Question

What is meant by absorption, assimilation and egestion ?

Answer 1

1. Nutrition:- It is the process of taking in food and converting it into energy that is required for vital activity.
2. There are five steps in nutrition:

• Ingestion
• Digestion
• Absorption
• Assimilation
• Egestion

Ingestion

1. This is the first step of nutrition in which food is taken in the mouth.
2. Food is chewed and churned with the help of teeth and mixed with saliva with the help of tongue.
3. When food is mixed with saliva then it called bolus.

Digestion

1. In this step the food is broken down into simpler nutrients with the help of certain enzymes.
2. Digestion of food is started in mouth and completed in small intestine.
3. During digestion, carbohydrate is broken down into simpler carbohydrate like glucose, fats are broken into fatty acid and glycerol and protein is broken into amino acids (peptide bonds)

Absorption

1. In this step, digested food is getting absorbed in blood.
2. For absorption, small intestine has several finger like projection called villi that increase the surface area and absorption.

Assimilation

1. In this step, digested food which is absorbed in blood moves to the needy cell or move towards liver for storing.

Egestion

1. In this process the undigested food is expelled out from the body from rectum (last part of large intestine)