Absorption of food

The mucosa of the small intestine(ileum) is projected in to the lumen as a large number of longitudinal and horizontal folds which vary greatly increases the surface area for rapid absorption of digested products of food. A number of branches of blood vessels from the intestinal wall extend up to the free inner ends of these folds and absorb most of the amino acids, different monosaccharides, mono and dinucleotides and a small fraction of digested lipids and transport them to the liver through heapatic portal system. In ileum, the fatty acids unite with the bile salts and get transformed in to an easily absorbable form through the process called saponification. The lymph vessels transport the fully digested fats as fatty acids and glycerol, saponified fatty acids and neutral fat formed by the recombination of fatty acids and glycerol by the action of intestinal lipase. The fatty substances mix with the colorless lymph and travel through the lymph vessels as milky alkaline fluid called pyolus.