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Preksha Dhyana :
than the best artificial intelligence modern technology could devise.
It is the seat of personality of love and hate, pleassure and pain-the centre of awareness of the world around us-the source of intellect and creativity. The brain is that portion of the central nervous system which is safely enclosed within the hard bony helmet i.e. the cavity of the skull.
The adult human brain weight about 1.4 kgs. It is composed of some 30,000 million neurons and five to ten times that number of glial cells.
The brain receives about 17% of the cardiac output and about 20% of the total oxygen consumed by the body even though it is only about 2% of the body weight. It has three major divisions :
(i) The forebrain consisting of the two cerebral hemispheres (the cerebrum) and interbrain (diencephalon).
(ii) The midbrain (mesencephalon) (iii) The hindbrain comprising of
(a) the pons, (b) the medulla oblongata, (c) the cerebellum.
The midbrain, pons and medulla oblongata together constitute the brainstem.
Cerebrum
The cerebrum is the most prominent portion of forebrain.
The forebrain and mid brain together make up the cerebrum. It constitutes the bulk of the brain about seven-eighth of its total weight and entirely fills the upper part of the skull. It is composed of an outer grey layer beneath which is a mass of white tissues. Its wrinkled surface allows a very large number of brain-cells to be packed into a limited space.
A deep cleft along the midline of the body seems to separate the cerebrum into two identical hemispheres. Actually, however, the two halves are not completely
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