Nervous nervous system Central nervous system Central nervous

Nervous System

Nervous system
is a network of neurons and nerve fibers. These nerves connect the brain and
body to play many functions. These neurons carry messages from brain and send
them to the body to perform a specific function. In return other neurons carry
messages from body to brain as output information.

Structure of
nervous system

Nervous system
is divided into two major divisions:

·        
Central
nervous system

·        
Peripheral
nervous system

Central nervous
system

Central nervous
system is composed of brain and spinal cord.

Skull

Brain is
enclosed into skull. Skull is a bony outer shell that protects the brain from
physical damage. Inside the skull, there is a protective tissues also called Meninges
which is further divide into three layers:

·        
Dura
matter

·        
Arachnoid

·        
Pia
matter

Dura matter

It is the outer
thickest layer of meninges. It contain cerebrospinal fluid.

Arachnoid

It is the
middle layer of meninges and loosely attached to the pia matter by web like
fibers. It allows the movement of cerebrospinal fluid to provide protection and
nutrition to the brain cells.

Pia matter

It is the inner
most and delicate layer of meninges which is composed of connective tissues
that cover the brain and spinal cord. This layer holds the blood vessels and
provide nutrition and oxygen to the brain.

Cerebrospinal
fluid

Cerebrospinal
fluid is present in and around the brain that protects the brain from shock or
any physical brain injury. It provides the nutrition and oxygen to the brain
cells and also remove waste to and from the brain.

Brain

Brain has three
main parts:

·        
Fore
brain

·        
Mid
brain

·        
Hind
brain

 

The table given
below shows the Subdivisions and principal structures of brain

 

Main parts

Sub divisions

Principle structure

Forebrain

Telencephalon
 
 
diencephalon

Cerebral cortex
Basal ganglia
Limbic system
Thalamus
Hypothalamus

Midbrain

Mesencephalon

Tectum
Tegmentum

Hindbrain

Metencephalon
 
Myelencephalon

Cerebellum
Pons
Medulla
oblongata

 

Forebrain

Fore brain is
the main part of brain which is located on the top and front of the brain. It
is divided into two main subdivisions:

·        
Telencephalon

·       Diencephalon

Telencephalon