DIGESTIVE SYSTEM anatomy and physiology of Bsc nursing pdf/pptx
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About This Presentation
This is PDF anatomy and physiology the book of Bsc nursing.
This is provide better sentence formation to understand the Anatomy and physiology. It's easy to read during your exams day. In this , the language used its very good and understandable.
Slide Content
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Introduction
The alimentary canal
begins at the mouth,
passes through the
thorax, abdomen and
pelvis and ends at
the anus
The alimentary canal
begins at the mouth,
passes through the
thorax, abdomen and
pelvis and ends at
the anus
Introduction
The digestive system is used for breaking down food into
nutrients which then pass into the circulatory system and
are taken to where they are needed in the body.
The purpose of digestion is to change the foodstuffs by
mechanical and chemical action to simple forms, which
can be easily absorbed into blood and utilized by various
tissues in the body.
The digestive system is used for breaking down food into
nutrients which then pass into the circulatory system and
are taken to where they are needed in the body.
The purpose of digestion is to change the foodstuffs by
mechanical and chemical action to simple forms, which
can be easily absorbed into blood and utilized by various
tissues in the body.
Introduction
What is digestion?
Food and drink must be changed into smaller molecules of
nutrients to be absorbed into the blood and carried to cells
throughout the body. Digestion is the process by which food
and liquid are broken down into smaller parts. The body can
then use them to build and nourish cells and to make energy.
Digestion involves:
The mixing of food
The movement of food through the digestive tract
A chemical breakdown of large molecules of food into smaller
molecules
Digestion begins in the mouth, where food and liquids are
taken in. It's completed in the small intestine.
What is digestion?
Food and drink must be changed into smaller molecules of
nutrients to be absorbed into the blood and carried to cells
throughout the body. Digestion is the process by which food
and liquid are broken down into smaller parts. The body can
then use them to build and nourish cells and to make energy.
Digestion involves:
The mixing of food
The movement of food through the digestive tract
A chemical breakdown of large molecules of food into smaller
molecules
Digestion begins in the mouth, where food and liquids are
taken in. It's completed in the small intestine.
Organs Included in Digestion
The digestive system is made up of the digestive tract and
other organs that aid in digestion.
The digestive tract is a series of hollow organs joined in a
long, twisting tube from the mouth to the anus. It consists
of the following:
Mouth
Esophagus
Stomach
Small intestine
Large intestine (includes the colon and rectum)
Anus
The digestive system is made up of the digestive tract and
other organs that aid in digestion.
The digestive tract is a series of hollow organs joined in a
long, twisting tube from the mouth to the anus. It consists
of the following:
Mouth
Esophagus
Stomach
Small intestine
Large intestine (includes the colon and rectum)
Anus
Organs that help with digestion
They are not part of the digestive tract:
Tongue
Glands in the mouth that make saliva
Pancreas
Liver
Gallbladder
Parts of other organ systems, such as nerves and blood,
also play a major role in the digestive process.
They are not part of the digestive tract:
Tongue
Glands in the mouth that make saliva
Pancreas
Liver
Gallbladder
Parts of other organ systems, such as nerves and blood,
also play a major role in the digestive process.
Movement of Food
Muscles propel food and liquid along the digestive tract in a wave-like
movement. This movement is called peristalsis. In general, there are 6 steps in
the process of moving food and liquid through the digestive system:
The first step in the digestive process occurs in the mouth. This is where food is
chewed and broken down into a size that can be safely swallowed. The start of
swallowing food or liquid is voluntary. But once it begins, the process becomes
involuntary and continues under the control of the nerves.
The esophagus connects the throat above with the stomach below. It's the first
organ into which the swallowed food goes.
Where the esophagus and stomach join, there is a ring-like valve that closes the
passage between the 2 organs. When food nears the closed ring, the
surrounding muscles relax and allow the food to pass into the stomach. It then
closes again.
Muscles propel food and liquid along the digestive tract in a wave-like
movement. This movement is called peristalsis. In general, there are 6 steps in
the process of moving food and liquid through the digestive system:
The first step in the digestive process occurs in the mouth. This is where food is
chewed and broken down into a size that can be safely swallowed. The start of
swallowing food or liquid is voluntary. But once it begins, the process becomes
involuntary and continues under the control of the nerves.
The esophagus connects the throat above with the stomach below. It's the first
organ into which the swallowed food goes.
Where the esophagus and stomach join, there is a ring-like valve that closes the
passage between the 2 organs. When food nears the closed ring, the
surrounding muscles relax and allow the food to pass into the stomach. It then
closes again.
Movement of Food
First, the stomach stores the swallowed food and liquid. This needs the muscle of the
upper part of the stomach to relax and accept large volumes of swallowed material.
Second, the lower part of the stomach mixes up the food, liquid, and digestive juices
made by the stomach through muscle action.
Third, the stomach empties the contents into the small intestine.
The food is digested in the small intestine. It's dissolved by the juices from the pancreas,
liver, and intestine. The contents of the intestine are mixed and pushed forward to allow
further digestion.
Last, the digested nutrients are absorbed through the intestinal walls. The waste
products, including undigested parts of the food (fiber) and older cells that have been
shed from the lining of the intestine (mucosa), move into the colon. Waste products in
the colon often remain for a day or two until the feces are expelled by a bowel movement.
First, the stomach stores the swallowed food and liquid. This needs the muscle of the
upper part of the stomach to relax and accept large volumes of swallowed material.
Second, the lower part of the stomach mixes up the food, liquid, and digestive juices
made by the stomach through muscle action.
Third, the stomach empties the contents into the small intestine.
The food is digested in the small intestine. It's dissolved by the juices from the pancreas,
liver, and intestine. The contents of the intestine are mixed and pushed forward to allow
further digestion.
Last, the digested nutrients are absorbed through the intestinal walls. The waste
products, including undigested parts of the food (fiber) and older cells that have been
shed from the lining of the intestine (mucosa), move into the colon. Waste products in
the colon often remain for a day or two until the feces are expelled by a bowel movement.
Layers of Alimentary Canal Organs
Four layers
Mucosa
Submucosa
Muscularisexterna
Serosa
Four layers
Mucosa
Submucosa
Muscularisexterna
Serosa
Layers of Alimentary Canal Organs
Mucosa
Innermost, moist membrane , smooth muscle layer
Submucosa
Just beneath the mucosa, contains blood vessels and
nerve endings
Muscularisexterna—smooth muscle
Inner circular layer and outer longitudinal layer
Serosa—outer membrane
Mucosa
Innermost, moist membrane , smooth muscle layer
Submucosa
Just beneath the mucosa, contains blood vessels and
nerve endings
Muscularisexterna—smooth muscle
Inner circular layer and outer longitudinal layer
Serosa—outer membrane
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MUCOSA
The mucosa, or innermost of the GI tract, is a mucous
membrane. It is composed of:
epithelium,
connective tissue (lamina propria) and
a layer of smooth muscle (muscularismucosa).
The mucosa, or innermost of the GI tract, is a mucous
membrane. It is composed of:
epithelium,
connective tissue (lamina propria) and
a layer of smooth muscle (muscularismucosa).
Epithelium
The epithelium in the mouth, pharynx, esophagus,
and anal canal is stratified squamousepithelium that
serves a protective function. Simple columnar
epithelium, which functions in secretion and
absorption, lines the stomach and intestines or firmly
seal neighboring simple columnar epithelial cells to
restrict leakage between the cells. Among the
epithelial cells are few exocrine cells that secrete
mucus into the lumen of the tract, and several types of
endocrine cells, collectively called enteroendocrine
cells, which secrete hormones.
The epithelium in the mouth, pharynx, esophagus,
and anal canal is stratified squamousepithelium that
serves a protective function. Simple columnar
epithelium, which functions in secretion and
absorption, lines the stomach and intestines or firmly
seal neighboring simple columnar epithelial cells to
restrict leakage between the cells. Among the
epithelial cells are few exocrine cells that secrete
mucus into the lumen of the tract, and several types of
endocrine cells, collectively called enteroendocrine
cells, which secrete hormones.
Lamina Propria
The lamina propriais a areolarconnective tissue
containing many blood and lymphatic vessels, by
which nutrients absorbed into the GI tract. This layer
supports the epithelium and binds it to the muscularis
mucosae. This contains the mucosa-associated
lymphatic tissue (MALT), immune system cells that
protect against disease.
The lamina propriais a areolarconnective tissue
containing many blood and lymphatic vessels, by
which nutrients absorbed into the GI tract. This layer
supports the epithelium and binds it to the muscularis
mucosae. This contains the mucosa-associated
lymphatic tissue (MALT), immune system cells that
protect against disease.
MuscularisMucosae
Muscularismucosaethrow the mucous membrane of
the stomach and small intestine into many small folds,
which increase the surface area for digestion and
absorption.
Muscularismucosaethrow the mucous membrane of
the stomach and small intestine into many small folds,
which increase the surface area for digestion and
absorption.
SUBMUCOSA
The submucosaconsists of areolarconnective tissue
that binds the mucosa to the muscularis. It contains
many blood and lymphatic vessels that receive
absorbed food molecules. The network of neurons in
this layer known as the submucosalplexus.
The submucosaconsists of areolarconnective tissue
that binds the mucosa to the muscularis. It contains
many blood and lymphatic vessels that receive
absorbed food molecules. The network of neurons in
this layer known as the submucosalplexus.
MUSCULARIS
The muscularisof the mouth, pharynx, contains
skeletal muscle that produces voluntary swallowing. It
also forms the external anal sphincter, which permits
voluntary control of defecation. The rest of the tract,
the muscularisconsists of smooth muscle with circular
fibers inner and an outer sheet of longitudinal fibers.
Contractions of the smooth muscle help break down
food, mix it with digestive secretions, and propel it
along the tract. Between the layers of the muscularisis
a plexus of neurons the myentericplexus.
The muscularisof the mouth, pharynx, contains
skeletal muscle that produces voluntary swallowing. It
also forms the external anal sphincter, which permits
voluntary control of defecation. The rest of the tract,
the muscularisconsists of smooth muscle with circular
fibers inner and an outer sheet of longitudinal fibers.
Contractions of the smooth muscle help break down
food, mix it with digestive secretions, and propel it
along the tract. Between the layers of the muscularisis
a plexus of neurons the myentericplexus.
SEROSA
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
SEROSA
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
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Layers of Alimentary Canal Organs
Mucosa
Innermost, moist membrane , smooth muscle layer
Submucosa
Just beneath the mucosa, contains blood vessels and
nerve endings
Muscularisexterna—smooth muscle
Inner circular layer and outer longitudinal layer
Serosa—outer membrane
Mucosa
Innermost, moist membrane , smooth muscle layer
Submucosa
Just beneath the mucosa, contains blood vessels and
nerve endings
Muscularisexterna—smooth muscle
Inner circular layer and outer longitudinal layer
Serosa—outer membrane
MUCOSA
The mucosa, or innermost of the GI tract, is a mucous
membrane. It is composed of:
epithelium,
connective tissue (lamina propria) and
a layer of smooth muscle (muscularismucosa).
The mucosa, or innermost of the GI tract, is a mucous
membrane. It is composed of:
epithelium,
connective tissue (lamina propria) and
a layer of smooth muscle (muscularismucosa).
Epithelium
The epithelium in the mouth, pharynx, esophagus,
and anal canal is stratified squamousepithelium that
serves a protective function. Simple columnar
epithelium, which functions in secretion and
absorption, lines the stomach and intestines or firmly
seal neighboring simple columnar epithelial cells to
restrict leakage between the cells. Among the
epithelial cells are few exocrine cells that secrete
mucus into the lumen of the tract, and several types of
endocrine cells, collectively called enteroendocrine
cells, which secrete hormones.
The epithelium in the mouth, pharynx, esophagus,
and anal canal is stratified squamousepithelium that
serves a protective function. Simple columnar
epithelium, which functions in secretion and
absorption, lines the stomach and intestines or firmly
seal neighboring simple columnar epithelial cells to
restrict leakage between the cells. Among the
epithelial cells are few exocrine cells that secrete
mucus into the lumen of the tract, and several types of
endocrine cells, collectively called enteroendocrine
cells, which secrete hormones.
Lamina Propria
The lamina propriais a areolarconnective tissue
containing many blood and lymphatic vessels, by
which nutrients absorbed into the GI tract. This layer
supports the epithelium and binds it to the muscularis
mucosae. This contains the mucosa-associated
lymphatic tissue (MALT), immune system cells that
protect against disease.
The lamina propriais a areolarconnective tissue
containing many blood and lymphatic vessels, by
which nutrients absorbed into the GI tract. This layer
supports the epithelium and binds it to the muscularis
mucosae. This contains the mucosa-associated
lymphatic tissue (MALT), immune system cells that
protect against disease.
MuscularisMucosae
Muscularismucosaethrow the mucous membrane of
the stomach and small intestine into many small folds,
which increase the surface area for digestion and
absorption.
Muscularismucosaethrow the mucous membrane of
the stomach and small intestine into many small folds,
which increase the surface area for digestion and
absorption.
SUBMUCOSA
The submucosaconsists of areolarconnective tissue
that binds the mucosa to the muscularis. It contains
many blood and lymphatic vessels that receive
absorbed food molecules. The network of neurons in
this layer known as the submucosalplexus.
The submucosaconsists of areolarconnective tissue
that binds the mucosa to the muscularis. It contains
many blood and lymphatic vessels that receive
absorbed food molecules. The network of neurons in
this layer known as the submucosalplexus.
MUSCULARIS
The muscularisof the mouth, pharynx, contains
skeletal muscle that produces voluntary swallowing. It
also forms the external anal sphincter, which permits
voluntary control of defecation. The rest of the tract,
the muscularisconsists of smooth muscle with circular
fibers inner and an outer sheet of longitudinal fibers.
Contractions of the smooth muscle help break down
food, mix it with digestive secretions, and propel it
along the tract. Between the layers of the muscularisis
a plexus of neurons the myentericplexus.
The muscularisof the mouth, pharynx, contains
skeletal muscle that produces voluntary swallowing. It
also forms the external anal sphincter, which permits
voluntary control of defecation. The rest of the tract,
the muscularisconsists of smooth muscle with circular
fibers inner and an outer sheet of longitudinal fibers.
Contractions of the smooth muscle help break down
food, mix it with digestive secretions, and propel it
along the tract. Between the layers of the muscularisis
a plexus of neurons the myentericplexus.
SEROSA
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
SEROSA
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
A superficial layer called the serosa. It is a serous
membrane composed of areolarconnective tissue and
simple squamousepithelium (mesothelium). The
serosais also called the visceral peritoneum because it
forms a portion of the peritoneum. The esophagus
lacks a serosa, only a single layer of areolarconnective
tissue called the adventitia forms the superficial layer
of this organ.
NEURAL SUPPLY OF THE GI TRACT
Enteric Nervous System-the “brain of the gut,” consists of about
100 million neurons that extend from the esophagus to the anus.
The neurons of the ENS are arranged into two plexuses: the
myentericplexus and submucosalplexus.
The myentericplexus or plexus of Auerbachis located between the
longitudinal and circular smooth muscle layers of the muscularis.
The submucosalplexus, or plexus of Meissner, is found within the
submucosa.
The plexuses of the ENS consist of motor neurons, interneurons,
and sensory neurons. The motor neurons of the myentericplexus
supply the longitudinal and circular smooth muscle layers of the
muscularis, which controls GI tract motility.
Enteric Nervous System-the “brain of the gut,” consists of about
100 million neurons that extend from the esophagus to the anus.
The neurons of the ENS are arranged into two plexuses: the
myentericplexus and submucosalplexus.
The myentericplexus or plexus of Auerbachis located between the
longitudinal and circular smooth muscle layers of the muscularis.
The submucosalplexus, or plexus of Meissner, is found within the
submucosa.
The plexuses of the ENS consist of motor neurons, interneurons,
and sensory neurons. The motor neurons of the myentericplexus
supply the longitudinal and circular smooth muscle layers of the
muscularis, which controls GI tract motility.
NEURAL SUPPLY OF THE GI TRACT
The motor neurons of the submucosalplexus supply the
secretorycells of the epithelium, controlling the secretions of
the GI tract.
The interneuronsof the ENS interconnect the neurons of the
myentericand submucosalplexuses.
The sensory neurons of the ENS supply the epithelium and
contain receptors in the lumen of the GI tract like
chemoreceptors, which respond to certain chemicals in the
food present in the lumen, mechanoreceptors, as stretch
receptors, that are activated when food stretches the wall of a
GI organ.
The motor neurons of the submucosalplexus supply the
secretorycells of the epithelium, controlling the secretions of
the GI tract.
The interneuronsof the ENS interconnect the neurons of the
myentericand submucosalplexuses.
The sensory neurons of the ENS supply the epithelium and
contain receptors in the lumen of the GI tract like
chemoreceptors, which respond to certain chemicals in the
food present in the lumen, mechanoreceptors, as stretch
receptors, that are activated when food stretches the wall of a
GI organ.
NEURAL SUPPLY OF THE GI TRACT
Autonomic Nervous System
ENS is regulated by the neurons of the autonomic nervous
system.
The vagus(X) nerves supply parasympathetic fibers to most
parts of the GI tract, the large intestine, which is supplied
with parasympathetic fibers from the sacral spinal cord.
The parasympathetic nerves that supply the GI tract form
neural connections with the ENS. Parasympathetic
preganglionicneurons of the vagusor pelvic splanchnic
nerves synapse with parasympathetic postganglionic neurons
located in the myentericand submucosalplexuses.
Autonomic Nervous System
ENS is regulated by the neurons of the autonomic nervous
system.
The vagus(X) nerves supply parasympathetic fibers to most
parts of the GI tract, the large intestine, which is supplied
with parasympathetic fibers from the sacral spinal cord.
The parasympathetic nerves that supply the GI tract form
neural connections with the ENS. Parasympathetic
preganglionicneurons of the vagusor pelvic splanchnic
nerves synapse with parasympathetic postganglionic neurons
located in the myentericand submucosalplexuses.
NEURAL SUPPLY OF THE GI TRACT
Stimulation of the parasympathetic nerves that supply
the GI tract causes an increase in GI secretion and
motility by increasing the activity of ENS neurons.
Sympathetic nerves that supply the GI tract arise from
the thoracic and upper lumbar regions of the spinal
cord. The sympathetic nerves that supply the GI tract
cause a decrease in GI secretion and motility by
inhibiting the neurons of the ENS. Emotions such as
anger, fear, and anxiety may slow digestion because they
stimulate the sympathetic nerves that supply the GI
tract.
Stimulation of the parasympathetic nerves that supply
the GI tract causes an increase in GI secretion and
motility by increasing the activity of ENS neurons.
Sympathetic nerves that supply the GI tract arise from
the thoracic and upper lumbar regions of the spinal
cord. The sympathetic nerves that supply the GI tract
cause a decrease in GI secretion and motility by
inhibiting the neurons of the ENS. Emotions such as
anger, fear, and anxiety may slow digestion because they
stimulate the sympathetic nerves that supply the GI
tract.
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Functions of the digestive system
Ingestion:Food must be placed into the mouth before it can be
acted on; this is an active, voluntary process called ingestion.
Propulsion:If foods are to be processed by more than one
digestive organ, they must be propelled from one organ to the
next; swallowing is one example of food movement that depends
largely on the propulsive process called peristalsis (involuntary,
alternating waves of contraction and relaxation of the muscles in
the organ wall).
Food breakdown: mechanical digestion. Mechanical digestion
prepares food for further degradation by enzymes by physically
fragmenting the foods into smaller pieces, and examples of
mechanical digestion are: mixing of food in the mouth by the
tongue, churning of food in the stomach, and segmentation in
the small intestine.
Ingestion:Food must be placed into the mouth before it can be
acted on; this is an active, voluntary process called ingestion.
Propulsion:If foods are to be processed by more than one
digestive organ, they must be propelled from one organ to the
next; swallowing is one example of food movement that depends
largely on the propulsive process called peristalsis (involuntary,
alternating waves of contraction and relaxation of the muscles in
the organ wall).
Food breakdown: mechanical digestion. Mechanical digestion
prepares food for further degradation by enzymes by physically
fragmenting the foods into smaller pieces, and examples of
mechanical digestion are: mixing of food in the mouth by the
tongue, churning of food in the stomach, and segmentation in
the small intestine.
Functions of the digestive system
Food breakdown: chemical digestion. The sequence of
steps in which the large food molecules are broken down
into their building blocks by enzymes is called chemical
digestion.
Absorption:Transport of digested end products from the
lumen of the GI tract to the blood or lymph is absorption,
and for absorption to happen, the digested foods must first
enter the mucosal cells by active or passive transport
processes.
Defecation: Defecation is the elimination of indigestible
residues from the GI tract via the anus in the form of feces.
Food breakdown: chemical digestion. The sequence of
steps in which the large food molecules are broken down
into their building blocks by enzymes is called chemical
digestion.
Absorption:Transport of digested end products from the
lumen of the GI tract to the blood or lymph is absorption,
and for absorption to happen, the digested foods must first
enter the mucosal cells by active or passive transport
processes.
Defecation: Defecation is the elimination of indigestible
residues from the GI tract via the anus in the form of feces.
Process of digestion
1. INGESTION
2. PROPULSION
3. DIGESTION
4. ABSORPTION
5. EXCRETION
1. INGESTION
2. PROPULSION
3. DIGESTION
4. ABSORPTION
5. EXCRETION
1. Ingestion
Ingestion or taking in of
food and mastication are
functions performed by
mouth and teeth, aided by
tongue.
Pharynx and esophagus
are concerned with
swallowing.
Ingestion or taking in of
food and mastication are
functions performed by
mouth and teeth, aided by
tongue.
Pharynx and esophagus
are concerned with
swallowing.
2. PROPULSION
This mixes and moves
the contents along the
alimentary tract.
Peristalsis :-waves of
contraction and
relaxation of muscles in
the organ wall
This mixes and moves
the contents along the
alimentary tract.
Peristalsis :-waves of
contraction and
relaxation of muscles in
the organ wall
3. Digestion
It occurs in the stomach and upper part of small intestine
Mechanical breakdown of food by, chewing (mastication)
Chemical digestion of food into small molecules by the action of
enzymes present in secretions produced by glands and accessory
organs of the digestive system.
It occurs in the stomach and upper part of small intestine
Mechanical breakdown of food by, chewing (mastication)
Chemical digestion of food into small molecules by the action of
enzymes present in secretions produced by glands and accessory
organs of the digestive system.
4. ABSORPTION
This is the process by
which the products of
digestion pass through the
walls of some organs of
the alimentary canal into
the blood for circulation
and use by body cells.
This is the process by
which the products of
digestion pass through the
walls of some organs of
the alimentary canal into
the blood for circulation
and use by body cells.
5. ELIMINATION OR
EXCRETION
Food that has been eaten
but cannot be digested and
absorbed is excreted from
the alimentary canal in
faecesby the process of
defaecation.
EXCRETION
Food that has been eaten
but cannot be digested and
absorbed is excreted from
the alimentary canal in
faecesby the process of
defaecation.
RangoliDosi
Nursing Tutor
Nursing Tutor
MOUTH
The mouth or oral cavity is the first part of the digestive
tube.
It is formed by muscles and bones:
Anteriorly: by the lips
Posteriorly: it is continuous with the oropharynx
Laterally : by the muscles of the cheeks
Superiorly: by the bony hard palate and muscular soft
palate
Inferiorly: by the muscular tongue and the soft tissues of
the floor of the mouth.
The mouth or oral cavity is the first part of the digestive
tube.
It is formed by muscles and bones:
Anteriorly: by the lips
Posteriorly: it is continuous with the oropharynx
Laterally : by the muscles of the cheeks
Superiorly: by the bony hard palate and muscular soft
palate
Inferiorly: by the muscular tongue and the soft tissues of
the floor of the mouth.
The oral cavity is lined throughout with mucous
membrane, consisting of sturdy, stratified squamous
epithelium containing small mucus-secreting glands.
The palate forms the roof of the mouth & is divided
into the anterior hard palate & posterior soft palate.
The uvula is a curved fold of muscle covered with
mucous membrane , hanging down from the middle.
membrane, consisting of sturdy, stratified squamous
epithelium containing small mucus-secreting glands.
The palate forms the roof of the mouth & is divided
into the anterior hard palate & posterior soft palate.
The uvula is a curved fold of muscle covered with
mucous membrane , hanging down from the middle.
Oral Cavity
Food enters the digestive tract through the mouth, or oral
cavity, a mucous membrane-lined cavity.
Lips. The lips (labia) protect its anterior opening.
Cheeks. The cheeks form its lateral walls.
Palate. The hard palate forms its anterior roof, and the soft
palate forms its posterior roof.
Uvula. The uvula is a fleshy finger-like projection of the
soft palate, which extends inferiorly from the posterior
edge of the soft palate.
Vestibule. The space between the lips and the cheeks
externally and the teeth and gums internally is the
vestibule.
Food enters the digestive tract through the mouth, or oral
cavity, a mucous membrane-lined cavity.
Lips. The lips (labia) protect its anterior opening.
Cheeks. The cheeks form its lateral walls.
Palate. The hard palate forms its anterior roof, and the soft
palate forms its posterior roof.
Uvula. The uvula is a fleshy finger-like projection of the
soft palate, which extends inferiorly from the posterior
edge of the soft palate.
Vestibule. The space between the lips and the cheeks
externally and the teeth and gums internally is the
vestibule.
Oral Cavity
Oral cavity proper. The area contained by the teeth is the
oral cavity proper.
Tongue. The muscular tongue occupies the floor of the
mouth and has several bony attachments-two of these are
to the hyoid bone and the styloidprocesses of the skull.
Lingual frenulum. The lingual frenulum, a fold of
mucous membrane, secures the tongue to the floor of the
mouth and limits its posterior movements.
Palatine tonsils. At the posterior end of the oral cavity are
paired masses of lymphatic tissue, the palatine tonsils.
Lingual tonsil. The lingual tonsils cover the base of the
tongue just beyond.
Oral cavity proper. The area contained by the teeth is the
oral cavity proper.
Tongue. The muscular tongue occupies the floor of the
mouth and has several bony attachments-two of these are
to the hyoid bone and the styloidprocesses of the skull.
Lingual frenulum. The lingual frenulum, a fold of
mucous membrane, secures the tongue to the floor of the
mouth and limits its posterior movements.
Palatine tonsils. At the posterior end of the oral cavity are
paired masses of lymphatic tissue, the palatine tonsils.
Lingual tonsil. The lingual tonsils cover the base of the
tongue just beyond.
The Lips
The lips are two fleshy folds that surround the oral orifice.
They are covered on the outside by skin and are lined on
the inersideby mucous membrane. The substance of the
lips is made up by the orbicularisorismuscle and the
muscles that radiate from the lips into the face.
Also included the labial blood vessels and nerves,
connective tissue, and many small salivary glands.The
philtrumis the shallow vertical groove seen in the midline
on the outer surface of the upper lip. Median folds of
mucous membrane-the labial frenula-connect the inner
surface of the lips to the gums.
The lips are two fleshy folds that surround the oral orifice.
They are covered on the outside by skin and are lined on
the inersideby mucous membrane. The substance of the
lips is made up by the orbicularisorismuscle and the
muscles that radiate from the lips into the face.
Also included the labial blood vessels and nerves,
connective tissue, and many small salivary glands.The
philtrumis the shallow vertical groove seen in the midline
on the outer surface of the upper lip. Median folds of
mucous membrane-the labial frenula-connect the inner
surface of the lips to the gums.
The Oral Cavity
The mouth extends from the lips to the pharynx. The
entrance into the pharynx, the oropharyngealisthmus,
is formed one each side by the palatoglossalfold. The
mouth is divided into the vestibule and the mouth
cavity proper.
The mouth extends from the lips to the pharynx. The
entrance into the pharynx, the oropharyngealisthmus,
is formed one each side by the palatoglossalfold. The
mouth is divided into the vestibule and the mouth
cavity proper.
Vestibule
The vestibule lies between the lips and the cheeks
externally and between the gums and the teeth
internally. This slit like space communicates with the
exterior through the oral fissure between the lips.
When the jaws are closed, it communicates with the
mouth proper behind the third molar tooth on each
side .
The vestibule lies between the lips and the cheeks
externally and between the gums and the teeth
internally. This slit like space communicates with the
exterior through the oral fissure between the lips.
When the jaws are closed, it communicates with the
mouth proper behind the third molar tooth on each
side .
Vestibule
The vestibule is limited above and below by the
reflection of the mucous membrane from the Iipsand
cheeks to the gums. The lateral wall of the vestibule is
formed by the cheek, which is made up by the
buccinators muscle and is lined with mucous
membrane. The tone of the buccinators muscle and
that of the muscles of the lips keep's the walls of the
vestibule in contact with one another. The duct of the
parotid salivary gland opens on a small papilla into the
vestibule opposite the upper second molar tooth.
The vestibule is limited above and below by the
reflection of the mucous membrane from the Iipsand
cheeks to the gums. The lateral wall of the vestibule is
formed by the cheek, which is made up by the
buccinators muscle and is lined with mucous
membrane. The tone of the buccinators muscle and
that of the muscles of the lips keep's the walls of the
vestibule in contact with one another. The duct of the
parotid salivary gland opens on a small papilla into the
vestibule opposite the upper second molar tooth.
Mouth Proper
The mouth proper
has a roof and a floor
Roof of Mouth :
The roof of the
mouth is formed by
the hard palate in
front and the soft
palate behind.
The mouth proper
has a roof and a floor
Roof of Mouth :
The roof of the
mouth is formed by
the hard palate in
front and the soft
palate behind.
Mouth Proper (Roof)
Roof : The greater palatine and nasopalatinenerves from the
maxillary division of the trigeminal nerve.
The roof of the mouth proper consists of the hard and soft
palates.
The hard palate is found anteriorly. It is a bony plate that
separates the nasal cavity from the oral cavity. It is covered
superiorly by respiratory mucosa (ciliated pseudostratified
columnar epithelium) and inferiorly by oral mucosa (stratified
squamousepithelium).
The soft palate is a posterior continuation of the hard palate. In
contrast to the hard palate, it is a muscular structure. It acts as a
valve that can lower to close the oropharyngealisthmus, and
elevate to separate the nasopharynxfrom the oropharynx.
Roof : The greater palatine and nasopalatinenerves from the
maxillary division of the trigeminal nerve.
The roof of the mouth proper consists of the hard and soft
palates.
The hard palate is found anteriorly. It is a bony plate that
separates the nasal cavity from the oral cavity. It is covered
superiorly by respiratory mucosa (ciliated pseudostratified
columnar epithelium) and inferiorly by oral mucosa (stratified
squamousepithelium).
The soft palate is a posterior continuation of the hard palate. In
contrast to the hard palate, it is a muscular structure. It acts as a
valve that can lower to close the oropharyngealisthmus, and
elevate to separate the nasopharynxfrom the oropharynx.
Mouth Proper (Cheeks):
The cheeks are formed by the buccinatormuscle,
which is lined internally by the oral mucous
membrane.
The buccinatormuscle contracts to keep food between
the teeth when chewing, and is innervated by the
buccalbranches of the facial nerve (CN VII).
The cheeks are formed by the buccinatormuscle,
which is lined internally by the oral mucous
membrane.
The buccinatormuscle contracts to keep food between
the teeth when chewing, and is innervated by the
buccalbranches of the facial nerve (CN VII).
Floor of Mouth :
The floor is formed largely by the anterior two thirds
of the tongue and by the reflection of the mucous
membrane from the sides of the tongue to the gum of
the mandible. A fold of mucous membrane called the
frenulumof the tongue connects the undersurface of
the tongue in the midline to the floor of the mouth.
The floor is formed largely by the anterior two thirds
of the tongue and by the reflection of the mucous
membrane from the sides of the tongue to the gum of
the mandible. A fold of mucous membrane called the
frenulumof the tongue connects the undersurface of
the tongue in the midline to the floor of the mouth.
Floor of Mouth :
The floor of the oral cavity consists of several
structures:
Muscular diaphragm –comprised of the bilateral
mylohyoidmuscles. It provides structural support to the
floor of the mouth, and pulls the larynx forward during
swallowing.
Geniohyoidmuscles –pull the larynx forward during
swallowing.
Tongue –connected to the floor by the frenulumof the
tongue, a fold of oral mucosa.
Salivary glands and ducts.
The floor of the oral cavity consists of several
structures:
Muscular diaphragm –comprised of the bilateral
mylohyoidmuscles. It provides structural support to the
floor of the mouth, and pulls the larynx forward during
swallowing.
Geniohyoidmuscles –pull the larynx forward during
swallowing.
Tongue –connected to the floor by the frenulumof the
tongue, a fold of oral mucosa.
Salivary glands and ducts.
Mucous Membrane of the Mouth
In the vestibule, the mucous
membrane is tethered to the
buccinators muscle by elastic
fibers in the submucosathat
prevent redundant folds of
mucous membrane from being
bitten between the teeth when
the jaws are closed. The
mucous membrane of the
gingiva, or gum, is strongly
attached to the alveolar
periosteum.
In the vestibule, the mucous
membrane is tethered to the
buccinators muscle by elastic
fibers in the submucosathat
prevent redundant folds of
mucous membrane from being
bitten between the teeth when
the jaws are closed. The
mucous membrane of the
gingiva, or gum, is strongly
attached to the alveolar
periosteum.
Sensory innervations of the Mouth :
Sensory innervationof the oral cavity is supplied by the branches
of thetrigeminal nerve(CN V).
The hard palate is innervated by thegreater
palatineandnasopalatinenerves,both of which are branches of
the maxillary nerve (CN V2). The soft palate is innervated
bylesser palatinenerve, another branch of the maxillary nerve.
The floor of the oral cavity receives sensory innervationfrom
thelingual nerve–a branch of the mandibular(V3) division of
the trigeminal nerve. The tongue is also innervated by special
sensory fibresfor taste from thechordatympani, a branch of the
facial nerve (CN VII).
The cheeks are innervated by thebuccalnerve. It is also a branch
of the mandibulardivision of the trigeminal nerve(not to be
confused with the buccalbranches of the facial nerve).
Sensory innervationof the oral cavity is supplied by the branches
of thetrigeminal nerve(CN V).
The hard palate is innervated by thegreater
palatineandnasopalatinenerves,both of which are branches of
the maxillary nerve (CN V2). The soft palate is innervated
bylesser palatinenerve, another branch of the maxillary nerve.
The floor of the oral cavity receives sensory innervationfrom
thelingual nerve–a branch of the mandibular(V3) division of
the trigeminal nerve. The tongue is also innervated by special
sensory fibresfor taste from thechordatympani, a branch of the
facial nerve (CN VII).
The cheeks are innervated by thebuccalnerve. It is also a branch
of the mandibulardivision of the trigeminal nerve(not to be
confused with the buccalbranches of the facial nerve).
RangoliDosi
Nursing Tutor
Nursing Tutor
TONGUE
The tongue is a muscular organ in the mouth, that
manipulates food for mastication, and is used in the act of
swallowing.
It is of importance in the digestive system and is the
primary organ of taste in the gustatory system.
The tongue is an accessory digestive organ composed of
skeletal muscle, it forms the floor of the oral cavity. The
tongue is divided into 2 symmetrical halves that extend its
entire length and it is attached inferiorly to the hyoid bone,
styloidprocess of the temporal bone, and mandible. Each
half of the tongue consists of extrinsic and intrinsic
muscles.
The tongue is a muscular organ in the mouth, that
manipulates food for mastication, and is used in the act of
swallowing.
It is of importance in the digestive system and is the
primary organ of taste in the gustatory system.
The tongue is an accessory digestive organ composed of
skeletal muscle, it forms the floor of the oral cavity. The
tongue is divided into 2 symmetrical halves that extend its
entire length and it is attached inferiorly to the hyoid bone,
styloidprocess of the temporal bone, and mandible. Each
half of the tongue consists of extrinsic and intrinsic
muscles.
Tongue Functions
Mastication (chewing)
Deglutition (swallowing)
Speech
Taste
Mastication (chewing)
Deglutition (swallowing)
Speech
Taste
Structure of the Tongue
Parts of Tongue
Root
Tip
Body
Dorsum
Oral Part
Pharyngeal Part
Posterior Part
Inferior Surface
Root
Tip
Body
Dorsum
Oral Part
Pharyngeal Part
Posterior Part
Inferior Surface
Tongue
Root of Tongue Attached to –
Above -StyloidProcess & Soft Palate
Below -Mandible & Hyoid Bone
In between the mandible and hyoid bones, it is related
to the Geniohyoidand Mylohyoidmuscles
Tip of Tongue
It forms the anterior free end which at rest lies behind
the Upper Incisor Teeth
Root of Tongue Attached to –
Above -StyloidProcess & Soft Palate
Below -Mandible & Hyoid Bone
In between the mandible and hyoid bones, it is related
to the Geniohyoidand Mylohyoidmuscles
Tip of Tongue
It forms the anterior free end which at rest lies behind
the Upper Incisor Teeth
Dorsum of Tongue
It is convex in all the directions & divided by a faint V-shaped
groove called as SulcusTerminale
Oral part or papillarvpart:
It is placed on the floor of the mouth.
The margins are free & in contact with gums and teeth
Each margin shows a 4-5 vertical folds called as FoliatePapillae
Surfaces-
Superior-Has a median furrow & covered with papillae
Inferior-Covered with smooth mucous membrane which shows a
median fold called Fre1111/u/11 Linguae.
On either side of Frenulum, there is prominence made by Deep
LingulalVeins
It also has a folds called PlicaFimbriatawhich is directed
forwards and medially towards Tip of Tongue.
It is convex in all the directions & divided by a faint V-shaped
groove called as SulcusTerminale
Oral part or papillarvpart:
It is placed on the floor of the mouth.
The margins are free & in contact with gums and teeth
Each margin shows a 4-5 vertical folds called as FoliatePapillae
Surfaces-
Superior-Has a median furrow & covered with papillae
Inferior-Covered with smooth mucous membrane which shows a
median fold called Fre1111/u/11 Linguae.
On either side of Frenulum, there is prominence made by Deep
LingulalVeins
It also has a folds called PlicaFimbriatawhich is directed
forwards and medially towards Tip of Tongue.
Dorsum of Tongue
Pharyngeal Part or Lymphoid part –
It lies behind the palatoglossalarches and the sulcusterminalis.
Its mucous membrane has no papilaebut has many Lymphoid
follicles which collectively forms Lingual Tonsil
Its posterior surface called as Base Of Tongue & forms anterior wall
of Oropharynx.
Posterior Part-
It is connected to epiglottis by 3 folds of mucous membrane, they
are Right, Median & Left GlossoepiglotticFolds.
On either side of median fold there is depression called as
Vallecula.
Pharyngeal Part or Lymphoid part –
It lies behind the palatoglossalarches and the sulcusterminalis.
Its mucous membrane has no papilaebut has many Lymphoid
follicles which collectively forms Lingual Tonsil
Its posterior surface called as Base Of Tongue & forms anterior wall
of Oropharynx.
Posterior Part-
It is connected to epiglottis by 3 folds of mucous membrane, they
are Right, Median & Left GlossoepiglotticFolds.
On either side of median fold there is depression called as
Vallecula.
Tongue
The tongue is the central part of the oral cavity. It’s a
muscular organ whose base is attached to the floor of the
oral cavity, whilst its apex is free and mobile.
The tongue is predominantly muscle. There are 8 in total; 4
intrinsic muscles and 4 extrinsic. Besides the muscles, the
other important feature of the tongue is its mucosa. The
dorsal tongue mucosa is covered with lingual papillae
which function as the sensory receptors for taste. There are
four types: filiform, fungiform, vallataeand foliate papillae.
The papillae have different shapes upon which they are
named.
All the papillae act as taste receptors except for the filiform,
which have a purely mechanical role.
The tongue is the central part of the oral cavity. It’s a
muscular organ whose base is attached to the floor of the
oral cavity, whilst its apex is free and mobile.
The tongue is predominantly muscle. There are 8 in total; 4
intrinsic muscles and 4 extrinsic. Besides the muscles, the
other important feature of the tongue is its mucosa. The
dorsal tongue mucosa is covered with lingual papillae
which function as the sensory receptors for taste. There are
four types: filiform, fungiform, vallataeand foliate papillae.
The papillae have different shapes upon which they are
named.
All the papillae act as taste receptors except for the filiform,
which have a purely mechanical role.
Papillae of Tongue
Papillae are the projections of mucous membrane (corium) which gives
the roughness. These are of 3 types-
Circumvallateor VallatePapillae:
They are large in size about 1-2 mm in diameter & are totally 8-12 in number.
Situated exactly in front of sulcusterminalis
Each papillae is a cylindrical projection surrounded by a circular sulcus. The walls
of this papillae have Taste Buds.
FungiformPapillae:
These are numerous and mostly present near the tip & margins of Tongue. Some
are also scattered over Dorsum.
Smaller than CircumvallatePapillae, but larger than FiliformPapillae.
Each papilla ha narrow pedicle and large rounded head.
They are distinguished by their bright red color.
Papillae are the projections of mucous membrane (corium) which gives
the roughness. These are of 3 types-
Circumvallateor VallatePapillae:
They are large in size about 1-2 mm in diameter & are totally 8-12 in number.
Situated exactly in front of sulcusterminalis
Each papillae is a cylindrical projection surrounded by a circular sulcus. The walls
of this papillae have Taste Buds.
FungiformPapillae:
These are numerous and mostly present near the tip & margins of Tongue. Some
are also scattered over Dorsum.
Smaller than CircumvallatePapillae, but larger than FiliformPapillae.
Each papilla ha narrow pedicle and large rounded head.
They are distinguished by their bright red color.
Papillae of Tongue
FiliformPapillae or Conical Papillae:
It covers the presulcalarea of dorsum and gives
characteristic Velvety appearance.
These are smallest and numerous.
Each papilla is pointed and covered with keratin &
apex is often spilt into filamentous processes.
Foliate papillae:
are small folds located bilaterally on the
posterolateralsides of the tongue. They are richly
covered with taste buds.
FiliformPapillae or Conical Papillae:
It covers the presulcalarea of dorsum and gives
characteristic Velvety appearance.
These are smallest and numerous.
Each papilla is pointed and covered with keratin &
apex is often spilt into filamentous processes.
Foliate papillae:
are small folds located bilaterally on the
posterolateralsides of the tongue. They are richly
covered with taste buds.
Types of Taste
Sweet Taste-Produced by Organic Substances like
Monosaccharides, Polysaccharides,
Glycerol,Aldehydes, Ketones.
Salt Taste-Produced by Chlorides and Nitrates of Na,
K & Ammonia.
Sour Taste-Produced because of Hydrogen ions.
Bitter Taste-Produced due to organic substances like
Strychnine, Morphine, PiricAcid, Bile Salts, Salts of
Ca, Mg & Ammonium.
Umami-Produced due to Glutamate, particularly
Monosodium Glutamate.
Sweet Taste-Produced by Organic Substances like
Monosaccharides, Polysaccharides,
Glycerol,Aldehydes, Ketones.
Salt Taste-Produced by Chlorides and Nitrates of Na,
K & Ammonia.
Sour Taste-Produced because of Hydrogen ions.
Bitter Taste-Produced due to organic substances like
Strychnine, Morphine, PiricAcid, Bile Salts, Salts of
Ca, Mg & Ammonium.
Umami-Produced due to Glutamate, particularly
Monosodium Glutamate.
Papilla and Taste Buds
Sensation of Taste
Structure of Taste Buds
Each Taste Bud is a bundle of receptor cells.
It contains about 40 cells which are the modified epithelial
cells Cellsare divided into 4 groups
Type 1 cells
Type 2 cells
Type 3 cells
Type 4 cells
Type 1, 2, 3 have microvilliwhich project into an opening in
epithelium covering the tongue. This opening is called as
Taste Pore
Structure of Taste Buds
Each Taste Bud is a bundle of receptor cells.
It contains about 40 cells which are the modified epithelial
cells Cellsare divided into 4 groups
Type 1 cells
Type 2 cells
Type 3 cells
Type 4 cells
Type 1, 2, 3 have microvilliwhich project into an opening in
epithelium covering the tongue. This opening is called as
Taste Pore
Tongue Muscles
Tongue mobility and strength are important for the
processes of speech and mastication. These abilities
are determined by the tongue muscles. Muscles that
make up the inside of the tongue are called the
intrinsic muscles of the tongue. They are responsible
for many of the tongue’s functions; such as talking,
mastication and any other action that requires the
tongue to move. These muscles control movements
such as twirling, curling, flattening and broadening of
the tongue.
Tongue mobility and strength are important for the
processes of speech and mastication. These abilities
are determined by the tongue muscles. Muscles that
make up the inside of the tongue are called the
intrinsic muscles of the tongue. They are responsible
for many of the tongue’s functions; such as talking,
mastication and any other action that requires the
tongue to move. These muscles control movements
such as twirling, curling, flattening and broadening of
the tongue.
Tongue Muscles
Muscles that are located outside the tongue and only
attach to it in specific regions are called the extrinsic
muscles of the tongue. These assist the tongue and
support it in more complex actions such as protrusion
and retraction.
The 4 intrinsic muscles of the tongue are: the superior
longitudinal, inferior longitudinal, transverse and
vertical muscles.
Muscles that are located outside the tongue and only
attach to it in specific regions are called the extrinsic
muscles of the tongue. These assist the tongue and
support it in more complex actions such as protrusion
and retraction.
The 4 intrinsic muscles of the tongue are: the superior
longitudinal, inferior longitudinal, transverse and
vertical muscles.
Types of Tongue Muscles
A) Extrinsic muscles–
Which originate outside the tongue and insert into the
tongue. which includes hyoglossus, genioglossusand
styloglossusmuscles.
The extrinsic muscles move the tongue from side to side
and in and out to move food for chewing, shape the food
or force the food to the back of the mouth for
swallowing.
They form the floor of the mouth and hold the tongue
in position.
A) Extrinsic muscles–
Which originate outside the tongue and insert into the
tongue. which includes hyoglossus, genioglossusand
styloglossusmuscles.
The extrinsic muscles move the tongue from side to side
and in and out to move food for chewing, shape the food
or force the food to the back of the mouth for
swallowing.
They form the floor of the mouth and hold the tongue
in position.
Muscles of Tongue
The Middle Fibrous septum divides the tongue into
right and left halves.
Each half contains:-
Extrinsic -It contains 4 muscles which connect the
tongue to mandible . to hyoid bone, to styloidprocess &
to palate.
Genioglossus-Protrudes the tongue
Hyoglossus-Depresses the Tongue
Styloglossus-Retracts the Tongue
Palatoglossus-Elevates the Tongue
The Middle Fibrous septum divides the tongue into
right and left halves.
Each half contains:-
Extrinsic -It contains 4 muscles which connect the
tongue to mandible . to hyoid bone, to styloidprocess &
to palate.
Genioglossus-Protrudes the tongue
Hyoglossus-Depresses the Tongue
Styloglossus-Retracts the Tongue
Palatoglossus-Elevates the Tongue
Types of Tongue Muscles
B) Intrinsic muscles –
Originate in and insert within the tongue.
They alter the shape and size of the tongue for speech
and swallowing.
The intrinsic muscles are longitudinalissuperior,
longitudinalisinferior, transversuslinguaeand verticalis
linguaemuscles.
B) Intrinsic muscles –
Originate in and insert within the tongue.
They alter the shape and size of the tongue for speech
and swallowing.
The intrinsic muscles are longitudinalissuperior,
longitudinalisinferior, transversuslinguaeand verticalis
linguaemuscles.
Muscles of Tongue
Intrinsic -It contains 4 muscles which occupy the
upper part & attached to submucousfibrous layer. They
alter the shape of the tongue.
Sup. Longitudinal -Shortens the tongue & makes dorsum
concave
Inf. Longitudinal -Shortens the tongue makes its convex
Transverse -Makes the tongue narrow & elongated
Vertical -Makes tongue broad & flattened
Intrinsic -It contains 4 muscles which occupy the
upper part & attached to submucousfibrous layer. They
alter the shape of the tongue.
Sup. Longitudinal -Shortens the tongue & makes dorsum
concave
Inf. Longitudinal -Shortens the tongue makes its convex
Transverse -Makes the tongue narrow & elongated
Vertical -Makes tongue broad & flattened
Muscles of Tongue
Key facts about the intrinsic muscles of the tongue
Superior
longitudinal
Origin-submucosaof posterior tongue, lingual septum
Insertion-apex/anterolateralmargins of tongue
Innervation-hypoglossal nerve (CN XII)
Action-retracts and broadens tongue, elevates apex of
tongue
Inferior
longitudinal
Origin-root of tongue, body of hyoid bone
Insertion-apex of tongue
Innervation-hypoglossal nerve (CN XII)
Action-retracts and broadens tongue, lowers apex of tongue
Transverse
muscle
Origin-lingual septum
Insertion-lateral margin of tongue
Innervation-hypoglossal nerve (CN XII)
Action-narrows and elongates tongue
Vertical
muscle
Origin-root of tongue, genioglossusmuscle
Insertion-lingual aponeurosis
Innervation-hypoglossal nerve (CN XII)
Action-broadens and elongates tongue
Superior
longitudinal
Origin-submucosaof posterior tongue, lingual septum
Insertion-apex/anterolateralmargins of tongue
Innervation-hypoglossal nerve (CN XII)
Action-retracts and broadens tongue, elevates apex of
tongue
Inferior
longitudinal
Origin-root of tongue, body of hyoid bone
Insertion-apex of tongue
Innervation-hypoglossal nerve (CN XII)
Action-retracts and broadens tongue, lowers apex of tongue
Transverse
muscle
Origin-lingual septum
Insertion-lateral margin of tongue
Innervation-hypoglossal nerve (CN XII)
Action-narrows and elongates tongue
Vertical
muscle
Origin-root of tongue, genioglossusmuscle
Insertion-lingual aponeurosis
Innervation-hypoglossal nerve (CN XII)
Action-broadens and elongates tongue
Key facts about the extrinsic muscles of the tongue
GenioglossusOrigin-Superior mental spine of mandible
Insertion-entire length of dorsum of tongue, lingual
aponeurosis, body of hyoid bone
Innervation-hypoglossal nerve (CN XII)
Action-depresses and protrudes tongue (bilateral
contraction); deviates tongue contralaterally(unilateral
contraction)
Hyoglossus Origin-body and greater horn of hyoid bone
Insertion-inferior/ventral parts of lateral tongue
Innervation-hypoglossal nerve (CN XII)
Action-depresses and retracts tongue
StyloglossusOrigin-anterolateralaspect of styloidprocess (of temporal
bone), stylomandibularligament
Insertion-blends with inferior longitudinal muscle
(longitudinal part); blends with hyoglossusmuscle (oblique
part)
Innervation-hypoglossal nerve (CN XII)
Action-retracts and elevates lateral aspects of tongue
GenioglossusOrigin-Superior mental spine of mandible
Insertion-entire length of dorsum of tongue, lingual
aponeurosis, body of hyoid bone
Innervation-hypoglossal nerve (CN XII)
Action-depresses and protrudes tongue (bilateral
contraction); deviates tongue contralaterally(unilateral
contraction)
Hyoglossus Origin-body and greater horn of hyoid bone
Insertion-inferior/ventral parts of lateral tongue
Innervation-hypoglossal nerve (CN XII)
Action-depresses and retracts tongue
StyloglossusOrigin-anterolateralaspect of styloidprocess (of temporal
bone), stylomandibularligament
Insertion-blends with inferior longitudinal muscle
(longitudinal part); blends with hyoglossusmuscle (oblique
part)
Innervation-hypoglossal nerve (CN XII)
Action-retracts and elevates lateral aspects of tongue
Key facts about the extrinsic muscles of the tongue
PalatoglossusOrigin-palatine aponeurosisof soft palate
Insertion-lateral margins of tongue, blends with intrinsic
muscles of tongue
Innervation-vagusnerve (CN X) (via branches of pharyngeal
plexus)
Action-elevates root of tongue, constricts isthmus of fauces
PalatoglossusOrigin-palatine aponeurosisof soft palate
Insertion-lateral margins of tongue, blends with intrinsic
muscles of tongue
Innervation-vagusnerve (CN X) (via branches of pharyngeal
plexus)
Action-elevates root of tongue, constricts isthmus of fauces
Blood Supply:
Arterial Supply:
Lingual Artery -Branch of Ext. Carotid Artery
TonsillarArtery -Branch of FacialArtery
Pharyngeal Branch of Ext. Carotid Artery
VenousDrainage:
DeepLingual Vein
LymphaticDrainage:
Tip of Tongue -SubmentalNodes
Rt& Lthalves-SubmandiblarNodes
Posteriorpart-UpperDeepCervical Nodes
The wholelymphfinallydrains intojugulo-omohyoid
nodes.
Arterial Supply:
Lingual Artery -Branch of Ext. Carotid Artery
TonsillarArtery -Branch of FacialArtery
Pharyngeal Branch of Ext. Carotid Artery
VenousDrainage:
DeepLingual Vein
LymphaticDrainage:
Tip of Tongue -SubmentalNodes
Rt& Lthalves-SubmandiblarNodes
Posteriorpart-UpperDeepCervical Nodes
The wholelymphfinallydrains intojugulo-omohyoid
nodes.
Tongue
Nerve Supply:
Motor Nerves-
All Intrinsic & Extrinsic Muscles supplied by
Hypoglossal Nerve, except Palatoglossus.
Palatoglossusis supplied by cranial root of Accessory
Nerve.
Sensory Nerves-
Lingual Nerve & ChordaTympani -Taste of Anterior
Two-Third GlossopharyngealNerve -Taste of
Posterior One -Third VagusNerve -Taste of Posterior
Part
Nerve Supply:
Motor Nerves-
All Intrinsic & Extrinsic Muscles supplied by
Hypoglossal Nerve, except Palatoglossus.
Palatoglossusis supplied by cranial root of Accessory
Nerve.
Sensory Nerves-
Lingual Nerve & ChordaTympani -Taste of Anterior
Two-Third GlossopharyngealNerve -Taste of
Posterior One -Third VagusNerve -Taste of Posterior
Part
RangoliDosi
Nursing Tutor
Nursing Tutor
TEETH -Introduction
The teeth form a part of the chewing or masticatory
apparatus and are fixed to the jaw.
Teeth are small, calcified, hard, whitish structure s found
in the mouth for mechanically breaking down items of
food by cutting and crushing them.
They are among the most distinctive features of
mammals.
The human teeth function to mechanically break down
items of food by cutting and crushing them in preparation
for swallowing and digesting.
Humans have four types of teeth: incisors, canines,
premolars, and molars, each with a specific function.
The teeth form a part of the chewing or masticatory
apparatus and are fixed to the jaw.
Teeth are small, calcified, hard, whitish structure s found
in the mouth for mechanically breaking down items of
food by cutting and crushing them.
They are among the most distinctive features of
mammals.
The human teeth function to mechanically break down
items of food by cutting and crushing them in preparation
for swallowing and digesting.
Humans have four types of teeth: incisors, canines,
premolars, and molars, each with a specific function.
Parts and Types of Teeth
Each tooth consists of
three parts, a crown,
neck and root.
Crown: the part
protrudes from the gum
Neck: is the part
between the crown and
root
Root: the part
embedded in the bone
Each tooth consists of
three parts, a crown,
neck and root.
Crown: the part
protrudes from the gum
Neck: is the part
between the crown and
root
Root: the part
embedded in the bone
Crown
Part of the teeth above gum.
Outer most covering of crown is enamel.
Enamel is the hardest material in the body.
Enamel is the hardest and most highly mineralized
substance of the body.
It is one of the four major tissues which make up the
tooth, along with dentin, and dental pulp.
The normal color of enamel varies from light yellow to
grayish white.
Part of the teeth above gum.
Outer most covering of crown is enamel.
Enamel is the hardest material in the body.
Enamel is the hardest and most highly mineralized
substance of the body.
It is one of the four major tissues which make up the
tooth, along with dentin, and dental pulp.
The normal color of enamel varies from light yellow to
grayish white.
Neck
Part of the teeth between crown and root.
Inside the neck, a cavity is seen and it is the pulp cavity.
Blood vessels and nerve fibresare seen inside the pulp cavity.
Tissues of teeth get nourishment through these blood vessels.
DENTIN
Most of the teeth is composed of dentine that is covered by enamel
over the crown and cementumover the root.
DENTAL PULP
The dental pulp is the central part of the tooth filled with soft
connective tissue.
This tissue contains blood vessels and nerves that enter the tooth
from a hole at the apex of the root.
Part of the teeth between crown and root.
Inside the neck, a cavity is seen and it is the pulp cavity.
Blood vessels and nerve fibresare seen inside the pulp cavity.
Tissues of teeth get nourishment through these blood vessels.
DENTIN
Most of the teeth is composed of dentine that is covered by enamel
over the crown and cementumover the root.
DENTAL PULP
The dental pulp is the central part of the tooth filled with soft
connective tissue.
This tissue contains blood vessels and nerves that enter the tooth
from a hole at the apex of the root.
Root
Part of teeth seen inside the gum.
Material that fixes teeth to the soc ketof jaw bone is
cement.
CEMENTUM
Cementumis a specialized bone like substance covering
the root of a tooth.
It is softer than dentin and enamel.
Part of teeth seen inside the gum.
Material that fixes teeth to the soc ketof jaw bone is
cement.
CEMENTUM
Cementumis a specialized bone like substance covering
the root of a tooth.
It is softer than dentin and enamel.
Cross Section of Teeth
Types of Teeth
Four types of teeth .They are:
Incisors
Canines
Premolars
Molars
Four types of teeth .They are:
Incisors
Canines
Premolars
Molars
Incisors
Flat crown.
Single root.
Helps in cutting and biting.
Incisors are present at the front of the mouth. These teeth
have sharp edges and are adapted for cutting food into
small, chewable pieces. Humans have eight incisors, four
incisors in the upper jaw and four in the lower jaw.
Flat crown.
Single root.
Helps in cutting and biting.
Incisors are present at the front of the mouth. These teeth
have sharp edges and are adapted for cutting food into
small, chewable pieces. Humans have eight incisors, four
incisors in the upper jaw and four in the lower jaw.
Canines
Pointed Crown
Single Root
Help in holding and tearing
Canines are also called cuspids. They are situated at the
‘corners’ of the dental arches. They are characteristically
sharp, elongated and pointy surface. Their primary
function is to grip and tear food (tough food such as meat).
Humans have four canines, two in the upper jaw and two in
the lower jaw.
Pointed Crown
Single Root
Help in holding and tearing
Canines are also called cuspids. They are situated at the
‘corners’ of the dental arches. They are characteristically
sharp, elongated and pointy surface. Their primary
function is to grip and tear food (tough food such as meat).
Humans have four canines, two in the upper jaw and two in
the lower jaw.
Premolar
Two ridges in crown.
One or two roots.
Helps in chewing and grinding.
Premolars are also called bicuspids and are located behind
the canines. These teeth have a flat surface with ridges,
which is adapted for crushing and grinding food into
smaller portions. Humans have eight premolars, two on
each side of the jaws.
Two ridges in crown.
One or two roots.
Helps in chewing and grinding.
Premolars are also called bicuspids and are located behind
the canines. These teeth have a flat surface with ridges,
which is adapted for crushing and grinding food into
smaller portions. Humans have eight premolars, two on
each side of the jaws.
Molars
Two or three ridges in crown.
Two or three roots.
Helps in chewing and grinding.
Molars are the largest and strongest teeth. It has a large and
flat biting surface, which is well-adapted for grinding food.
Humans have 12 molars, six in each jaw. Four of those are
wisdom teeth, which is also called the third molar, which
come in between the ages of 17 to 25.
Two or three ridges in crown.
Two or three roots.
Helps in chewing and grinding.
Molars are the largest and strongest teeth. It has a large and
flat biting surface, which is well-adapted for grinding food.
Humans have 12 molars, six in each jaw. Four of those are
wisdom teeth, which is also called the third molar, which
come in between the ages of 17 to 25.
Wisdom Teeth
Impacted wisdom teeth are third molars at the back
of the mouth that don't have enough room to emerge
or develop normally.
Wisdom teeth are the last adult teeth to come into
the mouth (erupt). Most people have four wisdom
teeth at the back of the mouth —two on the top, two
on the bottom.
Impacted wisdom teeth can result in pain, damage to
other teeth and other dental problems. In some cases,
impacted wisdom teeth may cause no apparent or
immediate problems. But because they're hard to
clean, they may be more vulnerable to tooth decay
and gum disease than other teeth are.
Impacted wisdom teeth that cause pain or other
dental complications are usually removed. Some
dentists and oral surgeons also recommend removing
impacted wisdom teeth that don't cause symptoms to
prevent future problems.
Impacted wisdom teeth are third molars at the back
of the mouth that don't have enough room to emerge
or develop normally.
Wisdom teeth are the last adult teeth to come into
the mouth (erupt). Most people have four wisdom
teeth at the back of the mouth —two on the top, two
on the bottom.
Impacted wisdom teeth can result in pain, damage to
other teeth and other dental problems. In some cases,
impacted wisdom teeth may cause no apparent or
immediate problems. But because they're hard to
clean, they may be more vulnerable to tooth decay
and gum disease than other teeth are.
Impacted wisdom teeth that cause pain or other
dental complications are usually removed. Some
dentists and oral surgeons also recommend removing
impacted wisdom teeth that don't cause symptoms to
prevent future problems.
Primary Teeth
Among deciduous (primary) teeth, ten are found in
the maxilla (upper jaw) and ten in the mandible (lower
jaw), for a total of 20. The dental formula for primary
teeth is 2.1.0.2/2.1.0.2.
Two types of incisors –centrals and laterals,onecanine
& two types of molars –first and second.
All primary teeth are normally later replaced with their
permanent counterparts.
Start to come in (erupt) at about 6 months of age
Among deciduous (primary) teeth, ten are found in
the maxilla (upper jaw) and ten in the mandible (lower
jaw), for a total of 20. The dental formula for primary
teeth is 2.1.0.2/2.1.0.2.
Two types of incisors –centrals and laterals,onecanine
& two types of molars –first and second.
All primary teeth are normally later replaced with their
permanent counterparts.
Start to come in (erupt) at about 6 months of age
Permanent Teeth
Among permanent teeth, 16 are found in the maxilla
and 16 in the mandible, for a total of 32. The dental
formula is 2.1.2.3/2.1.2.3.
Age 18, all 32 of the permanent teeth have usually
erupted.
Among permanent teeth, 16 are found in the maxilla
and 16 in the mandible, for a total of 32. The dental
formula is 2.1.2.3/2.1.2.3.
Age 18, all 32 of the permanent teeth have usually
erupted.
Functions Of Teeth
Two incisor -for cutting
One canine -for tearing
Two premolar-for crushing
Three molar-for grinding
Two incisor -for cutting
One canine -for tearing
Two premolar-for crushing
Three molar-for grinding
Teeth
BLOOD SUPPLY
Maxillary arteries
VENOUS DRAINAGE
Internal jugular veins
NERVE SUPPLY
Maxillary nerves
Mandibularnerves
BLOOD SUPPLY
Maxillary arteries
VENOUS DRAINAGE
Internal jugular veins
NERVE SUPPLY
Maxillary nerves
Mandibularnerves
Pharynx –Introduction
The pharynx, more commonly known as the throat, is a 12-
14 cm, or 5 inch, long tube extending behind the nasal and
oral cavities until the voice box (larynx) and the esophagus.
Essentially, it forms a continuous muscular passage for air,
food, and liquids to travel down from your nose and mouth
to your lungs and stomach.
Thick fibresof muscle and connective tissue attach the
pharynx to the base of the skull and surrounding
structures. Both circular and longitudinal muscles occur in
the walls of the pharynx; the circular muscles form
constrictions that help push food to the esophagus and
prevent air from being swallowed, while the longitudinal
fibreslift the walls of the pharynx during swallowing.
The pharynx, more commonly known as the throat, is a 12-
14 cm, or 5 inch, long tube extending behind the nasal and
oral cavities until the voice box (larynx) and the esophagus.
Essentially, it forms a continuous muscular passage for air,
food, and liquids to travel down from your nose and mouth
to your lungs and stomach.
Thick fibresof muscle and connective tissue attach the
pharynx to the base of the skull and surrounding
structures. Both circular and longitudinal muscles occur in
the walls of the pharynx; the circular muscles form
constrictions that help push food to the esophagus and
prevent air from being swallowed, while the longitudinal
fibreslift the walls of the pharynx during swallowing.
Pharynx –Introduction
The functions of the pharynx are accomplished by two
sets of muscles which help push the food bolus further
down the digestive tract. In addition, they also help
with swallowing and speaking.
The functions of the pharynx are accomplished by two
sets of muscles which help push the food bolus further
down the digestive tract. In addition, they also help
with swallowing and speaking.
Parts of Pharynx
The anterior portion is the nasal pharynx, the back section of the
nasal cavity. The nasal pharynx connects to the second region,
the oral pharynx, by means of a passage called an isthmus.
The oral pharynx begins at the back of the mouth cavity and
continues down the throat to the epiglottis, a flap of tissue that
covers the air passage to the lungs and that channels food to the
esophagus. Triangular-shaped recesses in the walls of this region
house the palatine tonsils, two masses of lymphatic tissue prone
to infection. The isthmus connecting the oral and nasal regions
is extremely beneficial in humans. It allows them to breathe
through either the nose or the mouth and, when medically
necessary, allows food to be passed to the esophagus by nasal
tubes.
The anterior portion is the nasal pharynx, the back section of the
nasal cavity. The nasal pharynx connects to the second region,
the oral pharynx, by means of a passage called an isthmus.
The oral pharynx begins at the back of the mouth cavity and
continues down the throat to the epiglottis, a flap of tissue that
covers the air passage to the lungs and that channels food to the
esophagus. Triangular-shaped recesses in the walls of this region
house the palatine tonsils, two masses of lymphatic tissue prone
to infection. The isthmus connecting the oral and nasal regions
is extremely beneficial in humans. It allows them to breathe
through either the nose or the mouth and, when medically
necessary, allows food to be passed to the esophagus by nasal
tubes.
Parts of Pharynx
The third region is the laryngeal pharynx, which
begins at the epiglottis and leads down to the
esophagus. Its function is to regulate the passage of air
to the lungs and food to the esophagus. Two small
tubes (eustachiantubes) connect the middle ears to
the pharynx and allow air pressure on the eardrum to
be equalized. Head colds sometimes inflame the
tubes, causing earaches and hearing difficulties. Other
medical afflictions associated with the pharynx
include tonsillitis, cancer, and various types of throat
paralyses caused by polio, diphtheria, rabies, or
nervous-system injuries.
The third region is the laryngeal pharynx, which
begins at the epiglottis and leads down to the
esophagus. Its function is to regulate the passage of air
to the lungs and food to the esophagus. Two small
tubes (eustachiantubes) connect the middle ears to
the pharynx and allow air pressure on the eardrum to
be equalized. Head colds sometimes inflame the
tubes, causing earaches and hearing difficulties. Other
medical afflictions associated with the pharynx
include tonsillitis, cancer, and various types of throat
paralyses caused by polio, diphtheria, rabies, or
nervous-system injuries.
Muscles and Blood Supply of
Pharynx
Muscles Pharyngeal constrictors:Superior,
middle and inferior muscles
Longitudinal
muscles:Palatopharyngeus,
salpingopharyngeus, stylopharyngeus
Arteries Facial artery, lingual artery, maxillary
artery (branches of external carotid
artery)
Nerves Pharyngeal plexus: receives branches
of vagusnerve (CN X),
glossopharyngealnerve (CN IX) and
maxillary nerve (CN V2)
Pharynx
Muscles Pharyngeal constrictors:Superior,
middle and inferior muscles
Longitudinal
muscles:Palatopharyngeus,
salpingopharyngeus, stylopharyngeus
Arteries Facial artery, lingual artery, maxillary
artery (branches of external carotid
artery)
Nerves Pharyngeal plexus: receives branches
of vagusnerve (CN X),
glossopharyngealnerve (CN IX) and
maxillary nerve (CN V2)
RangoliDosi
Nursing Tutor
Nursing Tutor
Pharynx
Pharynx –Introduction
The pharynx, more commonly known as the throat, is a 12-
14 cm, or 5 inch, long tube extending behind the nasal and
oral cavities until the voice box (larynx) and the esophagus.
Essentially, it forms a continuous muscular passage for air,
food, and liquids to travel down from your nose and mouth
to your lungs and stomach.
Thick fibresof muscle and connective tissue attach the
pharynx to the base of the skull and surrounding
structures. Both circular and longitudinal muscles occur in
the walls of the pharynx; the circular muscles form
constrictions that help push food to the esophagus and
prevent air from being swallowed, while the longitudinal
fibreslift the walls of the pharynx during swallowing.
The pharynx, more commonly known as the throat, is a 12-
14 cm, or 5 inch, long tube extending behind the nasal and
oral cavities until the voice box (larynx) and the esophagus.
Essentially, it forms a continuous muscular passage for air,
food, and liquids to travel down from your nose and mouth
to your lungs and stomach.
Thick fibresof muscle and connective tissue attach the
pharynx to the base of the skull and surrounding
structures. Both circular and longitudinal muscles occur in
the walls of the pharynx; the circular muscles form
constrictions that help push food to the esophagus and
prevent air from being swallowed, while the longitudinal
fibreslift the walls of the pharynx during swallowing.
Structures Associated with the
Pharynx
Superiorly : the inferior surface of the base of the
skull.
Inferiorlyit is continuous with the oesophages.
Anteriorly: the wall is incomplete because of the
openings into the nose, mouth and larynx.
Posteriorly: areolartissue, involuntary muscle and
bodies of the first six cervical vertebrae.
Pharynx
Superiorly : the inferior surface of the base of the
skull.
Inferiorlyit is continuous with the oesophages.
Anteriorly: the wall is incomplete because of the
openings into the nose, mouth and larynx.
Posteriorly: areolartissue, involuntary muscle and
bodies of the first six cervical vertebrae.
Lower Limit of Pharynx
Nasopharynx
Lower border of soft palate or
Junction between hard and softpalate
Oropharynx
Tip ofepiglottis or
Hypoid bone or
Base of vallecula
Hypopharynx
Lower borderof cricoidor
Lowerborder of C6 vertebrate
Nasopharynx
Lower border of soft palate or
Junction between hard and softpalate
Oropharynx
Tip ofepiglottis or
Hypoid bone or
Base of vallecula
Hypopharynx
Lower borderof cricoidor
Lowerborder of C6 vertebrate
Parts of Pharynx
Nasopharynx
The anterior portion is the nasal pharynx, the back section of
the nasal cavity. The nasal pharynx connects to the second
region, the oral pharynx, by means of a passage called an
isthmus.
Posterior to the nasal cavity is the nasopharynx, which also
lies inferior to the sphenoid bone but superior to the soft
palate’s level. The nasopharynxis a passageway for air only,
because it is located above the mouth. It is continuous with
the nasal cavity via the posterior nasal apertures and is lined
with pseudostratifiedcil-iatedepithelium, which assists the
efforts of the nasal mucosa to transport mucus. The
pharyngeal tonsil, also called the adenoids, is located very
high up on the posterior wall of the nasopharynx. This tonsil
traps pathogens from the incoming air and destroys them.
Nasopharynx
The anterior portion is the nasal pharynx, the back section of
the nasal cavity. The nasal pharynx connects to the second
region, the oral pharynx, by means of a passage called an
isthmus.
Posterior to the nasal cavity is the nasopharynx, which also
lies inferior to the sphenoid bone but superior to the soft
palate’s level. The nasopharynxis a passageway for air only,
because it is located above the mouth. It is continuous with
the nasal cavity via the posterior nasal apertures and is lined
with pseudostratifiedcil-iatedepithelium, which assists the
efforts of the nasal mucosa to transport mucus. The
pharyngeal tonsil, also called the adenoids, is located very
high up on the posterior wall of the nasopharynx. This tonsil
traps pathogens from the incoming air and destroys them.
Parts of Pharynx
Oropharynx
The oral pharynx begins at the back of the mouth cavity and
continues down the throat to the epiglottis, a flap of tissue that
covers the air passage to the lungs and that channels food to the
esophagus. Triangular-shaped recesses in the walls of this region
house the palatine tonsils, two masses of lymphatic tissue prone to
infection. The isthmus connecting the oral and nasal regions is
extremely beneficial in humans. It allows them to breathe through
either the nose or the mouth and, when medically necessary, allows
food to be passed to the esophagus by nasal tubes.
The oropharynxis continuous with the oral cavity via an archway
known as the isthmus of the fauces. The oropharynxlies posterior
to the oral cavity. Both air and food pass through the oropharynx
because it extends inferiorly from the level of the soft palate to the
epiglottis. The oropharynxcontains two palatinetonsilsas well as
the lingual tonsil.
Oropharynx
The oral pharynx begins at the back of the mouth cavity and
continues down the throat to the epiglottis, a flap of tissue that
covers the air passage to the lungs and that channels food to the
esophagus. Triangular-shaped recesses in the walls of this region
house the palatine tonsils, two masses of lymphatic tissue prone to
infection. The isthmus connecting the oral and nasal regions is
extremely beneficial in humans. It allows them to breathe through
either the nose or the mouth and, when medically necessary, allows
food to be passed to the esophagus by nasal tubes.
The oropharynxis continuous with the oral cavity via an archway
known as the isthmus of the fauces. The oropharynxlies posterior
to the oral cavity. Both air and food pass through the oropharynx
because it extends inferiorly from the level of the soft palate to the
epiglottis. The oropharynxcontains two palatinetonsilsas well as
the lingual tonsil.
Pharynx
Pharyngotympanictube.
The pharyngotympanictubes,
which drain the middle ear
open into the nasopharynx.
Palatine tonsils. The palatine
tonsils are in the oropharynx
at the end of the soft palate.
Lingual tonsils. The lingual
tonsils lie at the base of the
tongue.
Pharyngotympanictube.
The pharyngotympanictubes,
which drain the middle ear
open into the nasopharynx.
Palatine tonsils. The palatine
tonsils are in the oropharynx
at the end of the soft palate.
Lingual tonsils. The lingual
tonsils lie at the base of the
tongue.
Parts of Pharynx
Laryngopharynx
The third region is the laryngeal pharynx,alsoknown as hypopharynx.
which begins at the epiglottis and leads down to the esophagus. Its
function is to regulate the passage of air to the lungs and food to the
esophagus. Two small tubes (eustachiantubes) connect the middle ears
to the pharynx and allow air pressure on the eardrum to be equalized.
colds sometimes inflame the tubes, causing earaches and hearing
difficulties. Other medical afflictions associated with the pharynx
include tonsillitis, cancer, and various types of throat paralyses caused
by polio, diphtheria, rabies, or nervous-system injuries.
The laryngopharynxalso allows air and food to pass and is also lined
with a stratified squamousepithelium and lies directly posterior to the
epiglottis. The laryn-gopharynxextends to the larynx, at which point
respi-ratoryand digestive paths separate. The esophagus is the tube-
like structure that allows food and fluids to pass to the stomach. Air
enters the larynx anteriorly. When we swallow, passage of air
temporarily stops so food can pass.
Laryngopharynx
The third region is the laryngeal pharynx,alsoknown as hypopharynx.
which begins at the epiglottis and leads down to the esophagus. Its
function is to regulate the passage of air to the lungs and food to the
esophagus. Two small tubes (eustachiantubes) connect the middle ears
to the pharynx and allow air pressure on the eardrum to be equalized.
colds sometimes inflame the tubes, causing earaches and hearing
difficulties. Other medical afflictions associated with the pharynx
include tonsillitis, cancer, and various types of throat paralyses caused
by polio, diphtheria, rabies, or nervous-system injuries.
The laryngopharynxalso allows air and food to pass and is also lined
with a stratified squamousepithelium and lies directly posterior to the
epiglottis. The laryn-gopharynxextends to the larynx, at which point
respi-ratoryand digestive paths separate. The esophagus is the tube-
like structure that allows food and fluids to pass to the stomach. Air
enters the larynx anteriorly. When we swallow, passage of air
temporarily stops so food can pass.
Muscles and Blood Supply of
Pharynx
Muscles Pharyngeal constrictors:Superior,
middle and inferior muscles
Longitudinal
muscles:Palatopharyngeus,
salpingopharyngeus, stylopharyngeus
Arteries Facial artery, lingual artery, maxillary
artery (branches of external carotid
artery)
Nerves Pharyngeal plexus: receives branches
of vagusnerve (CN X),
glossopharyngealnerve (CN IX) and
maxillary nerve (CN V2)
Pharynx
Muscles Pharyngeal constrictors:Superior,
middle and inferior muscles
Longitudinal
muscles:Palatopharyngeus,
salpingopharyngeus, stylopharyngeus
Arteries Facial artery, lingual artery, maxillary
artery (branches of external carotid
artery)
Nerves Pharyngeal plexus: receives branches
of vagusnerve (CN X),
glossopharyngealnerve (CN IX) and
maxillary nerve (CN V2)
RangoliDosi
Nursing Tutor
Nursing Tutor
Oesophagusor
Food Pipe (Gullet)
Food Pipe (Gullet)
Introduction
The oesophagusis a fibromusculartube,
approximately 25cm in length, that transports food
from the pharynx to the stomach.
It originates at the inferior border of the cricoid
cartilage (C6) and extends to the cardiac orifice of the
stomach (T11).
The oesophagusis a fibromusculartube,
approximately 25cm in length, that transports food
from the pharynx to the stomach.
It originates at the inferior border of the cricoid
cartilage (C6) and extends to the cardiac orifice of the
stomach (T11).
Anatomical Course
The oesophagusbegins in the neck, at the level of C6.
Here, it is continuous superiorly with the laryngeal part of
the pharynx (the laryngopharynx).
It descends downward into the superior mediastinumof
the thorax, positioned between the trachea and the
vertebral bodies of T1 to T4. It then enters the abdomen via
the oesophagealhiatus (an opening in the right crusof the
diaphragm) at T10.
The abdominal portion of the oesophagusis approximately
1.25cm long –it terminates by joining the cardiac orifice of
the stomach at level of T11.
The oesophagusbegins in the neck, at the level of C6.
Here, it is continuous superiorly with the laryngeal part of
the pharynx (the laryngopharynx).
It descends downward into the superior mediastinumof
the thorax, positioned between the trachea and the
vertebral bodies of T1 to T4. It then enters the abdomen via
the oesophagealhiatus (an opening in the right crusof the
diaphragm) at T10.
The abdominal portion of the oesophagusis approximately
1.25cm long –it terminates by joining the cardiac orifice of
the stomach at level of T11.
Anatomical Structure
The oesophagusshares a similar structure with many of the
organs in the alimentary tract:
Adventitia –outer layer of connective tissue.
Muscle layer –external layer of longitudinal muscle and
inner layer of circular muscle. The external layer is composed
of different muscle types in each third:
Superior third –voluntary striated muscle
Middle third –voluntary striated and smooth muscle
Inferior third –smooth muscle
Submucosa
Mucosa –non-keratinisedstratified squamousepithelium
(contiguous with columnar epithelium of the stomach).
The oesophagusshares a similar structure with many of the
organs in the alimentary tract:
Adventitia –outer layer of connective tissue.
Muscle layer –external layer of longitudinal muscle and
inner layer of circular muscle. The external layer is composed
of different muscle types in each third:
Superior third –voluntary striated muscle
Middle third –voluntary striated and smooth muscle
Inferior third –smooth muscle
Submucosa
Mucosa –non-keratinisedstratified squamousepithelium
(contiguous with columnar epithelium of the stomach).
Anatomical Structure
Food is transported
through the oesophagus
byperistalsis–rhythmic
contractions of the
muscles which propagate
down the oesophagus.
Hardening of these
muscular layers can
interfere with peristalsis
and cause difficulty in
swallowing (dysphagia).
Food is transported
through the oesophagus
byperistalsis–rhythmic
contractions of the
muscles which propagate
down the oesophagus.
Hardening of these
muscular layers can
interfere with peristalsis
and cause difficulty in
swallowing (dysphagia).
OesophagealSphincters
There are two sphincters present in the oesophagus,
known as the upper and lower oesophagealsphincters.
They act to prevent the entry of air and the reflux of
gastric contents respectively.
Upper OesophagealSphincter
The upper sphincter is an anatomical, striated muscle
sphincter at the junction between the pharynx and
oesophagus. It is produced by the cricopharyngeus
muscle. Normally, it is constricted to prevent the
entrance of air into the oesophagus.
There are two sphincters present in the oesophagus,
known as the upper and lower oesophagealsphincters.
They act to prevent the entry of air and the reflux of
gastric contents respectively.
Upper OesophagealSphincter
The upper sphincter is an anatomical, striated muscle
sphincter at the junction between the pharynx and
oesophagus. It is produced by the cricopharyngeus
muscle. Normally, it is constricted to prevent the
entrance of air into the oesophagus.
OesophagealSphincters
Lower OesophagealSphincter
The lower oesophagealsphincter is located at the
gastro-oesophagealjunction (between the stomach
and oesophagus). The gastro-oesophagealjunction is
situated to the left of the T11 vertebra, and is marked
by the change from oesophagealto gastric mucosa.
Lower OesophagealSphincter
The lower oesophagealsphincter is located at the
gastro-oesophagealjunction (between the stomach
and oesophagus). The gastro-oesophagealjunction is
situated to the left of the T11 vertebra, and is marked
by the change from oesophagealto gastric mucosa.
OesophagealSphincters
The sphincter is classified as a physiological (or functional)
sphincter, as it does not have any specific sphinctericmuscle.
Instead, the sphincter is maintained by four factors:
Oesophagusenters the stomach at an acute angle.
Walls of the intra-abdominal section of the oesophagusare
compressed when there is a positive intra-abdominal pressure.
Prominent mucosal folds at the gastro-oesophagealjunction aid in
occluding the lumen.
Right crusof the diaphragm has a “pinch-cock” effect.
During oesophagealperistalsis, the sphincter is relaxed to allow
food to enter the stomach. Otherwise at rest, the function of this
sphincter is to prevent the reflux of acidic gastric contents into
the oesophagus.
The sphincter is classified as a physiological (or functional)
sphincter, as it does not have any specific sphinctericmuscle.
Instead, the sphincter is maintained by four factors:
Oesophagusenters the stomach at an acute angle.
Walls of the intra-abdominal section of the oesophagusare
compressed when there is a positive intra-abdominal pressure.
Prominent mucosal folds at the gastro-oesophagealjunction aid in
occluding the lumen.
Right crusof the diaphragm has a “pinch-cock” effect.
During oesophagealperistalsis, the sphincter is relaxed to allow
food to enter the stomach. Otherwise at rest, the function of this
sphincter is to prevent the reflux of acidic gastric contents into
the oesophagus.
Anatomical Relations
The anatomical relations of the oesophagusgive rise to
four physiological constrictions in its lumen –it is
these areas where food/foreign objects are most likely
to become impacted. They can be remembered using
the acronym ‘ABCD‘:
Arch of aorta
Bronchus (left main stem)
Cricoidcartilage
Diaphragmatic hiatus
The anatomical relations of the oesophagusgive rise to
four physiological constrictions in its lumen –it is
these areas where food/foreign objects are most likely
to become impacted. They can be remembered using
the acronym ‘ABCD‘:
Arch of aorta
Bronchus (left main stem)
Cricoidcartilage
Diaphragmatic hiatus
Anatomical Relations
Anterior Posterior Right Left
Cervical and
thoracic
•Trachea
•Left recurrent
laryngeal
nerve
•Pericardium
•Thoracic
vertebral
bodies
•Thoracic duct
•Azygousveins
•Descending
aorta
•Pleura
•Terminal part
of azygous
vein
•Subclavian
artery
•Aortic arch
•Thoracic duct
•Pleura
Abdominal
•Left vagus
nerve
•Posterior
surface of the
heart
•Right vagus
nerve
•Left crusof
the diaphragm
Anterior Posterior Right Left
Cervical and
thoracic
•Trachea
•Left recurrent
laryngeal
nerve
•Pericardium
•Thoracic
vertebral
bodies
•Thoracic duct
•Azygousveins
•Descending
aorta
•Pleura
•Terminal part
of azygous
vein
•Subclavian
artery
•Aortic arch
•Thoracic duct
•Pleura
Abdominal
•Left vagus
nerve
•Posterior
surface of the
heart
•Right vagus
nerve
•Left crusof
the diaphragm
Vasculature
In respect to its arterial and venous supply, the
oesophaguscan be divided into its thoracic and
abdominal components.
Thoracic
The thoracic part of the oesophagusreceives its arterial
supply from the branches of the thoracic aorta and the
inferior thyroid artery (a branch of the thyrocervical
trunk).
Venous drainage into the systemic circulation occurs via
branches of the azygousveins and the inferior thyroid
vein.
In respect to its arterial and venous supply, the
oesophaguscan be divided into its thoracic and
abdominal components.
Thoracic
The thoracic part of the oesophagusreceives its arterial
supply from the branches of the thoracic aorta and the
inferior thyroid artery (a branch of the thyrocervical
trunk).
Venous drainage into the systemic circulation occurs via
branches of the azygousveins and the inferior thyroid
vein.
Vasculature
Abdominal
The abdominal oesophagusis supplied by the left gastric
artery (a branch of the coeliactrunk) and left inferior
phrenicartery. This part of the oesophagushas a mixed
venous drainage via two routes:
To the portal circulation via left gastric vein
To the systemic circulation via the azygousvein.
These two routes form a porto-systemic anastomosis, a
connection between the portal and systemic venous
systems.
Abdominal
The abdominal oesophagusis supplied by the left gastric
artery (a branch of the coeliactrunk) and left inferior
phrenicartery. This part of the oesophagushas a mixed
venous drainage via two routes:
To the portal circulation via left gastric vein
To the systemic circulation via the azygousvein.
These two routes form a porto-systemic anastomosis, a
connection between the portal and systemic venous
systems.
Innervation
The oesophagusis innervated by the oesophageal
plexus, which is formed by a combination of the
parasympathetic vagaltrunks and sympathetic fibres
from the cervical and thoracic sympathetic trunks.
Two different types of nerve fibrerun in the vagal
trunks. The upper oesophagealsphincter and upper
striated muscle is supplied by fibresoriginating from
the nucleus ambiguus. Fibressupplying the lower
oesophagealsphincter and smooth muscle of the lower
oesophagusarise from the dorsal motor nucleus.
The oesophagusis innervated by the oesophageal
plexus, which is formed by a combination of the
parasympathetic vagaltrunks and sympathetic fibres
from the cervical and thoracic sympathetic trunks.
Two different types of nerve fibrerun in the vagal
trunks. The upper oesophagealsphincter and upper
striated muscle is supplied by fibresoriginating from
the nucleus ambiguus. Fibressupplying the lower
oesophagealsphincter and smooth muscle of the lower
oesophagusarise from the dorsal motor nucleus.
Lymphatics
The lymphatic drainage of the oesophagusis divided
into thirds:
Superior third –deep cervical lymph nodes.
Middle third –superior and posterior mediastinal
nodes.
Lower third –left gastric and celiac nodes.
The lymphatic drainage of the oesophagusis divided
into thirds:
Superior third –deep cervical lymph nodes.
Middle third –superior and posterior mediastinal
nodes.
Lower third –left gastric and celiac nodes.
RangoliDosi
Nursing Tutor
Nursing Tutor
Stomach Anatomy
Introduction –Stomach
Location. The C-shaped stomach is on the left side of the
abdominal cavity, nearly hidden by the liver and the
diaphragm.
Function. The stomach acts as a temporary “storage tank”
for food as well as a site for food breakdown.
Cardiac region. The cardiac region surrounds the
cardioesophagealsphincter, through which food enters the
stomach from the esophagus.
Fundus. The fundusis the expanded part of the stomach
lateral to the cardiac region.
Body. The body is the midportion, and as it narrows
inferiorly, it becomes the pyloric antrum, and then the
funnel-shaped pylorus.
Location. The C-shaped stomach is on the left side of the
abdominal cavity, nearly hidden by the liver and the
diaphragm.
Function. The stomach acts as a temporary “storage tank”
for food as well as a site for food breakdown.
Cardiac region. The cardiac region surrounds the
cardioesophagealsphincter, through which food enters the
stomach from the esophagus.
Fundus. The fundusis the expanded part of the stomach
lateral to the cardiac region.
Body. The body is the midportion, and as it narrows
inferiorly, it becomes the pyloric antrum, and then the
funnel-shaped pylorus.
Introduction –Stomach
Pylorus. The pylorus is the terminal part of the stomach
and it is continuous with the small intestine through the
pyloric sphincter or valve.
Size. The stomach varies from 15 to 25 cm in length, but its
diameter and volume depend on how much food it
contains; when it is full, it can hold about 4 liters (1 gallon)
of food, but when it is empty it collapses inward on itself.
Rugae.The mucosa of the stomach is thrown into large
folds called rugaewhen it is empty.
Greater curvature. The convex lateral surface of the
stomach is the greater curvature.
Lesser curvature. The concave medial surface is the lesser
curvature.
Pylorus. The pylorus is the terminal part of the stomach
and it is continuous with the small intestine through the
pyloric sphincter or valve.
Size. The stomach varies from 15 to 25 cm in length, but its
diameter and volume depend on how much food it
contains; when it is full, it can hold about 4 liters (1 gallon)
of food, but when it is empty it collapses inward on itself.
Rugae.The mucosa of the stomach is thrown into large
folds called rugaewhen it is empty.
Greater curvature. The convex lateral surface of the
stomach is the greater curvature.
Lesser curvature. The concave medial surface is the lesser
curvature.
Introduction –Stomach
Lesser omentum. The lesser omentum, a double layer of
peritoneum, extends from the liver to the greater
curvature.
Greater omentum. The greater omentum, another
extension of the peritoneum, drapes downward and covers
the abdominal organs like a lacy apron before attaching to
the posterior body wall, and is riddled with fat, which helps
to insulate, cushion, and protect the abdominal organs.
Stomach mucosa. The mucosa of the stomach is a simple
columnar epithelium composed entirely of mucous cells
that produce a protective layer of bicarbonate-rich alkaline
mucus that clings to the stomach mucosa and protects the
stomach wall from being damaged by acid and digested by
enzymes.
Lesser omentum. The lesser omentum, a double layer of
peritoneum, extends from the liver to the greater
curvature.
Greater omentum. The greater omentum, another
extension of the peritoneum, drapes downward and covers
the abdominal organs like a lacy apron before attaching to
the posterior body wall, and is riddled with fat, which helps
to insulate, cushion, and protect the abdominal organs.
Stomach mucosa. The mucosa of the stomach is a simple
columnar epithelium composed entirely of mucous cells
that produce a protective layer of bicarbonate-rich alkaline
mucus that clings to the stomach mucosa and protects the
stomach wall from being damaged by acid and digested by
enzymes.
Introduction –Stomach
Gastric glands. This otherwise smooth lining is dotted with millions
of deep gastric pits, which lead into gastric glands that secrete the
solution called gastric juice.
Intrinsic factor.Some stomach cells produce intrinsic factor, a
substance needed for the absorption of vitamin b12 from the small
intestine.
Chief cells. The chief cells produce protein-digesting enzymes, mostly
pepsinogens.
Parietal cells. The parietal cells produce corrosive hydrochloric acid,
which makes the stomach contents acidic and activates the enzymes.
Enteroendocrinecells. The enteroendocrinecells produce local
hormones such as gastrin, that are important to the digestive activities
of the stomach.
Chyme. After food has been processed, it resembles heavy cream and
is called chyme.
Gastric glands. This otherwise smooth lining is dotted with millions
of deep gastric pits, which lead into gastric glands that secrete the
solution called gastric juice.
Intrinsic factor.Some stomach cells produce intrinsic factor, a
substance needed for the absorption of vitamin b12 from the small
intestine.
Chief cells. The chief cells produce protein-digesting enzymes, mostly
pepsinogens.
Parietal cells. The parietal cells produce corrosive hydrochloric acid,
which makes the stomach contents acidic and activates the enzymes.
Enteroendocrinecells. The enteroendocrinecells produce local
hormones such as gastrin, that are important to the digestive activities
of the stomach.
Chyme. After food has been processed, it resembles heavy cream and
is called chyme.
Layers of Stomach
The stomach wall has four layers
The outermost layer, the serous layer (serosa), consists of
squamousepithelial tissue and continues as a double fold from the
lower edge of the stomach to cover the intestine.
The second layer, the muscular layer (muscularis), extends from
the fundusto the antrumand consists of three smooth muscle
layers, which are the longitudinal layer, the circular layer, and the
oblique layer.
The third layer, the submucouslayer (submucosa), consists of
connective tissue that contains blood vessels, lymphatics, and nerve
plexuses.
The innermost layer, the mucous layer (mucosa), consists of a
muscular layer that is arranged in longitudinal folds, or rugae, that
can expand as the stomach fills. This layer also contains glands that
secrete about 1500 mLof gastric juice per day.
The stomach wall has four layers
The outermost layer, the serous layer (serosa), consists of
squamousepithelial tissue and continues as a double fold from the
lower edge of the stomach to cover the intestine.
The second layer, the muscular layer (muscularis), extends from
the fundusto the antrumand consists of three smooth muscle
layers, which are the longitudinal layer, the circular layer, and the
oblique layer.
The third layer, the submucouslayer (submucosa), consists of
connective tissue that contains blood vessels, lymphatics, and nerve
plexuses.
The innermost layer, the mucous layer (mucosa), consists of a
muscular layer that is arranged in longitudinal folds, or rugae, that
can expand as the stomach fills. This layer also contains glands that
secrete about 1500 mLof gastric juice per day.
Blood and Nerve Supply
The celiac artery provides the blood supply required for
the motor and secretoryactivities of the stomach.
The splenicvein provides venous drainage for the right
side of the stomach, and the gastric vein provides it for the
left.
Numerous lymphatic channels arise in the submucosa
and terminate in the thoracic duct.
The stomach is innervated by the autonomic nervous
system.
Sympathetic fibers arise from the celiac plexus, and
parasympathetic fibers arise from the gastric branch of the
vagusnerve.
The celiac artery provides the blood supply required for
the motor and secretoryactivities of the stomach.
The splenicvein provides venous drainage for the right
side of the stomach, and the gastric vein provides it for the
left.
Numerous lymphatic channels arise in the submucosa
and terminate in the thoracic duct.
The stomach is innervated by the autonomic nervous
system.
Sympathetic fibers arise from the celiac plexus, and
parasympathetic fibers arise from the gastric branch of the
vagusnerve.
Structure & Function of Mucosa
The epithelial cells of the gastric mucosa are packed very
close together and serve as a protective barrier, preventing
diffusion of hydrogen ions into the mucosa.
The surface epithelial cells produce alkaline mucus and
secrete a bicarbonate-laden fluid.
The mucus further protects the gastric mucosa by delaying
back-diffusion of hydrogen ions and trapping them for
neutralization by the secreted bicarbonate.
The gastric mucosal cells can compensate for cell
destruction. Epithelial cells are in a constant state of
growth, migration, and desquamation, and they are shed at
a rate of one half million cells per minute.
The epithelial cells of the gastric mucosa are packed very
close together and serve as a protective barrier, preventing
diffusion of hydrogen ions into the mucosa.
The surface epithelial cells produce alkaline mucus and
secrete a bicarbonate-laden fluid.
The mucus further protects the gastric mucosa by delaying
back-diffusion of hydrogen ions and trapping them for
neutralization by the secreted bicarbonate.
The gastric mucosal cells can compensate for cell
destruction. Epithelial cells are in a constant state of
growth, migration, and desquamation, and they are shed at
a rate of one half million cells per minute.
Structure & Function of Mucosa
The gastric mucosa also has the ability to increase blood flow,
providing an additional buffer for acid neutralization and aiding
in the removal of toxic metabolites and chloride ions from
injured mucosa.
The gastric mucosal cells synthesize a family of unsaturated fatty
acids known as prostaglandins.
Prostaglandins facilitate mucosal bicarbonate secretion and
inhibit acid secretion by preventing the activation of parietal
cells by histamine (a local biochemical mediator).
Certain lipid-soluble substances such as alcohol, aspirin, and
other nonsteroidalanti-inflammatory drugs, regurgitated bile,
and uremic toxins, can break through the mucosal barrier and
penetrate the cells, causing their destruction, edema, and
eventual bleeding.
The gastric mucosa also has the ability to increase blood flow,
providing an additional buffer for acid neutralization and aiding
in the removal of toxic metabolites and chloride ions from
injured mucosa.
The gastric mucosal cells synthesize a family of unsaturated fatty
acids known as prostaglandins.
Prostaglandins facilitate mucosal bicarbonate secretion and
inhibit acid secretion by preventing the activation of parietal
cells by histamine (a local biochemical mediator).
Certain lipid-soluble substances such as alcohol, aspirin, and
other nonsteroidalanti-inflammatory drugs, regurgitated bile,
and uremic toxins, can break through the mucosal barrier and
penetrate the cells, causing their destruction, edema, and
eventual bleeding.
Gastric Secretion
The stomach has two types of glands—oxyntic(also
known as gastric glands), and pyloric—that contain cells
of various types that secrete 1500 to 2400 mLof gastric
juice into the lumen per day, depending on the diet and
other stimuli.
Gastric juice is composed of hydrochloric acid (HCl),
pepsin (necessary for the breakdown of protein), mucus,
intrinsic factor (necessary for vitamin B12 absorption),
sodium, and potassium
Pepsinogen, secreted by the chief cells of the stomach
lining, is converted to its active form, pepsin, in the acidic
environment of the stomach.
The stomach has two types of glands—oxyntic(also
known as gastric glands), and pyloric—that contain cells
of various types that secrete 1500 to 2400 mLof gastric
juice into the lumen per day, depending on the diet and
other stimuli.
Gastric juice is composed of hydrochloric acid (HCl),
pepsin (necessary for the breakdown of protein), mucus,
intrinsic factor (necessary for vitamin B12 absorption),
sodium, and potassium
Pepsinogen, secreted by the chief cells of the stomach
lining, is converted to its active form, pepsin, in the acidic
environment of the stomach.
Gastric Secretion
The cardiac glands secrete mucus and pepsinogen. The
oxynticglands contain parietal cells, which secrete HCland
intrinsic factor, and chief cells, which secrete pepsinogen.
Pyloric glands contain mucous cells, which secrete mucus
and pepsinogen, and G-cells, which secrete gastrin.
Gastric glands are stimulated by the parasympathetic
stimulation and gastrinand inhibited by gastric-inhibitory
peptide and enterogastrone.
Histamine and entero-oxyntinalso stimulate the parietal
cells to produce acid, and secretinstimulates the chief cells
to produce pepsinogen.
The cardiac glands secrete mucus and pepsinogen. The
oxynticglands contain parietal cells, which secrete HCland
intrinsic factor, and chief cells, which secrete pepsinogen.
Pyloric glands contain mucous cells, which secrete mucus
and pepsinogen, and G-cells, which secrete gastrin.
Gastric glands are stimulated by the parasympathetic
stimulation and gastrinand inhibited by gastric-inhibitory
peptide and enterogastrone.
Histamine and entero-oxyntinalso stimulate the parietal
cells to produce acid, and secretinstimulates the chief cells
to produce pepsinogen.
Digestive Hormones
SOURCE HORMONE
STIMULUS FOR
SECRETION
ACTION
Mucosa of
the stomach
Gastrin Presence of
partially digested
proteins in the
stomach
Stimulates gastric glands to
secrete hydrochloric acid
and pepsinogen; growth of
gastric mucosa; promotes
gastric motility
Histamine Acid in the
stomach
Stimulates acid secretion
Somatostatin Acid in the
stomach
Inhibits acid and
pepsinogensecretion and
release of gastrin
Acetylcholine Vagusand local
nerves in stomach
Stimulates release of
pepsinogenand acid
secretion
Gastrin-releasing
peptide
(bombesin)
Vagus and local
nerves in stomach
Stimulates gastrinand
release of pepsinogenand
acid secretion
SOURCE HORMONE
STIMULUS FOR
SECRETION
ACTION
Mucosa of
the stomach
Gastrin Presence of
partially digested
proteins in the
stomach
Stimulates gastric glands to
secrete hydrochloric acid
and pepsinogen; growth of
gastric mucosa; promotes
gastric motility
Histamine Acid in the
stomach
Stimulates acid secretion
Somatostatin Acid in the
stomach
Inhibits acid and
pepsinogensecretion and
release of gastrin
Acetylcholine Vagusand local
nerves in stomach
Stimulates release of
pepsinogenand acid
secretion
Gastrin-releasing
peptide
(bombesin)
Vagus and local
nerves in stomach
Stimulates gastrinand
release of pepsinogenand
acid secretion
Anatomical Relations of the
Stomach
Anteriorly Diaphragm, liver (left lobe), and
anterior abdominal wall
Posteriorly Omentalbursa (lesser sac), pancreas,
left kidney and adrenal gland, spleen,
and splenicartery
Superiorly Esophagus and diaphragm
Inferiorly and laterally Transverse mesocolon
Stomach
Anteriorly Diaphragm, liver (left lobe), and
anterior abdominal wall
Posteriorly Omentalbursa (lesser sac), pancreas,
left kidney and adrenal gland, spleen,
and splenicartery
Superiorly Esophagus and diaphragm
Inferiorly and laterally Transverse mesocolon
Stomach Bed
The stomach bed refers to the structures upon which the
stomach rests. These include
transverse colon and its mesocolon
diaphragm,
splenicartery,
left suprarenal gland,
left splenicflexure
the tail of the pancreas
left kidney.
The term was introduced around 1896 by Philip Polson of
the Catholic University School of Medicine, Dublin.
However this was brought into disrepute by surgeon
anatomist J Massey.
T
D
S
S
S
P
K
The stomach bed refers to the structures upon which the
stomach rests. These include
transverse colon and its mesocolon
diaphragm,
splenicartery,
left suprarenal gland,
left splenicflexure
the tail of the pancreas
left kidney.
The term was introduced around 1896 by Philip Polson of
the Catholic University School of Medicine, Dublin.
However this was brought into disrepute by surgeon
anatomist J Massey.
T
D
S
S
S
P
K
Stomach Bed
Region of Abdomen
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