Maharashtra Board Class 4 EVS Chapter 11 A Look inside the Body PDF Download

A Look Inside The Body

Can You Recall?

Why does the chest expand when we breathe in?

The doctor puts her fingers on your wrist to feel your pulse. You, too, can feel your pulse. What causes this throbbing?

Internal Organs

We have many different tasks to do. We use certain specific parts of the body to do them.

Can You Recall?

Which parts of our body do we use for the following?

Seeing, Walking, Hearing, Writing.

What is meant by external organs? Give some examples.

Which parts of the body are called sensory organs? Why are they called so?

A part of the body that is used to perform a certain function is called an organ. We use our legs to walk. Hence, our legs are our organs for walking. We use our ears for hearing. Hence, our ears are the organs for hearing.

Organs on the outside of our body are our external organs. Ears, nose, arms and legs are on the outside of our body. Hence, they are our external organs. They can be easily seen.

Organs that make us aware of the situation around us are called sensory organs. Eyes, ears, nose, tongue and skin are our sensory organs.

Teacher's Note

External organs are parts we can see and touch on our body. Like our eyes help us see, our nose helps us smell things around us in daily life.

Exam Trick

Remember: Sensory organs = organs for senses. Eyes see, ears hear, nose smells. Just remember the five senses to identify sensory organs.

Points to Remember

External organs are on the outside of the body.
Sensory organs help us know about things around us.
Eyes, ears, nose, tongue and skin are sensory organs.
An organ does a special job in the body.
We can easily see external organs.

Special Places For Internal Organs

Can You Tell?

Some biscuits were put in a glass jar. The jar was then shaken and turned over. What happens to the biscuits?

A pack of biscuits was shaken in the same way. What happens to the biscuits?

The biscuits in the jar could break into pieces. But not the ones in the pack. Why?

The organs inside the body that perform certain important bodily functions need to be secure. The structure of our body is such that our internal organs can remain in their places no matter how much we move. There are hollow spaces for these organs inside the head and the torso. They are called cavities.

The cavity inside the head is called the cranial cavity.

Teacher's Note

Internal organs are inside our body. Like our heart, lungs and stomach are inside. They stay safe inside special spaces called cavities, just like how a phone stays safe in a case.

Exam Trick

Remember: Internal = inside. Cavities = hollow spaces. So internal organs stay in hollow spaces inside our body to stay safe and protected.

Points to Remember

Internal organs are inside the body and cannot be seen from outside.
Cavities are hollow spaces in the head and torso.
The cranial cavity is inside the head.
Internal organs stay in cavities to remain safe.
Blood vessels carry blood through the body.

The Oesophagus

Many functions of the body go on inside the body. A network of blood vessels is spread throughout the body. Blood flows through them continuously. The air we breathe in is carried to all parts of the body through the blood. The food that we eat is digested. These functions are carried out by different organs called internal organs. Let us learn a few things about them.

Can You Tell?

This man is filling the water from the tap into a drum. The drum is some distance away from the tap. Still, the water from the tap is flowing into the drum. Why is this so?

The picture alongside shows two internal organs – the mouth and the stomach. These organs help in the digestion of food. The stomach is situated in the abdominal cavity. There is a tube in the thoracic cavity to transport food from the mouth to the stomach. It is called the oesophagus or the gullet.

We use our mouth to eat our food. The tongue tells us the taste of the food. We chew food with our teeth. As we chew it, our saliva mixes with the food. As a result, the food forms a moist ball. It is easy to swallow this soft ball. This food passes through the throat into the oesophagus. The wall of the oesophagus is flexible. This makes it possible to carry the food from the throat to the stomach easily.

Teacher's Note

The oesophagus is a tube that carries food like a pipe carries water. When you swallow food, it goes down this tube to your stomach, just like water flows down from a tap.

Exam Trick

Remember: Oesophagus = gullet = food pipe. It connects mouth to stomach. Think of it as a slide for food going down into your belly.

Points to Remember

The oesophagus carries swallowed food to the stomach.
It is in the thoracic cavity.
The oesophagus has flexible walls.
Food forms a moist ball in the mouth.
Saliva mixes with food when we chew.

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