The human body requires a constant supply of food in order to carry on its numerous activities. The food we take performs two main functions in our body. First, it supplies proteins for the growth of the body and second, it supplies energy to the tissues for the day-to-day work. Do you know how the food is digested in our body and how we get essential substances from it?
The process of digestion is very complex and elaborate. It starts from our mouth itself. When we chew food the saliva produced in the mouth moistens it. The saliva contains a substance called ptyalin which converts the starch of the food into sugar. This is the first stage of digestion. Therefore we should swallow the food only after properly chewing it.
After that the food material passes through the oesophagus to the stomach where the gastric juices get mixed with it. The walls of the stomach secret juices containing an enzyme called pepsin and hydrochloric acid. Pepsin converts the molecules of proteins into peptones.
From stomach the food goes to the small intestine, where it mixes with three other digestive juices – bile, pancreatic juice and intestinal juice. Bile is produced by the liver. Its main function is to digest the fats. The pancreatic juice is basic in nature and neutralizes the acids. It digests the proteins also. The intestinal juice converts sugar into glucose. Here many enzymes also mix with the food. Food is mainly digested here. The digested food is absorbed by the blood vessels present in the walls of the small intestine. The remaining waste of the food now goes to the large intestine and is finally excreted out of the body through the anus.