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人体生理学6
, ]! ^+ j6 X& B+ o5 E7 SDid you ever wonder why it is that most people in our(are) programmed + d% ]! \8 k' v
这个词组用得很形象!(to) sleep at night (instead of during)the day? If there is something about the cycle of linght and dark, it tells(that’s telling) us when to sleep. Then shouldn’t& z9 v1 J$ ^# e
the sleep cycle of a blind person be different? As it turns out, many blind people, people with no visual perception of light at all, do have the same sleep cycle as sighted people. So now you are wondering, how can this happen, the answer is hormone. One hormone in particular. It’s called melatonin褪黑激素.
$ J7 q* [3 \/ S/ U- ZIn sighted people, the level of melatonin goes up at night, or when it’s dark and goes down in the day or or when it’s light. It is believed that it is the present(presence) of this home in the blood that gives us the urge to sleep. If (an) increased
8 k% H& a8 b' ^% [! l, Q8 w& {(in) melatonin褪黑激素 levels (programmes) sighted people to sleep at night, then what about blind people?
9 @+ E+ t+ ^7 e% y3 }* [' [% ?* LA researcher, called Doctor XX tells us an interesting experiment. He tried shining a bright light into the eyes of some blind people. When he did this, he noticed that the level of melatonin褪黑激素 in the blood of these subjects此处做对象讲 went down in the blood, just as it would do for sight people. 2 ~; Y% X# e( F. V0 Z
Somehow, the eys of these subjects, even though they were damaged or have no perception of light, could tell their brain when there is(was)) p/ P1 h8 N! n J+ E, z/ S* o
more or less light.
& p6 T4 l0 N9 K2 H0 {9 ?Now this doesn’t work for all blind people. In fact, most of XX subjects have no hormone response to light at all. For(Further) researcher may be able to explain the senstivity to light in terns of the blindness of the subject.
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本帖最后由 yrs207 于 2008-8-29 16:23 编辑 ]