The Skin

The skin is the largest organ of the body.

The skin is the body's first line of defense against heat, sunlight, injury, and infection. Skin also helps control body temperature and helps the body get rid of excess water and salts (through sweating).

• The most important layers are:
• the epidermis (outer or upper layer)
• the dermis (inner or lower layer)

The epidermis is mostly made up of flat, scale-like cells called squamous cells. Under this layer are round cells called basal cells. The lower part of the epidermis also contains melanocytes, the cells that make the pigment melanin.

• The dermis contains:
• blood vessels
• lymph vessels
• hair follicles
• sweat glands
• sebaceous glands (glands that produce sebum, an oily substance that keeps the skin moist)

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