brain regrowth

brain regrowth - Marine biologists often muse that...

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Marine biologists often muse that astronomers spend so much time looking outside of Earth while only 5% of our own planet’s oceans have been explored. Neuroscientists make the same consideration in the exploration of our own body. One of the most complex organs, our brain, has been dissected and investigated many times over, yet we still do not fully understand the intricacy of what goes on in our very own heads. What we do know is deep, and yet only barely scratches the surface. The brain, as well as the rest of our central nervous system, is composed primarily of two specialized cells known as neurons and glial cells 1 . The former are the cells of particular importance and number approximately 100 billion in our brains. The variety of these cells is immense, as neurons range in size from a fraction of an inch to several feet long. The process that shares information between neurons is that which allows us to think, move, and process. Tiny fibers known as dendrites that are attached to the cell body of a neuron act as receptors to receive electrical impulses from other neurons 2 . These fibers receive both excitatory and inhibitory impulses, which act in concert. When a cell body is excited past a given threshold, it fires what is called an action potential and a small, electrical current runs down a long axon to the axon terminal where these excitatory responses are passed 1 Gage, Fred H. "Brain, Repair Yourself." Scientific American 2003: 47-53. 2 ibid
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on to the dendrites of yet another neuron. Neurons can be of three different varieties and either control transmission of sensation information – bipolar neurons – information of movement – multipolar neurons – or simply function as communicative cells – interneurons 1 . A definitive feature of all of these neurons, however, is in their reproduction and it is this issue that is of particular interest for modern neuroscientists. Our body’s cells die and are replicated many times over. We receive entirely new collections of skin cells many times through our life. The cells that make up our livers, our hair, our fingernails, and other organs and systems in our body constantly replicate to replace those that have died 2 . The cells that make up our nervous system, however, were
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This essay was uploaded on 04/16/2008 for the course PSYC 101 taught by Professor Graham during the Spring '07 term at UCSD.

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brain regrowth - Marine biologists often muse that...

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