Topic 6.1: Digestion & Absorption

Essential Idea:  The structure of the wall of the small intestine allows it to move, digest and absorb food.
At SHS, Topic 6.1 is taught in the following class unit(s):

Statements & Objectives:

6.1.U1  The contraction of circular and longitudinal muscle of the small intestine mixes the food with enzymes and moves it along the gut.
  • Outline the role of peristalsis in the digestive process.
6.1.U2  The pancreas secretes enzymes into the lumen of the small intestine.
  • List the name and substrate of the three major classes of enzymes secreted by the pancreas.
6.1.U3  Enzymes digest most macromolecules in food into monomers in the small intestine.
  • List the name, substrate and product of four pancreatic enzymes that hydrolyze food in the small intestine.
  • List the name, substrate and product of six enzymes produced by gland cells in the small intestine wall.
  • Describe why enzymes produced by gland cells in the small intestine wall often remain immobilized in the cell membrane.
6.1.U4  Villi increase the surface area of epithelium over which absorption is carried out.
  • List three adaptations that increase the surface area for absorption on the small intestine.
  • Draw the villi as viewed in cross section.
  • Label the following on a diagram of a villi:  capillary, epithelial cell, lacteal, and goblet cell.
  • State the function of the following villi structures: capillary, epithelial cell, lacteal, and goblet cell.
6.1.U5  Villi absorb monomers formed by digestion as well as mineral ions and vitamins.
  • Define absorption.
  • List materials absorbed by the villi cells of the small intestine.
6.1.U6  Different methods of membrane transport are required to absorb different nutrients.
  • List four methods of membrane transport required to absorb nutrients.
  • Describe the absorption of triglycerides.
  • Describe the absorption of glucose.
6.1.A1  Processes occurring in the small intestine that results in the digestion of starch and transport of the products of digestion to the liver.
  • Describe the structure of starch.
  • Outline the source, function and specificity of amylase.
  • Outline the digestion of maltose, maltotriose and dextrins into glucose.
  • Describe absorption of glucose by villus epithelial cells.
  • Describe transport of glucose into and through villi capillaries.
6.1.A2  Use of dialysis tubing to model absorption of digested food in the intestine.
  • Explain the use of dialysis tubing as a model for the small intestine.
6.1.S1  Production of an annotated diagram of the digestive system.
  • State the role of the digestive system.
  • Draw a diagram of the human digestive system.
  • Outline the function of the following digestive system structures:  mouth, esophagus, stomach, small intestine, pancreas, liver, gall bladder, and large intestine.
6.1.S2  Identification of tissue layers in transverse sections of the small intestine viewed with a microscope or in a micrograph.
  • Outline the function of the four layers of tissue found in the wall of the small intestine.
  • Label the four layers of tissue found in the wall of the small intestine as viewed with a microscope or in a micrograph.
6.1.NOS  Use models as representations of the real world-dialysis tubing can be used to model absorption in the intestine.
  • Explain the use of models in physiology research.
  • State two examples of model systems used to study digestion.
  • State limitations of using model systems in physiology research.
"When we try to pick out anything by itself, we find it hitched to everything else in the Universe." 
 John Muir,   1911