Histology of the Gastrointestinal Tract'

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Histology of the Gastrointestinal Tract. Biology
316.
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• ESOPHAGUS
• Mucosa stratified squamous epithelium,
  nonkeratinized
• Submucosa unremarkable
• Muscularis
• skeletal
• mixed skeletal/smooth
• smooth
• Adventitia

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Layers of the esophagus
siumed.edu
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Esophagus
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Stomach Mucosa simple columnar
epithelium Submucosa connective tissue
Muscularis 2 layers of smooth muscle
(inner circular, outer
longitudinal ) Serosa
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Stomach
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STOMACH

• Mucosa Simple columnar epithelium

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Schematic of layers of the stomach
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Stomach mucosa pits and glands
Parietal cells HCl, intrinsic factor Chief
cells Pepsin Mucus-secreting cells on the
surface and in the gastric pits Endocrine cells
ghrelin (stimulates appetite) gastrin
(influences secretion)
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Histology of the Stomach Low Power View
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Gastric Mucosa
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Pyloric Region of the Stomach. Note that the
mucosa looks somewhat different, but it is still
simple columnar epithelium
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Small Intestine Duodenum, Jejunum,
Ileum,
Specializations for absorption Folds of
plasma membranes microvilli Folds of mucosa
villi, with glandular
crypts in between
Folds of submucosa plicae circulares Musculari
s inner circular, outer longitudinal
smooth muscle Serosa
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Small Intestine Duodenum, Jejunum,
Ileum,
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Small Intestine Duodenum, Jejunum,
Ileum,
Small Intestine Duodenum, Jejunum,
Ileum,
VILLUS Simple Columnar Epithelium Lamina
Propria Crypts
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Small Intestine Duodenum, Jejunum,
Ileum,
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Small Intestine Duodenum, Jejunum,
Ileum,
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Another View of the Jejunum
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Small Intestine Duodenum, Jejunum,
Ileum,
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Small Intestine Duodenum, Jejunum,
Ileum,
FUNCTIONS Digestion with pancreatic
enzymes proteins fats
starch Absorption amino acids
fats
glucose
water Secretion disaccharidases
mucus Movement peristalsis
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Large Intestine Mucosa simple columnar
epithelium with increasing number of goblet cells
Submucosa Muscularis 3 layers (outer layer
is taenia coli)
Serosa
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Large Intestine
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Large Intestine
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Colon 3 layers of muscularis
TAENIA COLI
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OUR FRIEND, THE LIVER the hepatic lobule
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OUR FRIEND, THE LIVER
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Portal Triad
Branch of the hepatic portal vein
Branch of the hepatic artery
Branch of the bile duct
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More of the portal triad..
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The Hepatocyte, the Sinusoid, and the Bile
Canaliculus
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Our Friend, the Gall Bladder
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Pancreas
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PANCREAS
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ISLET OF LANGERHANS surrounded by pancreatic
acini
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