We will conclude this chapter by looking a the marvellous organ we have - that is the BRAIN. Human brain is considered as the most complicated organ in the animal kingdom. It has more than 10 billion (1 billion = lOOx Id lakhs) neurons, and 10 to 50 times more number of glial cells. The cerebral cortex alone has about 2.6billion neurons in it. Each neuron may receive about 1000 to 10,000 inputs (information from other neurons) and conduct electrical impulses at a speed of 0.6 to 120 meters/min. Brain weight is abouj 2% of body weight but it consumes about 20% of the total oxygen consumed by the body. Unlike other tissues, brain is solely dependent on glucose fox its energy requirements (liver, muscle can use fatty acids for energy production but brain can not). Unfortunately, very little is known about the way it functions. Forexamplc, we do not know much about memory. We do not know why we can learn and remember only some type of information more easily. Similarly, how and why dreaming occurs.
The greatness of human brain is to analyze a problem and think of a solution. We can do this even when full information on the problem is not available. At the same time, the human brain has aesthetic sense to appreciate poetry, music and sculpture, paintings and the beauty of objects and nature. Another wonderful capacity of human brain is communication through Language. Noother animal can pass on so much of information through sounds as a human being can. Several animals can make sounds and communicate to a very limited extent through these sounds. Man has developed the ability through his brain, to give a script to the sounds so that all the information he has gathered in his life time is written down and passed on to the next generation. With this skill in communication, humans have become a superior race and rule the planet. The thinking of a human brain can give peace to world (like that of Buddha) or destroy the world (like that of Hi tlei).
The decade 1990 to 2000 is known as "Decade of Brain" and large number of scientists are working hard to understand the working of human brain.
