Why does the skin become wrinkled after soaking in water

We all know that if the skin is soaked in water for too long, it will become dehydrated, white and wrinkled. This is mainly caused by the stratum corneum cells of the skin absorbing water. This phenomenon is a normal physiological manifestation and there is no need to worry too much. However, in normal times, we should not run our fingers for a long time, otherwise the skin will easily break after wrinkling, and skin rupture will cause infection. It is recommended that everyone can understand the principle of wrinkling caused by soaking in water.

Simply put, the phenomenon of wrinkled skin on fingers after soaking in water is caused by the stratum corneum cells of the skin on fingers and other parts absorbing water and swelling.

Our skin is divided into three layers: epidermis, dermis and subcutaneous tissue. The cells in the epidermis are constantly growing, renewing, and eventually dying to become surface keratinocytes. It is generally believed that skin water absorption and wrinkling mainly occur in this layer.

Structure of the Skin

There are currently two main explanations for the principle of water absorption by stratum corneum cells.

"Semipermeable membrane" theory: The cell membrane has the properties of a semipermeable membrane, which allows water to flow from the low concentration side to the high concentration side. Although keratinocytes are "dead cells", they do not affect the semipermeability of the membrane. The fluid inside the cell has a higher concentration than the water outside, so it absorbs water from the outside into the cell.

"Capillary action" theory: There are a large number of proteins in the keratinocytes. These proteins produce capillary action on water, absorbing external water into the cells. This is the same principle as how paper towels and sponges absorb water.

The internal structure of the stratum corneum can be vividly described as a "city wall" - keratinocytes are the "bricks" on the wall, and lipids are the "mud" used to build the wall. The function of lipids is not only to connect cells, but also to act as a good barrier to prevent the passage of water. In this case, moisture can only break through gradually layer by layer.

Keratinocytes and lipids

Therefore, the skin soaked in water does not swell as a whole inside and out, but the outer cells swell more and the inner cells swell less, forming a fan-shaped pattern. This results in an increase in the surface area of ​​the outermost layer of skin. This layer of skin wrinkles under pressure.