Digestive System

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Digestive System
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FUNCTIONS

• Digest food
• Absorb nutrients
• Excrete wastes

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STRUCTURES

• MAIN ORGANS
• MOUTH
• PHARYNX (UES)
• ESOPHAGUS (LES)
• STOMACH (PS)
• DUODENUM
• JEJUNUM
• ILEUM (ICV)
• CECUM
• ASCENDING COLON
• TRANSVERSE COLON
• DESCENDING COLON
• SIGMOID COLON
• RECTUM
• ANAL CANAL

• ACCESSORY ORGANS
• TEETH TONGUE
• SALIVARY GLANDS
• PAROTID
• SUBMANDIBULAR
• SUBLINGUAL
• LIVER
• GALLBLADDER
• PANCREAS
• APPENDIX

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1) Mouth/Oral Cavity 2) Pharynx

• Chemical digestion of carbohydrates Salivary
  glands secrete salivary amylase
  
• Mechanical digestion of food into a bolus Teeth
  and tongue

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3) UES, 4) Esophagus, 5) LES

• Upper Esophageal Sphincter- prevents air from
  entering upon respiration
  
• Esophagus Muscular wallsperistalsis
• Lower Esophageal Sphincter- prevents backflow of
  acidic food contents

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6) Stomach, 7) Pyloric Sphincter

• Mechanical digestion of food into chyme
  3 layers of muscle (longitudinal,
  circular, oblique)
  
• Chemical digestion of
  proteins
  
• PepsinogenHCl
• Pepsin
• When empty, lining
  lies in
  folds called
  rugae

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SI 8) Duodenum, 9) Jejunum, 10) Ileum

• Mech/Chem Digestion
• Absorption of Nutrients
• Circular folds
• Plicae (plica, s)
• Folds covered with
• Villi (villus, s)
• Fingerlike projections
• Covered w/ microvilli
• Nutrient absorption takes
• place in capillaries of villi
• Plicae/Villiinc SA
  inc nutrient absorption
  

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Absorption of nutrients in the SI Villi
Microvilli
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Duodenum

• Bile from liver/gallbladder
  emulsifies fat (breaks it into
  smaller
  droplets)mech dig.
• Lipase from pancreas breaks
  fat into glycerol fatty
  acids
  
• 
  

Other pancreatic enzymes Proteases (prote
in)
Amylase (carbohydrates)
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Small Intestine, contd

• Secrete intestinal enzymes
• Peptidases (peptides
  amino acids)
  
• Sucrase, lactase, maltase (disaccharidesmonosach
  arides)
  
• Animation

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11) Ileocecal valve

• Plicae of the small intestine large intestine,
  appendix

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Large Intestine

• 12) Cecum
• 13) Ascending
• Colon
• 14) Transverse
• Colon
• 15) Descending
• Colon
• 16) Sigmoid Colon
• 17) Rectum
• 18) Anal Canal

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Large Intestine

• Water Absorption/Stool Formation
• Transit time
• Too fastdiarrhea
• Too slowconstipation
• Animation
• Vitamins B K Production
• Result from bacteria feeding on undigested
  material
  

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Peritoneum

• Visceral Peritoneum surrounds
• digestive tract
• Parietal Peritoneum lines abdominal cavity
• Extensions
• Greater Omentum hangs down from lower edge of
  stomach/transverse colon over intestines (lace
  apron)
  
• Mesentery connects intestines/ anchors
  intestines to posterior abdominal wall

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• Review