Histology of the digestive system

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Histology of the digestive system
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Gastrointestinal tract (GI tract)

• Mouth
• Internal nonkeratinized stratified squamous
  epithelium
• Middle buccinator muscles, bone

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• 2. pharynx skeletal muscle nonkeratinized
  stratified squamous epithelium

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• 3. esophagus
• a. nonkeratinized stratified squamous epithelium
• b. skeletal (superior) smooth muscle (inferior)

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4. esophagus to anal canalDeep to superficial

• Mucosa
• Epithelium touches food
• Nsse protection
• Simple columnar (stomach/intestines)
  secretion/absorption
• exocrine cells (mucus)
• endocrine cells (hormones)
• Lamina propria (conn.)- blood/lymph vessels, MALT
• Smooth muscle makes folds, inc. SA

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• Submucosa
• Binds mucosa to muscularis
• Blood/lymph vessels/neurons

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• Muscularis
• Skeletal muscle until middle esophagus
  (swallowing) external anal sphincter
• Smooth muscle
• Inner circular fibers
• Outer longitudinal fibers

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• Serosa connective and simple squamous epithelium
  (reduce friction)

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ACCESSORY ORGANS
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pancreas

• Small clusters of glandular epithelial
• 99 called acini (exocrine function secrete
  pancreatic juice for digestion)
• 1 called pancreatic islets (endocrine function)

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liver

• Consists of many lobules
• Contains epithelial cells called hepatocytes
  arranged irregularly around a central vein.
  Capillaries, called sinusoids, are highly present
  and contain fixed phagocytes (to removed WBCs and
  RBC, bacteria, etc)

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gallbladder

• Mucosa is simple columnar epithelium