Why do fingers wrinkle in water

I was swimming with the girls last saturday at Woodlands Swimming Complex,
we were resting and chatting when i realised this : Jessie22 kept "protruding" her palms in the air (you can imagine that action)
Then , she asked a question which puzzled everyone(or is it only me?)

"Why do fingers wrinkle in water ?"

AND NOW ... THE TRUTH IS REVEALED !!!

The outer layer of the skin(epidermis), is made up of a protein called keratin.
These cells divide rapidly at the bottom of epidermis, pushing the higher cells upward.
Stratum corneum is just the upper layer of the epidermis.

so when you go swimming, the keratin absorbs the water and swells.
(so i think it means the partially permeable membrane is indeed present)
The inside of the fingers, however, does not swell. As a result, there is relatively too much stratum corneum and it wrinkles, just like a 百褶裙 . (good description?)

and regarding to Jessie22 's question : why doesn't the other parts of the body skin wrinkle ?


This bunching up/wrinkling occurs on fingers/toes simply because the epidermis is much thicker on the hands and feet than elsewhere on the body. (The hair and nails, which contain different types of keratin, also absorb some water. This is why the nails get softer after bathing or doing the dishes.)

and yes it's directly opposite of what JY had suggested , that is "because the skin on our hands are thinner"
it is in fact , thicker .

lesson learnt:
Soaking in water does hydrate the skin, but only temporary.
water quickly evaporates, leaving the skin dryer than before(oh my god)
But if oil is added before the skin dries, much of the absorbed water is retained.
Thus, applying a bath oil or heavy lotion directly after a bath or swimming is a good method of hydrating the skin.




credits:http://www.sciam.com/





P.S. Next time we go swimming , remind me to bring moisturiser :)