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We regenerate plenty. Our bodies are constantly regenerating. We keep growing new skin to replace old (dandruff is a simple example), damaged organs can recover
by vacri 10y ago
We regenerate plenty. Our bodies are constantly regenerating. We keep growing new skin to replace old (dandruff is a simple example), damaged organs can recover (eg liver problems), and even exercising to increase strength involves regeneration (broken muscle fibres grow back stronger). We don't regenerate large external body parts in general, but we do regenerate some bits quite well - like the palms of our hands.
If you cut us, do we not bleed? Then clot? Then grow new tissue to heal the wound? Sometimes so that there is no evidence of a cut afterwards?
- Grishnakh 10y agoThat last part isn't regeneration, it's scarring. If it were regeneration, the skin would grow back just like new. The reason we scar instead of regenerating is to reduce the chance of infection; regenerating, as many simpler animals do when injured, takes longer and leaves the wound open to infection. We opted for scarring to avoid this. As for evidence of a cut afterwards, if you look at the skin under a microscope, layer by layer, you'll probably see the evidence, though it probably depends on the severity of the injury. Anything that goes through all the layers of skin leaves a scar, to my knowledge. As for growing new skin to replace old, the new skin we grow isn't a perfect replacement. If it were, older people wouldn't have wrinkles. We have a limited healing capacity, but it's not regeneration. Regeneration would have us growing tissues that are identical to those we had when we were young, with no evidence of scarring at all.