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Body replaces itself, but not individual limbs

  1. Jul 29, 2009 #1
    How is it that, although the human body mostly regenerates itself every dozen or so years, it cannot replace more than a very simple severed part?

    http://en.wikipedia.org/wiki/Regeneration_(biology)" [Broken]
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jul 29, 2009 #2
    Because whoever designed the human body did a horrible job and should've been axed long ago.

    Anyway I think the main reason is not that it can't but why it can't, and if i'm not mistaken it was evolutionary. Most animals would probably not survive after losing a limb, so why invest so much energy in regrowing it? Too bad we haven't found the 'switch' to turn it back on.
  4. Jul 29, 2009 #3

    Andy Resnick

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    The human body replaces itself much faster than 'every dozen or so years'- the intestinal epithelium is replaced every few days.

    In any case, the ability to regenerate is driven by stem cells- and we (terminally differentiated human beings) no longer have the stem cells able to regrow entire limbs (or organs).
  5. Jul 29, 2009 #4
    It's not that we can't, it's simply that our body doesn't want to. Basically... if you have a computer, you can't create Word files without MS Office. As soon as we know how to install MS Office (i.e. modify cells and use stem cells), regeneration should be possible. It's a complicated process though, with high risk of cancer induction.

    I actually read an interesting article regarding this subject recently. Since 2007, we're able to give cells an innocent virus that turns a fully developed cell back into a stem cell; since last year this is also possible for human cells. However, there are still a lot of complications in the way and it will be at least 10 years before this technology because viable.
  6. Jul 29, 2009 #5


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    Or we don't have the niche that sends the correct signals to activate the stem cells to start organizing themselves in a new limb.
  7. Nov 2, 2010 #6
    Please, is there anybody here who REALLY WANTS to start an experiment in HUMAN LIMBS REGROWING? Not just posting messages, but to act in practice?
  8. Dec 22, 2010 #7
    Axolotls can regenerate limbs so the mechanism has evolved at least once.

    Interesting work been done with enzyme extracted from pig bladders - can regrow distal digit, chop of the last bone in your thumb, coat it with this enzyme and the thumb regenerates, nail and all.

    development is a phased system with the messengers for limb generation appearing at the appropriate time in utero, if you could paint the right messengers on the stump of a limb it should regenerate, worth looking into
  9. Dec 22, 2010 #8
    As mack said, axolotls show that there is no physical impossibility. So the character may have been lost through neutral mutation (neutral because when one lose a limb, most of the time survival is unlikely).
  10. Dec 27, 2010 #9
    I think monique is quite right in that its an information problem and not a physical one. Ive long held the belief that it would be easier to regrow an entire body than to replace a finger. But who knows, maybe someday someone will find the "regeneration button".
  11. Dec 27, 2010 #10
    Information, like a hologram?
  12. Dec 27, 2010 #11
    Information, like a secret key turning some cells to start a new limb.
  13. Dec 28, 2010 #12


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