Naked Science Forum
General Science => General Science => Topic started by: thedoc on 13/09/2013 23:45:07
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We are told that if a cut is itching it is healing, and that scratching itches is bad for healing, why have we evolved this tendency to cause the healing cut to itch?
Asked by Toby Tennent
Visit the webpage for the podcast in which this question is answered. (http://www.thenakedscientists.com/HTML/podcasts/naked-scientists/show/2011.03.20/)
[chapter podcast=3026 track=11.03.13/Naked_Scientists_Show_11.03.13_8077.mp3](https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.thenakedscientists.com%2FHTML%2Ftypo3conf%2Fext%2Fnaksci_podcast%2Fgnome-settings-sound.gif&hash=f2b0d108dc173aeaa367f8db2e2171bd) ...or Listen to the Answer[/chapter] or [download as MP3] (http://nakeddiscovery.com/downloads/split_individual/11.03.13/Naked_Scientists_Show_11.03.13_8077.mp3)
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Wounds heal as new cells born at the wound margin migrate into the base of the injury, unite with their counterparts and then draw the wound closed by activating contractile elements that apply tension.
This shrinkage and tension activates the mechanoreceptive nerves that signal itch sensation, creating the urge to scratch...
Chris
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I quote 'upregulate the activity of these itch sensitive nerves'. The writer must be American. Love 'em like brothers but maybe this is the reason for the longevity of Latin as the accepted language of learning...clarity and certainty are priceless, especially when communicating complex or novel ideas.
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David...how would you have stated it then???
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http://www.merriam-webster.com/medical/upregulation I know this is an ancient conversation, but this person David has got his panties in a knot. In attempting to discredit someone, he managed to make himself look like a fool. European, I suspect.
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Chris you didn't answer the question. The guy is asking - if scratching a healing wound is NOT RECOMMENDED, then why have we evolved to have the irrepressible urge to SCRATCH IT? Because in our evolution, if a cave man kept scratched his healing wounds and reinfecting them, then that trait would have been lost.
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I'm guessing that the cavemen failed to realise that their constant stupid scratching was keeping their wound from healing perished; while those who exercised a modicum of self-discipline and self-denial (arts that seem to have been lost to modern youth as Western civilisation declines ever faster) survived and reproduced. Based upon this hypothesis, I predict that modern humans have an alert system that causes them to pay attention to any wound they have just scratched and cease scratching it if it becomes clear that the constant scratching is not helping the wound heal one little bit.
But all this is merely lay logic; something anyone could do, who has paid a modicum of attention to learning how natural selection works. I reckon dr Chris is smart enough to know this, which is why as a challenge to the intellectually lazy he has refused to address this no-brainer and instead chosen to give us the much more interesting benefit of his specialist knowledge as a Doctor; something we our GPs never have time to explain to us.
Thank you Doctor Chris; the neurobiology, microbiology, mechanics and chemistry of wound healing are fascinating and draw to our attention the miracle that is the human body, hopefully reinforcing the tragedies that are the modern cultures of violence and making some of us resolve to eschew violence and cultivate our compassion.
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Where did you get this crap? I guess you don't know what cytokines and histamines are......
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Hey this is for Greg, I have a wound currently that is healing, pretty nice one its going to leave a noticeable scar. It was still superficial but it went down to the facia, anyway my wound is a bit itchy currently but its around the border of it, so I dont know that a caveman would stand there and itch it but I did learn a little about cytokines and histamine anyway it feels good to scratch it. I am just glad that rattlesnake did not get me, it was gigantic. Wow and the captcha has me picking out photos of bunnies, how appropriate. I kid you not when I say this snake was easily 5 to 5 1/2 feet long, and the largest prairie rattler every caught was only 4 feet.. I saw its rattle too and it was no kingsnake.
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OK first this answer is just a re post from an AARP article so who knows if any of it is true or just a wives tale !!! Second no one still has answered a very good question. There are many reactions our bodies have that are good for us, like the jerk reaction when we touch something hot, but also many, like itching a wound, that do us more harm. Another example would be why are eyes are drawn to blinding light at night like an approaching cars high beams or an intense blinding spotlight. Does any one have an actual explanation how itching or blinding light helped cavemen after all I'm sure most of you believe Darwin that evolution is real and the fittest survive while the bad genes die off as a race. So why didn't my ancestors die off so that I don't have these destructive reactions ??? Must have been good back then for some reason. I expect to get nasty comments from the intellectually challenged.