Class 4 Science

Digestion of Food – Class 4

Digestion of Food

What is Digestion?

Our body needs energy to perform our daily activities. We need energy to work, to play, to dance, to study or to perform any other activities. From where do we get this energy? We get energy from the food that we eat. But our body cannot directly use the food to get energy. To get energy, the food we eat must be digested properly. The foot we eat such as chapati, rice, dal, vegetables, milk, fruits and vegetables, etc. is broken down into smaller and simpler forms. This process of breaking down of food into simpler forms inside our body is called digestion. This digested food is then taken to all parts of our body by the blood.

What is a Digestive System?

Digestion in our body takes place in a number of steps. Several internal organs of our body helps in digestion of food. These organs together make up our digestive system. Look at the image given below. It marks all the organs that make up the digestive system.

Digestive System

Digestive System

The Digestive System

Digestion in the Mouth

Saliva is a digestive juice produced by the salivary gland in the mouth. When we chew food, our teeth break the food into smaller pieces. Our tongue mixes the smaller pieces of food with saliva. This makes the food soft so that it can be swallowed easily. Our tongue then helps to push the food into a thin and long tube called the food pipe.

Digestion in the Stomach

From the food pipe the food passes into the stomach. In the stomach the food mixes up with more digestive juices. These juices start to break down proteins and fats into simpler substances. In the stomach, the food remains for up to three hours.

Digestion in the Small Intestine

From the stomach, the food passes into the small intestine. The shape of small intestine is like a long, coiled tube. The inner walls of the small intestine produce certain juices. Other organs such as the liver and pancreas also produce juices which are poured into the small intestine. The food mixes with these juices and is completely digested.

The digested food is now in a simple, soluble form. It is absorbed into the blood through the walls of the small intestine. The blood then carries the digested food to all parts of the body. This digested food is used to produce energy.

What happens to the undigested food? Some parts of the food are not digested by the body. They pass into a pipe-like organ called the large intestine. Water from the undigested food is absorbed by the large intestine. The solid waste that remains passes out of the body through the opening called the anus.

Good Eating Habits

We can also play a part in proper digestion of food by our body. We must follow the rules as mentioned below:

  • We should eat our food at fixed time.
  • We should chew our food properly before swallowing it. We should not eat in a hurry. Properly chewed food helps in faster digestion of the food.
  • After having meal we should rinse our mouth thoroughly.
  • Water helps in digestion of food. We should drink sufficient quantity of water every day.
  • We should eat lots of vegetables and fruits. They gives us nutrients to keep our body healthy. We should also eat food that give us roughage or fibre. Our body cannot digest fibre but fibre helps to remove waster from our body.

Click Next button for Exercises on the chapter – Digestion of Food for Class 4.

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Mamta