Nervous System- Basic

Nervous system

Human body is maintained and regulated by various systems but the nervous system is the head of all the system.

Nervous system controls all the activities of the body and it works very faster as compared with all the other systems.

It is divided into three parts-
  • Central nervous system
  • Peripheral nervous system
  • Autonomic nervous system


Central nervous system

Central nervous system includes brain and spinal cord.
It is formed by neurons and supporting cells neuroglia.


Structures of brain and spinal cord are arranged into two layers gray matter and white matter.

Gray matter is formed by nerve cell bodies and the proximal parts of nerve fibers, arising from nerve cell bodies.

White matter is formed by remaining parts of nerve fibers.

In brain, white matter is placed in the inner part and gray matter is placed in the outer part.

In spinal cord, white matter is in the outer part and gray matter is in the inner part.

Brain is situated in the skull. It is continued as spinal cord in the vertebral canal through the foramen magnum of the skull bone.

Brain and spinal cord are surrounded by three layers of meninges called the outer dura mater, middle arachnoid mater and inner pia mater.

The space between arachnoid mater and pia mater is known as subarachnoid space. This space is filled with a fluid called cerebrospinal fluid.

Brain and spinal cord are actually suspended in the cerebrospinal fluid.


Brain is divided into three parts-

        1. Prosencephalon (fore brain)
        2. Mesencephalon (midbrain)
        3. Rhombencephalon (hindbrain)

Prosencephalon

It is further divided into two parts-

A. Telencephalon-
    a. Cerebral hemispheres
    b. 
Basal ganglia
    c. Hippocampus
    d. Amydaloid Nucleus

B. Diencephalon-
    a. Thalamus
    b. Metathalamus
    c. Subthalamus
    d. Hypothalamus


Mesencephalon (midbrain)

Rhombencephalon is further divided into two parts-
A. Metencephalon
    a. Pons
    b. Cerebellum
B. Myelencephalon -

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