Why do fingers prune when in water for a long amount of time?

Answer 1

I hadn't heard of the salt and mineral theories before. Generally known reason is this: (from Ask Yahoo and Discovery Magazine)

"Your skin is comprised of two layers -- the epidermis and the dermis. The epidermis produces an oily protein called sebum, which is effective in repelling water. It's also the material that causes fingerprints.
Inevitably, a nice long soak in a bathtub sloughs off the excess sebum from your epidermis. As a result, your skin starts to take on water. The top layer of the epidermis is known as the stratum corneum, which is Latin for "horny layer." These are the tough, dead skin cells that are constantly being sloughed off your body in your clothes, your bed, and in the form of dandruff. Disturbing, but true.

Your fingers and toes have especially thick layers of stratum corneum. Once deprived of sebum, they swell up with water, causing wrinkles. This osmosis effect is harmless and temporary. One you get out of the tub, the extra water evaporates, leaving your skin even drier than before because there is no sebum to help retain moisture. This is a good time to apply lotion or oil to help your skin retain some of the water. "
http://ask.yahoo.com/20030421.html
http://www.discoverymagazine.com/digger/d01dd/d0110dd.html

Plus a more general easier answer, which still says the same thing, from Dr. Kar's homework:

"When you're in a bath for half an hour or so, water can soak into the callus.
Unless you're one of those religious people who crawls on your belly for hundreds of kilometres, you don't have much callus on your belly, which is why you don't get a wrinkled belly when you soak in a bath.

So the reason that you wrinkle when you sit in water for a long time, is because the water soaks into any skin on your body that has lots of callus on it. "

http://www.abc.net.au/science/k2/homework/s95618.htm

Answer 2

Osmosis.
The surrounding (sweet-)water contains less salts than your body cells. This imbalance on the two sides of the cell wall generates osmotic pressure. The salt ions can't pass the cell membrane but the water can and so flows into the cells, diluting the salts inside until the relative content is identical on both sides. This causes the cells to swell, which we see as pruning.

Answer 3

Basically osmosis. As we sit in the water our bodily water moves through our skin to the bath water that has chemicals in it trying to reach an equilibrium leaving our fingers looking a little depleted.

You can do an experiment by putting a carrot in some salty water. It will do the same thing.

Answer 4

This typically happens when the water contains more mineral content than the skin cells. Chlorine is the culprit in pool and bath water. Cells want to obtain a balance of minerals and salts between the inside and the outside of the cell membrane. This causes the cells to push their water content out and since they can't really create a balance in this instance, they end up shriveled. Hope this explained it for you :-)

Answer 5

Wrinkly arms and feet, or pruning as some human beings call it, take place whilst your epidermis soaks up water. Our epidermis has a sort of water resistant oil on it stated as sebum. that's why water rolls precise off your epidermis interior the tub or bathe. in case you spend too plenty time interior the water, the sebum washes away and guess what? you at the instant are not so water resistant anymore. Your epidermis soaks up the water inflicting it to swell in some places which makes it seem wrinkly. Now, this in elementary terms occurs on your feet and arms as a results of fact they have no hair. The hair follicles at something of your physique are waiting to maintain making adequate sebum so it does not wash away. The wrinkly epidermis isn't risky or everlasting. once you get out of the water, it does not take long to your pruny arms and feet to pass back to standard.

Answer 6

"The outermost layer of the skin swells when it absorbs water. It is tightly attached to the skin underneath, so it compensates for the increased area by wrinkling."
Also, over the entirety of your body the skin is generally a thinner layer and therefore doesn't wrinkle like the fingers and toes.
I've heard the more dehydrated you are all together the more water your body absorbs.