we all know that when washing clothes for a long time, or soaking in the swimming pool for too long, the hands and feet will start to wrinkle. What’s the reason? Will there be any harm? Let’s follow it.
Why do hands wrinkle after a long time of blistering
explanation 1:
cells absorb water, expand and squeeze each other, resulting in
one view is that the skin of fingers and toes will wrinkle after soaking in water for a longer time, This is caused by the skin absorbing water. Human skin is divided into epidermis, dermis and subcutaneous tissue. Water absorption is generally considered to occur in the epidermis.
there are two main explanations for the principle of skin water absorption. One is the semi permeable membrane theory, that is, the cell membrane has the characteristics of semi permeable membrane. Although the keratinocytes in the epidermal layer are & ldquo; Dead cells & rdquo;, However, this characteristic is still maintained, so that water can flow from the low concentration side to the high concentration side. The liquid in the cell is the one with higher concentration for bath water or swimming pool water, so it will absorb water inward. The second is the capillarity theory, that is, when the liquid is inside a thin tubular object, due to the difference between its surface tension (cohesion) and adhesion and overcoming the phenomenon of change caused by gravity, paper towels and sponges can lead a small amount of water upward through capillarity, and there are a large number of proteins in keratinocytes. This theory holds that proteins have capillarity on water, The water outside the cell is sucked into the cell. Eventually, the water absorbing cells begin to expand.
however, there are not only keratinocytes in the stratum corneum, but also lamellar lipids between cells, which will block the passage of water. Therefore, the expansion degree of the outer cells of the water soaked skin must be greater than that of the inner cells. The cells squeeze each other. When the space is insufficient, it will naturally wrinkle.
some people believe that according to the water absorption theory, as long as the immersion time in water is long enough, the folds will eventually disappear. Just like soaking soybeans, the epidermis will wrinkle at the beginning, but after soaking overnight, the fully absorbent soybeans will expand all over the body.
explanation 2:
increased neural activity leads to vasoconstriction
however, some scientists believe that the contraction of skin after immersion is not the result of water absorption and expansion of cells, but an unconscious reaction controlled by the autonomic nervous system like heartbeat and sweating. The most powerful argument supporting this view is that cell water absorption can occur under any circumstances, while nerve damaged fingers will not wrinkle after immersion.
this explanation suggests that when the skin is soaked in water, the intracellular electrolyte balance changes, so the neural activity in these parts begins to increase. Increased nerve activity will lead to vasoconstriction and reduce blood flow at these sites. Finally, the tension of the skin in these parts decreases and begins to relax and wrinkle.
no matter what explanation, there are still some questions, such as why only fingers and toes wrinkle, and why only mammals such as humans and rhesus monkeys have this feature. Most of the questions have not been satisfactorily answered so far.
Latest research:
wrinkled fingers grasp wet objects more firmly
in addition to explaining the principle of finger wrinkling, some scientists hope to find out the origin of this phenomenon. One view is that this is the result of human evolution. Because a research team has found that the wrinkled lines of fingers of different people are very similar. It is a grid structure conducive to discharging water between fingers and contacted objects, which can increase the friction when grasping things, but there has been no evidence to prove this hypothesis.
in a recent study, the experimental results of scientists greatly support this statement. In the experiment, participants held dry and wet marble with their hands soaked in warm water for 30 minutes. The results show that fingers soaked in water and wrinkled can grasp wet marble faster, but there is no obvious improvement effect on dry marble. In the experiment of using thumb and index finger to move objects such as glass marbles from one container to another, participants with wet fingers also performed much better than those with dry fingers. Simardes, an evolutionary biologist at the University of Newcastle, one of the co authors of
, said that wrinkled fingers are like patterned tires. After increasing the contact area, the friction will increase. Wrinkled fingers made it easier for human ancestors to collect food in wet vegetation and rivers, while wrinkled toes made them more stable in the rain.
There is no harm
is generally no harm. If wrinkles are accompanied by peeling, it is called sweat herpes. If public slippers and towels can be transmitted to other members of the family. Sweat herpes is a kind of hand eczema. People with this disease are generally prone to hand sweating. In addition, regular contact with alkaline washing products, gasoline and other substances can also destroy the natural protective layer of their hands, which is easy to lead to this disease.
the disease occurs frequently in spring and autumn. It is common on the side of the fingers and the pulp of the fingers, as well as on the palm. There are transparent small blisters, and then there is circular peeling. Some people’s blisters are not obvious. At the beginning, they show peeling of their hands, especially at the end of their fingers. Apply triamcinolone urea ointment for treatment. For patients with sweating hands, after not peeling, they can soak their hands with 2-3% formaldehyde, which can reduce hand sweating and prevent recurrence.
why only hands and feet wrinkle
finger wrinkling should be an unconscious response controlled by the human autonomic nervous system, just like breathing and sweating. Wrinkled fingers can help our ancestors collect food in a humid environment, while wrinkled toes can help them stand more stable in the rain. But there is no more authoritative answer, which is still under study.