Most sensitive part of the human body

  1. fluidistic

    fluidistic 3,336
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    Hello,
    I've been taught in high school that the most sensitive part of the human body was the index finger. However recently I've read that it is the clitoris...
    But I've a doubt if it is true. I'd like to know the sensitivity of the human eye. I don't have any anatomy book nor medical book. Wikipedia doesn't say anything about it...
    I'd be glad if you could tell me the eye' sensitivity. (of touch of course).
    Thank you.
     
  2. jcsd
  3. mgb_phys

    mgb_phys 8,952
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    Zero - you don't have any nerves on the bits of your eye you can touch ( cornea )
     
    Last edited: Nov 19, 2008
  4. fluidistic

    fluidistic 3,336
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    Thanks for the answer mgb_phys. That really surprises me! I feel that if I put my finger on my eye it will hurts (especially if my finger is dirty). How is that possible if I have no nerve?
     
  5. mgb_phys

    mgb_phys 8,952
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    Sorry I was wrong, the surface of the front of your eye - the cornea, does have lots of nerve endings.
    Oddly it doesn't have any blood vessels - must have been what I was remembering.
     
  6. Moonbear

    Moonbear 12,265
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    That's incorrect. Sensory information from the cornea is transmitted to to the brain via the trigeminal nerve.

    (Edit: You updated your remark while I was still typing.)

    I think when they talk about sensitivity, though, they're talking about the ability to discriminate what part of the organ is being touched, or 2-point perception (i.e., if you move two pins closer and closer together, how far apart are they when you can no longer detect them as two separate points). The fingers are best at that.
     
  7. fluidistic

    fluidistic 3,336
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    I mostly agree with that, but I remember I've read the number of .... nerves (I don't remember the name sorry) can be calculated for a given area so it is possible to compare a region of the body with another in term of the number of these cells or whatever they are.
    If I've time I'll search for it on the Internet and post it here. The index finger has a lot but not that much as the clitoris does. I was curious about the eye. I feel that my eye feels much more than my index. For example if a fly walk over my index I'd feel it and it would tickle me, while on my eye it would hurt really bad.
     
  8. Moonbear

    Moonbear 12,265
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    That doesn't mean it's more sensitive. It means your finger can discriminate better among different types of sensations. The eye can pretty much only detect pain...light touch, big poke, it's all the same sensation. The finger can discriminate among many different types of sensation...pain, light touch, pressure, temperature.
     
  9. fluidistic

    fluidistic 3,336
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    You're right Moonbear. I guess that's because fingers have a lot of different specified cells that can measure pressure, heat and so on. While the eye has probably one type of them or mostly one type of them.
    But still, if I have a dust on my finger I wouldn't know it while on my eye yes. I believe that the eye is more sensitive in this case.
     
  10. somasimple

    somasimple 716
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    Hi all,

    Normally the most sensitive part is lips, followed by thumb.

    [​IMG]
     
  11. Somasimple is correct to point out that what we usually think of in common speech as "sensitivity" maps very well onto the size of representation in somatosensory cortex. Thus the lips and thumb are the most sensitive. It is interesting to wonder about why this correspondence exists...
     
  12. somasimple

    somasimple 716
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    Simple: Taste and Touch => two senses that help while you discover the world around yourself. BTW, they are quite the same as a single cell.
     
  13. DaveC426913

    DaveC426913 16,365
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    Don't discount your tongue. A stray hair (head or face) can feel like a log on your tongue. I don't know anywhere else on the body that's more sensitive than that.
     
  14. somasimple

    somasimple 716
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    You're right! Tongue wins.
     
  15. marcusl

    marcusl 2,130
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    I think it's the ego.
     
  16. DaveC426913

    DaveC426913 16,365
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    :rofl:
     
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