ABSTRACT
As the largest organ of the body, the skin provides a protective barrier for the body against the external world and also prevents transepidermal water loss (TEWL), permitting an aqueous organism to live in a rather arid environment. In addition, there are many other functions provided by skin that are often overlooked. For example, the skin maintains body temperature through two mechanisms: (1) one in which the body is cooled by the action of sweating, via sweat glands and (2) the other by the vasoconstriction or vasodilation of the blood vessels in the dermis, which either decreases or increases the flow of blood to the dermis from other internal organs. If the internal organs are overheated, vasodilation occurs in the dermis, allowing increased blood flow, which in turn releases heat to the environment. Through the combined process of sweating, sebum production, and desquamation, a thin film is present on the surface skin, protecting it from bacterial infections and invasion by foreign substances, as well as hydrating and lubricating the surface. Another essential function of skin is sensation, which is provided by a complex network of nerves located in the dermis and at the base of the epidermis.
