ABSORPTION FROM THE SMALL INTESTINE


 ABSORPTION FROM THE SMALL INTESTINE


Introduction :

          Mixing all the products of carbohydrates, proteins and lipid as well as eaten foods, electrolytes, vitamins and water in blood and lymphatic system passing through the walls of small intestine is known as absorption. Absorption takes place mostly in duodenum and jejunum. But, the initial absorption of bile salts and vitamin B12 takes place in ileum. Whole the process of absorption is done by the microvilli of small intestine. 

        There is a lymphatic duct or lacteal found in each of villus which is surrounded by the network of blood vessels and is being covered with entrosites. There are goblet cells found in between them. These villi remain in touch of chime coming in intestine. Food is absorbed by them.    

        The last product of the digestion of carbohydrates named glucose, fructose and galactose; the last product of the digestion of protein named amino acids and water as well as electrolytes, etc. are being absorbed by the cells of villi layer. From where, this absorbed substance is forwarded to the liver through portal veins after reaching in blood cells. The last product of the digestion of lipid named fatty acids and glycerol are absorbed by the entrosites. From where, these are reached in the lymph of villi and then are reached in Cisterna chili. After that, they are reached in the left subclevian vein through throracic duct and then mixed in blood.