The Intestines

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The Intestines

• p. 461-467, 474-478

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Small Intestine Anatomy

• Pyloric sphincter
• Duodenum
• Jejunum
• Ileum
• Ileocecal valve
• Coils attached to mesentery

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Small Intestine Functions

• Completes chemical digestion
• Absorbs nutrients H2O
• Huge surface area (villi microvilli in jejunum
  ileum)

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Sm. Intestinal Secretions

• Goblet cells mucus
• Intestinal glands secrete brush border
  enzymes to digest
• Carbs ? monosacch.
• Proteins ? AAs
• Duodenum also receives secretions of liver (via
  bile duct) pancreas (via pancreatic ducts)

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Nutrient Absorption

• Huge surface area
• Circular folds, villi, microvilli
• Absorption ? capillary beds, lacteals
• Peyers patches keep bacteria out of
  bloodstream

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Large Intestine Anatomy

• Haustra
• Ileocecal valve
• Cecum
• Appendix
• Colon
• Ascending
• Transverse
• Descending
• Sigmoid
• Rectum
• Anal canal

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Large Intestine Functions

• No digestive function
• Goblet cells mucus
• Beneficial bacteria make vitamins we can use
  (K, some B) and gas
• Absorbs water, some vitamins, electrolytes
  but no villi
• Elimination of feces