Question

Explain the process of digestion of food in mouth, stomach and small intestine in human body.

Answer 1

Digestive system

1. The digestive system of the human body comprises a group of organs that work together in converting food into energy and other basic nutrients to power the body.
2. The food we take in is digested and utilized by our body, and the unused parts of the food are defecated.
3. The digestive system of the human body is the sum of the gastrointestinal tract (GIT; also called the alimentary canal) and accessory organs (tongue, liver, pancreas, etc.). These two parts together help in the digestion process.

Digestion in the mouth:

1. Digestion of food begins in the mouth.
   
2. Saliva present in the mouth contains a digestive enzyme, called salivary amylase, which breaks down starch into sugar.

Digestion in the stomach:

1. Stomach stores and mixes the food received from the esophagus with gastric juices.
   
2. The main components of gastric juice are hydrochloric acid, mucus, and pepsinogen.
3. Hydrochloric acid dissolves bits of food and creates an acidic medium.
   
4. In this medium, pepsinogen is converted to pepsin, which is a protein-digesting enzyme.
   
5. Mucus protects the inner lining of the stomach from the action of HCl.

Digestion in the small intestine:

1. Small intestine is the site for the complete digestion of carbohydrates, proteins, and fats.
   
2. It produces intestinal juice from the glands present in its wall.
   
3. The intestinal juice helps in the further digestion of food.
   
4. Small intestine also obtains digestive juices from the liver and pancreas that helps in the mixing of food.
5. The liver produces bile juice that causes the emulsification of fats and the pancreas produces pancreatic juice for digesting proteins and emulsified fats.
6. This digested food is finally absorbed through the intestinal walls.