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Human Body
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separated: deep inside, a thick bank of nerve fibres as well as three smaller bands interlink the two halves and provide for an interchange of information between them. Each hemisphere controls the voluntary movements of the other side of the body. Each hemisphere is further divided into four main regions called lobes :
(i) Frontal lobe; (ii) Parietal lobe; (iii) Occipetal lobe; and (iv) Temporal lobe.
The cerebrum contains millions of neurons that are the basis of mind. In fact, man's ascendancy over his environment and other species is due to the size of his cerebrum, which is bigger in man than in any other animal. There are three varieties of activity associated with cerebrum :
(i) Sensory perception : The perception of pain, temparture, touch and the special senses of sight, hearing taste and smell.
(ii) The initiation and control of the contraction of voluntary muscles.
(iii) The mental activities involved in memory, intelligence, sense of responsibility, thinking, reasoning, moral sense and learning are attributed to the higher centres. Cerebral Cortex
Our memories, hopes, plans, attitudes and personality--are all stored within a thin outer layer of the brain composed of grey matter in the cerebrum called the cerebral cortex. It is crumpled and wrinkled. If stretched out flat, it would cover nearly 4000 sq. cms. Its average thickness is 1.6 to 4 mm. It contains 10 to 14 billion neurons.
Research has yielded elaborate functional maps of the cerebral cortex. Out of the several lobes in which the cerebrum is divided, the frontal lobe is concerned with personality, behaviour and movement. The lowest left frontal part is the centre for speech. The next are the two parietal lobes which are involved in the analysis of sensations and recognition of the body in relation to its surroundings. Occipetal lobes, situated on the top of the cerebellum at the back of the head comprise the visual area of the brain. A separate projection on either side of the brain is the
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