Question

Give a brief account on the process of digestion in human beings

Answer 1

The process of break down of complex food substances into simpler components and their absorption by the body is called the digestion. In human, two types of digestion occur, the physical digestion in which mechanical churning of food takes place and the chemical digestion in which the enzymatic activities break down the food. It occurs through the steps of ingestion, digestion, absorption, assimilation, and egestion. The digestion process in humans can be described as follows:

1. The food is ingested in the mouth where both the physical and chemical digestion occurs. Teeth help in physical digestion and salivary amylase helos in chemical digestion of starch.
2. In the stomach, the proteins are digested through the chemical digestion by the pepsin and HCl while the churning of food occurs through the contraction in stomach walls.
3. In the small intestine, the chemical digestion occurs predominantly and the complete digestion takes place. The bile from the liver and pancreatic juice form pancreas provide the enzymes of the digestion. Proteins are digested by the trypsin, chymotrypsin, carboxypeptidases, dipeptidases. Fats are emulsified by bile and digested by lipases. Pancreatic amylase further breaks down the starch.
4. The digested food is absorbed by the villi present in the small intestine and the nutrients reach the bloodstream.
5. The blood will provide these nutrients to the tissues where the assimilation will occur.
6. The undigested food and water move to the large intestine where the water is absorbed and the undigested food is converted to feces which are egested out of the body by the anal canal via the rectum.