Page 60 - ACTIVE SCIENCE 4 TOC

The food or bolus then goes into the stomach through the food pipe. The food pipe
contracts and relaxes so as to push the food down into the stomach. The stomach

is a muscular bag where food stays for many hours. It produces digestive juices
and acid which help to digest the food.

The remaining undigested food is pushed into a long coiled tube called the small

intestine. The small intestine, along with the liver and pancreas produces a juice
that mixes with the food and digests it. The walls of the intestine absorb all the
nutrients from the digested food. Then the blood vessels which carry digested food

absorb these nutrients and transport them to all parts of the body.

Undigested food passes into the large intestine where the extra water and
minerals are absorbed. The rectum stores the remaining solid waste until it

passes out through the anus.

Activity 7.1

Find out why your stomach produces a rumbling sound in between meals.

Let’s Recapitulate

Fill in the blanks.

1. The process of breaking down of food into a simpler form is called _____________.

2. _____________ is a digestive liquid secreted by the salivary glands.
3. The undigested food pushed into a long tube is called _____________.

4. The extra water is absorbed by _____________.
5. The food stays in the stomach for _____________.

M icrobes

We cannot see microbes with naked eyes. Microbes can only be seen through a
microscope because they are very tiny in size. They can grow anywhere – on or
inside our body, on soil, food, stagnant water, etc. Microbes which cause diseases

are called germs or pathogens.

There are four kinds of microbes.

Bacteria

Bacteria (sing. bacterium) are made up of single cell. They can be
rod-shaped, spiral or round in shape. Bacteria can cause many
diseases like typhoid, tuberculosis and pneumonia. Bacteria

67
Active Science-4