This marvel of nature named skin is very complex. Its purposes are multiple. As the first link between the body and the external world it has to ensure :
- chemical and bacterial protection
- thermal regulation
- absorption of shocks and vibrations
- protection against the sun
- and very important : allow feeling.
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Skin structure is made of 3 layers, epidermis, dermis and hypodermis.
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Back to the weird fingers. After more than 30 minutes in
the tub, the epidermis has absorbed a lot of water. But the dermis, which is deeper, has not absorbed as much.
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The epidermis has swelled. If this inflation were uniform (the same everywhere), the finger would just be fatter.
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But the skin is not uniform. It is tensed in the direction of the length of the finger. Therefore, the epidermis inflates following that direction. And if you look closer, your toes wrinkle as well.