What It Looks Like . . .
Skin is a waterproof, flexible, but tough protective covering for your body. Normally the surface is smooth, punctuated only with hair and pores for sweat. A cross-section of skin shows the major parts. It is divided into three layers. The outer layer is the epidermis. The dermis is in the middle and fat forms the innermost layer. Blood vessels, nerves, hair follicles, oil glands and sweat glands are located in the dermis.
What It Does . . .
The major function of skin is to provide a barrier between you and the outside environment. Without this protective covering, your life on earth would be impossible. The outermost layer of the epidermis is made up of sheets of dead cells that serve as the major waterproof barrier to the environment. In addition, special cells called melanocytes inside the epidermis produce brown pigment which helps protect you from ultraviolet light.
The middle layer, the dermis, provides a tough, flexible foundation for the epidermis. In the dermis, sweat glands and blood vessels help to regulate body temperature, and nerve endings send the sensations of pain, itching, touch, and temperature to the brain. Oil glands produce a substance called sebum which help to moisturize the skin. Hair is primarily decorative in humans. The fat under the dermis provides insulation and helps to store calories.