Chapter 4: Central Nervous System

Introduction to CNS

As has been said before the function of the heart and the lungs is to provide the brain with oxygenated blood so that it can carry out its functions. Its functions are that:-

1. It is the seat of personality and intellect
2. It is the means by which the individual controls their body both consciously i.e. by making a wilful movement or unconsciously. Unconscious control is under the authority of the autonomic nervous system. This is the part of the nervous system which controls functions you would not normally be aware of such as control of blood pressure, pulse, breathing, functions of the stomach and gut and so on.

The nervous system consists of the brain, which is an electrical organ and is connected to the rest of the body by way of the spinal cord and the spinal cord is connected to the limbs and the internal organs via the peripheral nerves. The important point here is that neither the brain nor the spinal cord can recover from an injury either by being repaired or by repairing on their own. Nerves, however, can recover from injury. The brain is particularly vulnerable to lack of oxygen and in the situation where someone has stopped breathing, after 3-5 minutes irreparable brain damage occurs. The brain also requires a supply of sugar, which is obtained from foodstuffs and from release by the liver during conditions of fasting. In certain medical illnesses such as diabetes, there can be variations in the blood sugar level. The most critical of which is a drop in blood sugar, which can result in confusion, coma and brain damage.