Absorption

• the small intestine is the region where nutrients are absorbed
• most water is absorbed from the small intestine but that some is also absorbed from the colon
• Increasing rate of absorption:

  1. Large surface area
  2. Short distance
  3. Large concentration gradient
• structure or whatever

  A) epithelial cell

  B) blood capillary

  C) lacteal

  D) microvilli

  E) lymph vessel

  
• Villi increases surface area of the small intestine. They are lined with intestinal epithelial cells with microvilli (small projections) to further increase the surface area
• the lining of the villi is one epithelial cell thick to shorten the distance
• The villi have blood capillaries that transport glucose and amino acids away from the small intestine in the blood. A lacteal runs through the centre of the villus to transport fatty acids and glycerol away from the small intestine in the lymph. By constantly moving the nutrients away from the small intestine and to the rest of the body via these transport systems, the concentration gradient is maintained