The brain is a versatile organ. It controls most of the activities of the body. The beating of the heart, your respiration, your digestive process, your movements, your memory, the thinking processes and of course your emotions, are all under the control of the brain. These are only examples of what brain can do. There are trillions of neurons in the brain. But we use only a small fraction of the brain’s capacity. It has been estimated that an average human being, in his life time, utilizes only five percent of the capacity of the brain. The brain is like a machine. It has to be continuously used, otherwise it will become dysfunctional. It has been learnt through evolution that many human beings are incapable of putting the brain to use properly. That is precisely why the brain has evolved in such a way that it can carry on several functions without the human beings directly getting involved. Thus, the autonomic nervous system has come into existence.
Activities under our voluntary control are regulated by the somatic nervous system. There are many actions of the brain which are not under our control. These vital activities are controlled by the autonomic nervous system. Thus, we breathe without being aware of it. We breathe even when we are sleeping, our heart goes on beating, and there is no way we can stop it. Likewise, once we have swallowed food, there is only one fate possible-digestion.
Which is more important-the heart or the brain? This is a rather difficult question. There was a time when death was defined as the ceasing of the functioning of the heart. Now we define death as the death of the brain. The brain is the master organ, controlling everything and issuing orders left and right. But for the same brain to function normally, the heart must supply the blood and through that the oxygen, fuel and nutrients. The kidney has the excretory function and kidney failure can lead to death. When the kidneys fail, ammonia builds up in the body and this causes irreparable damage to the brain. The same thing will happen if the liver fails. Thus, every organ in the body is important in its own way.
On average, it has been estimated that we lose about ten thousand brain cells a day. Why is it that we don’t feel this loss? This is because there are trillions of neurons in the brain and moreover, we are only using a negligible portion of the capacity of the brain. We very often forget the importance of the brain (this itself is a function of the brain). The importance of the brain is brought to the fore only when there is a problem concerned with some part of the brain. Thus, Alzheimer’s disease, where there is near total loss of memory, indicates the role of the brain in remembering. Parkinson’s disease results when the brain starts producing decreased amounts of the neurotransmitter dopamine. It is the brain which tells us that we are hungry and it is the brain which tells us that we are sleepy.
Recent studies have indicated that the brain can develop up to the age of forty. Then, it is no wonder that many of the young adults behave like children.