The skin covers the whole body and in natural foramens — a mouth, a nose, etc., passes in the mucous. The skin is not only a mechanical cover of a body. It represents the difficult organ closely bound to function of other organs. The skin protects an organism from various adverse physical, chemical and biological stimuluses. By means of huge number of sensitive apparatus and nerves she perceives influence of these stimuluses and transfers them to a brain. Thanks to such ability of a skin the person perceives various stimuluses and receives representation about subjects which surround it. Almost all stimuluses which arrive from an environment, conduct to a number of changes (reflex reaction) in a skin. Under the influence of a cold blood vessels are narrowed, the skin turns pale, becomes rough and hair rise. At a heat it reddens.
Protective functions of a skin. Thanks to the durability and elasticity the skin effectively protects subject tissues and organs from mechanical damage. The cornual layer эпидермы not only does not pass water in depth, but also is steady concerning a number of chemical substances which we meet in daily, especially acids and alkalis. However some substances can partially get through a healthy skin. Those are the flying substances, some gases and separate medical products. Mercury (together with its salts) and Acidum salicylicum easily get through a skin into an organism and at contact to an extensive surface and in high concentration can cause various lesions of a skin and even a poisoning.
Through hair and fatty canaliculuses of a skin animal, vegetative and other Adepses, especially are soaked up when they are rubed in a skin. This ability of a skin is used in cosmetics at preparation of various solutions (spirituous, etc.), creams or lipsticks (with various Adepses) in which medical products vitamins are included, hormones, etc., for penetration is deep in a skin and in the general circulation.
Besides, the skin protects an organism and from harmful influence of solar and ultra-violet beams. Their most part is absorbed and reflected by a cornual layer and only an insignificant part — pigmental substances of a false skin.
The skin rather effectively protects an organism from pathogenic microorganisms. Through the intact cornual layer microbes not in a condition to get into an organism, and an acidic secret потовых and fatty glands frames adverse medium for their development. At presence, however, and even an insignificant graze or a scratch penetration of microbes becomes quite possible. Besides, the healthy skin allocates also the especial substances destroying microbes. The more purely a skin, the ability to destroy microbes above.
The skin accepts appreciable participation in formation of protective antibodies of an organism.
Within days, as well as throughout a year air temperature constantly varies, however the body temperature always remains to a constant. This difficult process also is the important function of a skin.