Our Central Nervous System

Have you read a fairy tale or watched an animated cartoon movie sometime ago?

Can you recall its characters, story, dialogues, etc.? What helps you to learn new things, to think and to recall? No doubt, it's your brain which is in charge of these activities. Brain is an amazing machine, which is involved in thinking, reasoning, learning, taking Important decisions, responding and a lot more.

Our brain works even when we are sleeping. It controls and coordinates the functions of the entire body and performs the simplest of tasks, e.g. blinklng of an eye, to more complex ones, e.g. solving math questions. All these done by the brain.

Our brain  (control room of the central nervous system)

The human brain is located inside the head, which is protected by a bone called the skull. The skull is very hard. Can you explain what a human brain looks like?

Have you ever seen a walnut? It is pinkish brown in colour. The human brain is the same shape as a walnut, but unlike a walnut it is soft and soggy and has many folds and wrinkles.

The human brain is an organ which is made up of cells called nerve cells, also called neurons. It consists of millions of neurons; without neurons, we cannot survive. These neurons are linked together like beads in a string. They work in strong coordination with each other and control all body movements and activities.

Brain is the control centre of the body and  do many complex tasks. Brain cells need oxygen to perform their functions properly. 

Due to lack of oxygen, brain cells start to die and we become unconscious.

Do you know?

Our brain weighs about 3 pounds and uses 1/4th of the total oxygen and blood in our body.

Structure of brain

The human brain is divided into three main parts on the basis of their specific jobs:

• Cerebrum

• Cerebellum

• Medulla

1. Cerebrum

The largest and uppermost part of the brain is the cerebrum. It makes 85% of the brain's weight. It is divided into two parts vertically. The right part controls the left side of the body and vice versa.

Scientists think that the right part of the cerebrum helps us to think about abstract things like colours and shapes. The left part is involved in analytical thinking, for example when you are solving a maths problem, it helps you to think logically. The cerebrum is the thinking part of the brain and controls our voluntary actions, i.e. the ones that can be controlled.

The cerebrum controls actions like listening, reading, thinking, remernbering and reasoning. It also controls all the five senses:

sight, hearing, smell, taste and touch. Besides, it also controls our feeling.

2. Cerebellum

The cerebellum, located at the back of the brain, is below the cerebrum and above the medulla. It is much smaller than the cerebrum. It's main function is to control body movemant and coordination of muscles.

It is our cerebellum that helps to stand in upright position and move around. This control the jumping, walking, riding, swimming, and many more physical activities.

3. Medulla

The smallest and lowest part of the brain is called the medulla or brain stem. The medulla lies beneath the cerebellum. It connects the brain to the spinal cord, which runs down the neck and back. It controls involuntary actions, i.e. the ones that work automatically, without us even thinking about them. The medulla controls all Involuntary actions  of the body like breathing, digestion of food, heartbeat and blood circulation. 

When the rest of the brain sleeps, do you know which part of the brain keeps working?

It is the medulla. The medulla connects to the spinal cord, which is a long piece of nerve tissues running down from the brain through the backbone. It is surrounded by the vertebral column, which provides safety to the spinal cord.

The spinal cord comprises multiple nerves that collectively form the nervous system.

Can you tell?

Which part of the brain does a juggler need the most to stay balanced?

Good job, you are right. It is the cerebrum. The cerebrum controls body balance, movement and coordination of muscles.

The nervous system

The nervous system is made up of the brain, the spinal cord and a network of nerves all over the body. The nervous system helps us to communicate by sending and receiving countless messages and allows our brain to control what is going on in our surroundings.

We use our brain for numerous activities in our daily routine, such as solving math questions, doing homework, playing video games, etc. The procedure moves forward when the spinal cord sends messages to the brain, the nerves carry these messages in the form of impulse to the brain and then the brain commands the right part to act upon. Nerves work like jointed wires that carry communication signals all around the body. The two main types of nerves are:

• Sensory nerves that carry messages from our sense organs to the spinal cord, which carries them to the brain.

• Motor nerves that carry messages from our brain to our muscles to tell them what to do.

For example, if you put a hand on ice, your sensory nerves will send a message to your brain via the spinal cord that the ice is cold. In response, your brain will send a message to your muscles through motor nerves to move the hand away.

Key points

1. The human brain is protected by a bone called the skull.
2. Brain cells which make up the brain are called neurons.
3. The human brain is divided into three main parts cerebrum, cerebellum and medulla on the basis of their specific jobs.
4. The largest part of the brain is the cerebrum; it is the thinking part of the brain and controls our voluntary actions. 
5. The cerebrum controls body balance, movement and coordination of muscles, while the medulla controls all involuntary actions.
6. The nervous system consists of the brain, the spinal cord and nerves. It helps us to communicate by sending and receiving messages.