The Gastro-intestinal Tract, Liver, Biliary System and Pancreas

Abstract

The gastro-intestinal tract stretches from the mouth to the anus. It is a muscular tube, specialised to convey, digest, and absorb food. The lining mucosa contains mucous cells and others which secrete chemicals to digest the food. The products of digestion pass through the gut wall. Some of the fat enters the lacteals, passes to the lymphatic duct, into the blood stream, and finally reaches the liver. The rest of the fat enters the portal system and so reaches the liver. Proteins and sugars after breakdown enter the veins and are also conveyed to the liver. The lower bowel, the large intestine, does not digest food but absorbs water.