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Thread: regarding homeostasis

  1. #1 regarding homeostasis 
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    i was wondering, since homeostasis is defined as the maintanence of a constant internal environment, why cant the contractions of the circular and radial muscles in the iris be considered as a form of homeostasis? since they control the amount of light entering the eye? i wrote this in my exam but it was marked wrong
    thanks


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  3. #2  
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    The iris is a control system but not really regulating an internal environment.


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  4. #3  
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    so the inside of the eye cannot be considered an internal environment?
    thanks so much
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  5. #4  
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    The inside of the eye is an internal environment but the light entering it is external.
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  6. #5  
    Forum Cosmic Wizard paralith's Avatar
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    the amount of light that enters the eye for sight is in no where near significant enough amounts to actually affect the homeostasis of the body. When it comes to body temperature, nutrient amount, etc, that light doesn't change anything.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
    ~Jean-Paul Sartre
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  7. #6 Re: 
    Forum Freshman Aures's Avatar
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    Quote Originally Posted by paralith
    the amount of light that enters the eye for sight is in no where near significant enough amounts to actually affect the homeostasis of the body. When it comes to body temperature, nutrient amount, etc, that light doesn't change anything.
    The amount of light (sunlight, specifically) entering the eye, drastically affects first the levels of Melatonin secretion, which consequentially affects your sleep and body temperature rhythm. That's definitely a form of homeostasis.

    While, the light entering the eye seems to affect the general homeostasis, the iris movements are instant reflexive in a purpose of vision regulation only. So , Ellybelly, you're kinda wrong.
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  8. #7  
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    ohhh, ok, i sort of get it :-D
    thank you everyone!
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