Skin (hereinafter – the “S.”) (article in Russian[ru] – “кожа“) – is the outer covering of the body of animals and humans, exercising functions of defense against external influences, as well as touch, metabolism (including gas exchange), excretion, sometimes thermoregulation. S. prevents penetration into the internal environment of microorganisms, toxins, mechanical damage, takes mechanical, thermal and painful effects, defines animal coloring, highlights odorous, toxic or nutritional substances serving signals in security or rearing of offspring.
The skin consists of an outer (epithelial) and internal (connective tissue) layers separated by a basal membrane and often forming numerous derivatives (see Fig. 1, 2, 3).– Далее –