Human respiration

1. Human Human
RespirationRespiration
DR Rana Amjad AliDR Rana Amjad Ali

2. What is Human Respiration?What is Human Respiration?
•The human respiratory
system allows one to
obtain oxygen, eliminate
carbon dioxide.
•Breathing consists of
two phases, inspiration
and expiration
–Inspiration- the process of
taking in air
–Expiration- the process of
blowing out air

3. Organs in the Respiratory SystemOrgans in the Respiratory System
STRUCTURE FUNCTION
nose / nasal cavity
 warms, moistens, & filters air as it is
inhaled
pharynx (throat)  passageway for air, leads to trachea
larynx
 the voice box, where vocal chords are
located
trachea (windpipe)
 keeps the windpipe "open"
 trachea is lined with fine hairs called
cilia which filter air before it reaches the
lungs
bronchi
 two branches at the end of the trachea,
each lead to a lung
bronchioles
 a network of smaller branches leading from
the bronchi into the lung tissue &
ultimately to air sacs
alveoli
 the functional respiratory units in the lung
where gases are exchanged

4. Malfunctions & Diseases of the Respiratory System
asthma
severe allergic reaction
characterized by the
constriction of bronchioles
bronchitis
inflammation of the lining of
the bronchioles
emphysema
condition in which the alveoli
deteriorate, causing the lungs
to lose their elasticity
pneumonia
condition in which the alveoli
become filled with fluid,
preventing the exchange of
gases
lung cancer
irregular & uncontrolled growth
of tumors in the lung tissue

5. Respiratory CycleRespiratory Cycle
•Respiration rate is the number of
breaths per minute
•Human respiration rate is controlled
by a part of the brain called the
medulla
–Sends signals to adjust levels of oxygen
present in your body by changing your
breathing rate

6. Respiratory Respiratory
Overview Overview PicturePictureNasal
Cavity
Nose
Mouth
Bronchus
Bronchiole
Alveolus
Diaphragm
Throat
(pharynx)
Windpipe
(Trachea)
Left lungs
Rib
s
MB

7. Nose and Mouth PictureNose and Mouth Picture
Nasal Cavity
Nostril
Oral Cavity
Pharynx
MB

8. The Pharynx and TracheaThe Pharynx and Trachea
our pharynx (throat) gathers air after it passes
through our nose and then the air is passed down to
our trachea (windpipe).
our trachea is held open by “incomplete rings
of cartilage.” Without these rings our trachea
might close off and air would not be able to get
to and from our lungs.
Pharynx
(Throat)
Mouth
Trachea

9. our trachea (windpipe) splits up into
two bronchi tubes. These two tubes keep
splitting up and form our bronchiole.
The Bronchi Tubes The Bronchi Tubes
and Bronchiole and Bronchiole
IntroIntro
MB

10. The Bronchi Tubes and The Bronchi Tubes and
BronchioleBronchiole
These bronchi tubes split up, like
tree branches, and get smaller and smaller
inside our lungs.
The air flows past our bronchi tubes
and into our bronchiole. These tubes
keep getting smaller and smaller until they
finally end with small air sacs (called alveoli).
MB

11. Alveoli and Bronchi PictureAlveoli and Bronchi Picture
Trachea
Bronchi Tubes
Bronchiole
Alveoli
MB

12. The Alveoli and Capillary The Alveoli and Capillary
NetworkNetwork
alveoli are tiny air sacs
that fill up with air/oxygen when we
breath in.
our alveoli are surrounded by
many tiny blood vessels called
capillaries.
The walls of our alveoli (and capillaries) are
so thin that the oxygen or carbon dioxide can
pass through them, traveling right into, or
out of our blood stream.

13. Alveoli PictureAlveoli Picture
Capillary
Red Blood
Cell
Oxygen is
picked up
Carbon
Dioxide is
dropped off
Wall
of the
air
sac
MB

14. Al veolusAl veolus
Bronchiole
Respiratory Bronchiole
Alveolar Duct
Alveolar Sac
Capillaries
JH

15. Looking at the Al veol iLooking at the Al veol i

16. Ch emical sCh emical s
Red blood cell carrying Carbon dioxide
Chemical change is taking place in cell
Red blood cell carrying oxygen
Alveolus
Contiguous Basal Laminae (Membrane)
Capillary

17. Di ff usi onDi ff usi on
Oxygen
Carbon Dioxide
Alveolus
Contiguous Basal Laminae (Membrane*)
Capillary
* A specialized thin layer of skin
that oxygen and carbon dioxide
can pass through.
Oxygen diffuses
through the
membrane into
the blood
stream. Carbon
Dioxide diffuses
through the
membrane and
enters the
alveolus.

18. Cool pi cturesCool pi ctures
JH

19. Intro Intro
to to
Di apDi ap
hraghrag
mm
The Diaphragm is an important factor
in breathing.
JH

20. Diagram of DiaphragmDiagram of Diaphragm
JH

21. Respiratory Respiratory
Overview ReviewOverview Review
CO
2
JH
The Pharynx, or
throat, is located
where passages from
the nose and mouth
came together.
Air Passing over the
mucus membrane of
the nasal cavity is
moistened, warmed,
and filtered
Inside the lungs
the Bronchi
branch into small
tubes called
bronchioles
At the end of the
bronchioles are
bunches of
alveoli, air sacs,
arranged like
grapes on a stem
Air enters the
trachea, or wind
pipe which leads
to and from the
lungs
The trachea divides
into two tubes
called bronchi
If one lobe is injured
or diseased, the other
lobes may be able to
function normally

22. The The
RespiraRespira
tory tory
SystemSystem

23. 23
Respiration IncludesRespiration Includes
•Pulmonary ventilation
–Air moves in and out of lungs
–Continuous replacement of gases in alveoli (air sacs)
•External respiration
–Gas exchange between blood and air at alveoli
–O2 (oxygen) in air diffuses into blood
–CO2 (carbon dioxide) in blood diffuses into air
•Transport of respiratory gases
–Between the lungs and the cells of the body
–Performed by the cardiovascular system
–Blood is the transporting fluid
•Internal respiration
–Gas exchange in capillaries between blood and tissue
cells
–O2 in blood diffuses into tissues
–CO2 waste in tissues diffuses into blood

24. 24
Cellular RespirationCellular Respiration
•Oxygen (O2) is used by the cells
•O2 needed in conversion of glucose
to cellular energy (ATP)
•All body cells
•Carbon dioxide (CO2) is produced as
a waste product
•The body’s cells die if either the
respiratory or cardiovascular system
fails

25. 25
The Respiratory OrgansThe Respiratory Organs
Conducting zone
–Respiratory passages
that carry air to the
site of gas exchange
–Filters, humidifies and
warms air
Respiratory zone
–Site of gas exchange
–Composed of
•Respiratory
bronchioles
•Alveolar ducts
•Alveolar sacs
Conducting zone labeled

31. 31
NoseNose
•Provides airway
•Moistens and warms
air
•Filters air
•Resonating chamber
for speech
•Olfactory receptors
External nose

32. 32
Nasal cavity
–Air passes through nares (nostrils)
–Nasal septum divides nasal cavity in midline (to right & left
halves)
•Perpendicular plate of ethmoid bone, vomer and septal
cartilage
–Connects with pharynx posteriorly through choanae
(posterior nasal apertures*)
–Floor is formed by palate (roof of the mouth)
•Anterior hard palate and posterior soft palate
*
palate

33. 33
Linings of nasal cavity
•Vestibule* (just above nostrils)
–Lined with skin containing sebaceous and sweat glands and
nose hairs
–Filters large particulars (insects, lint, etc.)
•The remainder of nasal cavity: 2 types of mucous membrane
–Small patch of olfactory mucosa near roof (cribriform plate)
–Respiratory mucosa: lines most of the cavity
*
Olfactory
mucosa

34. 34
Respiratory Respiratory
MucosaMucosa
•Pseudostratified
ciliated columnar epithelium
•Scattered goblet cells
•Underlying connective tissue lamina
propria
–Mucous cells – secrete mucous
–Serous cells – secrete watery fluid with
digestive enzymes, e.g. lysozyme
•Together all these produce a
quart/day
–Dead junk is swallowed

35. 35
Nasal Conchae
•Inferior to each is a meatus*
•Increases turbulence of air
•3 scroll-like structures
•Reclaims moisture on the way
out
*
*
*
(its own bone)
Of ethmoid

36. 36
Paranasal sinuses
–Frontal, sphenoid, ethmoid and maxillary
bones
–Open into nasal cavity
–Lined by same mucosa as nasal cavity and
perform same functions
–Also lighten the skull
–Can get infected: sinusitis

37. 37
The Pharynx (throat)The Pharynx (throat)
•3 parts: naso-, oro- and laryngopharynx
•Houses tonsils (they respond to inhaled antigens)
•Uvula closes off nasopharynx during swallowing so
food doesn’t go into nose
•Epiglottis posterior to the tongue: keeps food out of
airway
•Oropharynx and laryngopharynx serve as common
passageway for food and air
–Lined with stratified squamous epithelium for protection
*
*

38. 38
The Larynx (voicebox)The Larynx (voicebox)
•Extends from the level of the 4
th
to the
6
th
cervical vertebrae
•Attaches to hyoid bone superiorly
•Inferiorly is continuous with trachea
(windpipe)
•Three functions:
1.Produces vocalizations (speech)
2.Provides an open airway (breathing)
3.Switching mechanism to route air and food
into proper channels
•Closed during swallowing
•Open during breathing

39. 39
•Framework of the larynx
–9 cartilages connected by membranes and
ligaments
–Thyroid cartilage with laryngeal prominence
(Adam’s apple) anteriorly
–Cricoid cartilage inferior to thyroid cartilage: the
only complete ring of cartilage: signet shaped and
wide posteriorly

40. 40
–Behind thyroid cartilage and above
cricoid: 3 pairs of small cartilages
1.Arytenoid: anchor the vocal cords
2.Corniculate
3.Cuneiform
–9
th
cartilage: epiglottis

41. 41

42. 42
Epliglottis* (the 9
th

cartilage)
Elastic cartilage covered by mucosa
On a stalk attached to thyroid cartilage
Attaches to back of tongue
During swallowing, larynx is pulled
superiorly
Epiglottis tips inferiorly to cover and
seal laryngeal inlet
Keeps food out of lower respiratory
tract
*
*
Posterior views

43. 43
•Cough reflex: keeps all but air out of
airways
•Low position of larynx is required for
speech (although makes choking
easier)
•Paired vocal ligaments: elastic fibers,
the core of the true vocal cords

44. 44
•Pair of mucosal vocal folds (true
vocal cords) over the ligaments:
white because avascular

45. 45
•Glottis is the space between the vocal cords
•Laryngeal muscles control length and size of opening by
moving arytenoid cartilages
•Sound is produced by the vibration of vocal cords as air
is exhaled

46. 46
Trachea (the windpipe)Trachea (the windpipe)
•Descends: larynx through neck into
mediastinum
•Divides in thorax into two main (primary)
bronchi
•16-20 C-shaped rings
of hyaline cartilage
joined by fibroelastic
connective tissue
•Flexible for bending
but stays open despite
pressure changes
during breathing

47. 47
•Posterior open parts of tracheal cartilage abut
esophagus
•Trachealis muscle can decrease diameter of trachea
–Esophagus can expand when food swallowed
–Food can be forcibly expelled
•Wall of trachea has layers common to many tubular
organs – filters, warms and moistens incoming air
–Mucous membrane (pseudostratified epithelium with cilia
and lamina propria with sheet of elastin)
–Submucosa ( with seromucous glands)
–Adventitia - connective tissue which contains the tracheal
cartilages)

48. 48

49. 49
Carina*Carina*•Ridge on
internal
aspect of
last
tracheal
cartilage
•Point where
trachea
branches
(when alive
and
standing is
at T7)
•Mucosa
highly
sensitive to
irritants:
cough reflex
*

50. 50
•Bronchial tree bifurcation
–Right main bronchus (more susceptible
to aspiration)
–Left main bronchus
•Each main or primary bronchus runs into
hilus of lung posterior to pulmonary
vessels
1. Oblique fissure
2. Vertebral part
3. Hilum of lung
4. Cardiac impression
5. Diaphragmatic surface
(Wikipedia)

51. 51
•Main=primary bronchi divide into
secondary=lobar bronchi, each supplies
one lobe
–3 on the right
–2 on the left
•Lobar bronchi branch into tertiary =
segmental bronchi
•Continues dividing: about 23 times
•Tubes smaller than 1 mm called bronchioles
•Smallest, terminal bronchioles, are less the 0.5
mm diameter
•Tissue changes as becomes smaller
–Cartilage plates, not rings, then disappears
–Pseudostratified columnar to simple columnar to
simple cuboidal without mucus or cilia
–Smooth muscle important: sympathetic relaxation
(“bronchodilation”), parasympathetic constriction
(“bronchoconstriction”)

52. 52
Respiratory ZoneRespiratory Zone
•End-point of respiratory tree
•Structures that contain air-exchange chambers are called alveoli
•Respiratory bronchioles lead into alveolar ducts: walls consist of alveoli
•Ducts lead into terminal clusters called alveolar sacs – are microscopic
chambers
•There are 3 million alveoli!

53. 53
Gas ExchangeGas Exchange
•Air filled alveoli account for most of the lung
volume
•Very great area for gas exchange (1500 sq ft)
•Alveolar wall
–Single layer of squamous epithelial cells (type 1
cells) surrounded by basal lamina
–0.5um (15 X thinner than tissue paper)
–External wall covered by cobweb of capillaries
•Respiratory membrane : fusion of the basal
laminas of
–Alveolar wall
–Capillary wall
Alveolar sac
Respiratory
bronchiole
Alveolar
duct
Alveoli
(air on one side;
blood on the
other)

54. 54
Bronchial
“tree” and
associated
Pulmonary
arteries

55. 55
•This “air-blood barrier” (the
respiratory membrane) is where gas
exchange occurs
–Oxygen diffuses from air in alveolus
(singular of alveoli) to blood in capillary
–Carbon dioxide diffuses from the blood
in
the capillary into the air in
the alveolus

56. 56
Surfactant Surfactant
•Type II cuboidal epithelial cells are
scattered in alveolar walls
•Surfactant is a detergent-like
substance which is secreted in fluid
coating alveolar surfaces – it
decreases tension
•Without it the walls would stick
together during exhalation
•Premature babies – problem
breathing is largely because lack
surfactant

57. 57
Microscopic detail of alveoliMicroscopic detail of alveoli
•Alveoli surrounded by fine elastic fibers
•Alveoli interconnect via alveolar pores
•Alveolar macrophages – free floating “dust
cells”
•Note type I and type II cells and joint
membrane

58. 58
Lungs and Lungs and
PleuraPleura
Pleural cavity – slit-like potential space filled with
pleural fluid
•Lungs can slide but separation from pleura is
resisted (like film between 2 plates of glass)
•Lungs cling to thoracic wall and are forced to
expand and recoil as volume of thoracic cavity
changes during breathing
Around each lung is a
flattened sac of serous
membrane called pleura
Parietal pleura – outer
layer
Visceral pleura – directly
on lung

59. 59
LungsLungs
•Each is cone-shaped with anterior, lateral
and posterior surfaces contacting ribs
•Superior tip is apex, just deep to clavicle
•Concave inferior surface resting on
diaphragm is the base
apex apex
base base

60. 60
•Hilus or (hilum)
–Indentation on mediastinal (medial) surface
–Place where blood vessels, bronchi, lymph vessel,
and nerves enter and exit the lung
•“Root” of the lung
–Above structures attaching lung to mediastinum
–Main ones: pulmonary artery and veins and main
bronchus
Medial view R lung Medial view of L lung

61. 61
•Right lung: 3 lobes
–Upper lobe
–Middle lobe
–Lower lobe
•Left lung: 2 lobes
–Upper lobe
–Lower lobe
Oblique fissure
Oblique fissure
Horizontal fissure
Abbreviations in medicine:
e.g.” RLL pneumonia”
Each lobe is served
by a lobar
(secondary)
bronchus

62. 62
•Each lobe is made up of
bronchopulmonary segments separated
by dense connective tissue
–Each segment receives air from an individual
segmental (tertiary) bronchus
–Approximately 10 bronchopulmonary segments
in each lung
–Limit spread of infection
–Can be removed more easily because only small
vessels span segments
•Smallest subdivision seen with the naked
eye is the lobule
–Hexagonal on surface, size of pencil eraser
–Served by large bronchiole and its branches
–Black carbon is visible on connective tissue
separating individual lobules in smokers and city
dwellers

63. 63
•Pulmonary arteries bring oxygen-poor
blood to the lungs for oxygenation
–They branch along with the bronchial tree
–The smallest feed into the pulmonary capillary
network around the alveoli
•Pulmonary veins carry oxygenated blood
from the alveoli of the lungs to the heart

64. 64
•Stroma – framework of connective tissue
holding the air tubes and spaces
–Many elastic fibers
–Lungs light, spongy and elastic
–Elasticity reduces the effort of breathing
•Blood supply
–Lungs get their own blood supply from
bronchial arteries and veins
•Innervation: pulmonary plexus on lung
root contains sympathetic,
parasympathetic and visceral sensory
fibers to each lung
–From there, they lie on bronchial tubes and
blood vessels within the lungs

65. 65
•Bronchopulmonary – means both bronchial
tubes and lung alveoli together
–Bronchopulmonary segment – chunk receiving
air from a segmental (tertiary) bronchus*:
tertiary means it’s the third order in size; also,
the trachea has divided three times now
•“Anatomical dead space”
–The conducting zone which doesn’t participate
in gas exchange
Primary bronchus:
(Left main)
Secondary:
(left lower lobar bronchus)
(supplying
left lower
lobe)
Does this clarify a little?
*
Understand the concepts; you
don’t need to know the names of
the tertiary bronchi

66. 66
VentilationVentilation
•Breathing = “pulmonary ventilation”
–Pulmonary means related to the lungs
•Two phases
–Inspiration (inhalation) – air in
–Expiration (exhalation) – air out
•Mechanical forces cause the movement of
air
–Gases always flow from higher pressure to
lower
–For air to enter the thorax, the pressure of the
air in it has to be lower than atmospheric
pressure
•Making the volume of the thorax larger means the air
inside it is under less pressure
(the air has more space for as many gas particles,
therefore it is under less pressure)
•The diaphragm and intercostal muscles accomplish
this

67. 67
Muscles of InspirationMuscles of Inspiration
•During inspiration, the
dome shaped
diaphragm flattens as
it contracts
–This increases the
height of the thoracic
cavity
•The external
intercostal muscles
contract to raise the
ribs
–This increases the
circumference of the
thoracic cavity
Together:

68. 68
Inspiration continuedInspiration continued
•Intercostals keep the thorax stiff so sides
don’t collapse in with change of diaphragm
•During deep or forced inspiration,
additional muscles are recruited:
–Scalenes
–Sternocleidomastoid
–Pectoralis minor
–Quadratus lumborum on 12
th
rib
–Erector spinae
(some of these “accessory muscles” of
ventilation are visible to an observer; it usually
tells you that there is respiratory distress –
working hard to breathe)

69. 69
Expiration Expiration
•Quiet expiration in healthy
people is chiefly passive
–Inspiratory muscles relax
–Rib cage drops under force of
gravity
–Relaxing diaphragm moves
superiorly (up)
–Elastic fibers in lung recoil
–Volumes of thorax and lungs
decrease simultaneously,
increasing the pressure
–Air is forced out

70. 70
Expiration continuedExpiration continued
•Forced expiration is active
–Contraction of abdominal wall muscles
•Oblique and transversus predominantly
–Increases intra-abdominal pressure
forcing the diaphragm superiorly
–Depressing the rib cage, decreases
thoracic volume
•Some help from internal intercostals and
latissimus dorsi
(try this on yourself to feel the different muscles
acting)

71. 71
Neural Control of VentilationNeural Control of Ventilation
•Reticular formation in medulla
–Responsible for basic rate and rhythm
–Can be modified by higher centers
•Limbic system and hypothalamus, e.g. gasp with certain
emotions
•Cerebral cortex – conscious control
•Chemoreceptors
–Central – in the medulla
–Peripheral: see next slide
•Aortic bodies on the aortic arch
•Carotid bodies at the fork of the carotid artery: monitor
O2 and CO2 tension in the blood and help regulate
respiratory rate and depth
The carotid sinus (dilated area near fork) helps regulate
blood pressure and can affect the rate (stimulation
during carotid massage can slow an abnormally fast
heart rate)

72. 72
Peripheral Peripheral
chemoreceptors chemoreceptors
regulating respirationregulating respiration
•Aortic bodies*
–On aorta
–Send sensory info to
medulla through X
(vagus n)
•Carotid bodies+
–At fork of common
carotid artery
–Send info mainly through
IX (glossopharyngeal n)
*
+

73. 73
•There are many diseases of the respiratory
system, including asthma, cystic fibrosis, COPD
(chronic obstructive pulmonary disease – with
chronic bronchitis and/or emphysema) and
epiglottitis
example:
normal emphysema

74. 74
you might want to think twice about you might want to think twice about
smoking….smoking….

75. IntroductionIntroduction
•The Circulatory System is the
main cooling and transportation
system for the human body
•The body has about 5 liters of
blood continuously traveling
through it by way of the
Circulatory System
•In the Circulatory System, the
heart, lungs, and blood vessels
have to work together
•The Circulatory System has
three different parts: pulmonary
circulation (lungs), coronary
circulation (heart), and
systemic circulation, (the rest of
the system’s processes).

76. The HeartThe Heart
This organ is what pumps
oxygen rich blood, nutrients,
hormones, and the other things
your body needs to maintain
your health, to your organs and
tissues.
The pulmonary veins you see
on the right side of the diagram
come from your lungs, where
the blood cells collect oxygen.
It’s then pumped out to the rest
of the body through the Aorta
(Top).
All of the blue sections show
blood cells carrying waste,
(C0
2
) moving back to the lungs
(where the C0
2
will be replaced
by oxygen) through the
Pulmonary Artery (Top, blue)
Pulmonary Veins
Pulmonary Artery
(Inferior Vena Cava)
From the Body
(Aortic Artery) To the body
Whenever the blood is pumped from
one section of the heart another a valve
closes behind it preventing the blood
from moving backwards.
By The Way…
Valves: (tricuspid valve semilunar
(pulmonary) valve, bicuspid (mitral)
valve, and the semilunar (aortic) valve
(Superior Vena Cava)
From the Body

77. Blood Flow through Blood Flow through
HeartHeart
•Blood from the body travels
into the right atrium, moves
into the right ventricle, and is
finally pushed into lungs in
the pulmonary arteries
•The blood then picks up
oxygen and travels back to
the heart into the left atrium
through the pulmonary veins
•The blood then travels
through the to the Left
Ventricle and exits to the
body through the Aorta…
Right Atrium
Left Atrium

78. Circulation back to Circulation back to
HeartHeart
•Capillaries carry the blood
to…
•Venules that connect to
veins and the…
•Veins (wide blood vessels)
carries the oxygen-poor
blood back to the heart.
To upper body
From upper
body
To lung
To lung
From lung
Left Atrium
Left
Ventricle
To lower body
From
lower
body
Right
Ventricle
Right
Atrium
From
lung