We all know that when you wash clothes for a long time or soak in the swimming pool for too long, your hands and feet will start to wrinkle. What's the reason? Will there be any harm? Let's learn about it.
Why does blister long, the hand can wrinkle
Explanation 1:
It is caused by water absorption and expansion of cells.
One view is that if you soak in water for a little longer, the skin of fingers and toes will wrinkle, which 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 absorbing water. One is the theory of semipermeable membrane, that is, cell membrane has the characteristics of semi permeable membrane. Although the keratinocytes in the epidermis are "dead cells", they still maintain this characteristic, so that water can flow from the low concentration side to the high concentration side. The liquid in the cell is the higher concentration for bath water or swimming pool water, so it will absorb water inward. The second is the theory of capillarity, that is, when the liquid is inside a thin tube, due to the difference of its surface tension (cohesion) and adhesion and overcoming the phenomenon of gravity change, paper towel and sponge can lead a small amount of water upward through capillary action, and there are a large number of proteins in keratinocytes. According to the theory, protein has capillary effect on water and absorbs water outside the cell Into the cell. Eventually, the absorbing cells start to expand.
However, there are not only keratinocytes in the stratum corneum, but also thin lipid between the cells, which will block the passage of water. Therefore, the degree of swelling of the outer layer cells of the skin soaked in water must be larger than that of the inner skin, and the cells squeeze each other. When the space is insufficient, the skin will naturally wrinkle.
Some people believe that according to the theory of water absorption, as long as the water immersion time is long enough, wrinkles will eventually disappear. Just like soaking soybeans, the skin will wrinkle at the beginning, but after soaking overnight, the soybeans that absorb enough water will expand all over the body.
Explanation 2:
Increased nerve activity leads to vasoconstriction.
However, some scientists believe that the contraction of the skin after soaking is not the result of the swelling of cells by absorbing water, but an unconscious response controlled by the autonomic nervous system, like heartbeat and sweating. The most powerful argument for this is that cell water absorption can occur under any circumstances, while nerve damaged fingers do not wrinkle after immersion.
This explanation suggests that when the skin is soaked in water, the intracellular electrolyte balance changes, so that nerve activity in these areas begins to increase. Increased nerve activity will lead to vasoconstriction and decrease blood flow in these areas. In the end, the tension of these parts of the skin is reduced, and the skin begins to relax and wrinkle.
No matter which explanation, there are still some questions, such as why only fingers and toes wrinkle, why only humans and mammals such as rhesus monkeys have this feature, and most of the questions have not been fully answered.
New research:
Wrinkled fingers grip wet objects better
In addition to explaining how wrinkling works, there are also scientists who hope to find out why. One view is that this is the result of human evolution. Because a research team has found that the wrinkles of fingers of different people are very similar, which is a kind of grid structure which is conducive to drain the moisture between fingers and the objects contacted, which can increase the friction force when grasping things. However, there is no evidence to prove this hypothesis.
In a new study, scientists' results strongly support this claim. In the experiment, dry and wet marble blocks were grasped with dry and warm hands for 30 minutes. The results showed that the fingers which had been soaked in water and had wrinkled could grasp the wet marble more quickly, but it had no obvious effect on the dry marble. Participants with wet fingers also performed better than those with dry fingers in experiments using thumbs and forefingers to move objects such as marbles from one container to another.
One of the co authors of the study, evolutionary biologist smardes of the University of Newcastle, UK, said that a wrinkled finger is like a patterned tire, and friction increases as the contact area increases. Wrinkled fingers made it easier for human ancestors to gather food in wet vegetation and rivers, while wrinkled toes helped them stand firm in the rain.
Is there any harm
Generally, there is no harm. If the wrinkle is accompanied by peeling phenomenon, called sweating herpes, if public slippers, towels, etc. can be transmitted to other members of the family. Sweating herpes is a type of hand eczema. People with this disease are generally prone to sweating. In addition, frequent contact with alkaline washing products and gasoline can also damage the natural protective layer of the hands, which can easily lead to the disease.
This disease spring autumn good hair, in the finger side, finger belly more, palm also has, appear transparent blister, later appear ring peeling. Some people blister is not obvious, the first performance for the hand peeling, finger tip more obvious. The treatment was applied with triamcinolone urea ointment. For patients with sweating hands, after not peeling, can use 2-3% formaldehyde bubble hand, can reduce hand sweating, but also prevent recurrence.
Why only the hand and foot can 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 humid environment, while wrinkled toes can help them stand more stable in the rain. However, there is no more authoritative answer, which is still under study.
