1.4.4 Absorption in the Small Intestine
The internal lining of small intestine is modified to make tiny finger like projections called villi. Simple sugars and amino acids pass through the wall of the villi into the blood capillaries of villi. Mineral salts and vitamins also pass in the blood capillaries of villi. Absorption occurs by a combination of diffusion and active transport. Glycerol and fatty acids are absorbed by the lacteal and ultimately will be poured into the blood.
The absorbed food in the blood capillaries of the villi passes into the blood stream. They are then carried away in the capillaries, which join up to form veins. These veins unite to form one large vein called the hepatic portal vein. This vein carries all the blood from the intestine to the liver, which may store or alter any of the digestion products.