Question

Explain the physiology of digestion in stomach.

Answer 1

Digestion: The breaking down of complex and insoluble organic substances such as carbohydrates, proteins and fats into simpler and soluble substances like glucose, amino acids and fatty acids respectively so that they can be easily absorbed into the body is known as digestion. This is a hydrolytic process and is carried out by various enzymes.

The activities of the digestive system can be grouped under five stages.

1. Ingestion: This is the taking of food into the alimentary tract, i.e. eating and drinking.

2. Propulsion: This mixes and moves the contents along the alimentary tract.

3. Digestion. This consists of:

• mechanical digestion: breakdown of food by, e.g. mastication (chewing)

• chemical digestion: breakdown of food into small molecules by enzymes produced by digestive glands.

4. Absorption: This is the process by which digested food substances pass through the walls of alimentary canal into the blood and lymph capillaries to use by body cells.

5. Elimination: undigested and unabsorbed substances are excreted from the alimentary canal as faeces by the process of defecation.