Stock Photo - ´SKIN, ILLUSTRATION<BR>The skin has three layers: the epidermis, the body’s natural defense against infection; the dermis, which contains hair follicles, sweat and sebaceous glands, nerves and blood vessels; and the hypodermis, which is rich in adipose tissue. The skin forms a protective covering over the entire body.´´ Skin accounts for about 10% of the total body weight. In addition to its protective function, skin is also a sensorial organ and participates in thermoregulation. Body heat is evacuated by dilatation of the blood vessels in the skin and evaporation of perspiration. Here the three skin layers are represented with a sebaceous gland next to a hair follicle and a small muscle causing piloerection (erection of the hair).´