There are many skin ridges on the surface of palm skin, which are separated by tiny parallel grooves to form skin texture. Fingerprint is the most prominent part of skin texture. Everyone has a unique fingerprint in the world and it will remain unchanged for life. Fingerprints help the police identify criminals. In addition, in the medical field, some unusual fingerprints can also indicate abnormal chromosome or embryo development.
The color of skin is mainly determined by the content of melanin in skin. Human skin contains different melanin, which forms the skin color of different races. Melanin is a kind of black or brown particle, which can block ultraviolet rays harmful to human body in sunlight. So in Europe, there is less sunshine, less melanin and white skin; In Africa, the hot sun, the human body produces more melanin, so African skin is black or brown-black; Yellow people generally live in temperate regions, so their skin color is lighter.
Skin is the main channel for human body to dissipate heat. When the outside temperature is higher than the skin temperature (33℃), sweating becomes the main way to dissipate heat. When sweating a lot, the sweat drips or dries, and the heat dissipation effect is not good; If it is left on the skin surface and gradually evaporated, the heat dissipation effect will be better.
The skin thickness of different parts of the human body surface is different. The skin of eyelids and lips is very thin, but the skin of soles and palms is very thick. If the skin epidermis is worn for a long time, it will become thick and hard, so people who often walk barefoot usually have hard soles.