Absorption

• Absorption = Movement of digested food molecules through wall of the intestine into the blood or lymph.
• The small intestine is the region for absorption of digested food.
• The small intestine is folded into many villi which increase the surface area for absorption. One villus will have tiny folds on the cells on its outside called microvilli.
• More surface area means more absorption can happen
• Capillary: transports glucose and amino acids
• Vein: delivers absorbed products to liver via hepatic portal vein.
• Gland: produces enzymes
• Lacteal: absorbs fatty acid and glycerol
• Epithelium: only one cell thick for faster transport. The cells of the epithelium are folded to form microvilli.
• Small intestine and colon absorb water:

  • The small intestine absorbs 5 to 10 dm cubed per day
  • The colon absorbs 0.3 to 0.5 dm cubed per day