diastole
Atria Contract Relax Relax
Ventricles Relax Contract Relax
AV valves Open Closed Open
Semilunar Closed Open Closed
valves
76
reference to ventricular diastole. Systole is when the heart muscles contract. Atrial systole helps fill
the ventricles while ventricular systole is responsible for pushing the blood into the pulmonary artery
and aorta.
The time of cardiac cycle is the reverse ratio of heartbeat per minute. If heart beat per minute is 72,
then the time of cardiac cycle is 60/ 72 = 0.8 seconds.
In a single cardiac cycle of man
1. Auricular systole
2. Auricular diastole
3. Ventricular systole
4. Ventricular diastole
= 0.1 sec
= 0.7 sec
= 0.3 sec
= 0.5 sec
0.8 sec
0.8 sec
0.80.1
0.2
0.3
0.40.5
0.6
0.7
Auricles
Ventricles
- Systole
- Diastole
Outer circle
Inner circle
Diastole: Relaxation
During atrial diastole blood enters the left atrium from the pulmonary vein and the right atrium from
the inferior and superior vena cava. As ventricular diastole begins, the atria are already well into
their diastolic period. The ventricles have just finished contracting, so the ventricular pressure is
dropping as relaxation begins. When the pressure within the ventricles drops below the atrial pressure,
the AV valves open. Blood passively pours into the atria and flows through the open AV valves into
the ventricles. As the blood collects in the ventricle, the pressure builds. In order to continue filling
the ventricle, the SA node depolarizes, initiating atrial systole. The contraction of the atrium forces
more blood into the ventricle in diastole. Nearly 90% of the blood passively flows into the ventricles
while the remaining 10% enter due to atrial systole.
Systole: Contraction
The increasing volume of blood in the ventricles increases the pressure in the ventricles. When this
pressure exceeds that in the atria, the AV valves are forced closed. The closing of these AV valves
creates the first heart sound (lub). By this time, the atria have finished systole and have entered
their diastolic period. There is a delay of about 0.1 sec (100 milliseconds) between the contraction
of the atria and the contraction of the ventricles. This delay provides enough time for the atria to
complete their contraction before the ventricles begin their turn and prevents the chambers from
competing with each other. Imagine if the atria and ventricles contracted all at once. The blood flow
would not be as controlled or efficient.
The heart contracts in a repeatable sequence. First the atria contracts, then the ventricles. This,
along with the heart valves, allows the blood to flow in one direction. When the ventricles begin to
contract at the onset of systole, both the AV and semilunar valves on either side of the ventricles are
closed. This is called isovolumetric contraction. The volume of blood in the ventricles does not
change because all the valves are closed, so there is no place for the blood to go. As a result,
isovolumetric contraction increases the pressure in the ventricles. When the ventricular pressure
exceeds the arterial pressures (pulmonary and aortic), the pulmonary and aortic semilunar valves
reference to ventricular diastole. Systole is when the heart muscles contract. Atrial systole helps fill
the ventricles while ventricular systole is responsible for pushing the blood into the pulmonary artery
and aorta.
The time of cardiac cycle is the reverse ratio of heartbeat per minute. If heart beat per minute is 72,
then the time of cardiac cycle is 60/ 72 = 0.8 seconds.
In a single cardiac cycle of man
1. Auricular systole
2. Auricular diastole
3. Ventricular systole
4. Ventricular diastole
= 0.1 sec
= 0.7 sec
= 0.3 sec
= 0.5 sec
0.8 sec
0.8 sec
0.80.1
0.2
0.3
0.40.5
0.6
0.7
Auricles
Ventricles
- Systole
- Diastole
Outer circle
Inner circle
Diastole: Relaxation
During atrial diastole blood enters the left atrium from the pulmonary vein and the right atrium from
the inferior and superior vena cava. As ventricular diastole begins, the atria are already well into
their diastolic period. The ventricles have just finished contracting, so the ventricular pressure is
dropping as relaxation begins. When the pressure within the ventricles drops below the atrial pressure,
the AV valves open. Blood passively pours into the atria and flows through the open AV valves into
the ventricles. As the blood collects in the ventricle, the pressure builds. In order to continue filling
the ventricle, the SA node depolarizes, initiating atrial systole. The contraction of the atrium forces
more blood into the ventricle in diastole. Nearly 90% of the blood passively flows into the ventricles
while the remaining 10% enter due to atrial systole.
Systole: Contraction
The increasing volume of blood in the ventricles increases the pressure in the ventricles. When this
pressure exceeds that in the atria, the AV valves are forced closed. The closing of these AV valves
creates the first heart sound (lub). By this time, the atria have finished systole and have entered
their diastolic period. There is a delay of about 0.1 sec (100 milliseconds) between the contraction
of the atria and the contraction of the ventricles. This delay provides enough time for the atria to
complete their contraction before the ventricles begin their turn and prevents the chambers from
competing with each other. Imagine if the atria and ventricles contracted all at once. The blood flow
would not be as controlled or efficient.
The heart contracts in a repeatable sequence. First the atria contracts, then the ventricles. This,
along with the heart valves, allows the blood to flow in one direction. When the ventricles begin to
contract at the onset of systole, both the AV and semilunar valves on either side of the ventricles are
closed. This is called isovolumetric contraction. The volume of blood in the ventricles does not
change because all the valves are closed, so there is no place for the blood to go. As a result,
isovolumetric contraction increases the pressure in the ventricles. When the ventricular pressure
exceeds the arterial pressures (pulmonary and aortic), the pulmonary and aortic semilunar valves
77
open, ejecting blood into the respective blood vessels. Once the ventricles enter diastole, the
ventricular pressures fall. When these pressures fall below that in their respective arteries, the
valves close again. This creates the second heart sound (dub). Systole is now over and another
diastole has begun; the cycle continues again.
Diastole SystoleSystole
1st 2nd 3rd
Q
P
R
S
T
v
a
c
Phonocardiogram
Electrocardiogram
Ventricular volume
Ventricular pressure
Atrial pressure
Aortic pressure
Atrial
systole
Aortic valve
closes
Rapid
inflowEjection
Aortic
valve
opens
A-V valve closes
A-V valve opens
Isovolumic
contraction
Isovolumic
relaxationDiastasis
120
100
80
60
40
20
0
130
90
50
V
o
lu
m
e
(
m
l)
P
r
e
s
s
u
r
e
(
m
m
H
g
)
Volumes of blood related with cardiac cycle
During diastole, filling of the ventricles normally increases the volume of each ventricle to about 120
milliliters. This volume is known as end diastolic volume. Then as the ventricles empty during
systole, the volume decreases by about 70 milliliters, which is called the stroke volume (i.e. the
volume of blood pumped by each ventricle in the aorta in one stroke or beat). The remaining volume
in each ventricle is now about 50 milliliters is called end systolic volume.
The fraction of the end diastolic volume which is ejected out is called the ejection fraction. (usually
around 60% or 7/12). EF = SV/EDV
Cardiac output - It is the amount of blood pumped by each ventricle per minute. Its value in a
normal adult is about 5 liter/minute.
Cardiac output = Stroke volume x heart rate.
End diastolic volume 120 ml.
open, ejecting blood into the respective blood vessels. Once the ventricles enter diastole, the
ventricular pressures fall. When these pressures fall below that in their respective arteries, the
valves close again. This creates the second heart sound (dub). Systole is now over and another
diastole has begun; the cycle continues again.
Diastole SystoleSystole
1st 2nd 3rd
Q
P
R
S
T
v
a
c
Phonocardiogram
Electrocardiogram
Ventricular volume
Ventricular pressure
Atrial pressure
Aortic pressure
Atrial
systole
Aortic valve
closes
Rapid
inflowEjection
Aortic
valve
opens
A-V valve closes
A-V valve opens
Isovolumic
contraction
Isovolumic
relaxationDiastasis
120
100
80
60
40
20
0
130
90
50
V
o
lu
m
e
(
m
l)
P
r
e
s
s
u
r
e
(
m
m
H
g
)
Volumes of blood related with cardiac cycle
During diastole, filling of the ventricles normally increases the volume of each ventricle to about 120
milliliters. This volume is known as end diastolic volume. Then as the ventricles empty during
systole, the volume decreases by about 70 milliliters, which is called the stroke volume (i.e. the
volume of blood pumped by each ventricle in the aorta in one stroke or beat). The remaining volume
in each ventricle is now about 50 milliliters is called end systolic volume.
The fraction of the end diastolic volume which is ejected out is called the ejection fraction. (usually
around 60% or 7/12). EF = SV/EDV
Cardiac output - It is the amount of blood pumped by each ventricle per minute. Its value in a
normal adult is about 5 liter/minute.
Cardiac output = Stroke volume x heart rate.
End diastolic volume 120 ml.
78
End systolic volume 50 ml.
Stroke volume = EDV – ESV = 70 ml (approx.)
Filling of heart (Ventricles)
Blood normally flows from the great veins into the atria. About 75% of the blood flows directly
through the atria into the ventricles even before the atria contracts. Then atrial contraction usually
causes an additional 25% filling of the ventricles.
Atrial systole fills 25% of ventricles
Atrial diastole fills 75% of ventricles
1st stage: 70% (Rapid inflow)
2nd stage: 5% (Diastasis, AV valves are open)
Last stage: 25% (Due to atrial contraction)
Diastolic filling of ventricle
Distribution of blood in body
Heart Sounds
These heart sounds can be heard with the help of Stethoscope.
Study of heart-sounds by marking them on a graph is termed as Phonocardiography.
Measurement of electrical activity of the cardiac muscles at the time of heart beat is necessary
for healthy working of the heart. The transmission of impulses in the sarcolemma of cardiac-
muscle fibers is in the form of electrochemical waves and the graph marked by the machine
timetime
Intensity
Intensity
I Heart Sound II Heart Sound
LUB DUB
Dull ; prolonged (0.15 sec) Sharp, shorter timed, high pitch (0.1 sec)
Systolic (ventricular) onset Diastolic sound
Caused by vibrations after closure of AV valves Caused by closure of semilunar valves
Distribution of Blood Flow in various organs at rest in Man
Brain 700 ml/mt (14%) approx
Heart 300 ml/mt (7%)
Muscles 1200 ml/mt (20%)
Skin 500 ml/mt (8%)
Kidney 1100–1300 ml/mt (20 – 25%)
Abdominal organs 1400 ml/mt (20-25%)
Others 600 ml/mt 10%)
Total 5800 ml/mt
Systemic – 84%
HEART – 7%
Pulmonary – 9 %
Arteries – 13%
Veins – 64%
Capillaries – 7%
and Arterioles
End systolic volume 50 ml.
Stroke volume = EDV – ESV = 70 ml (approx.)
Filling of heart (Ventricles)
Blood normally flows from the great veins into the atria. About 75% of the blood flows directly
through the atria into the ventricles even before the atria contracts. Then atrial contraction usually
causes an additional 25% filling of the ventricles.
Atrial systole fills 25% of ventricles
Atrial diastole fills 75% of ventricles
1st stage: 70% (Rapid inflow)
2nd stage: 5% (Diastasis, AV valves are open)
Last stage: 25% (Due to atrial contraction)
Diastolic filling of ventricle
Distribution of blood in body
Heart Sounds
These heart sounds can be heard with the help of Stethoscope.
Study of heart-sounds by marking them on a graph is termed as Phonocardiography.
Measurement of electrical activity of the cardiac muscles at the time of heart beat is necessary
for healthy working of the heart. The transmission of impulses in the sarcolemma of cardiac-
muscle fibers is in the form of electrochemical waves and the graph marked by the machine
timetime
Intensity
Intensity
I Heart Sound II Heart Sound
LUB DUB
Dull ; prolonged (0.15 sec) Sharp, shorter timed, high pitch (0.1 sec)
Systolic (ventricular) onset Diastolic sound
Caused by vibrations after closure of AV valves Caused by closure of semilunar valves
Distribution of Blood Flow in various organs at rest in Man
Brain 700 ml/mt (14%) approx
Heart 300 ml/mt (7%)
Muscles 1200 ml/mt (20%)
Skin 500 ml/mt (8%)
Kidney 1100–1300 ml/mt (20 – 25%)
Abdominal organs 1400 ml/mt (20-25%)
Others 600 ml/mt 10%)
Total 5800 ml/mt
Systemic – 84%
HEART – 7%
Pulmonary – 9 %
Arteries – 13%
Veins – 64%
Capillaries – 7%
and Arterioles
79
(due to voltage difference) is termed as E
lectrocardiogram and this process is termed as
Electrocardiography. It was first of all recorded by Waller. Einthovan is known as the father
of electrocardiography.
Murmur: Any abnormal heart sound other than lub or dub. This may be due to physiological
reasons like the increased volume of blood etc. or pathological reason like defects in the
valves. Narrowing of valves is called valvular stenosis.
Blood pressure
Blood pressure (BP) refers to the force per unit area that blood exerts on a vessel wall. It is
measured in millimeters of mercury (mmHg). Therefore, the pressure from a column of mercury
that is 120 mm high is equivalent to a BP of 120 mmHg. Clinically, BP refers to systemic arterial
blood pressure in the biggest arteries
close to the heart, where BP is similar to
that generated by the heart. From these
large arteries, blood pressure
continuously decreases along each path
that blood flow can take through the
vascular system. Once the blood gets
back to the heart, it is at a very low
pressure (near 0 mmHg). The heart then
gives it a new “boost” of energy, raising
BP again. It is this pressure gradient that
continues moving blood as blood moves
from areas of higher pressure to areas
of lower pressure.
The highest BP is in the aorta and the bigger systemic arteries. In a healthy young adult, BP increases
to around 110 mmHg during ventricular systole (contraction) and decreases to around 70 mmHg
during ventricular diastole (relaxation). The highest arterial pressure achieved during systole is
called the systolic blood pressure. The lowest arterial pressure reached during diastole is the
diastolic blood pressure.
The pressure of blood steadily decreases as blood travels farther and farther away from the left
ventricle. In the blood that moves from systemic arteries into systemic arterioles and then into
capillaries, pressure drops to approximately 35 mmHg. In capillaries, there are no BP fluctuations,
but pressure falls to around 16 mmHg when blood reaches the venous end of capillaries. Because
of their distance from the left ventricle, BP in systemic venules and veins drops further. By the time
blood reaches the right ventricle, its pressure is typically 0 mmHg.
The instrument by which we can measure BP is called sphygmomanometer. Hales measured BP
in horse first of all.
120
100
80
60
40
20
0
Diastolic
pressure
Mean pressure
Systolic pressure
B
lo
o
d
p
r
e
s
s
u
r
e
(
m
m
H
g
)
Aorta
Arteries
Arterioles
Capillaries
Venules
Veins
V
enae cavae
(due to voltage difference) is termed as E
lectrocardiogram and this process is termed as
Electrocardiography. It was first of all recorded by Waller. Einthovan is known as the father
of electrocardiography.
Murmur: Any abnormal heart sound other than lub or dub. This may be due to physiological
reasons like the increased volume of blood etc. or pathological reason like defects in the
valves. Narrowing of valves is called valvular stenosis.
Blood pressure
Blood pressure (BP) refers to the force per unit area that blood exerts on a vessel wall. It is
measured in millimeters of mercury (mmHg). Therefore, the pressure from a column of mercury
that is 120 mm high is equivalent to a BP of 120 mmHg. Clinically, BP refers to systemic arterial
blood pressure in the biggest arteries
close to the heart, where BP is similar to
that generated by the heart. From these
large arteries, blood pressure
continuously decreases along each path
that blood flow can take through the
vascular system. Once the blood gets
back to the heart, it is at a very low
pressure (near 0 mmHg). The heart then
gives it a new “boost” of energy, raising
BP again. It is this pressure gradient that
continues moving blood as blood moves
from areas of higher pressure to areas
of lower pressure.
The highest BP is in the aorta and the bigger systemic arteries. In a healthy young adult, BP increases
to around 110 mmHg during ventricular systole (contraction) and decreases to around 70 mmHg
during ventricular diastole (relaxation). The highest arterial pressure achieved during systole is
called the systolic blood pressure. The lowest arterial pressure reached during diastole is the
diastolic blood pressure.
The pressure of blood steadily decreases as blood travels farther and farther away from the left
ventricle. In the blood that moves from systemic arteries into systemic arterioles and then into
capillaries, pressure drops to approximately 35 mmHg. In capillaries, there are no BP fluctuations,
but pressure falls to around 16 mmHg when blood reaches the venous end of capillaries. Because
of their distance from the left ventricle, BP in systemic venules and veins drops further. By the time
blood reaches the right ventricle, its pressure is typically 0 mmHg.
The instrument by which we can measure BP is called sphygmomanometer. Hales measured BP
in horse first of all.
120
100
80
60
40
20
0
Diastolic
pressure
Mean pressure
Systolic pressure
B
lo
o
d
p
r
e
s
s
u
r
e
(
m
m
H
g
)
Aorta
Arteries
Arterioles
Capillaries
Venules
Veins
V
enae cavae
80
BP calculations
A
verage arterial BP, or mean arterial pressure (MAP), is about one third of the difference between
the systolic and diastolic BP. MAP is determined using the following equation:
MAP = Diastolic BP + 1/3 (systolic BP – diastolic BP)
So someone with a BP of 120/80 mmHg would have a MAP of approximately 98 mmHg (i.e. 80 + 1/
3(120 -80)).
You have already learned that cardiac output can be calculated by multiplying heart rate by stroke
volume. Cardiac output can also be estimated by dividing MAP by the resistance of the peripheral
circulation (i.e. total peripheral resistance (TPR), or systemic vascular resistance (SVR), using the
following formula:
CO = MAP
TPR (equation 1)
The same equation can be reconfigured to estimate MAP
MAP = CO x TPR (equation 2)
This means that if stroke volume or heart rates increases, the subsequent increase in cardiac output will result in an increase in MAP, assuming resistance does not change. Similarly, reduced cardiac output results in a reduced MAP, again assuming a constant amount of resistance.
Factors affecting blood pressure: BP may be affected by following factors.
Exercise: At the time of physical labour BP is increased.
Emotions and excitement: In the state of excitement or emotions BP is increased in man.
At the time of adrenal secretion at the time of fear and in some hereditory conditions BP is
increased.
Contraction of blood vessels: BP is increased when contraction takes place in arteries and
blood capillaries.
Body posture: In a laying (relaxing) person BP is low as compared to a standing man.
Sex: In women, BP is slightly low as compared to men.
Obesity: In obese persons BP is increased.
Age: BP increases as the age advances.
Pulse: The pulse is left in the radial artery present in the wrist of a man. It is also felt in the artery of
neck region. The graph of pulse of an artery is marked by an instrument that is called sphygmograph.
Pulse pressure is the pressure difference which generates a pulse. This is systolic minus diastolic BP.
4.2.5 Cardiac disorders
A. Ischemic heart diseases
If the lumen of any of the coronary artery gets narrowed due to obstruction or cholesterol deposition,
the cardiac tissues enter a condition of more demand and less supply whenever the person performs
excretion. Under such hypoxic conditions a pain might arise in heart muscles, this condition is
called Angina pectoris. This condition is reversible when the demand supply ratio is reestablished
BP calculations
A
verage arterial BP, or mean arterial pressure (MAP), is about one third of the difference between
the systolic and diastolic BP. MAP is determined using the following equation:
MAP = Diastolic BP + 1/3 (systolic BP – diastolic BP)
So someone with a BP of 120/80 mmHg would have a MAP of approximately 98 mmHg (i.e. 80 + 1/
3(120 -80)).
You have already learned that cardiac output can be calculated by multiplying heart rate by stroke
volume. Cardiac output can also be estimated by dividing MAP by the resistance of the peripheral
circulation (i.e. total peripheral resistance (TPR), or systemic vascular resistance (SVR), using the
following formula:
CO = MAP
TPR (equation 1)
The same equation can be reconfigured to estimate MAP
MAP = CO x TPR (equation 2)
This means that if stroke volume or heart rates increases, the subsequent increase in cardiac output will result in an increase in MAP, assuming resistance does not change. Similarly, reduced cardiac output results in a reduced MAP, again assuming a constant amount of resistance.
Factors affecting blood pressure: BP may be affected by following factors.
Exercise: At the time of physical labour BP is increased.
Emotions and excitement: In the state of excitement or emotions BP is increased in man.
At the time of adrenal secretion at the time of fear and in some hereditory conditions BP is
increased.
Contraction of blood vessels: BP is increased when contraction takes place in arteries and
blood capillaries.
Body posture: In a laying (relaxing) person BP is low as compared to a standing man.
Sex: In women, BP is slightly low as compared to men.
Obesity: In obese persons BP is increased.
Age: BP increases as the age advances.
Pulse: The pulse is left in the radial artery present in the wrist of a man. It is also felt in the artery of
neck region. The graph of pulse of an artery is marked by an instrument that is called sphygmograph.
Pulse pressure is the pressure difference which generates a pulse. This is systolic minus diastolic BP.
4.2.5 Cardiac disorders
A. Ischemic heart diseases
If the lumen of any of the coronary artery gets narrowed due to obstruction or cholesterol deposition,
the cardiac tissues enter a condition of more demand and less supply whenever the person performs
excretion. Under such hypoxic conditions a pain might arise in heart muscles, this condition is
called Angina pectoris. This condition is reversible when the demand supply ratio is reestablished
81Helpline : 92200 34567 www.targeteducare.com
(i.e. when the person stops exertion and rests). A
coronary artery by pass grafting (CABG) may
be required to provide additional channel of blood supply in such cases.
In CABG a part of internal mammary artery or a segment of patients own saphenous vein is used as
the bypass channel.
Myocardial infarction (MI): This is cellular death of cardiac tissue due to anoxia.
When the blood supply to the heart completely stops due to complete block of a coronary artery,
under reduced oxygen condition the heart tries to reestablish the blood supply by working even
harder, thus aggravating the situation even further. Due to this reason the cardiac tissue starts dying
by necrosis and myocardial infarction sets in, this is an irreversible condition. It is also called as
heart attack in common language.
A blockage of left anterior descending artery (LAD) can be most fatal for the heart, (widows artery).
B. Congenital heart diseases
These are the diseases present since birth due to defects in the development of heart where
there is incomplete separation of oxygenated and deoxygenated parts of blood due to which
there is mixing of pure and impure blood. Some common types are:
Patent foramen ovale – The foramen ovale fails to close after birth as a result of which there
is an atrial septal defect, through which the impure blood in right atrium reaches the left
atrium and mixes with the pure blood present there.
Patent ductus arteriosus – The ductus arteriosus fails to close after birth due to which the
impure blood in the pulmonary arch mixes with the pure blood in the aortic arch.
Ventricular septal defect – The interventricular septum is incomplete thus allowing mixing
of the blood in the two ventricles.
Mixing of impure deoxygenated blood in the pure oxygenated blood in any of the above cases
leads to decrease in the quantity of oxygen supply to the body. Thus, symptoms of cyanosis
(bluish discoloration of skin) develop.
Such babies are called blue babies. These children get exhausted early due to inefficient
oxygen supply.
C. Hypertension
It is also called high blood pressure. Hypertension or high blood pressure is the occurrence of
persistent systolic arterial pressure of more than 140 mmHg and diastolic arterial pressure of more
than 90 mmHg. Hypertension is of two types primary and secondary.
Secondary hypertension is due to an underlying cause like hormonal or obstructional. Primary
hypertension is also called essential hypertension. 90% of the hypertensive patients suffer from this
type of hypertension. It is caused by several factors like arteriosclerosis, atherosclerosis, varicose
veins, obesity etc.
High blood pressure must be managed. Excessive high blood pressure, say 220/120 mmHg is
dangerous as it may cause hemorrhages in different parts of body causing blindness (due to optic
(i.e. when the person stops exertion and rests). A
coronary artery by pass grafting (CABG) may
be required to provide additional channel of blood supply in such cases.
In CABG a part of internal mammary artery or a segment of patients own saphenous vein is used as
the bypass channel.
Myocardial infarction (MI): This is cellular death of cardiac tissue due to anoxia.
When the blood supply to the heart completely stops due to complete block of a coronary artery,
under reduced oxygen condition the heart tries to reestablish the blood supply by working even
harder, thus aggravating the situation even further. Due to this reason the cardiac tissue starts dying
by necrosis and myocardial infarction sets in, this is an irreversible condition. It is also called as
heart attack in common language.
A blockage of left anterior descending artery (LAD) can be most fatal for the heart, (widows artery).
B. Congenital heart diseases
These are the diseases present since birth due to defects in the development of heart where
there is incomplete separation of oxygenated and deoxygenated parts of blood due to which
there is mixing of pure and impure blood. Some common types are:
Patent foramen ovale – The foramen ovale fails to close after birth as a result of which there
is an atrial septal defect, through which the impure blood in right atrium reaches the left
atrium and mixes with the pure blood present there.
Patent ductus arteriosus – The ductus arteriosus fails to close after birth due to which the
impure blood in the pulmonary arch mixes with the pure blood in the aortic arch.
Ventricular septal defect – The interventricular septum is incomplete thus allowing mixing
of the blood in the two ventricles.
Mixing of impure deoxygenated blood in the pure oxygenated blood in any of the above cases
leads to decrease in the quantity of oxygen supply to the body. Thus, symptoms of cyanosis
(bluish discoloration of skin) develop.
Such babies are called blue babies. These children get exhausted early due to inefficient
oxygen supply.
C. Hypertension
It is also called high blood pressure. Hypertension or high blood pressure is the occurrence of
persistent systolic arterial pressure of more than 140 mmHg and diastolic arterial pressure of more
than 90 mmHg. Hypertension is of two types primary and secondary.
Secondary hypertension is due to an underlying cause like hormonal or obstructional. Primary
hypertension is also called essential hypertension. 90% of the hypertensive patients suffer from this
type of hypertension. It is caused by several factors like arteriosclerosis, atherosclerosis, varicose
veins, obesity etc.
High blood pressure must be managed. Excessive high blood pressure, say 220/120 mmHg is
dangerous as it may cause hemorrhages in different parts of body causing blindness (due to optic
82
arteries), nephritis (renal artery), brain stroke or CVA (due to rupturing of cerebral artery). Brain
stroke may cause loss of speech, paralysis and other malfunctions of the body. Continued
hypertension also affects muscles and valves of the heart. The damage is called hypertensive heart
disease. Therefore, regular treatment with controlled diet and reduced salt intake should be
undertaken. Excessive physical exercise should be avoided.
D. Hypotension
It is also called low blood pressure. Hypotension or low blood pressure is the occurrence of persistent
systolic arterial pressure of less than 110 mmHg and diastolic arterial pressure of less than 70
mmHg. It is caused by persistent vasodilation of arterioles, reduced ventricular pumping, valvular
defects, anemia and deficient diet. Low blood pressure results in weakness, dizziness, blurred
vision etc. it can be corrected only after knowing the cause. However, temporary relief can be
obtained through intake of glucose and salt rich drink.
E. Arrhythmias
Arrhythmias (or dysrhythmias) are the abnormal rhythms in heart rate or conduction pathway.
Some tend to be harmless while others can be fatal. Arrhythmias can range from having an occasional
extra beat or a skipped beat to having fibrillation of the atria or ventricles. Arrhythmias can also arise
when the heart either beats too slowly (bradycardia) or too quickly (tachycardia).
Arrhythmias are much more serious and deadly when the ventricles beat in an uncontrolled manner.
This arrhythmia, called ventricular fibrillation, does not produce a productive heart contraction and
will be fatal if not corrected. Atrial fibrillation, on the other hand, is a common arrhythmias arising
when multiple cells outside of the SA node spontaneously depolarize at high rates. In this case the
atria quiver instead of beat, but because most of the blood in atria moves into the ventricles passively
due to pressure difference even before the atria contract, it is not nearly as damaging as ventricular
fibrillation. People at risk of atrial fibrillation still need to be managed because the condition increases
their risk of thromboemboli (blood clots that move to other parts of the body) and stroke.
F. Atherosclerosis
It is irregular thickening of arterial walls and narrowing of their lumen due to deposition of yellow
plaques of atheromas in their tunica intima and inner part of tunica media. Atheromas consist of
cholesterol and other lipoid materials. They are formed from low density lipoproteins or LDL. LDL
can pass through endothelium. It gets precipitated inside artery. Normally blood contains an enzymes
paraxonase which prevents LDL precipitation. However, a diet rich in cholesterol (e.g. egg, butter,
ghee) overcomes the effect of enzyme and causes deposition of LDL. It slowly brings about
atherosclerosis. Atherosclerosis causes hypertension due to stenosis or narrowing of arteries, arterial
occlusion, kidney damage, brain stroke, reduced limb activity, angina and myocardial infarction.
The effect can be reduced by controlling hypertension and lowering body lipid levels through diet
and medicines.
G. Arteriosclerosis
arteries), nephritis (renal artery), brain stroke or CVA (due to rupturing of cerebral artery). Brain
stroke may cause loss of speech, paralysis and other malfunctions of the body. Continued
hypertension also affects muscles and valves of the heart. The damage is called hypertensive heart
disease. Therefore, regular treatment with controlled diet and reduced salt intake should be
undertaken. Excessive physical exercise should be avoided.
D. Hypotension
It is also called low blood pressure. Hypotension or low blood pressure is the occurrence of persistent
systolic arterial pressure of less than 110 mmHg and diastolic arterial pressure of less than 70
mmHg. It is caused by persistent vasodilation of arterioles, reduced ventricular pumping, valvular
defects, anemia and deficient diet. Low blood pressure results in weakness, dizziness, blurred
vision etc. it can be corrected only after knowing the cause. However, temporary relief can be
obtained through intake of glucose and salt rich drink.
E. Arrhythmias
Arrhythmias (or dysrhythmias) are the abnormal rhythms in heart rate or conduction pathway.
Some tend to be harmless while others can be fatal. Arrhythmias can range from having an occasional
extra beat or a skipped beat to having fibrillation of the atria or ventricles. Arrhythmias can also arise
when the heart either beats too slowly (bradycardia) or too quickly (tachycardia).
Arrhythmias are much more serious and deadly when the ventricles beat in an uncontrolled manner.
This arrhythmia, called ventricular fibrillation, does not produce a productive heart contraction and
will be fatal if not corrected. Atrial fibrillation, on the other hand, is a common arrhythmias arising
when multiple cells outside of the SA node spontaneously depolarize at high rates. In this case the
atria quiver instead of beat, but because most of the blood in atria moves into the ventricles passively
due to pressure difference even before the atria contract, it is not nearly as damaging as ventricular
fibrillation. People at risk of atrial fibrillation still need to be managed because the condition increases
their risk of thromboemboli (blood clots that move to other parts of the body) and stroke.
F. Atherosclerosis
It is irregular thickening of arterial walls and narrowing of their lumen due to deposition of yellow
plaques of atheromas in their tunica intima and inner part of tunica media. Atheromas consist of
cholesterol and other lipoid materials. They are formed from low density lipoproteins or LDL. LDL
can pass through endothelium. It gets precipitated inside artery. Normally blood contains an enzymes
paraxonase which prevents LDL precipitation. However, a diet rich in cholesterol (e.g. egg, butter,
ghee) overcomes the effect of enzyme and causes deposition of LDL. It slowly brings about
atherosclerosis. Atherosclerosis causes hypertension due to stenosis or narrowing of arteries, arterial
occlusion, kidney damage, brain stroke, reduced limb activity, angina and myocardial infarction.
The effect can be reduced by controlling hypertension and lowering body lipid levels through diet
and medicines.
G. Arteriosclerosis
83
It is a group of degenerative disease characterized by thickening and loss of elasticity of arterial
w
alls. Typical arteriosclerosis occurs in elderly persons. In one type calcium gets deposited in the
tunica media of arteries. In another type the lumen of arterioles becomes narrow. Atherosclerosis is
also considered to be a type of arteriosclerosis. Limb arteries suffer the most. It causes pain, cramps
and numbness of extremities.
H. Varicose veins
On prolonged standing or due to defect in the valves of the veins of the legs.. these veins may
become dilated, torturous and thickened (most commonly affected is the saphenous vein). Such
veins become clearly visible and prominent. Treatment is surgical removal of such veins.
4.3 BLOOD VASCULATURE
Tissue
cells
Venous
end of
capillary
Interstitial
fluid
Blood flow
Arterial end of capillary
Atherosclerosis Arteriosclerosis
Deposition of lipids (cholesterol) on the walls Hardening of arteries due to thickening along with
(such depositions are called atheromatous deposition of calcium salts with cholesterol.
plaque)
Takes place in lumen of large and medium size Can take place in medium to small arteries of
arteries of body. limbs.
Plaques are formed due to proliferation of No plaque formation occurs, but the arteries
smooth muscles of the inner wall of arteries are stiff and rigid due to calcification.
(due to platelet derived growth factors).
Encroachment of lumen of artery is present. There is not much encroachment of lumen.
Artery lumen may get blocked resulting in no Artery becomes hard, loses its capacity of
blood supply. distension and may rupture.
It is a group of degenerative disease characterized by thickening and loss of elasticity of arterial
w
alls. Typical arteriosclerosis occurs in elderly persons. In one type calcium gets deposited in the
tunica media of arteries. In another type the lumen of arterioles becomes narrow. Atherosclerosis is
also considered to be a type of arteriosclerosis. Limb arteries suffer the most. It causes pain, cramps
and numbness of extremities.
H. Varicose veins
On prolonged standing or due to defect in the valves of the veins of the legs.. these veins may
become dilated, torturous and thickened (most commonly affected is the saphenous vein). Such
veins become clearly visible and prominent. Treatment is surgical removal of such veins.
4.3 BLOOD VASCULATURE
Tissue
cells
Venous
end of
capillary
Interstitial
fluid
Blood flow
Arterial end of capillary
Atherosclerosis Arteriosclerosis
Deposition of lipids (cholesterol) on the walls Hardening of arteries due to thickening along with
(such depositions are called atheromatous deposition of calcium salts with cholesterol.
plaque)
Takes place in lumen of large and medium size Can take place in medium to small arteries of
arteries of body. limbs.
Plaques are formed due to proliferation of No plaque formation occurs, but the arteries
smooth muscles of the inner wall of arteries are stiff and rigid due to calcification.
(due to platelet derived growth factors).
Encroachment of lumen of artery is present. There is not much encroachment of lumen.
Artery lumen may get blocked resulting in no Artery becomes hard, loses its capacity of
blood supply. distension and may rupture.
84
In closed type of blood vascular system blood vessels are of 3
t
ypes: arteries, veins and capillaries.
Normally artery carries pure blood from heart to the different
organs of the body.Veins carry impure blood from body organs
to the heart and this blood is impure normally. Capillaries are
present in the organs, and these are the vessels through which
exchange takes place.
Within a blood vessel there are three main layers. Endothelial
cells are on the inside (lumen) of a blood vessel. In some
vessels, they are wrapped by smooth muscle cells. Fibroblasts
secrete extracellular matrix in the large vessels, creating a
connective tissue outer layer.
The structural variations between the major vessel types are
due to the relative thickness and composition of three vessel wall layers called tunics. The specific
function of each vessel type is dependent on the presence or absence of the three tunics, as well as
the extent of the tunic structures. The three tunics, from inside to outside, are the tunica interna,
tunica media, and tunica externa.
A. Tunica interna
The tunica interna forms the interior lining of blood vessels and is in direct contact with the blood.
This layer consists of endothelium, which forms a continuous sheet of cells that lines the lumen of
vessels. The endothelium is physically supported by the underlying basement membrane. The
basement membrane is composed largely of collagen fibers that provide both strength and flexibility.
The basement membrane anchors the endothelium to the outermost component of the tunica interna,
the internal elastic lamina. The internal elastic lamina is a sheet of elastic fibers with numerous
openings that allow movement of solutes between the layers. The internal elastic lamina adheres
the tunica interna to the tunica media.
B. Tunica media
The tunica media is composed of smooth muscles and connective tissue layers. In most vessel
types this is the thickest tunic. The smooth muscle cells of the tunica media are oriented such that
they encircle the lumen of the vessel. These cells regulate the size of the vessel lumen by contracting
or relaxing upon stimulus of associated neurons, circulating hormones or local signaling molecules.
The flow and distribution of blood, as well as blood pressure, are controlled by the dilation and
contraction of blood vessels. The connective tissue of the tunica media is composed of elastic
fibers that are interspersed within the muscle cell layers and that also form a separate sheet like
layer, the external elastic lamina, between the tunica media and tunica externa. The elastic fibers
allow vessels to expand and recoil without loss of tension.
Endothelial
lining
Smooth
muscle
Collagen
In closed type of blood vascular system blood vessels are of 3
t
ypes: arteries, veins and capillaries.
Normally artery carries pure blood from heart to the different
organs of the body.Veins carry impure blood from body organs
to the heart and this blood is impure normally. Capillaries are
present in the organs, and these are the vessels through which
exchange takes place.
Within a blood vessel there are three main layers. Endothelial
cells are on the inside (lumen) of a blood vessel. In some
vessels, they are wrapped by smooth muscle cells. Fibroblasts
secrete extracellular matrix in the large vessels, creating a
connective tissue outer layer.
The structural variations between the major vessel types are
due to the relative thickness and composition of three vessel wall layers called tunics. The specific
function of each vessel type is dependent on the presence or absence of the three tunics, as well as
the extent of the tunic structures. The three tunics, from inside to outside, are the tunica interna,
tunica media, and tunica externa.
A. Tunica interna
The tunica interna forms the interior lining of blood vessels and is in direct contact with the blood.
This layer consists of endothelium, which forms a continuous sheet of cells that lines the lumen of
vessels. The endothelium is physically supported by the underlying basement membrane. The
basement membrane is composed largely of collagen fibers that provide both strength and flexibility.
The basement membrane anchors the endothelium to the outermost component of the tunica interna,
the internal elastic lamina. The internal elastic lamina is a sheet of elastic fibers with numerous
openings that allow movement of solutes between the layers. The internal elastic lamina adheres
the tunica interna to the tunica media.
B. Tunica media
The tunica media is composed of smooth muscles and connective tissue layers. In most vessel
types this is the thickest tunic. The smooth muscle cells of the tunica media are oriented such that
they encircle the lumen of the vessel. These cells regulate the size of the vessel lumen by contracting
or relaxing upon stimulus of associated neurons, circulating hormones or local signaling molecules.
The flow and distribution of blood, as well as blood pressure, are controlled by the dilation and
contraction of blood vessels. The connective tissue of the tunica media is composed of elastic
fibers that are interspersed within the muscle cell layers and that also form a separate sheet like
layer, the external elastic lamina, between the tunica media and tunica externa. The elastic fibers
allow vessels to expand and recoil without loss of tension.
Endothelial
lining
Smooth
muscle
Collagen
85
C. Tunica externa
T
his tunic forms the outermost layer merging with the surrounding tissues and anchoring the blood
vessel in place. The tunica externa is composed of mostly collagen fibers. There are many nerves
in the tunica externa and in larger vessels, a system of vessels that supply the vessel tissues called
the vasa vasorum.
Interna:
endothelium
Wall 1 mm thick
Lumen Lumen
Interna:
endothelium
Wall
0.5 mm
thick
Artery Vein
Media:
smooth
muscle cells
Externa:
fibroblasts
and ECM
All layers are well developed in the walls of arteries as compared to the walls of veins. Walls of
arteries are thick and more muscular, and these walls are elastic and non-collapsible.The walls of
veins are thin, less muscular, non elastic and collapsible.
In the walls of blood capillaries only endothelium layer is found. Its cells are flat and squamous, their
walls are perforated. These blood capillaries join the arteries with the veins.
Blood capillaries were discovered by a scientist named as Marcello Malpighi.
ARTERY VEINS
It carries blood from the heart to the organs. It carries blood from organs to the heart.
All the arteries carry pure blood except All the veins carry impure blood except
pulmonary artery which carries impure blood. pulmonary vein which carries pure blood
Blood flows with a high pressure and speed. In the vein, blood flows with a low pressure and speed.
Arteries are deeply situated in the body. Veins are superficial just below the skin.
The walls of arteries are thick and tough. The walls of veins are thin and soft.
Their lumen is constricted. Their lumen is wide.
Valves are absent in the walls of arteries, Walls of veins contain valves.
These are pinkish or bright red in color. These are deep red or bluish in color.
Arteries do not collapse when empty, Veins usually collapse when empty.
because their walls are thick.
Their tunica media layer is much thicker as Their tunica media layer of wall is thinner as
compared to veins. compared to arteries.
C. Tunica externa
T
his tunic forms the outermost layer merging with the surrounding tissues and anchoring the blood
vessel in place. The tunica externa is composed of mostly collagen fibers. There are many nerves
in the tunica externa and in larger vessels, a system of vessels that supply the vessel tissues called
the vasa vasorum.
Interna:
endothelium
Wall 1 mm thick
Lumen Lumen
Interna:
endothelium
Wall
0.5 mm
thick
Artery Vein
Media:
smooth
muscle cells
Externa:
fibroblasts
and ECM
All layers are well developed in the walls of arteries as compared to the walls of veins. Walls of
arteries are thick and more muscular, and these walls are elastic and non-collapsible.The walls of
veins are thin, less muscular, non elastic and collapsible.
In the walls of blood capillaries only endothelium layer is found. Its cells are flat and squamous, their
walls are perforated. These blood capillaries join the arteries with the veins.
Blood capillaries were discovered by a scientist named as Marcello Malpighi.
ARTERY VEINS
It carries blood from the heart to the organs. It carries blood from organs to the heart.
All the arteries carry pure blood except All the veins carry impure blood except
pulmonary artery which carries impure blood. pulmonary vein which carries pure blood
Blood flows with a high pressure and speed. In the vein, blood flows with a low pressure and speed.
Arteries are deeply situated in the body. Veins are superficial just below the skin.
The walls of arteries are thick and tough. The walls of veins are thin and soft.
Their lumen is constricted. Their lumen is wide.
Valves are absent in the walls of arteries, Walls of veins contain valves.
These are pinkish or bright red in color. These are deep red or bluish in color.
Arteries do not collapse when empty, Veins usually collapse when empty.
because their walls are thick.
Their tunica media layer is much thicker as Their tunica media layer of wall is thinner as
compared to veins. compared to arteries.
86
Outer
coat
Smooth
muscle
Basement
membrane
Endothelium
Artery
Metarteriole
Thoroughfare
channel
Venule
Capillaries
Precapillary
sphincters
Arteriole
Elastic tissue
Elastic tissue
Outer coat
Smooth muscle rings over elastic
tissue
Basement
membrane
Endothelium
Basement membrane Endothelium
Arteriole
Capillary
Structure of artery, arteriole and capillary Capillary network
Basement
membrane
Tight junction
Endothelial nucleus
Pinocytotic vesicles
Endothelial
cell
Intercellular
cleft
Red blood cell in lumen
Pericyte
Basement membrane
Endothelial nucleus
Tight junction
Endothelial cell
Intercellular cleft
Red blood cell in lumen
Pericyte
Fenestrations
(pores)
Pinocytotic vesicles
Continuous capillaries Fenestrated capillaries
Pericyte
Endothelial cell
Red blood cell in lumen
Large intercellular cleft
Nucleus of endothelial cellTight junction
Incomplete basement membrane
Sinusoid capillaries
Types of capillaries
Outer
coat
Smooth
muscle
Basement
membrane
Endothelium
Artery
Metarteriole
Thoroughfare
channel
Venule
Capillaries
Precapillary
sphincters
Arteriole
Elastic tissue
Elastic tissue
Outer coat
Smooth muscle rings over elastic
tissue
Basement
membrane
Endothelium
Basement membrane Endothelium
Arteriole
Capillary
Structure of artery, arteriole and capillary Capillary network
Basement
membrane
Tight junction
Endothelial nucleus
Pinocytotic vesicles
Endothelial
cell
Intercellular
cleft
Red blood cell in lumen
Pericyte
Basement membrane
Endothelial nucleus
Tight junction
Endothelial cell
Intercellular cleft
Red blood cell in lumen
Pericyte
Fenestrations
(pores)
Pinocytotic vesicles
Continuous capillaries Fenestrated capillaries
Pericyte
Endothelial cell
Red blood cell in lumen
Large intercellular cleft
Nucleus of endothelial cellTight junction
Incomplete basement membrane
Sinusoid capillaries
Types of capillaries
87
Arterial system in man
Scalp, face, Ear,
Throat , Tongue ,
Thyroid gland
External carotid
( (
(Brain, Eye) Intern al carot id
Stomach
spl een
GB
Li ver
Leino gastric
Hepatic
Vi scera
Pelvic region
Peri neum
Gluteal region
Colon
Rectum
Anal canal
Internal mammary (Ventral body wall)
Left common carotid (Head)
Left subclavian
Pulmonary arteries
Coronary artery (Heart)
Descending aorta
Pulmona ry trun k
Phrenic (Diaphragm)
Coeliac
Left renal
Genital
Inf erior mesenteric
Ulnar
Radial
Int ernal iliac
Femoral (Leg)
Dee p femoral (Thigh)
Popliteal (Knee )
Anterior tibial
(Head + Shoulder) Vertebral
(Head) Right common carot id
(Head) Right subclavian
Brachiocephalic
Ascending aorta
(Foelimb) Brachial
Heart
Superior
mesenteric
Pancreas
Duodenum
Jejunum
Ileum
Caecum Right renal
(Ki dney)
(Dorsal body wall) Lumbar
Common iliac
External ili ac
Posterior tibi al
Arterial system in man
Scalp, face, Ear,
Throat , Tongue ,
Thyroid gland
External carotid
( (
(Brain, Eye) Intern al carot id
Stomach
spl een
GB
Li ver
Leino gastric
Hepatic
Vi scera
Pelvic region
Peri neum
Gluteal region
Colon
Rectum
Anal canal
Internal mammary (Ventral body wall)
Left common carotid (Head)
Left subclavian
Pulmonary arteries
Coronary artery (Heart)
Descending aorta
Pulmona ry trun k
Phrenic (Diaphragm)
Coeliac
Left renal
Genital
Inf erior mesenteric
Ulnar
Radial
Int ernal iliac
Femoral (Leg)
Dee p femoral (Thigh)
Popliteal (Knee )
Anterior tibial
(Head + Shoulder) Vertebral
(Head) Right common carot id
(Head) Right subclavian
Brachiocephalic
Ascending aorta
(Foelimb) Brachial
Heart
Superior
mesenteric
Pancreas
Duodenum
Jejunum
Ileum
Caecum Right renal
(Ki dney)
(Dorsal body wall) Lumbar
Common iliac
External ili ac
Posterior tibi al
88
Right internal jugular
(Face, neck)
Right subclavian
(Shoulder, arms)
Brachiocephalic
SVC (Pre cavals)
(Head, neck, arms, chest)
Heart
Hepatic
Hepatic portal
Right suprarenal
Right renal
Right ovarian
/Right testicular
Lumber
Common iliac
External iliac
Femoral
Great saphenous
(Longest vein of body)
Anterior tibial
Posterior tibial
Popliteal
Femoral (Leg)
Internal iliac / Hypogastric
Left testicular/ovarian
(Testes/ovaries, uterus)
Left renal
Left suprarenal
Inferior vena cava
(Post cavals)
Coronary
Left internal jugular
Left external jugular
Left subclavian
Phrenic (Diaphragm)
Left cephalic (Arms, shoulder)
Liver
(Cranium, parotid gland, facial muscles)
Right external jugular
Pelvis, pelvic
girdle, sacrum,
rectum, ureter,
urinary bladder,
rep. organs
Internal mammary (Ventral body wall)
Venous system in man
Right internal jugular
(Face, neck)
Right subclavian
(Shoulder, arms)
Brachiocephalic
SVC (Pre cavals)
(Head, neck, arms, chest)
Heart
Hepatic
Hepatic portal
Right suprarenal
Right renal
Right ovarian
/Right testicular
Lumber
Common iliac
External iliac
Femoral
Great saphenous
(Longest vein of body)
Anterior tibial
Posterior tibial
Popliteal
Femoral (Leg)
Internal iliac / Hypogastric
Left testicular/ovarian
(Testes/ovaries, uterus)
Left renal
Left suprarenal
Inferior vena cava
(Post cavals)
Coronary
Left internal jugular
Left external jugular
Left subclavian
Phrenic (Diaphragm)
Left cephalic (Arms, shoulder)
Liver
(Cranium, parotid gland, facial muscles)
Right external jugular
Pelvis, pelvic
girdle, sacrum,
rectum, ureter,
urinary bladder,
rep. organs
Internal mammary (Ventral body wall)
Venous system in man
89
Relative tissue makeupVessel type
illustration
Average
lumen
diameter (D)
and wall
thickness (T)
Endothelium
Elastic tissues
Smooth muscles
Fibrous
(collagenous) tissues
Elastic artery
Arteriole
Capillary
Muscular artery
Venules
Vein
D: 5.0 mm
T: 0.5 mm
D: 20.0 m
T: 1.0 m
D: 9.0 m
T: 0.5 m
D: 37.0 m
T: 1.0 m
D: 6.0 mm
T: 1.0 mm
D: 1.5 cm
T: 1.0 mm
4.4 PORTAL SYSTEM
When the vein of any organ of the body does not open in the caval vein or heart but it divides into
capillaries in any other organ and its blood is transported by vein of that other organs to the heart,
then this type of system is termed as portal system.
A. Renal portal system
Veins which collect blood from posterior parts of the body and legs combine to form a renal portal
vein. This vein goes into kidney and divides into capillaries kidneys separate nitrogenous wastes
from this blood. This partly purified blood is now transported to the heart. It is present in frog. In
mammals, renal portal system is absent.
In frog both the portal systems; renal portal system and hepatic portal system are present.
Relative tissue makeupVessel type
illustration
Average
lumen
diameter (D)
and wall
thickness (T)
Endothelium
Elastic tissues
Smooth muscles
Fibrous
(collagenous) tissues
Elastic artery
Arteriole
Capillary
Muscular artery
Venules
Vein
D: 5.0 mm
T: 0.5 mm
D: 20.0 m
T: 1.0 m
D: 9.0 m
T: 0.5 m
D: 37.0 m
T: 1.0 m
D: 6.0 mm
T: 1.0 mm
D: 1.5 cm
T: 1.0 mm
4.4 PORTAL SYSTEM
When the vein of any organ of the body does not open in the caval vein or heart but it divides into
capillaries in any other organ and its blood is transported by vein of that other organs to the heart,
then this type of system is termed as portal system.
A. Renal portal system
Veins which collect blood from posterior parts of the body and legs combine to form a renal portal
vein. This vein goes into kidney and divides into capillaries kidneys separate nitrogenous wastes
from this blood. This partly purified blood is now transported to the heart. It is present in frog. In
mammals, renal portal system is absent.
In frog both the portal systems; renal portal system and hepatic portal system are present.
90
B. Hepatic portal system
I
t is a portal system which brings venous blood directly from digestive tract, spleen, pancreas and
gall bladder to liver for extraction of nutrients and other metabolites by breaking up into single celled
thick capillaries and sinusoids. Portal vein is about 8 cm long. It is formed by following veins
Splenic from spleen and gastric from stomach which join to form lienogastric vein.
Superior mesenteric from small intestine, caecum, ascending and transverse parts of colon.
Inferior mesenteric from rectum, sigmoid and descending part of colon.
Cystic vein from gall bladder.
Paraumbilical vein from abdominal wall.
Duodenal vein from duodenum and pancreas.
Hepatic portal vein branches the branches enter into different liver lobes. They divide and redivide.
Ultimate branches of hepatic portal veins open into sinusoids for exchange of materials between
portal blood and liver cells. Along with deoxygenated blood of liver, portal blood is recollected by
venules which form hepatic veins.
Arterial
blood
Stomach and intestine
Nutrients and toxins
absorbed
Hepatic
portal vein
First capillary bed Second capillary bed
(liver sinusoids)
Hepatic
vein
Liver cells (hepatocytes)
Liver
Nutrients
and toxins
leave
Hepatic portal system
Inferior
vena cava
Venous
blood
C. Hypophyseal portal system
It is a portal system formed by a vein from hypothalamus which breaks up into capillaries in hypophysis
or pituitary gland. The vein is called hypophyseal portal vein. It is formed by union of capillaries and
venules in hypothalamus. The portal vein enters anterior lobe of pituitary gland or adenohypophysis
where it breaks up into capillaries. Hypophyseal portal system is a short circuit arrangement.
Hypothalamus produces a number or hormones for controlling endocrine activity of adenohypophysis.
They are poured into blood in hypothalamus. The same is directly drained by hypophyseal portal
vein into adenohypophysis.
B. Hepatic portal system
I
t is a portal system which brings venous blood directly from digestive tract, spleen, pancreas and
gall bladder to liver for extraction of nutrients and other metabolites by breaking up into single celled
thick capillaries and sinusoids. Portal vein is about 8 cm long. It is formed by following veins
Splenic from spleen and gastric from stomach which join to form lienogastric vein.
Superior mesenteric from small intestine, caecum, ascending and transverse parts of colon.
Inferior mesenteric from rectum, sigmoid and descending part of colon.
Cystic vein from gall bladder.
Paraumbilical vein from abdominal wall.
Duodenal vein from duodenum and pancreas.
Hepatic portal vein branches the branches enter into different liver lobes. They divide and redivide.
Ultimate branches of hepatic portal veins open into sinusoids for exchange of materials between
portal blood and liver cells. Along with deoxygenated blood of liver, portal blood is recollected by
venules which form hepatic veins.
Arterial
blood
Stomach and intestine
Nutrients and toxins
absorbed
Hepatic
portal vein
First capillary bed Second capillary bed
(liver sinusoids)
Hepatic
vein
Liver cells (hepatocytes)
Liver
Nutrients
and toxins
leave
Hepatic portal system
Inferior
vena cava
Venous
blood
C. Hypophyseal portal system
It is a portal system formed by a vein from hypothalamus which breaks up into capillaries in hypophysis
or pituitary gland. The vein is called hypophyseal portal vein. It is formed by union of capillaries and
venules in hypothalamus. The portal vein enters anterior lobe of pituitary gland or adenohypophysis
where it breaks up into capillaries. Hypophyseal portal system is a short circuit arrangement.
Hypothalamus produces a number or hormones for controlling endocrine activity of adenohypophysis.
They are poured into blood in hypothalamus. The same is directly drained by hypophyseal portal
vein into adenohypophysis.
91
Supraoptic nucleiParaventricular nuclei
Hypothalamus
Mamillary body
Superior hypophyseal artey
Infundibulum
Portal veins
Inferior hypophyseal artery
Posterior lobe of pituitary gland
Hypophyseal vein
Anterior lobe
of pituitary gland
Hypophyseal
veins
Endocrine
cells
Capillary beds
Optic chiasm
Median
eminence
Hypophyseal portal system
Supraoptic nucleiParaventricular nuclei
Hypothalamus
Mamillary body
Superior hypophyseal artey
Infundibulum
Portal veins
Inferior hypophyseal artery
Posterior lobe of pituitary gland
Hypophyseal vein
Anterior lobe
of pituitary gland
Hypophyseal
veins
Endocrine
cells
Capillary beds
Optic chiasm
Median
eminence
Hypophyseal portal system
92
1. The post caval is constituted by
a) Renal, gonadial and hepatic veins
b) Renal and gonadial veins
c) Gonadial and hepatic veins
d) Hepatic and renal veins
2. The cardiac pacemaker in a patient fails to
function normally. The doctors find that an
artificial pacemaker is to be grafted in him.
It is likely that it will be grafted at the site of
a) Atrioventricular bundle
b) Purkinje system
c) Sinoatrial node
d) Atrioventricular node
3. The connection between pulmonary and
aortic arches in foetus is
a) Ligamentum teres
b) Ductus arteriosus
c) Foramen ovale
d) All of the ovale
4. To which organ, does femoral artery supply
blood?
a) Dorsal part of thigh
b) All parts of hind limbs
c) Ventral part of hind limbs
d) Rectum
5. The difference between pulmonary arteries
and veins is that
a) Former is associated with lungs and later
with heart
b) Arteries have more thicker walls
c) Veins are more elastic
d) Veins have valves
6. The coronary sinus in the heart is situated
along its
a) Left margin
b) Right margin
c) Diaphragmatic surface
d) Lower border of the heart
Simple Questions
7. Post caval (IUC) opening in right auricle is
guarded by
a) Arterio ventricular valve
b) Tricuspid valve
c) Bicuspid valve
d) Eustachian valve
8. In which, blood circulation starts and ends
in capillaries?
a) Portal system b) Arterial system
c) Capillary system d) Lymphatic system
9. The heart sound ‘dub’ is produced when?
a) Tricuspid valve is opened
b) Mitral valve is opened
c) Mitral valve is closed
d) Semilunar valves at the base of aorta
get closed
10. Tricuspid valves are found in
a) All mammals b) All vertebrates
c) Prototherians d) Walrus
11. In man, heartbeat is initiated by
a) SA node b) Purkinje fibers
c) AV noradrenaline d) Bundle of His
12. Nature of valves in the heart is
a) Membranous b) Muscular
c) Tendinous d) Ligamentous
13. Which of the following is different from
others in absence of muscular coat?
a) Veins b) Arteries
c) Capillaries d) Arterioles
14. Absolute refractory period of heart is during
a) Contraction when the heart is in non
responding period
b) Expansion
c) Negative charge
d) Positive charge
15. Which one of the following minerals control
heart?
a) Sulphur b) Sodium
c) Iron d) Potassium
1. The post caval is constituted by
a) Renal, gonadial and hepatic veins
b) Renal and gonadial veins
c) Gonadial and hepatic veins
d) Hepatic and renal veins
2. The cardiac pacemaker in a patient fails to
function normally. The doctors find that an
artificial pacemaker is to be grafted in him.
It is likely that it will be grafted at the site of
a) Atrioventricular bundle
b) Purkinje system
c) Sinoatrial node
d) Atrioventricular node
3. The connection between pulmonary and
aortic arches in foetus is
a) Ligamentum teres
b) Ductus arteriosus
c) Foramen ovale
d) All of the ovale
4. To which organ, does femoral artery supply
blood?
a) Dorsal part of thigh
b) All parts of hind limbs
c) Ventral part of hind limbs
d) Rectum
5. The difference between pulmonary arteries
and veins is that
a) Former is associated with lungs and later
with heart
b) Arteries have more thicker walls
c) Veins are more elastic
d) Veins have valves
6. The coronary sinus in the heart is situated
along its
a) Left margin
b) Right margin
c) Diaphragmatic surface
d) Lower border of the heart
Simple Questions
7. Post caval (IUC) opening in right auricle is
guarded by
a) Arterio ventricular valve
b) Tricuspid valve
c) Bicuspid valve
d) Eustachian valve
8. In which, blood circulation starts and ends
in capillaries?
a) Portal system b) Arterial system
c) Capillary system d) Lymphatic system
9. The heart sound ‘dub’ is produced when?
a) Tricuspid valve is opened
b) Mitral valve is opened
c) Mitral valve is closed
d) Semilunar valves at the base of aorta
get closed
10. Tricuspid valves are found in
a) All mammals b) All vertebrates
c) Prototherians d) Walrus
11. In man, heartbeat is initiated by
a) SA node b) Purkinje fibers
c) AV noradrenaline d) Bundle of His
12. Nature of valves in the heart is
a) Membranous b) Muscular
c) Tendinous d) Ligamentous
13. Which of the following is different from
others in absence of muscular coat?
a) Veins b) Arteries
c) Capillaries d) Arterioles
14. Absolute refractory period of heart is during
a) Contraction when the heart is in non
responding period
b) Expansion
c) Negative charge
d) Positive charge
15. Which one of the following minerals control
heart?
a) Sulphur b) Sodium
c) Iron d) Potassium
93
16. Heart pumps blood more forcefully in older
persons than in younger persons due to
a) Decrease in O
2
content of blood
b) Decrease in elasticity of arteries
c) Fall in nutritional content of blood
d) Increase in elasticity of arteries
17. The ion that always keeps the cardiac
muscle unit in contracting state is
a) Sodium
b) Potassium
c) Calcium
d) Magnesium
18. QRST is related with
a) Ventricular contraction or depolarization
b) Auricular contraction
c) Auricular relaxation
d) Cardiac cycle
19. Vasa vasorum supplies blood to
a) Pericardium
b) Blood vessels
c) Tunica adventitia and external part of
tunica media
d) Vas deferens
20. The two branches of the iliac artery are
a) Femoral and renal
b) Femoral and sciatic
c) Vesiculo-epigastric and femoral
d) Renal and sciatic
21. The renal portal system of vertebrates is
significant for
a) Elimination of excess fats by kidneys
b) Removing nitrogenous wastes in
kidneys
c) Supplying food to the kidneys
d) Draining blood from the kidney
22. If due to some injury, the chordae tendinae
of the tricuspid valve of the human heart is
partially non-functional, what will be the
immediate effect?
a) The flow of blood into the aorta will be
slowed down
b) The pacemaker will stop working
c) The blood will tend to flow back into the
left atrium
d) The flow of blood into the pulmonary
artery will be reduced
23. The difference between systolic and
diastolic pressure is
a) Pulse pressure b) Pulse rate
c) Blood pressure d) Heartbeat
24. Systemic heart refers to
a) The heart that contracts under
stimulation from nervous syetm
b) Left auricle and left ventricle in higher
vertebrates
c) Entire heart in lower vertebrates
d) The two ventricles together in humans
25. First heart sound is
a) Lub sound at the end of systole.
b) Lub sound at the beginning of ventricular
systole
c) Dub sound at the end of systole
d) Dub sound at the beginning of ventricular
systole
26. A portal system is that in which
a) A vein begins from an organ and ends
in heart
b) An artery breaks up in an organ and
restarts by the union of its capillaries
c) The blood from gut is brought in to
kidneys before it is poured in to heart
d) A vein breaks up in an organ in to
capillaries and restarts by their union as
a new vein in the same organ
16. Heart pumps blood more forcefully in older
persons than in younger persons due to
a) Decrease in O
2
content of blood
b) Decrease in elasticity of arteries
c) Fall in nutritional content of blood
d) Increase in elasticity of arteries
17. The ion that always keeps the cardiac
muscle unit in contracting state is
a) Sodium
b) Potassium
c) Calcium
d) Magnesium
18. QRST is related with
a) Ventricular contraction or depolarization
b) Auricular contraction
c) Auricular relaxation
d) Cardiac cycle
19. Vasa vasorum supplies blood to
a) Pericardium
b) Blood vessels
c) Tunica adventitia and external part of
tunica media
d) Vas deferens
20. The two branches of the iliac artery are
a) Femoral and renal
b) Femoral and sciatic
c) Vesiculo-epigastric and femoral
d) Renal and sciatic
21. The renal portal system of vertebrates is
significant for
a) Elimination of excess fats by kidneys
b) Removing nitrogenous wastes in
kidneys
c) Supplying food to the kidneys
d) Draining blood from the kidney
22. If due to some injury, the chordae tendinae
of the tricuspid valve of the human heart is
partially non-functional, what will be the
immediate effect?
a) The flow of blood into the aorta will be
slowed down
b) The pacemaker will stop working
c) The blood will tend to flow back into the
left atrium
d) The flow of blood into the pulmonary
artery will be reduced
23. The difference between systolic and
diastolic pressure is
a) Pulse pressure b) Pulse rate
c) Blood pressure d) Heartbeat
24. Systemic heart refers to
a) The heart that contracts under
stimulation from nervous syetm
b) Left auricle and left ventricle in higher
vertebrates
c) Entire heart in lower vertebrates
d) The two ventricles together in humans
25. First heart sound is
a) Lub sound at the end of systole.
b) Lub sound at the beginning of ventricular
systole
c) Dub sound at the end of systole
d) Dub sound at the beginning of ventricular
systole
26. A portal system is that in which
a) A vein begins from an organ and ends
in heart
b) An artery breaks up in an organ and
restarts by the union of its capillaries
c) The blood from gut is brought in to
kidneys before it is poured in to heart
d) A vein breaks up in an organ in to
capillaries and restarts by their union as
a new vein in the same organ
94
27. p
a) More in veins and less in arteries
b) More in arteries and less in veins
c) Same
d) Not definite
28. After the death of human
a) Both veins and arteries are full of blood
b) Both veins and arteries are empty
c) Arteries are full of blood while veins are
empty
d) Veins are full of blood while arteries are
empty
29. Heart of man is
a) Myogenic b) Neurogenic
c) Cardiogenic d) Digenic
30. The frequency of heartbeat in our body is
maintained by
a) Chordae tendinae b) AV node
c) SA node d) Node of Ranvier
31. Single heart circuit occurs in
a) Fishes b) Frog
c) Reptiles d) Man
32. First heart transplant was performed by
a) William Harvey
b) Watson
c) Christian Bernard
d) Khorana
33. Internal elastic lamina is present in wall of
a) Arteries b) Veins
c) Both d) Heart
34. Impulse of heart beat originates from
a) SA node b) AV node
c) Vagus nerve d) Cardiac nerve
35. pH of arterial blood is
a) 6.0 b) 7.0
c) 7.8 d) 7.4
Difficult Questions
1. Given below are four statements regarding
human blood circulatory system:
1) Arteries are thick walled and have
narrow lumen as compared to veins
2) Angina is acute chest pain when the
blood circulation to the brain is reduced
3) Persons with blood group AB can donate
blood to any person with any blood group
under ABO system
4) Calcium ions play a very important role
in blood clotting
Which two of the above statements are
correct?
a) 1, 2 b) 2, 3
c) 3, 4 d) 1, 4
2. Right auricle of mammalian heart receives
blood from
a) Sinus venosus
b) Pulmonary veins
c) Pre cavals
d) Pre and post cavals
3. In the inguinal canal lies
a) Posterior mesenteric artery
b) Spermatic artery
c) Internal carotid artery
d) Dorsal artery
4. Which organ receives only oxygenated
blood?
a) Gill b) Spleen
c) Lung d) Liver
5. Starling’s law is related to
a) Venous return to heart
b) Force of heartbeat
c) Frequency of heartbeat
d) Peripheral resistance
6. The arteries used for measuring blood
pressure is
a) Common carotid b) External iliac
c) Bronchial d) Aorta
27. p
a) More in veins and less in arteries
b) More in arteries and less in veins
c) Same
d) Not definite
28. After the death of human
a) Both veins and arteries are full of blood
b) Both veins and arteries are empty
c) Arteries are full of blood while veins are
empty
d) Veins are full of blood while arteries are
empty
29. Heart of man is
a) Myogenic b) Neurogenic
c) Cardiogenic d) Digenic
30. The frequency of heartbeat in our body is
maintained by
a) Chordae tendinae b) AV node
c) SA node d) Node of Ranvier
31. Single heart circuit occurs in
a) Fishes b) Frog
c) Reptiles d) Man
32. First heart transplant was performed by
a) William Harvey
b) Watson
c) Christian Bernard
d) Khorana
33. Internal elastic lamina is present in wall of
a) Arteries b) Veins
c) Both d) Heart
34. Impulse of heart beat originates from
a) SA node b) AV node
c) Vagus nerve d) Cardiac nerve
35. pH of arterial blood is
a) 6.0 b) 7.0
c) 7.8 d) 7.4
Difficult Questions
1. Given below are four statements regarding
human blood circulatory system:
1) Arteries are thick walled and have
narrow lumen as compared to veins
2) Angina is acute chest pain when the
blood circulation to the brain is reduced
3) Persons with blood group AB can donate
blood to any person with any blood group
under ABO system
4) Calcium ions play a very important role
in blood clotting
Which two of the above statements are
correct?
a) 1, 2 b) 2, 3
c) 3, 4 d) 1, 4
2. Right auricle of mammalian heart receives
blood from
a) Sinus venosus
b) Pulmonary veins
c) Pre cavals
d) Pre and post cavals
3. In the inguinal canal lies
a) Posterior mesenteric artery
b) Spermatic artery
c) Internal carotid artery
d) Dorsal artery
4. Which organ receives only oxygenated
blood?
a) Gill b) Spleen
c) Lung d) Liver
5. Starling’s law is related to
a) Venous return to heart
b) Force of heartbeat
c) Frequency of heartbeat
d) Peripheral resistance
6. The arteries used for measuring blood
pressure is
a) Common carotid b) External iliac
c) Bronchial d) Aorta
95
7. The cardiac output in man under resting
condition is about
a) 2 l / min b) 4 l / min
c) 5 l / min d) 7 l / min
8. Which one indicates the hypertension?
a) 90 / 60 b) 120 / 85
c) 110 / 70 d) 140 / 100
9. Which layer of the wall of the blood vessel
is made up of circular smooth muscle?
a) Outer b) Middle
c) Both (a) and (b) d) Inner
10. Which one of the following statements is
correct regarding blood pressure?
a) 100 / 55 mmHg is considered an ideal
blood pressure
b) 105 / 50 mmHg makes one very active
c) 190 / 110 mmHg may harm vital organs
like brain and kidney
d) 130 / 90 mmHg is considered high and
requires treatment
11. ECG depicts the depolarization and
repolarization processes during the cardiac
cycle. In the ECG of a normal healthy
individual one of the following waves is not
represented:
a) Depolarization of atria
b) Repolarization of atria
c) Depolarization of Ventricles
d) Repolarization of Ventricles
12. During ventricular systole
a) Semilunar valves are closed
b) About 30% blood is pumped into aorta
from ventricles
c) Tricuspid and bicuspid valves are closed
d) Ventricular pressure declines
13. Most fatal thrombosis leading to myocardial
infarction is of
a) Right circumflex coronary artery
b) Right coronary artery
c) Left anterior descending artery
d) Left circumflex coronary artery
14. Heartbeat is accelerated by
a) Sympathetic nerves and acetylcholine
b) Cranial nerves and adrenaline
c) Cranial nerves and acetylcholine
d) Sympathetic nerves and epinephrine
15. Pacemaker of the heart is situated
a) In walls of left atrium close to opening of
pulmonary veins
b) In wall of right atrium close to Eustachian
valve
c) On interauricular septum
d) On the interventricular septum
16. The diagram given here is the standard
ECG of normal person. The P wave
represent the
R
P Q S
T
a) Initiation of the ventricular contraction b) Beginning of the systole c) End of systole
d) Contraction of both the atria
17. Sphygmomanometer measures
a) Blood pressure
b) Pulse rate
c) Rate of heartbeat
d) All
18. Systolic pressure is higher than diastolic
pressure because
a) Arteries are contracting during systole
b) Blood is pumped with a pressure in the
arteries by the heart during systole but
not during diastole
c) Arteries resist during systole only
d) Volume of blood is higher in systole than
that of diastole in the heart
7. The cardiac output in man under resting
condition is about
a) 2 l / min b) 4 l / min
c) 5 l / min d) 7 l / min
8. Which one indicates the hypertension?
a) 90 / 60 b) 120 / 85
c) 110 / 70 d) 140 / 100
9. Which layer of the wall of the blood vessel
is made up of circular smooth muscle?
a) Outer b) Middle
c) Both (a) and (b) d) Inner
10. Which one of the following statements is
correct regarding blood pressure?
a) 100 / 55 mmHg is considered an ideal
blood pressure
b) 105 / 50 mmHg makes one very active
c) 190 / 110 mmHg may harm vital organs
like brain and kidney
d) 130 / 90 mmHg is considered high and
requires treatment
11. ECG depicts the depolarization and
repolarization processes during the cardiac
cycle. In the ECG of a normal healthy
individual one of the following waves is not
represented:
a) Depolarization of atria
b) Repolarization of atria
c) Depolarization of Ventricles
d) Repolarization of Ventricles
12. During ventricular systole
a) Semilunar valves are closed
b) About 30% blood is pumped into aorta
from ventricles
c) Tricuspid and bicuspid valves are closed
d) Ventricular pressure declines
13. Most fatal thrombosis leading to myocardial
infarction is of
a) Right circumflex coronary artery
b) Right coronary artery
c) Left anterior descending artery
d) Left circumflex coronary artery
14. Heartbeat is accelerated by
a) Sympathetic nerves and acetylcholine
b) Cranial nerves and adrenaline
c) Cranial nerves and acetylcholine
d) Sympathetic nerves and epinephrine
15. Pacemaker of the heart is situated
a) In walls of left atrium close to opening of
pulmonary veins
b) In wall of right atrium close to Eustachian
valve
c) On interauricular septum
d) On the interventricular septum
16. The diagram given here is the standard
ECG of normal person. The P wave
represent the
R
P Q S
T
a) Initiation of the ventricular contraction b) Beginning of the systole c) End of systole
d) Contraction of both the atria
17. Sphygmomanometer measures
a) Blood pressure
b) Pulse rate
c) Rate of heartbeat
d) All
18. Systolic pressure is higher than diastolic
pressure because
a) Arteries are contracting during systole
b) Blood is pumped with a pressure in the
arteries by the heart during systole but
not during diastole
c) Arteries resist during systole only
d) Volume of blood is higher in systole than
that of diastole in the heart
96
19. Pericardial fluid is secreted by
a) Myocardium
b) Parietal peritoneum
c) Visceral peritoneum
d) Pericardium
20. Heartbeat becomes faster on stimulation by
a) Sympathetic nerves and adrenaline.
b) Sympathetic and parasympathetic
nerves.
c) Parasympathetic nerves and epinephrine
d) Parasympathetic nerves and acetylcholine
21. If heart of a mammal is injected with 2%
CaCl
2
solution, then
a) Heartbeat will increase
b) Heartbeat will decrease
c) Heartbeat will stop
d) No effect
22. Blood of which vessel in mammals carries
least percentage of urea
a) Dorsal aorta
b) Renal vein
c) Renal artery
d) Posterior vena cava
23. The small oval depression found on inter
auricular septum in adult human is termed
a) Foramen ovale
b) Fossa ovalis
c) Foramen of monro
d) Foramen of magnum
24. The pace maker in frog heart is
a) SA node b) AV node
c) Conus arteriosus d) Heart muscles
25. Heartbeat is controlled by which cranial
nerve
a) 10
th
b) 9
th
c) 3
rd
d) 5
th
26. In the given diagram, which blood vessel
represents vena cava?
B
C
A
D
a) C b) D
c) A d) B
27. Which one of the following vein breaks up
into capillaries?
a) Renal vein
b) Hepatic portal vein
c) Pelvic vein
d) Pulmonary vein
28. Which one of the following is a matching
pair?
a) Lub – sharp closure of AV valves at the
beginning of ventricular systole
b) Dub – Sudden opening of semilunar
valves at the beginning of ventricular
diastole
c) Pulsation of the radial artery – valves in
the blood vessels
d) Purkinje fibers – initiation of the heart
beat
29. The pulmonary trunk and aorta connected
by
a) Ligamentum arteriosus
b) Foramen ovale
c) Chordae tendinae
d) Carotid artery
30. Valves are present in
a) Atria, veins and ventricles
b) SA node, AV node and arteries
c) Pacemaker, veins and arteries
d) All of the above
19. Pericardial fluid is secreted by
a) Myocardium
b) Parietal peritoneum
c) Visceral peritoneum
d) Pericardium
20. Heartbeat becomes faster on stimulation by
a) Sympathetic nerves and adrenaline.
b) Sympathetic and parasympathetic
nerves.
c) Parasympathetic nerves and epinephrine
d) Parasympathetic nerves and acetylcholine
21. If heart of a mammal is injected with 2%
CaCl
2
solution, then
a) Heartbeat will increase
b) Heartbeat will decrease
c) Heartbeat will stop
d) No effect
22. Blood of which vessel in mammals carries
least percentage of urea
a) Dorsal aorta
b) Renal vein
c) Renal artery
d) Posterior vena cava
23. The small oval depression found on inter
auricular septum in adult human is termed
a) Foramen ovale
b) Fossa ovalis
c) Foramen of monro
d) Foramen of magnum
24. The pace maker in frog heart is
a) SA node b) AV node
c) Conus arteriosus d) Heart muscles
25. Heartbeat is controlled by which cranial
nerve
a) 10
th
b) 9
th
c) 3
rd
d) 5
th
26. In the given diagram, which blood vessel
represents vena cava?
B
C
A
D
a) C b) D
c) A d) B
27. Which one of the following vein breaks up
into capillaries?
a) Renal vein
b) Hepatic portal vein
c) Pelvic vein
d) Pulmonary vein
28. Which one of the following is a matching
pair?
a) Lub – sharp closure of AV valves at the
beginning of ventricular systole
b) Dub – Sudden opening of semilunar
valves at the beginning of ventricular
diastole
c) Pulsation of the radial artery – valves in
the blood vessels
d) Purkinje fibers – initiation of the heart
beat
29. The pulmonary trunk and aorta connected
by
a) Ligamentum arteriosus
b) Foramen ovale
c) Chordae tendinae
d) Carotid artery
30. Valves are present in
a) Atria, veins and ventricles
b) SA node, AV node and arteries
c) Pacemaker, veins and arteries
d) All of the above
97
31. P
a) Muscle fibers located in heart
b) Nerve fibers located in cerebrum
c) Connective tissue fibers joining one
bone to another bone
d) Sensory fibers extending from retina into
optic nerve
32. The tricuspid valve is present at the origin
of
a) Carotid arch
b) Pulmonary arch
c) Truncus arteriosus
d) Systemic arch
33. The following are the branches of dorsal
aorta
I. Intercostal
II. Phrenic
III. Coeliac
IV. Anterior mesenteric
V. Posterior mesenteric
Of these which set of arteries supply the
blood to the glands of digestive system?
a) I and II b) III and IV
c) IV and V d) II and III
34. With the increasing distance from heart the
elasticity as well as magnitude of the
muscular layer of arteries would
a) Decrease
b) Remains constant
c) Slightly decrease
d) Increase
35. Correctly match column I and column II
Column - I Column - II
A) Cardiac arrest i) Heart not pumping
blood affectively
B) Heart Failure ii) Heart muscle is
suddenly damages
C) Heart attack iii) Acute chest pain
D) Angina iv) Heart stops beating
a) A
i, Bii, Ciii, Div
b) Aiv, Bii, Ci, Diii
c) Aiv, Bi, Cii, Diii
d) Aii, Biii, Ci, Div
36. Fastest distribution of some injectable
material / medicine and with no risk of any
kind can be achieved by injecting it into the
a) Muscles b) Arteries
c) Veins d) Lymph vessels
ANSWER KEYS
Simple Questions
1.c 2.c 3.b 4.b 5.d 6.b 7.d 8.a 9.d 10.a 11.a 12.a
13.c 14.a 15.b 16.b 17.c 18.d 19.c 20.c 21.b 22.d 23.a 24.b
25.b 26.d 27.b 28.d 29.a 30.c 31.a 32.c 33.a 34.a 35.d
Difficult Questions
1.d 2.d 3.b 4.b 5.b 6.d 7.c 8.d 9.b 10.c 11.b 12.c
13.c 14.d 15.b 16.d 17.a 18.b 19.d 20.a 21.a 22.b 23.b 24.a
25.a 26.b 27.b 28.a 28.a 29.a 30.a 31.a 32.b 33.b 34.a 35.c
36.c
31. P
a) Muscle fibers located in heart
b) Nerve fibers located in cerebrum
c) Connective tissue fibers joining one
bone to another bone
d) Sensory fibers extending from retina into
optic nerve
32. The tricuspid valve is present at the origin
of
a) Carotid arch
b) Pulmonary arch
c) Truncus arteriosus
d) Systemic arch
33. The following are the branches of dorsal
aorta
I. Intercostal
II. Phrenic
III. Coeliac
IV. Anterior mesenteric
V. Posterior mesenteric
Of these which set of arteries supply the
blood to the glands of digestive system?
a) I and II b) III and IV
c) IV and V d) II and III
34. With the increasing distance from heart the
elasticity as well as magnitude of the
muscular layer of arteries would
a) Decrease
b) Remains constant
c) Slightly decrease
d) Increase
35. Correctly match column I and column II
Column - I Column - II
A) Cardiac arrest i) Heart not pumping
blood affectively
B) Heart Failure ii) Heart muscle is
suddenly damages
C) Heart attack iii) Acute chest pain
D) Angina iv) Heart stops beating
a) A
i, Bii, Ciii, Div
b) Aiv, Bii, Ci, Diii
c) Aiv, Bi, Cii, Diii
d) Aii, Biii, Ci, Div
36. Fastest distribution of some injectable
material / medicine and with no risk of any
kind can be achieved by injecting it into the
a) Muscles b) Arteries
c) Veins d) Lymph vessels
ANSWER KEYS
Simple Questions
1.c 2.c 3.b 4.b 5.d 6.b 7.d 8.a 9.d 10.a 11.a 12.a
13.c 14.a 15.b 16.b 17.c 18.d 19.c 20.c 21.b 22.d 23.a 24.b
25.b 26.d 27.b 28.d 29.a 30.c 31.a 32.c 33.a 34.a 35.d
Difficult Questions
1.d 2.d 3.b 4.b 5.b 6.d 7.c 8.d 9.b 10.c 11.b 12.c
13.c 14.d 15.b 16.d 17.a 18.b 19.d 20.a 21.a 22.b 23.b 24.a
25.a 26.b 27.b 28.a 28.a 29.a 30.a 31.a 32.b 33.b 34.a 35.c
36.c
98
1. B
a) Systolic pressure
b) Diastolic pressure
c) Both (a) and (b)
d) None of these
2. Maximum surface area of circulating system
is seen in
a) Heart b) Capillaries
c) Arterioles d) Veins
3. Murmur is a disorder of
a) Heart valves b) AV node
c) SA node d) Pulmonary vein
4. Which part of the circulatory system serves
to supply blood to the heart?
a) Coronary b) Portal
c) Pulmonary d) Systemic
5. The smallest blood vessel in the body is
a) Capillary b) Artery
c) Vein d) Vena cava
6. The atrio ventricular valves of the heart is
prevented from turning inside out by tough
strands of connective tissue is called as
a) Tendinous cords b) Tricuspids
c) Pocket valve d) Mitral valve
DPP - 4
7. Cardiac output is
a) The product of heart rate and stroke
volume
b) The product of auricular and ventricular
volume
c) The blood pumped in one minute
d) Both (a) and (c)
8. The blood returning to the heart from lungs
via pulmonary vein has more
a) RBC per ml of blood
b) Hemoglobin per ml of blood
c) Oxygen per ml of blood
d) Nutrient per ml of blood
9. “Vasa Vasorum” refers to
a) Jugular anastomosis
b) A network of blood vessels in an organ
c) “Vessels of vessels” nutritive in function
d) Carotid labyrinth regulating pressure of
blood vessels
10. The pulse beat is measured by the
a) Artery b) Capillary
c) Vein d) None of these
1. B
a) Systolic pressure
b) Diastolic pressure
c) Both (a) and (b)
d) None of these
2. Maximum surface area of circulating system
is seen in
a) Heart b) Capillaries
c) Arterioles d) Veins
3. Murmur is a disorder of
a) Heart valves b) AV node
c) SA node d) Pulmonary vein
4. Which part of the circulatory system serves
to supply blood to the heart?
a) Coronary b) Portal
c) Pulmonary d) Systemic
5. The smallest blood vessel in the body is
a) Capillary b) Artery
c) Vein d) Vena cava
6. The atrio ventricular valves of the heart is
prevented from turning inside out by tough
strands of connective tissue is called as
a) Tendinous cords b) Tricuspids
c) Pocket valve d) Mitral valve
DPP - 4
7. Cardiac output is
a) The product of heart rate and stroke
volume
b) The product of auricular and ventricular
volume
c) The blood pumped in one minute
d) Both (a) and (c)
8. The blood returning to the heart from lungs
via pulmonary vein has more
a) RBC per ml of blood
b) Hemoglobin per ml of blood
c) Oxygen per ml of blood
d) Nutrient per ml of blood
9. “Vasa Vasorum” refers to
a) Jugular anastomosis
b) A network of blood vessels in an organ
c) “Vessels of vessels” nutritive in function
d) Carotid labyrinth regulating pressure of
blood vessels
10. The pulse beat is measured by the
a) Artery b) Capillary
c) Vein d) None of these
99
5.1. LYMPHATIC CIRCULATORY SYSTEM
L
ike the circulatory system, the lymphatic system is made of a series of vessels, capillaries, and
organs. These structures collect excess fluid and cellular debris from the tissues and return them
back to the blood.
In the circulatory system, blood flows from arteries, through capillaries and into veins to be returned
to the heart. On its way through the capillaries, some fluid passes out across the capillary wall and
into the interstitial fluid in a process called capillary filtration. This filtration tends to occur across the
arterial end of the capillary, with most of the filtered fluid being reabsorbed at the venous end of the
capillary. This leaves a small amount of fluid that remains in the interstitial spaces between cells.
This filtered fluid is mostly plasma plus any plasma proteins that might have leaked from the blood
vessel as well. This excess interstitial fluid is collected by the lymphatic system.
The lymphatic system is essential for our survival. This system has three main functions:
To collect and recycle the excess interstitial fluid and its dissolved substances
To absorb fats and other substances from the digestive tract
To initiate and coordinate an immune response to remove cellular debris, bacteria, toxins,
fungi, parasites, and viruses that accumulate in our bodies.
Venous system
HeartLarge veins
Large lymphatic
vessels
Lymph node
Lymphatic capillary
Capillaries
(exchange vessels)
Small veins
Arterial system
Elastic arteries
(conducting vessels)
Muscular arteries
(distributing vessels)
Arterioles
(resistance vessels)
Terminal arteroids
Lymphatic circulatory system
UNIT 5 – LYMPHATIC SYSTEM
5.1. LYMPHATIC CIRCULATORY SYSTEM
L
ike the circulatory system, the lymphatic system is made of a series of vessels, capillaries, and
organs. These structures collect excess fluid and cellular debris from the tissues and return them
back to the blood.
In the circulatory system, blood flows from arteries, through capillaries and into veins to be returned
to the heart. On its way through the capillaries, some fluid passes out across the capillary wall and
into the interstitial fluid in a process called capillary filtration. This filtration tends to occur across the
arterial end of the capillary, with most of the filtered fluid being reabsorbed at the venous end of the
capillary. This leaves a small amount of fluid that remains in the interstitial spaces between cells.
This filtered fluid is mostly plasma plus any plasma proteins that might have leaked from the blood
vessel as well. This excess interstitial fluid is collected by the lymphatic system.
The lymphatic system is essential for our survival. This system has three main functions:
To collect and recycle the excess interstitial fluid and its dissolved substances
To absorb fats and other substances from the digestive tract
To initiate and coordinate an immune response to remove cellular debris, bacteria, toxins,
fungi, parasites, and viruses that accumulate in our bodies.
Venous system
HeartLarge veins
Large lymphatic
vessels
Lymph node
Lymphatic capillary
Capillaries
(exchange vessels)
Small veins
Arterial system
Elastic arteries
(conducting vessels)
Muscular arteries
(distributing vessels)
Arterioles
(resistance vessels)
Terminal arteroids
Lymphatic circulatory system
UNIT 5 – LYMPHATIC SYSTEM
100
5.1.1. Lymph vessels and capillaries
L
ymphatic vessels begin as capillaries. Both of these structures are thin walled, which allows lymph to
be transported across the membrane and collected in the vessels. Lymphatic capillaries have greater
permeability than blood capillaries and can absorb large molecules such as proteins and lipids. The
endothelial cells that make up the wall of a lymphatic capillary lack a basement membrane, loosely
attach to each other and slightly overlap. Interstitial fluid enters the lymphatic vessel when the pressure
is greater in the interstitial fluid than in lymph and nothing in the interstitial fluid is excluded from
entering the lymphatic capillaries. When pressure is greater inside the lymphatic capillary, the endothelial
cells prevent lymph from passing back into the interstitial spaces. Lymphatic capillaries are found
wherever blood capillaries are located except in the central nervous system and bone marrow.
Lymphatic capillaries unite to form larger lymphatic vessels. Structurally, lymphatic vessels are similar
to veins because they also have one way valves that function like gates to ensure the lymph only
flows in one direction. Like veins, skeletal muscle contraction exerts pressure on the lymph vessels
and forces the lymph forward through them. Lymph vessels are like oneway roads, with the lymph
being collected at the capillary beds and travels through the body into the thoracic cavity.
Systemic circulation
Lymphatic duct
Subclavian vein
Veins
Lymphatic vessel
Valve
Heart
Lymph node
Lymphatic capillaries
Systemic blood
capillaries
Arteries
Pulmonary blood
capillaries
Lymphatic capillaries
Lymph node
Pulmonary circulation
Interaction of blood and lymphatic vessels
Lymph is deposited in one of two large ducts in the chest region: the right lymphatic duct and the
thoracic duct. The lymph then travels from these ducts into venous circulation via the subclavian and
jugular veins. Left thoracic lymph duct (largest lymph vessel of body) is made up of lymph vessels
5.1.1. Lymph vessels and capillaries
L
ymphatic vessels begin as capillaries. Both of these structures are thin walled, which allows lymph to
be transported across the membrane and collected in the vessels. Lymphatic capillaries have greater
permeability than blood capillaries and can absorb large molecules such as proteins and lipids. The
endothelial cells that make up the wall of a lymphatic capillary lack a basement membrane, loosely
attach to each other and slightly overlap. Interstitial fluid enters the lymphatic vessel when the pressure
is greater in the interstitial fluid than in lymph and nothing in the interstitial fluid is excluded from
entering the lymphatic capillaries. When pressure is greater inside the lymphatic capillary, the endothelial
cells prevent lymph from passing back into the interstitial spaces. Lymphatic capillaries are found
wherever blood capillaries are located except in the central nervous system and bone marrow.
Lymphatic capillaries unite to form larger lymphatic vessels. Structurally, lymphatic vessels are similar
to veins because they also have one way valves that function like gates to ensure the lymph only
flows in one direction. Like veins, skeletal muscle contraction exerts pressure on the lymph vessels
and forces the lymph forward through them. Lymph vessels are like oneway roads, with the lymph
being collected at the capillary beds and travels through the body into the thoracic cavity.
Systemic circulation
Lymphatic duct
Subclavian vein
Veins
Lymphatic vessel
Valve
Heart
Lymph node
Lymphatic capillaries
Systemic blood
capillaries
Arteries
Pulmonary blood
capillaries
Lymphatic capillaries
Lymph node
Pulmonary circulation
Interaction of blood and lymphatic vessels
Lymph is deposited in one of two large ducts in the chest region: the right lymphatic duct and the
thoracic duct. The lymph then travels from these ducts into venous circulation via the subclavian and
jugular veins. Left thoracic lymph duct (largest lymph vessel of body) is made up of lymph vessels
101Helpline : 92200 34567 www.targeteducare.com
of head, neck left part of thorax, left anterior limb and both the hind limbs, alimentary canal, some parts
o
f thorax and abdomen. This duct is connected by a big bag like structure called cisterna chyli just
behind the diaphragm in abdominal cavity. It opens in left sub-clavian vein at its anterior side.
Lymphatic capillaries of intestinal villi are called lacteals. Their lymph is milky in colour due to the
absorbed fat from the intestine. It is called chyle. This chyle drains into cisterna chyli.
Unlike the cardiovascular circulation, the lymphatic circulation lacks a pump like the heart. Lymphatic
vessels are low pressure vessels similar to veins and the same muscle pump and respiratory pump
that promote venous return also facilitate lymph flow. Therefore, even though there is some smooth
muscle in lymphatic vessels, movement of the body is important to lymph circulation.
Heart
Collecting
lymphatic
vessels,
with valves
Lymphatic
capillary
Arterial systemVenous system
Lymph duct
Lymph trunk
Lymph node
Blood capillaries
Relationship of blood and lymph
capillaries. Lymph capillaries are
blind-ended tubes with one-way direction of flow.
Tissue cell
Tissue fluid
Lymphatic
capillaries
Blood
capillaries
Filaments anchored to connective tissue
Endothelial cell
Flaplike minivalve
Fibroblast in loose connective tissue
The endothelial cells that make up the lymphatic capillary
wall lack a basement membrane, loosely attach to each
other and slightly overlap
Lymphatic system
Anatomy of a lymphatic vessel
5.1.2. Lymph
The fluid flows through the lymphatic vessels until it is returned to the circulatory system to again
become a component of blood. Once interstitial fluid passes into lymphatic vessels, it is called
lymph. Lymph is a clear, pale-yellow fluid connective tissue.
Blood pressure is more, approximately 40 mmHg, at the side of arteriole side of blood capillaries.
Colloidal osmotic pressure of blood is 28 mmHg. Thus net filtration pressure of blood in this region
remains only 12 mmHg column. Blood is filtered and the filtrate is called tissue fluid which contains
of head, neck left part of thorax, left anterior limb and both the hind limbs, alimentary canal, some parts
o
f thorax and abdomen. This duct is connected by a big bag like structure called cisterna chyli just
behind the diaphragm in abdominal cavity. It opens in left sub-clavian vein at its anterior side.
Lymphatic capillaries of intestinal villi are called lacteals. Their lymph is milky in colour due to the
absorbed fat from the intestine. It is called chyle. This chyle drains into cisterna chyli.
Unlike the cardiovascular circulation, the lymphatic circulation lacks a pump like the heart. Lymphatic
vessels are low pressure vessels similar to veins and the same muscle pump and respiratory pump
that promote venous return also facilitate lymph flow. Therefore, even though there is some smooth
muscle in lymphatic vessels, movement of the body is important to lymph circulation.
Heart
Collecting
lymphatic
vessels,
with valves
Lymphatic
capillary
Arterial systemVenous system
Lymph duct
Lymph trunk
Lymph node
Blood capillaries
Relationship of blood and lymph
capillaries. Lymph capillaries are
blind-ended tubes with one-way direction of flow.
Tissue cell
Tissue fluid
Lymphatic
capillaries
Blood
capillaries
Filaments anchored to connective tissue
Endothelial cell
Flaplike minivalve
Fibroblast in loose connective tissue
The endothelial cells that make up the lymphatic capillary
wall lack a basement membrane, loosely attach to each
other and slightly overlap
Lymphatic system
Anatomy of a lymphatic vessel
5.1.2. Lymph
The fluid flows through the lymphatic vessels until it is returned to the circulatory system to again
become a component of blood. Once interstitial fluid passes into lymphatic vessels, it is called
lymph. Lymph is a clear, pale-yellow fluid connective tissue.
Blood pressure is more, approximately 40 mmHg, at the side of arteriole side of blood capillaries.
Colloidal osmotic pressure of blood is 28 mmHg. Thus net filtration pressure of blood in this region
remains only 12 mmHg column. Blood is filtered and the filtrate is called tissue fluid which contains
102
plasma, WBCs, O
2
and nutrients. The systemic venous pressure is as low as 15 mmHg, while
colloid osmotic pressure here remains 28 mmHg. Hence due to a negative pressure (-13 mmHg),
the lymph is poured from lymphatic into the veins.
WBCs and plasma are found in lymph but RBCs and platelets are absent. Lymph forms the second
circulatory system in the body. Lymphatic system is also known as the helping circulatory system.
Clotting capacity is present but it takes more time as compared to blood.
Differences between lymph and blood:
5.2. LYMPHATIC ORGANS
The major organs of the
lymphatic system can be
classified based on their role
in lymphocyte maturation.
Maturation takes place
within the red bone marrow
and the thymus gland, which
are primary lymphoid
organs. Antigens become
trapped within secondary
lymphoid organs such as
the lymph nodes, spleen,
and tonsils. These organs
are sites that contain
lymphocytes for destruction
of invading pathogens.
Blood Lymph
If forms circulatory system If forms lymphatic system
RBCs present RBCs absent
Neutrophils more Lymphocytes in largest amount
Soluble proteins in large amount but insoluble Soluble proteins in small amount but insoluble
proteins in small amount proteins in large amount
O
2
and nutrients in large amount but CO
2
very O
2
and nutrients in small amount but CO
2
in
less large amount
It is of red colour It is colouress, just like water
More WBC Lesser WBC
Adenoids
Tonsils
Right
lymphatic
duct
Bone
marrow Lymph vessels
Lymph node
Masses of
lymphocytes
and
macrophages
Lymphatic
capillary
Interstitial
fluid
Tissue cells
Lymphatic
vessel
Blood
capillary
Spleen
Thymus
Lymph nodes
Thymus
plasma, WBCs, O
2
and nutrients. The systemic venous pressure is as low as 15 mmHg, while
colloid osmotic pressure here remains 28 mmHg. Hence due to a negative pressure (-13 mmHg),
the lymph is poured from lymphatic into the veins.
WBCs and plasma are found in lymph but RBCs and platelets are absent. Lymph forms the second
circulatory system in the body. Lymphatic system is also known as the helping circulatory system.
Clotting capacity is present but it takes more time as compared to blood.
Differences between lymph and blood:
5.2. LYMPHATIC ORGANS
The major organs of the
lymphatic system can be
classified based on their role
in lymphocyte maturation.
Maturation takes place
within the red bone marrow
and the thymus gland, which
are primary lymphoid
organs. Antigens become
trapped within secondary
lymphoid organs such as
the lymph nodes, spleen,
and tonsils. These organs
are sites that contain
lymphocytes for destruction
of invading pathogens.
Blood Lymph
If forms circulatory system If forms lymphatic system
RBCs present RBCs absent
Neutrophils more Lymphocytes in largest amount
Soluble proteins in large amount but insoluble Soluble proteins in small amount but insoluble
proteins in small amount proteins in large amount
O
2
and nutrients in large amount but CO
2
very O
2
and nutrients in small amount but CO
2
in
less large amount
It is of red colour It is colouress, just like water
More WBC Lesser WBC
Adenoids
Tonsils
Right
lymphatic
duct
Bone
marrow Lymph vessels
Lymph node
Masses of
lymphocytes
and
macrophages
Lymphatic
capillary
Interstitial
fluid
Tissue cells
Lymphatic
vessel
Blood
capillary
Spleen
Thymus
Lymph nodes
Thymus
103
5.2.1. Lymph nodes
L
ymph nodes are oval shaped structures that are enclosed in a fibrous outer capsule. Superficial
lymph nodes are in the subcutaneous tissue and include inguinal nodes in the groin, axillary nodes
in the armpit and cervical nodes in the neck. Deep lymph nodes are everywhere else in the body
where there are lymph vessels. Nodes collect and filter lymph from several afferent vessels, and
several efferent vessels carry the lymph out from the node. The lymph fluid enters the lymph node
and slowly filters through the cortex and medullary regions. Any microbes that were collected in the
lymph are detected by the immune cells in the lymph nodes. Lymph nodes are primarily a site for
immune system activation.
5.2.2. Spleen
The spleen is located in the left, superior corner of the abdominal cavity, just posterior to the stomach,
and protected by the rib cage. Although it is about the size of a clenched fist, it is one of the largest
immune organ. Shaped like a big lymph node, the spleen similarly contains macrophages and
lymphocytes. Splenic macrophages can phagocytize cellular debris from defective red blood cells.
Foreign substances in the blood passing through the spleen can stimulate an immune response
because of the presence of lymphocytes.
Organ Description
TonsilsAdenoids are one of three sets of tonsils. They trap pathogens that enter through the
and mouth and nose. Also, the tonsils monitor the external environment that the mouth and
adenoidsnose are exposed to, and can react with an appropriate immune response for certain
pathogens.
Thymus A lobular (of or pertaining to a lobe) structure, which contains many immature, inactive
lymphocytes. As the lymphocytes mature, they leave the thymus to attack infected
cells in lymphatic tissue throughout the body.
Spleen The largest of the lymphatic organs, it houses lymphocytes for potential immune
response. Also, the resident phagocytes within the spleen perform the most basic
function of removing cell debris from the blood.
Lymph These house lymphocytes and macrophages, which destroy foreign material contained
nodes in the lymph fluid.
Lymph These transport lymph fluid throughout the lymphatic system.
vessels
Red All of our blood cells are generated from red bone marrow stem cells. These stem
bone cells differentiate into red blood cells, platelets, and several cells that play roles in
marrow immunity. These “immune cells’’ include lymphocytes, which carry out specific immunity
and neutrophils and macrophages (macrophages start as monocytes and mature into
macrophages in the tissues), which are nonspecific phagocytic cells.
5.2.1. Lymph nodes
L
ymph nodes are oval shaped structures that are enclosed in a fibrous outer capsule. Superficial
lymph nodes are in the subcutaneous tissue and include inguinal nodes in the groin, axillary nodes
in the armpit and cervical nodes in the neck. Deep lymph nodes are everywhere else in the body
where there are lymph vessels. Nodes collect and filter lymph from several afferent vessels, and
several efferent vessels carry the lymph out from the node. The lymph fluid enters the lymph node
and slowly filters through the cortex and medullary regions. Any microbes that were collected in the
lymph are detected by the immune cells in the lymph nodes. Lymph nodes are primarily a site for
immune system activation.
5.2.2. Spleen
The spleen is located in the left, superior corner of the abdominal cavity, just posterior to the stomach,
and protected by the rib cage. Although it is about the size of a clenched fist, it is one of the largest
immune organ. Shaped like a big lymph node, the spleen similarly contains macrophages and
lymphocytes. Splenic macrophages can phagocytize cellular debris from defective red blood cells.
Foreign substances in the blood passing through the spleen can stimulate an immune response
because of the presence of lymphocytes.
Organ Description
TonsilsAdenoids are one of three sets of tonsils. They trap pathogens that enter through the
and mouth and nose. Also, the tonsils monitor the external environment that the mouth and
adenoidsnose are exposed to, and can react with an appropriate immune response for certain
pathogens.
Thymus A lobular (of or pertaining to a lobe) structure, which contains many immature, inactive
lymphocytes. As the lymphocytes mature, they leave the thymus to attack infected
cells in lymphatic tissue throughout the body.
Spleen The largest of the lymphatic organs, it houses lymphocytes for potential immune
response. Also, the resident phagocytes within the spleen perform the most basic
function of removing cell debris from the blood.
Lymph These house lymphocytes and macrophages, which destroy foreign material contained
nodes in the lymph fluid.
Lymph These transport lymph fluid throughout the lymphatic system.
vessels
Red All of our blood cells are generated from red bone marrow stem cells. These stem
bone cells differentiate into red blood cells, platelets, and several cells that play roles in
marrow immunity. These “immune cells’’ include lymphocytes, which carry out specific immunity
and neutrophils and macrophages (macrophages start as monocytes and mature into
macrophages in the tissues), which are nonspecific phagocytic cells.
104
Instead of lymph flowing through it, the spleen contains blood. In fact, it serves as a reservoir for
b
lood which can be used for a small increase in circulating red blood cells during exercise or
emergency situations.
The spleen consists of two different kinds of tissue called white pulp and red pulp:
White pulp: It is scattered in the form of patches (in the splenic pulp) of long and irregular
size lymphatic endothelium. The meshes of this network are studded with numerous splenic
cells, lymphocytes. The splenic cells are mostly aggregated around arterioles forming nodules
which appear whitish and hence recognized as white pulp. Blood flowing into the spleen
through the splenic arteries enters the central arteries of the white pulp. Within this pulp, B
and T cells carry out immune functions similar to lymph nodes. White pulp also contains
macrophages that can remove blood-borne pathogens by phagocytosis.
Red pulp: It forms the maximum part of spleen. It is reddish due to excess RBCs and made
up of venous sinuses. A tissue is filled in intermediates spaces which form splenic cord. Red
pulp contains erythrocytes (dead and alive) and blood filled sinuses. Within the red pulp,
macrophages can remove worn-out red blood cells and platelets.
Capsule
Trabecule
Vascular sinusoid
Red pulp
Vein Artery
Periarterial
lymphatic
sheath (PALS)
Marginal zone
Follicle
White pulp
Spleen
Cord of Billroth found in spleen is big blood sinuses. It is possible to survive without a spleen if it is
damaged. However, removal of the spleen does diminish the ability to mount an immune response.
Instead of lymph flowing through it, the spleen contains blood. In fact, it serves as a reservoir for
b
lood which can be used for a small increase in circulating red blood cells during exercise or
emergency situations.
The spleen consists of two different kinds of tissue called white pulp and red pulp:
White pulp: It is scattered in the form of patches (in the splenic pulp) of long and irregular
size lymphatic endothelium. The meshes of this network are studded with numerous splenic
cells, lymphocytes. The splenic cells are mostly aggregated around arterioles forming nodules
which appear whitish and hence recognized as white pulp. Blood flowing into the spleen
through the splenic arteries enters the central arteries of the white pulp. Within this pulp, B
and T cells carry out immune functions similar to lymph nodes. White pulp also contains
macrophages that can remove blood-borne pathogens by phagocytosis.
Red pulp: It forms the maximum part of spleen. It is reddish due to excess RBCs and made
up of venous sinuses. A tissue is filled in intermediates spaces which form splenic cord. Red
pulp contains erythrocytes (dead and alive) and blood filled sinuses. Within the red pulp,
macrophages can remove worn-out red blood cells and platelets.
Capsule
Trabecule
Vascular sinusoid
Red pulp
Vein Artery
Periarterial
lymphatic
sheath (PALS)
Marginal zone
Follicle
White pulp
Spleen
Cord of Billroth found in spleen is big blood sinuses. It is possible to survive without a spleen if it is
damaged. However, removal of the spleen does diminish the ability to mount an immune response.
105
Functions of spleen:
Its macrophages engulf or phagocytoze and destroy worn out blood cells, live or dead
pathogens, cell debris etc.
In the embryonal stage, it produces RBCs.
Some antibodies are synthesized here.
In adult stage spleen works as blood bank. Its sinuses serve as reservoirs of blood when
required their blood is squeezed into circulation.
Spleen stores iron.
The size of spleen increases at the time of malaria because lymphocytes and dead RBC
number is increased in it at that time (splenomegaly).
TARGET POINTS
Lymphatic system present in class amphibian is of open type.
Lymph heart and lymph sinuses are found in frog but absent in the lymphatic system of mammals.
Peyer’s patches are present in mucosa of intestine and tonsils are present in mucosa of pharynx.
Functions of spleen:
Its macrophages engulf or phagocytoze and destroy worn out blood cells, live or dead
pathogens, cell debris etc.
In the embryonal stage, it produces RBCs.
Some antibodies are synthesized here.
In adult stage spleen works as blood bank. Its sinuses serve as reservoirs of blood when
required their blood is squeezed into circulation.
Spleen stores iron.
The size of spleen increases at the time of malaria because lymphocytes and dead RBC
number is increased in it at that time (splenomegaly).
TARGET POINTS
Lymphatic system present in class amphibian is of open type.
Lymph heart and lymph sinuses are found in frog but absent in the lymphatic system of mammals.
Peyer’s patches are present in mucosa of intestine and tonsils are present in mucosa of pharynx.
106
1. Which of the following best describes the
lymphatic system?
a) A one way route from the interstitial fluid
to the blood.
b) A one way route from the blood to the
interstitial fluid.
c) A direct two way exchange route
between blood and interstitial fluid.
d) An integral component of the
cardiovascular system
2. Compared with blood capillaries, lymphatic
capillaries
a) Are larger in diameter and have
overlapping endothelial cells
b) Lack-well organized layers separating
them from surrounding tissues
c) Are closed-ended tubes found in most
but not all the same locations
d) All of the above
3. Which selection includes all the major
components of the lymphatic system?
a) Lymphatic cells and structures, lymph
and lymph vessels
b) Thoracic duct, right lymphatic duct, and
lymph
c) Lymphocytes, lymph, and lymph nodes.
d) Spleen, thymus, and tonsils
4. A systematic defense against antigens,
initiated by lymphatic cells, is called
a) A cross reaction
b) Inflammation
c) Septicemia
d) An immune response
5. Lymph from which of the following body
regions drains into the thoracic duct?
a) Right side of the thorax
b) Right upper limb
c) Right lower limb
d) Right side of the head
Simple Questions
6. Which statement is false about lymphatic
nodules?
a) The center has proliferating B
lymphocytes and some macrophages.
b) T lymphocytes are located along the
periphery
c) Lymphatic nodules are completely
surrounded by a connective tissue
capsule
d) Lymphatic nodules in the ileum of the
small intestine are called Peyer patches
7. Which type of lymph vessel consists solely
of an endothelium and has one way valves
that allow interstitial fluid to enter?
a) Lymphatic vessel
b) Lymphatic capillary
c) Lymphatic duct
d) Lymphatic trunk
8. Which statement is true about lymph nodes?
a) Cancerous lymph nodes are swollen and
tender to the touch
b) The medulla of a lymph node contains
lymphatic nodules
c) Lymph enters the lymph node through
afferent lymphatic vessels
d) Lymphatic sinuses are located in the
cortex of a lymph node only
9. Oval clusters of lymphatic cells with some
extracellular matrix but no connective tissue
capsule are called
a) Lymph nodes
b) Lymphatic tissues
c) Lymphatic nodules
d) Medullary sinuses
1. Which of the following best describes the
lymphatic system?
a) A one way route from the interstitial fluid
to the blood.
b) A one way route from the blood to the
interstitial fluid.
c) A direct two way exchange route
between blood and interstitial fluid.
d) An integral component of the
cardiovascular system
2. Compared with blood capillaries, lymphatic
capillaries
a) Are larger in diameter and have
overlapping endothelial cells
b) Lack-well organized layers separating
them from surrounding tissues
c) Are closed-ended tubes found in most
but not all the same locations
d) All of the above
3. Which selection includes all the major
components of the lymphatic system?
a) Lymphatic cells and structures, lymph
and lymph vessels
b) Thoracic duct, right lymphatic duct, and
lymph
c) Lymphocytes, lymph, and lymph nodes.
d) Spleen, thymus, and tonsils
4. A systematic defense against antigens,
initiated by lymphatic cells, is called
a) A cross reaction
b) Inflammation
c) Septicemia
d) An immune response
5. Lymph from which of the following body
regions drains into the thoracic duct?
a) Right side of the thorax
b) Right upper limb
c) Right lower limb
d) Right side of the head
Simple Questions
6. Which statement is false about lymphatic
nodules?
a) The center has proliferating B
lymphocytes and some macrophages.
b) T lymphocytes are located along the
periphery
c) Lymphatic nodules are completely
surrounded by a connective tissue
capsule
d) Lymphatic nodules in the ileum of the
small intestine are called Peyer patches
7. Which type of lymph vessel consists solely
of an endothelium and has one way valves
that allow interstitial fluid to enter?
a) Lymphatic vessel
b) Lymphatic capillary
c) Lymphatic duct
d) Lymphatic trunk
8. Which statement is true about lymph nodes?
a) Cancerous lymph nodes are swollen and
tender to the touch
b) The medulla of a lymph node contains
lymphatic nodules
c) Lymph enters the lymph node through
afferent lymphatic vessels
d) Lymphatic sinuses are located in the
cortex of a lymph node only
9. Oval clusters of lymphatic cells with some
extracellular matrix but no connective tissue
capsule are called
a) Lymph nodes
b) Lymphatic tissues
c) Lymphatic nodules
d) Medullary sinuses
107
10. T
functions?
a) Initiates an immune response when
antigens are detected in the blood
b) Stores erythrocytes and platelets and
hemolyzes old, defective ones
c) Phagocytizes bacteria and foreign debris
from the blood
d) All of the above
11. Which one of the following does not
accurately describe the spleen?
a) Surrounded by a capsule composed of
dense irregular connective tissue
b) Divided into an outer cortex and an inner
medulla by fibrous trabeculae
c) White pulp contains clusters of lymphatic
cells encircling central arteries
d) Red pulp contains splenic cords and
sinusoids with numerous macrophages
12. With advancing age the lymphatic system
loose effectiveness in
a) Providing immunity and fighting disease
b) Transporting lymph to the bloodstream
c) Absorbing dietary lipids from the small
intestine
d) All of the above
13. Spleen increases in size during malaria due
to
a) More lymphocytes b) Dead RBC
c) Both d) None
14. Which of the following organs will only
receive oxygenated blood?
a) Skin b) Lungs
c) Spleen d) Liver
15. Lymph lacks
a) Erythrocytes b) Platelets
c) Plasma proteins d) All of these
16. Which one of the following organs can be
called a sort of “blood bank”?
a) Heart b) Liver
c) Spleen d) Lungs
17. Lymph nodes in man are found abundantly
in
a) Fingers b) Neck
c) Arms d) Legs
18. Lymph vessels pour their materials in
a) Vena cava which enters in right auricle
b) Pulmonary artery
c) Artery which enters in legs
d) Right ventricles
Difficult Questions
1. General functions of the lymphatic system
include
a) Fluid and nutrient transport
b) Lymphocyte development
c) The immune response
d) All of the above
2. How much excess interstitial fluid must the
lymphatic system return to the bloodstream
each day?
a) Less than 500 milliliters
b) Up to 1 liter
c) About 3 liters
d) Between 4 and 5 liters
3. Lymphocytes located in the ____ do not
participate in the immune response
a) Bloodstream
b) Lymphatic vessels
c) Thymus
d) Lymph nodes
4. Filter apparatus for dead RBC is
a) Spleen + kidney
b) Liver + kidney
c) Spleen + Liver + kidney
d) Liver + spleen
10. T
functions?
a) Initiates an immune response when
antigens are detected in the blood
b) Stores erythrocytes and platelets and
hemolyzes old, defective ones
c) Phagocytizes bacteria and foreign debris
from the blood
d) All of the above
11. Which one of the following does not
accurately describe the spleen?
a) Surrounded by a capsule composed of
dense irregular connective tissue
b) Divided into an outer cortex and an inner
medulla by fibrous trabeculae
c) White pulp contains clusters of lymphatic
cells encircling central arteries
d) Red pulp contains splenic cords and
sinusoids with numerous macrophages
12. With advancing age the lymphatic system
loose effectiveness in
a) Providing immunity and fighting disease
b) Transporting lymph to the bloodstream
c) Absorbing dietary lipids from the small
intestine
d) All of the above
13. Spleen increases in size during malaria due
to
a) More lymphocytes b) Dead RBC
c) Both d) None
14. Which of the following organs will only
receive oxygenated blood?
a) Skin b) Lungs
c) Spleen d) Liver
15. Lymph lacks
a) Erythrocytes b) Platelets
c) Plasma proteins d) All of these
16. Which one of the following organs can be
called a sort of “blood bank”?
a) Heart b) Liver
c) Spleen d) Lungs
17. Lymph nodes in man are found abundantly
in
a) Fingers b) Neck
c) Arms d) Legs
18. Lymph vessels pour their materials in
a) Vena cava which enters in right auricle
b) Pulmonary artery
c) Artery which enters in legs
d) Right ventricles
Difficult Questions
1. General functions of the lymphatic system
include
a) Fluid and nutrient transport
b) Lymphocyte development
c) The immune response
d) All of the above
2. How much excess interstitial fluid must the
lymphatic system return to the bloodstream
each day?
a) Less than 500 milliliters
b) Up to 1 liter
c) About 3 liters
d) Between 4 and 5 liters
3. Lymphocytes located in the ____ do not
participate in the immune response
a) Bloodstream
b) Lymphatic vessels
c) Thymus
d) Lymph nodes
4. Filter apparatus for dead RBC is
a) Spleen + kidney
b) Liver + kidney
c) Spleen + Liver + kidney
d) Liver + spleen
108
5. Which of the following is a function of the
white pulp of the spleen?
a) Phagocytizes erythrocytes
b) Serves as a blood cell reservoir
c) Elicits an immune response if antigens
are detected in the blood.
d) Serves as a site for hemopoiesis during
fetal life
6. What change occurs to the adult lymphatic
system as we get older?
a) The body produces and transports less
lymph
b) Greater numbers of B lymphocytes are
produced
c) Helper T-lymphocytes do not respond as
well to antigens
d) The lymph nodes enlarge
7. Large groups of lymphatic nodules in the
mucosa of the gastrointestinal, respiratory,
genital, and urinary tracts are collectively
called
a) MALT
b) Peyer patches
c) Germinal centers
d) Mucosal lymph nodes
8. Which of the following statements is false?
a) Blood pressure forces fluid out of
capillaries into the interstitial spaces
b) “Leaked” fluids can be returned to the
blood only by lymphatic vessels
c) Lymphatic vessels return excess
interstitial fluid to the venous circulation
d) Blood volume would drop precipitously
without the lymphatic drainage
9. Which of the following is false in comparing
lymphatic vessels with small veins?
a) Both have valves within the lumen
b) Both contain the same three tunics
c) Pressures in lymphatic vessels exceed
those in veins
d) Contraction of nearby skeletal muscles
helps propel fluids through both
10. The two largest lymph collecting vessels are
the
a) Cisternae chili and thoracic duct
b) Thoracic duct and right lymphatic duct
c) Left subclavian trunk and right lymphatic
duct
d) Left jugular trunk and right subclavian
trunk
11. Clusters of lymph nodes are found in which
of the following body regions?
a) Axillary b) Cervical
c) Inguinal d) All of the above
12. The thymus is a lymphatic organ that
a) Is divided into f our lobes by its
connective tissue capsule
b) Reaches a maximum weight of 30 to 50
grams at puberty
c) Is located in the posterior mediastinum,
inferior to the heart
d) Remains functional throughout
adulthood, especially after age 40
13. Removal of which organ will have least
effect in an adult human?
a) Spleen b) Liver
c) Pancreas d) Pituitary
14. The most important center of lymph
formation is
a) Liver
b) Spleen
c) Bone marrow
d) Mucosa of ileum
15. If spleen of human is removed from body
then
a) Animal will die
b) Number of blood platelets will increase
c) Number of blood platelets will decrease
d) There will be no effect on the number of
blood platelets
5. Which of the following is a function of the
white pulp of the spleen?
a) Phagocytizes erythrocytes
b) Serves as a blood cell reservoir
c) Elicits an immune response if antigens
are detected in the blood.
d) Serves as a site for hemopoiesis during
fetal life
6. What change occurs to the adult lymphatic
system as we get older?
a) The body produces and transports less
lymph
b) Greater numbers of B lymphocytes are
produced
c) Helper T-lymphocytes do not respond as
well to antigens
d) The lymph nodes enlarge
7. Large groups of lymphatic nodules in the
mucosa of the gastrointestinal, respiratory,
genital, and urinary tracts are collectively
called
a) MALT
b) Peyer patches
c) Germinal centers
d) Mucosal lymph nodes
8. Which of the following statements is false?
a) Blood pressure forces fluid out of
capillaries into the interstitial spaces
b) “Leaked” fluids can be returned to the
blood only by lymphatic vessels
c) Lymphatic vessels return excess
interstitial fluid to the venous circulation
d) Blood volume would drop precipitously
without the lymphatic drainage
9. Which of the following is false in comparing
lymphatic vessels with small veins?
a) Both have valves within the lumen
b) Both contain the same three tunics
c) Pressures in lymphatic vessels exceed
those in veins
d) Contraction of nearby skeletal muscles
helps propel fluids through both
10. The two largest lymph collecting vessels are
the
a) Cisternae chili and thoracic duct
b) Thoracic duct and right lymphatic duct
c) Left subclavian trunk and right lymphatic
duct
d) Left jugular trunk and right subclavian
trunk
11. Clusters of lymph nodes are found in which
of the following body regions?
a) Axillary b) Cervical
c) Inguinal d) All of the above
12. The thymus is a lymphatic organ that
a) Is divided into f our lobes by its
connective tissue capsule
b) Reaches a maximum weight of 30 to 50
grams at puberty
c) Is located in the posterior mediastinum,
inferior to the heart
d) Remains functional throughout
adulthood, especially after age 40
13. Removal of which organ will have least
effect in an adult human?
a) Spleen b) Liver
c) Pancreas d) Pituitary
14. The most important center of lymph
formation is
a) Liver
b) Spleen
c) Bone marrow
d) Mucosa of ileum
15. If spleen of human is removed from body
then
a) Animal will die
b) Number of blood platelets will increase
c) Number of blood platelets will decrease
d) There will be no effect on the number of
blood platelets
109
16. C
a) Faster than blood
b) Not possible
c) Slower than blood
d) A passive process
17. Compared to blood our lymph has
a) No plasma
b) Plasma without proteins
c) More WBC and no RBC
d) More RBC and less WBC
18. Which of the following does not accurately
describe activities or structures of lymph
nodes?
a) Lymph perlocates slowly through cortical
and then medullary sinuses
b) Lymphocytes line the sinuses and
phagocytize foreign debris from the
lymph
c) One or two efferent lymphatic vessels
drain the lymph node through the hilum
d) Lymph from one lymph node often flows
into another for further filtering
ANSWER KEYS
Simple Questions
1.a 2.d 3.a 4.d 5.c 6.c 7.b 8.c 9.c 10.d 11.b 12.a
13.c 14.c 15.d 16.c 17.b 18.a
Difficult Questions
1.d 2.c 3.c 4.d 5.c 6.c 7.a 8.b 9.c 10.b 11.d 12.b
13.a 14.d 15.d 16.c 17.c 18.b
16. C
a) Faster than blood
b) Not possible
c) Slower than blood
d) A passive process
17. Compared to blood our lymph has
a) No plasma
b) Plasma without proteins
c) More WBC and no RBC
d) More RBC and less WBC
18. Which of the following does not accurately
describe activities or structures of lymph
nodes?
a) Lymph perlocates slowly through cortical
and then medullary sinuses
b) Lymphocytes line the sinuses and
phagocytize foreign debris from the
lymph
c) One or two efferent lymphatic vessels
drain the lymph node through the hilum
d) Lymph from one lymph node often flows
into another for further filtering
ANSWER KEYS
Simple Questions
1.a 2.d 3.a 4.d 5.c 6.c 7.b 8.c 9.c 10.d 11.b 12.a
13.c 14.c 15.d 16.c 17.b 18.a
Difficult Questions
1.d 2.c 3.c 4.d 5.c 6.c 7.a 8.b 9.c 10.b 11.d 12.b
13.a 14.d 15.d 16.c 17.c 18.b
110
DPP - 5
1
. The lymphatic system
a) Is an open circulatory system
b) Contains one way valves
c) Returns fluids to the bloodstream
d) All of the above
2. Interstitial fluid is derived from fluid that is
forced out of the
a) Venule end of capillaries
b) Arteriole end of capillaries
c) Lymph vessels
d) Arteries
3. Fluid is driven through the lymphatic system
by
a) Contraction of the walls of the lymphatic
vessels
b) Pressure created by the pumping of the
heart
c) Contractions of the lymph nodes
d) Squeezing of the lymphatic vessels by
the body’s muscle
4. All of the following belong to the lymphatic
system except
a) Lymph
b) Lymphatic vessels
c) Red bone marrow
d) Yellow bone marrow
5. The first line of defense against disease
causing organisms is
a) Cell based immunity
b) Production of antibodies
c) Inflammation
d) The intact skin
6. Which of the following is not a major organ
of lymphatic system?
a) Lymph nodes
b) Thymus
c) Kidney
d) Spleen
7. Afferent lymph vessels are numerous in
number where as efferent lymph vessel is
a) Single
b) Double
c) Triple
d) Quadro
8. Lymph capillaries join together forming
larger lymph vessels which give rise to
a) Lymph duct
b) Thoracic duct
c) Thoracic lymph duct
d) Sperm duct
9. Spleen, thymus, tonsils and adenoids
produce
a) Erythrocytes
b) Thrombocytes
c) Phagocytes
d) Lymphocytes
10. Lymph nodes
a) Are bean shaped organs
b) Are located along lymphatic vessels
c) Are scattered throughout the body
d) All of the above
DPP - 5
1
. The lymphatic system
a) Is an open circulatory system
b) Contains one way valves
c) Returns fluids to the bloodstream
d) All of the above
2. Interstitial fluid is derived from fluid that is
forced out of the
a) Venule end of capillaries
b) Arteriole end of capillaries
c) Lymph vessels
d) Arteries
3. Fluid is driven through the lymphatic system
by
a) Contraction of the walls of the lymphatic
vessels
b) Pressure created by the pumping of the
heart
c) Contractions of the lymph nodes
d) Squeezing of the lymphatic vessels by
the body’s muscle
4. All of the following belong to the lymphatic
system except
a) Lymph
b) Lymphatic vessels
c) Red bone marrow
d) Yellow bone marrow
5. The first line of defense against disease
causing organisms is
a) Cell based immunity
b) Production of antibodies
c) Inflammation
d) The intact skin
6. Which of the following is not a major organ
of lymphatic system?
a) Lymph nodes
b) Thymus
c) Kidney
d) Spleen
7. Afferent lymph vessels are numerous in
number where as efferent lymph vessel is
a) Single
b) Double
c) Triple
d) Quadro
8. Lymph capillaries join together forming
larger lymph vessels which give rise to
a) Lymph duct
b) Thoracic duct
c) Thoracic lymph duct
d) Sperm duct
9. Spleen, thymus, tonsils and adenoids
produce
a) Erythrocytes
b) Thrombocytes
c) Phagocytes
d) Lymphocytes
10. Lymph nodes
a) Are bean shaped organs
b) Are located along lymphatic vessels
c) Are scattered throughout the body
d) All of the above
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