Question

Describe the central nervous system in human beings.

Answer 1

Central nervous system

1. The CNS consists of the brain and spinal cord. They form the central processing unit of our body.
2. It receives information in the form of electrical impulses, processes it, and sends it to appropriate effector organs.
3. The brain and the spinal cord are encased in a protective bony case called the skull and the vertebral column.
4. Further, there is a coating of connective tissue made of three layers of membranes together called the meninges.
5. The outer layer, the dura mater, is a tough protective coat. The middle layer, the arachnoid mater, is present between the two layers. The inner layer, the pia mater, is highly vascularized and in close contact with the brain and the spinal cord.
6. The space between the dura mater and arachnoid mater is called the subdural space. The space between the arachnoid mater and pia mater is called the subarachnoid space.
7. The space between the meninges is filled with an alkaline watery fluid called cerebrospinal fluid (CSF).
8. The brain is divided into the forebrain (cerebrum, thalamus, hypothalamus), midbrain, and hindbrain (cerebellum, pons, medulla oblongata).
9. The brain consists of sensory, motor, and associative areas. It helps in the control of various involuntary functions like heartbeat and breathing. Balance and muscular activity are also controlled by the brain.
10. The spinal cord extends from the medulla oblongata posteriorly in the neural canal of the vertebral column.
11. The spinal cord is responsible for reflex actions below the neck region. Sensory impulses are conducted from the sense organs to the brain and motor impulses back to the effector organs.
12. Nerves arise from the organs of the central nervous system. The nerves from the brain are called cranial nerves and the nerves from the spinal cord are called spinal nerves.