So this the first script-y/scienc-y writing thing I have ever really published, so don't judge too harshlessy, but I would still love any advice or constructive critism you have to help me improve. This is designed for SciShow episode, but I did find it a bit difficult to keep more to their style of writing and stop myself from slipping into my natural writing style :/
.... Anyway I hope you like it :D
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Why do our fingers go wrinkly?
At one time or another, most of us have experienced ‘pruney’ fingers, or the exaggerated wrinkling of fingers and toes that results from prolonged exposure to water.
Yet, it is actually a very unusual trait though out the animal kingdom, with humans and macaques being the only none species to have atrophy of the fingers.
But what actually causes this weird biological phenomenon?
Well, the common misconception, which you might believe, about what being absorbed between the skin layers, is but that – a common misconception.
Up until the late 1930s, it was accepted between the majorities of scientists that the atrophy of the fingers was caused by the washing away of the skin oil sebum, leading to slow osmosis into the top layers of skin causing them to swell.
However, when a group of researchers was experimenting on the impact of water on the speed of movement, they decided to include several sufferers of nerve damage.
And they discovered something very different to what they were expecting. The water did not cause a ‘pruney’ effect on their fingers and toes.
This showed scientists that the change was in fact an involuntary reaction by the body’s automatic nerves system – the system which also controls breathing, heart rate and perspiration.
In fact, the primary mechanism that contributes to the shrivelling of skin in response to water is vasoconstriction, the tightening of blood vessels under the epidermis, resulting in reduced blood flow to those areas.
In response to water, the nervous system restricts blood flow to the fingertips. The resulting loss of volume in each finger causes the skin to shrink inward, forming the wrinkles we associate with “pruney” fingers.
And in recent years, even more evidence has come to light to support this new explanation, as many diabetics and others suffering with thyroid problems, have been diagnosed with pro-longed atrophy of the fingers.
But why would the brain automatically signal wet skin to shrivel up? Moreover, why does this effect only involve the tips of fingers and toes?
In 2011, Mark Changizi, an evolutionary neurobiologist at 2AI Labs in Boise, Idaho, and his colleagues, suggested that wrinkling; now accepted as an active process must have an evolutionary function.
And the answer to what that function is, we will probably never be known for sure, but if you ‘hold on tight’ we can explain why many scientist now believe that it is because it increases our ability to grip wet objects.
The wrinkles appear to optimized to create an easier drainage system for the water, as well as a clearly increasing the friction.
And a more recent study asked volunteers to pick up marbles immersed in a bucket of water with one hand and then passing them through a small slot to be deposited by the other hand in a second container.
Volunteers with wrinkled fingers routinely completed the task faster than their smooth-skinned counterparts.
The team found there was no advantage from ridged fingers when moving dry objects.
Wrinkled fingers could have helped our ancestors to gather food from wet vegetation or streams. The analogous effect in the toes could help us to get a better footing in the rain.
So, next time you’re taking a nice long soak and reach for your rubber ducky, you may want to think about thanking evolution for the reason why it doesn’t slip away from your fingers.
Mystery solved!
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CITATION:
http://www.bbc.co.uk/news/science-environment-20951232
http://dujs.dartmouth.edu/news/why-do-our-fingers-get-pruney#.U_tIiPldXkU
http://www.scientificamerican.com/article/why-do-our-fingers-and-toes-wrinkle-during-a-bath/
Description:
Have you ever wondered why your fingers and toes turn ‘pruney’ after a nice bath? Well, Quick Questions has the answer.
