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Join Date: 17 Oct 2010
Location:  Saudi ArabiaPosts: 38 |
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Human Brain Skills-3 ( Childhood Development) |
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What is the Brain?
The brain is the portion of the central nervous system in vertebrates (animals with bones) that lies within the skull. In humans, the brain weighs about 3 pounds. Differences in weight and size do not correlate with differences in mental ability. The brain is the control center for movement, sleep, hunger, thirst, and virtually every other vital activity necessary to survive. The brain is a pinkish-gray mass that is composed of about 10 billion nerve cells. The nerve cells are linked to each other and together are responsible for the control of all mental functions. Nerve fibers in the brain are covered in a near-white substance called myelin and form the white matter of the brain. Nerve cell bodies, which are not covered by myelin sheaths, form the gray matter. The entire brain is enveloped in three protective sheets known as the meninges, continuations of the membranes that wrap the spinal cord. The two inner sheets enclose a shock-absorbing cushion of cerebrospinal fluid. Nerve fibers in the brain are covered in a near-white substance called myelin and form the white matter of the brain. Nerve cell bodies, which are not covered by myelin sheaths, form the gray matter. The brain is divided into three major parts, the hindbrain (including the cerebellum and the brain stem), the midbrain, and the forebrain (including the diencephalon and the cerebrum). The brain is a delicate organ that must be protected. When participating in activities such as skiing or snowboarding, wear a helmet to help reduce brain injuries. Also, try to avoid heat stroke because the brain can only function in a very narrow temperature range. |
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