digestive system

• alimentary canal: digestive tract from mouth to anus
• • mouth
  • esophagus
  • stomach: expandable muscular organ, to break down food
  • small intestine: chemical digestion and nutrient absorption
  • large intestine: water absorption, stool formation
  • rectum: holding area
  • anus
• accessory organs

  • salivary glands: secretes enzymes in mouth through saliva
  • liver: produces bile salts
  • gallbladder: store bile salts, releases it into small intestine
  • pancreas: produces enzymes for digestion and released into small intestine
• digestion: break down of food into nutrients
• Mouth

  • mastication: teeth mechanically process food through chewing
  • salivary glands: release saliva
• Salivary Glands

  • amylase: enzyme that breaks down carbohydrates
  • bolus: mass of food and saliva, rolled into ball by tongue
• esophagus

  • peristalsis: wave motion by muscular contraction to push food through the GI tract
• mucous cells - secrete mucus to protect the stomach wall
• parietal cells: secrete the hydrochloric acid or HCi
• chief cells: secrete pepsin enzyme that breaks down proteins
• chyme: acidic soup of partially digested food
• small intestine: duodenum, jejunum, ileum

  chyme combines with digestive secretions from accessory organs
• pancreas releases pancreatic juice into the small intestine

  • pH of >7 to neutralize acidic chyme
  • enzymes to digest food
  • liver secretes bile salts from gallbladder
• enzymes to digest food

  • lipase: breaks down lipids
  • amylase: breaks down carbs
  • trypsin: breaks down proteins, differs from pepsin, small intestine has a more basic pH
• liver secretes bile salts from gallbladder

  • emulsifies fats: breaks up large fats (lipids) globules into smaller globules, lipase breaks down lipids to smaller nutrients
• large intestine: ascending colon, transverse, descending, sigmoid (rectum)

  water, vitamins, and minerals are absorbed into body