ABSORPTION. 



107 



Their absorption is accomplished by the villous processes covering the 

 surface of the intestinal mucous membrane. 



The villi are small filiform or conical processes projecting from the surface 

 of the mucous membrane. Each villus consists of a basement membrane 

 supporting columnar epithelial cells. In the interior of the villus there is 

 frame work of connective tissue supporting arteries, capillaries and veins 

 and a single club-shaped lymph capillary. 



FIG. 16. 



Diagram of the portal vein (pv) arising in the alimentary tract and spleen (s) , and 

 carrying the blood from these organs to the liver. (Yeo's " Text-book of Physiology .) 



The function of the epithelium is the absorption of the products of 

 digestion. 



The water inorganic salts and the sugars after their absorption pass onward 

 into the interior of the villi; thence through the capillary wall into the blood 

 by which they are carried to the liver. 



The ammo-acids after absorption are synthesized in part to a form of 

 protein, similar, if not identical, with that present in the blood plasma. 



