The brain is responsible for all our actions. It is the brain that works with all parts of the body through the nerves by sending electrical signals. An average human brain weighs about 3 pounds. It has three main parts – cerebrum, cerebellum and the bran stem.
The largest portion is called cerebrum. The cerebrum is responsible for all our voluntary activities like laughing, crying, holding things, walking, talking and many more. The messages for carrying out such activities are sent in the form of electrical signals to the organs. The cerebrum is broken into two sides – a left side and a right side. The left side controls the right part of the body and right side controls the left part of our body.
The cerebellum or the “little brain” is located at the bottom of the brain. It is also divided into two hemispheres. This part of the brain coordinates movements. It lies beneath the cerebrum and has an important role in motor control.
Coating the surface of cerebrum and cerebellum is a vital layer of tissue called cortex. Much of the actual information processing in the brain takes place in the cerebral cortex.
The brain stem is what connects the base of the brain to the spinal cord. This part controls the flow of information between the brain and all parts of the body. Some reflex actions are controlled by the uppermost part of the brainstem. This part of the circuit is involved in the control of eye movements. But sometimes a very quick response is needed without the involvement of the brain and this action is called reflex action. Reflexes are processed directly in the spinal cord in order to respond quickly to danger. It also controls much of the involuntary actions. When a receptor is stimulated it sends a signal to the central nervous system and the bran coordinates the response.