Intestinal Digestion

• Intestinal digestion


  Most important part of the digestive tract
• Small intestine


  • Divided histologically into duodenum, jejunum, ileum
  • Carries out enzymic digestion, physical digestion and absorption

  
• Bile


  • Thick, green secretion from the liver
  • Stored in the gall bladder (except horse, rat, pigeon)
  • Contains inorganic ions, bile salts, bile pigments, lipids

  
• Function of bile


  Emulsification of fat globules to smaller droplets, increasing the surface area for lipase action

  
• Pancreatic juice


  Contains carbohydrases, proteases and lipase enzymes

  
• Intestinal juice


  Contains maltase, sucrase, lactase, peptidase, lipase

  
• Absorption of end-products of digestion

  Aided by increased surface area of villi

  
• Carbohydrate & simple sugar transport and absorption

  1. Na+-coupled substrate

  2. Substrates leave the cell via facilitated diffusion
• Amino acids transport and absorption

  1. Na+-coupled substrate

  2. Substrates leave the cell via facilitated diffusion
• Schematic representation of gastrointestinal activities