6.1  Digestion and Absorption

big ninja

Essential Idea:

The structure of the wall of the small intestine

allows it to move, digest and absorb food


  • The contraction of circular and longitudinal muscle of the small intestine mixes the food with enzymes and moves it along the gut
  • Enzymes digest most macromolecules in food into monomers in the small intestine
  • The pancreas secretes enzymes into the lumen of the small intestine
  • Villi increase the surface area of epithelium over which absorption is carried out
  • Villi absorb monomers formed by digestion as well as mineral ions and vitamins
  • Different methods of membrane transport are required to absorb different nutrients


  • Processes occurring in the small intestine that result in the digestion of starch and transport of the products of digestion to the liver
  • Use of dialysis tubing to model absorption of digested food in the intestine


  • Production of an annotated diagram of the digestive system
  • Identification of tissue layers in transverse sections of the small intestine viewed with a microscope or in a micrograph