Transcript 3.Digestive System II.ppt

Digestive part2
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Originally given by: Dr. Mohamad Tayeb
Written by: past year students
Edited & made up 2 date by:MOHAMMED AL-MOTIRY
Abo Malek
Special thanks for:- RAYAN ALBALLAA,
Dr.Abdullah,
The Alimentary canal
Esophagus-Stomach-Small intestine-Large intestine (colon)
Consists of 4 layers: 1-Mucosa (innermost layer):
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Epithelium (stratified squamous or simple
columnar)
Lamina propria (loose CT containing glands)
Muscularis mucosa (smooth muscle)
2-Submucosa of alimentar canal:Dense irregular Connective tissue
Contains glands in oesophagus & duodenum
The Alimentary canal
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3- Muscularis externa:- (smooth muscle)
Smooth and skeletal in esophagus
4- Serosa or adventitia:- serosa is a visceral
peritoneum consists of simple squamous
epithelium
Adventitia is C.T. covering without
epithelium.
Picture of layers of ailmentary canal
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Nervous tissue of alimentary canal:Meissneric plexus (submucosal plexus):Autonomic ganglia & nerves in submucosa.
(suplies the mucosa & submucosa(
 Auerbachs plexus (myenteric plexus) :Autonomic ganglia & nerves in muscularis
externa.
(suplies the muscle)
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Esophagus
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Mucosa: 1-The epithelium:- is non keratinized
stratified squamous epithelium
2-The lamina propria:- only in the upper and
lower part contain esophageal cardiac gland
(mucous gland)
3-muscularis mucosa:- is a single layer of
smooth muscle
Pic of mucosa of esophagus
Pic of mucosa of lower part of esophagus
(near the stomach)
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Esophagus
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4-Submucosa:-Contains mucous glands
called esophageal glands proper.
5-Muscularis externa:-inner circular & outer
longitudal muscle layer
In the upper 1/3 it’s the skeletal muscle-In the
middle 1/3 & In the lower 1/3 it’s smooth
muscle
6-adventisia:-cervical & thoracic part ,
Serosa in the Abdominal part.
Pic upper 1/3
Pic Middle 1/3
Pic lower 1/3
Pic of stomach
Stomach Cardia – Fundus - pylorus
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1-The epithelium:- of the stomach is simple
columnar secreting mucous
It forms invaginations into the lamina propria
called gastric pits (deeper in pylorus)
2-The lamina propria:- contains mucous
glands in Cardia & Pylorus (fundic glands are
not mucous glands)
3-muscularis mucosa:-2 – 3 layers of smooth
muscle.
Stomach
4-submucosa:- Does not contain glands
 5-muscularis externa:- inner oblique، middle
circular ، outer longitudinal layers.
 6-serosa
Cells of fundic glands
Five types of cells : 1.Parietal (oxyntic cells) Acidophilic cells secreting
HCL and intrensic factor.
 2.Chief (zymogenic) cells basophilic cells secreting
enzymes (pepsinogen , renin & lipase)
 3. Mucous neck cells secret mucous
 4.Neuroendocrine cells secrets hormones
 5.regenerative cells (stem cells)
 All of these cells are affected under conditions of
peptic ulcer.
Pic of gastric pit and fundic gland
Pyloric stomach
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The pyloric glands are mucous glands (similar
to cardiac glands)
The middle circular layer of muscularis
externa forms the pyloric sphincter preventing
the backflow of food from stomach
Small intestine
Duodenum-Jejunum-Ileum
1-The epithelium:- is simple columnar with goblet
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cells *important Recall that there is NO globlet cells
in Stomach and Esophagus.
2-The lamina propria:- contains intestinal
glands called crypts of lieberkhun.
3-muscularis mucosa:- 2 layers of smooth
muscle.
4-submucosa:-dense irregular C.T.
5-muscularic externa:- inner circularis - outer
longtudinal smooth muscle
6-serosa
Pic of mucosa of small intestine
Pic of mucosa of small intestine
Small intestine
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The mucosa forms projections called villi
(villus) containing C.T. ، smooth muscle and a
lymphatic vessel called lacteal.
The intestinal glands crypts of liberkhun
open between the villi.
Pic of intestinal villus
Cells of intestinal glands
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1.Goblet cells:- secrete mucous
2.paneth cells:- secrete lysozyme
(antibacterial)
3.Neuroendocrine cells:- secrete hormones
4.Regenerative cells:- stem cells
Duodenum
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Submucosa:- contains duodenal glands called
Brunners glands secreting alkaline mucous.
The goblet cells increase in number from the
duodenum toward jejunum & ileum.
ileum
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Lamina propria contains lymph nudules called
Peyers patches (may extend into the
submucosa).
The epithelium covering Peyers patches
consists of antigen presenting cells called
M cells (Microfold cells)
More goblet cells than duodenum & jejunum .
Colon – Appendix - Rectum
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No villi. have crypts of lieberkhun. But no
Paneth cells
Epithelum :- Simple columnar with more
goblet cells than in small intestines
Lamina Propria of appendix contains
numerous lymph nodules
muscularis externa:- outer longitudinal layer
in the colon forms three separate parts called
taeniae coli. No taenia coli in
appendix&rectum
Pic with tenia coli (large intestine)
Pic of intestinal mucosa comparision
between large and small intestine
Another pic of large intestine
Pic of appendix
Anal canal
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Epithelim:- Non keratinized stratified
squamous.
Lamina propria:- contains Anal mucous
glands.
The Inner circular layer of muscularis externa
froms internal anal sphincter.
Internal & Eternal submucosal hemorrhoidal
venous plexus in submucosa.
Microscopic Slides