Digestive enzymes are secreted by the salivary glands-salivary amylase and lipase, stomach - pepsin, pancreas-trypsin, chymotrypsin, lipase, lactase, etc and the small intestine - enterokinase. These enzymes helps to digest major constituents of our food namely carbohydrates, proteins and fats. so that they can be absorbed through the walls of the small intestine into the blood stream.