absorbtion

There are four essential aspects to absorbtion:

1) physical movement of the nutrient molecules from gut lumen to the wall of the gut tube.

2) maximizing the area of the epithelial cells across which absorbtion can occur.

3) mechanism for transport of the nutrient molecule across the cell membrane into the epithelial cell cytoplasm.

4) transport of the nutrient molecule out of the epitheali cell into the extracellular body fluids. The mammalian small intestine is highly specialized for digestion and especially absorbtion . The mammalian small intestine is higly specialized for digestion and especially aabsorbtion.

Villi and microvilli increases absorbtive surface of small intestine. Each villus containt of lacteal, which is a terminal branch of the lymphatic system and is a terminal branch of the lymphatic system and is an important route for reabsorbtion of lipids and water. The surface of microvilli is covered with a meshwork of mucopolysaccharide and glycoprotein filaments, the glycocalyx.

This surface coat is extremely resistant to proteolytic and mucolytic agents, hence forms a protective surface.