What are the main stages of digestion in man?

The alimentary canal deals with the digestion of food in four stages

1. Ingestion:

This involves the actual intake of food.

2. Digestion:

After the intake of food the process of digestion begins in the mouth (physical process) and is mainly carried out in the stomach and small intestine (chemical process)

3. Absorption:

This involves the passage of digestive food substance through the mucosa of the gastrointestinal tract into the blood and lymph.

4. Egestion:

Food substances that cannot be digested or that are not required by the body are eliminated as excretory material.

We will now study in some detail the various parts of the alimentary canal involved in the process of digestion.