The Nervous System

Nervous System

The nervous system consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body. Together, these organs are responsible for the control of the body and communication among its parts. The brain and spinal cord form the control center known as the central nervous system (CNS), where information is evaluated and decisions made. The sensory nerves and sense organs of the peripheral nervous system (PNS) monitor...

Functions of NS:-

• Sensory
• Integration
• Motor.   

Divisions of the Nervous System

Nervous Tissue:-
The majority of the nervous system is tissue made up of two classes of cells: neurons and neuroglia.

• Neurons. Neurons, also known as nerve cells, communicate within the body by transmitting electrochemical signals. Neurons look quite different from other cells in the body due to the many long cellular processes that extend from their central cell body.

                                       

• The cell body is the roughly round part of a neuron that contains the nucleus, mitochondria, and most of the cellular organelles. Small tree-like structures called dendrites extend from the cell body to pick up stimuli from the environment, other neurons, or sensory receptor cells. Long transmitting processes called axons extend from the cell body to send signals onward to other neurons or effector cells in the body. 
  
  There are 3 basic classes of neurons: 

1. Afferent neurons. 
2. Efferent neurons. 
3. Interneurons. 

• Neuroglia. Neuroglia, also known as glial cells, act as the “helper” cells of the nervous system. Each neuron in the body is surrounded by anywhere from 6 to 60 neuroglia that protect, feed, and insulate the neuron. 

Central Nervous System Consists:-

The brain:-

Brain is a soft, wrinkled organ that weighs about 3 pounds, is located inside the cranial cavity, where the bones of the skull surround and protect it. The approximately 100 billion neurons of the brain form the main control center of the body. The brain and spinal cord together form the central nervous system (CNS), where information is processed and responses originate. 

Spinal Cord:-

The spinal cord is a long, thin mass of bundled neurons that carries information through the vertebral cavity of the spine beginning at the medulla oblongata of the brain on its superior end and continuing inferiorly to the lumbar region of the spine.

Meninges
The meninges are the protective coverings of the central nervous system (CNS). They consist of three layers: 

• Dura mater
• Arachnoid mater
• Pia mater

Peripheral Nervous System Consists:-

• Cranial Nerves:- Consists 12 cranial nerve that originate from the brain.
• Spinal Nerves:- Consists 31 pairs of spinal nerve that originate from the spinal cord.

Why I  Choose This System?

These are the important parts of our Nervous system:-

Cerebellum:-

Part of the hindbrain in vertebrates. In humans it lies between the brainstem and the cerebrum, and plays an important role in sensory perception, motor output, balance, and posture.

cerebrum

In humans it is the largest part of the brain and is the seat of motor and sensory functions, as well as the higher mental functions such as consciousness, thought, reason, emotion, and memory.

spinal cord

A thick, whitish cord of nerve tissue that is a major part of the central nervous system. It extends from the brain stem through the spine, with nerves branching off to various parts of the body.

brain stem

The part of the brain that connects the spinal cord to the forebrain and cerebrum.