Page 101 - Volt Elevate The World Around Us Book 4

can use it is called digestion. Food passes through many organs to get digested. These

are the mouth, food pipe, stomach, small intestine and large intestine.

Process of Digestion

We take in food through our mouth. The
mouth consists of teeth and tongue.

Teeth help to break down the food into
small pieces. There are four kinds of teeth

in our mouth. They are incisors, canines,
premolars and molars. Each one serves a
different purpose.

Tongue is the fleshy organ present in the

mouth. It helps to taste and move the food.
The tongue has tiny taste buds that help it
to identify different tastes like sweet, salty, human digestive system

sour and bitter.

When we chew something with our teeth, it becomes soft and moist. This is because
saliva mixes with the food and moistens it. Saliva is a watery fluid secreted in our mouth
to soften what we eat. Saliva also breaks down the carbohydrates in the food into sugars

with the help of the enzymes present in it. This makes the food taste sweet. This is the
beginning of the process of digestion. The food does not get fully digested in the mouth.
The tongue rolls the moist food into a ball like substance called bolus and pushes it to
the back of the mouth where it is swallowed.

The food goes from the mouth to the stomach through the food pipe. In the stomach,

it is churned into a semi-fluid mixture. The walls of the stomach secrete digestive juices
which further breakdown the food into simpler form. The partially digested food from
the stomach enters the small intestine. Here, it is completely digested by the digestive
juices. This completely digested food passes through the walls of the small intestine

into the bloodstream. The blood absorbs the nutrients from the digested food and takes
them to different parts of the body to give us energy.

The non-absorbed or undigested food from the small intestine goes to the large
intestine. Here, water is absorbed from the food. The food gets converted into solid

waste which gets stored in the rectum for some time and is expelled out of the body as
faeces through an opening called anus.

Taste bud: Cluster of bulbous nerve endings on the tongue and in the lining of the mouth which provide the sense of
taste

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