Basic Functions Of The Nervous System

With all the billions of neurons we have in the body, things would be a complete mess if our neurons were not organised in some way.

To help tidy things up a bit, the body groups up these neurons by organising them together as the nervous system.

The nervous system therefore acts much like the body’s communication network, as it contains all the highways of information our brain uses to send and receive information to and from different parts of the body.

There are two main divisions of the nervous system; the central nervous system and the peripheral nervous system.

The Central Nervous System

The central nervous system consists of the brain and the spinal cord.

The Peripheral Nervous System

The peripheral nervous system consists of all the neural tissue that lies outside the central nervous system.

It can be further subdivided into the autonomic nervous system and the somatic nervous system.

Autonomic Nervous System

The autonomic nervous system mainly deals with involuntary (or automatic) responses, which means it can sometimes act independently from the brain without receiving information from it.

As a result, many of the processes that occur in the body which you don’t have to consciously think about (e.g. digestion, breathing, regulation of body temperature) are under the control of the autonomic nervous system. These are known as involuntary responses.

In addition to this, the autonomic nervous system is itself divided into two types (or divisions); the sympathetic division and the parasympathetic division.

The Sympathetic Division (Fight Or Flight)

The sympathetic division tends to be activated when there is an increase in autonomic activity.

For example, when you exercise the sympathetic division of the autonomic nervous system will increase your pulse and rate of respiration.

The Parasympathetic Division (Time To Rest)

The parasympathetic division of the autonomic nervous system works in reverse to the sympathetic division.

It is activated when there is a decrease in autonomic activity. For example, when you are very relaxed (such as during meditation) the parasympathetic division causes your pulse and rate of respiration to decrease.

So we can summarise both divisions of the autonomic nervous system by saying;

The sympathetic division (s)peeds things up and prepares your body for activity.

The parasympathetic division (p)rogressively slows things down so you can relax.

The Somatic Nervous System

The somatic nervous system is the other major division of the peripheral nervous system, and its role is to control the actions of the body (soma). For example, walking, talking or any other form of voluntary bodily movement.

The Brain

As stated previously, the brain and the spinal cord are part of the central nervous system.

In brief, the spine, which runs up the centre of your back, carries sensory messages from various parts of the body (e.g. hands, feet etc…) up to the brain.

In turn, the brain also sends messages down the spine in the form of motor messages, which result in the movement of your body.

The importance of these messages running up and down the spine, can be seen in people who have suffered from spinal injuries.

In serve cases where the spinal cord has become damaged, paralysis can occur where a person becomes unable to move their legs or other parts of their body.

Summary

• The two main divisions of the nervous system are the central nervous system and peripheral nervous system.

• The two divisions of the peripheral nervous system are the autonomic nervous system and the somatic nervous system.

• The autonomic nervous system is further subdivided into the sympathetic division and the parasympathetic division.

• The sympathetic division is active when you become active, and causes your heart to beat faster and increases your rate of breathing.

• The parasympathetic division is active when you are relaxed. It causes everything to slow down.

• The somatic division controls the actions of your body.

• The spinal cord acts like a two way communication highway, allowing the brain to send and receive information throughout the body.