字幕表 動画を再生する
-
Whether you're swimming or washing the dishes, or just taking a nice long well-deserved bath,
-
if you're immersed in water for longer than 10 minutes, chances are your fingers and toes
-
will emerge looking like raisins. So what's up with the wrinkle digits?
-
For years, a scientist study the phenomenon was the result of some type of osmosis
-
caused by water passing into the dry outer layer of skin.
-
The influx of water, the thinking wet would expand the skin surface area but
-
not the tissue below its. The skin would bunch up and wrinkled. But in 1935
-
a pair of doctors noticed that this affects didn't happen
-
in their patients with nerve damage. One patient, for example, was a boy who had lost feeling in three of his fingers
-
The researchers found that when his hands got wet, the fingers that could feel
-
wrinkled as normal, but the ones that were numb, remain smooth.
-
It turned out that the pretty digits weren't caused by just a passive flow of water through the skin,
-
it was an active responsive of the nervous system to prolonged moisture.
-
The nervous system causes the wrinkling by constricting the blood vessel below the skin
-
which causes the upper layers of skin to pucker.
-
Since the phenomenon is caused by an involuntary nervous bound,
-
some biologists have thought that it must have some evolutionary function.
-
But what possible purpose could it serve? One recent theory
-
suggests that wrinkly skin may have given our ancestors a better grip on
-
working in wet conditions, like gathering food from a stream, or damp vegetation
-
May have also given us better footing while walking across the landscapes in the rain.
-
In a 2013 study,
-
evolutionary biologists tested this theory by asking subjects with either
-
wrinkly or non wrinkly fingers to pick up a variety of wet and dry objects like marbles.
-
They found that the subjects with wrinkly digits picked up the wet objects 12 percent faster
-
than their counterparts, but there was no difference when it came to picking up dry objects.
-
The wrinkles apparently helped channel the water away
-
much like the treads on your car's tires. So then this raises the question,
-
if wrinkly skin gives us a better grip, then why isn't our skin wrinkly all the time?
-
Well, maybe because shriveled fingers and toes are less sensitive,
-
which is no advantage at all. Thanks for asking, and if you'd like to submit questions
-
for us to answer, or get these quick questions a few days early
-
check out PATREON.COM/SCISHOW, don't forget to go to YOUTUBE.COM//SCISHOW and subscribe.