Do you ever go for a swim and come out with wrinkles all over your hands and feet? Or maybe after a long comforting bath notice the strange texture on a few parts of your body? The wrinkles formed on often confuse many worrying them if this even is normal. As we delve into this topic today not only will we clear the truth but also explain amazing body mechanisms as we go by.
Wrinkles and osmosis:
An unknown fact about your skin, is that it is covered in its own special oil called sebum found on its outermost layer. It moistens, lubricates and protects your skin; in fact, it also makes your skin water proof causing water to run off your skin when you wash hands instead of being absorbed. However, it was noticed that staying in water long enough causes the sebum to wash away allowing water to penetrate the outer layer of your skin. This led to many believing that, water molecules naturally flow through a semipermeable membrane from a high concentration area to a low concentration area through a process called osmosis. When a person stays in a water bath for a prolonged time, osmosis occurs and the water flows into the upper skin cells, which then take up the water. Shrinking and expanding effects take place simultaneously in these skin cells, causing wrinkles.
However latest research lead to the conclusion that this actually isn’t the case. That’s because surgeons learned that if certain nerves to the fingers were cut, the wrinkling response would disappear. In fact, this wrinkling of skin is caused by another process resulting from your autonomic nervous system reaction.
Nervous System response:
Your sympathetic nervous system is part of a larger system in charge of unconscious body processes like digestion and breathing.
It’s mainly responsible for the “fight-or-flight response” that helped us run from a saber tooth tiger in prehistoric times.
The autonomic nervous system (ANS) plays a crucial role in the wrinkling of skin when exposed to water. This system, which controls involuntary bodily functions, triggers the reaction through a specific pathway. When your hands or feet are submerged in water, the ANS activates nerves that cause the blood vessels in the skin to constrict, a process known as vasoconstriction.
This constriction reduces the skin's volume and creates the distinctive wrinkling pattern, particularly on the fingers and toes. The reason for this response is thought to be functional: these wrinkles create channels that help water drain away, enhancing the skin's ability to grip wet or slippery surfaces.
Research on the theory:
In 2011, Changizi and his colleagues found evidence that wrinkled fingers indeed act as rain treads, channeling water away from the fingers and toes during wet conditions, allowing primates – humans and macaques, to be specific – to maintain tighter grips.
In other words, the wrinkles that result from exposure to water can be thought of as tiny, manual river drainage systems. In a typical ‘watershed’, multiple streams combine into larger channels, which eventually dump into a central river, much like twigs combine to form branches, which flow into a tree’s trunk. The pieces of land between the streams and brooks, on the other hand, are disconnected.
To see if wrinkled primate fingers had similar features to river basins, Changizi and his team analyzed photos of 28 human fingers. They found that wrinkled fingers had the exact inverse formation as river drainages, with a raised, interconnected “tree” of bumpy skin, punctuated by diverging, disconnected sunken channels.
Even if the wet-wrinkling response didn’t explicitly evolve to aid in gripping, it could still be that it remains useful for the task.
Why is the effect present only in hands and feet?
There are more keratin cells in the epidermis of the hands and feet (especially fingers and toes) than in the other parts of the body. Therefore, bunching up of the skin is less in other parts and so wrinkling does not happen there.
The wrinkling effect mostly pops up on the thickest layer of the skin. This layer is found on the inner surface of the hands and feet due to their constant rubbing against rough surfaces, i.e., the wrinkling effect is greater in hands and feet, where the thickest layer of the skin exists.
Evolutionary advantage:
The wrinkling of skin in water, particularly on fingers and toes, might have provided an evolutionary advantage to our ancestors in wet environments. The theory suggests that these wrinkles improved grip on slippery surfaces, such as wet rocks or vegetation, making it easier to gather food or navigate through damp terrains. This adaptive response would have been particularly beneficial for early humans who spent significant time in or near water, enhancing their ability to survive in diverse environments. The wrinkling is a function of the autonomic nervous system, indicating that it’s a controlled, purposeful reaction rather than just a byproduct of soaking.
This adaptation likely provided our ancestors with better traction when handling objects or moving through wet environments, contributing to survival in diverse conditions.
Conclusion:
The wrinkling effect on hands and feet might not be an example of osmosis but it tends to showcase the amazing body mechanisms present within that help improve our quality of life. If it wasn’t for our body’s fight or flight response that leads to such effects occurring survival in this world would have been impossible! Sources: https://www.webmd.com/a-to-z-guides/what-to-know-about-pruney-fingers
Assessed and Endorsed by the MedReport Medical Review Board