The Digestive System

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The Digestive System
Hey- chew on this! Weve made it to the..
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• Gastrointestinal System
• Function-physical and chemical breakdown of food
• Includes alimentary canal and accessory organs
• Accessory organs Salivary glands, tongue, teeth,
  liver, gallbladder, and pancreas

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Alimentary canal

• Mouth- physical and chemical breakdown.
• Mastication-the act of chewing
• Saliva contains enzyme amylase to break down
  carbohydrates

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• Pharynx- contains opening to trachea as well.
  Epiglottis covers opening of trachea.
• Esophagus-muscular tube dorsal to trachea
• Relies on a rhythmic wave-like motion called
  peristalsis

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Esophagus- transverse view
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• Sphincter-a circular muscle that constricts a
  passage or closes a natural orifice (opening)
• Cardiac sphincter
• Pyloric sphincter
• Food sits in stomach for 1-4 hours. Gastric
  juices contain hydrochloric acid- activates
  pepsin, kills bacteria.

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• Small intestine not so small! 20ft x 1
• Duodenum- 1st 10 inches. Bile and pancreatic
  juice enter here
• Jejunum- next 8 ft.
• Ileum- final 12 ft. When food leaves small
  intestine, digestion is complete

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• Small intestine has lots of enzymes peptidases
• maltase, sucrase, lactase, amylase.
• Lipase
• Bile
• Digested food is absorbed into the bloodstream.

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• Large intestine- 5 ft x 2. Separated from small
  intestine by ileocecal valve
• Final absorption of water, storage of
  indigestible material, absorption of vitamins B
  and K by bacteria.
• Colon connects to rectum- anal canal opens to the
  anus (final opening). Fecal material is expelled.

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But Wait! What about the accessory organs Liver,
gall bladder and pancreas

• Liver- largest gland in your body
• Secretes bile- emulsifies fat, makes them water
  soluble.
• Stores glucose in the form of glycogen
• Makes clotting proteins
• Detoxifies blood

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• Gall bladder- stores and concentrates bile
• Pancreas- produces insulin, pancreatic juices
  amylase and lipase. Insulin regulates the uptake
  of glucose by the cells

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Diseases

• Appendicitis
• Cholecystitis- gall bladder
• Cirrhosis- destruction of liver cells
• Diarrhea
• Diverticulitis
• Gasteroenteritis
• Hernia
• Pancreatitis
• Liver transplant
• Ulcer
• Colitis
• Bariatric surgery