(i) The pancreas secrete digestive enzymes into the duodenum. Pancreatic amylase digests starch to maltose, trypsin digests proteins to polypeptide and pancreatic lipase digests fats to fatty acids and glycerol.
(ii) The liver produces bile, which is stored in the gall bladder. Bile is released into the duodenum for the emulsification of fats. This increases the surface area for digestion by enzyme lipase.
Amino acids and glucose are taken first into the liver by the hepatic portal vein. They are required by the body and transported out of the liver by the hepatic vein. Amino acids are used for growth and repair of worn-out parts of the body and production of enzymes and hormones and glucose is utilised during tissue respiration to produce energy. In the liver, excess amino acids are deaminated, their amino groups are removed and converted to urea for excretion and glycogen for storage.