Digestion in the small intestine

In the small intestine, the digestive process is completed on the partly digested food by pancreatic juice, intestinal juice, and bile. The pancreatic juice is produced by the pancreas and pours into the small intestine through a tube, or duct. The pancreatic juice contains the enzymes trypsin, amylase, and lipase. Trypsin breaks down the partly digested proteins, amylase changes starch into simple sugars, and lipase splits fats into fatty acids and glycerol. The intestinal juice is produced by the walls of the small intestine. It has milder digestive effects than the pancreatic juice, but carries out similar digestion. Bile is produced in the liver, stored in the gall bladder, and flows into the small intestine through the bile duct. Bile contains chemicals that help break down and absorb fats.

When the food is completely digested, it is absorbed by tiny blood and lymph vessels in the walls of the small intestine. It is then carried into the circulation for nourishment of the body.