Digestion is a process in which complex food materials are broken down by enzymes into simpler substances, which can be easily assimilated by the body. The pancreatic duct and bile duct open into the duodenum of the Here the food gets mixed by bile juice and pancreatic juice. Bile juice does not contain any enzyme.
However, it plays an important part in digestion as it provides an alkaline medium to food and helps in emulsification of fat. The pancreatic juice contains the following enzymes, which act upon different kinds of food stuffs.
(i) Trypsin, which acts on proteins and changes them to peptones.
(ii) Pancreatic amylase, which acts on carbohydrates and changes them to maltose or to other complex sugars.
(iii) Lipase, which acts on fats and changes them to soluble fatty acids and glycerol.
The intestinal glands secrete enzymes like,
(a) Erepsin, which helps to convert peptides into amino acids.
(b) Maltase, which changes maltose to glucose.
(c) Lactase, which changes lactose into glucose and galactose.
(d) Sucrase, which changes sucrose into glucose and fructose.
In this way, the digestion of food is completed in the small intestine.