The integumentary system consists of the largest organ in the body: the skin. This extraordinary organ system protects the internal structures of the body from damage, prevents dehydration, stores fat, and produces vitamins and hormones. It also helps maintain homeostasis within the body by assisting with the regulation of body temperature and water balance.

The integumentary system is the body’s first line of defense against bacteria, viruses, and other pathogens. It also helps provide protection from harmful ultraviolet radiation. The skin is a sensory organ, too, with receptors for detecting heat and cold, touch, pressure, and pain. Components of the skin include hair, nails, sweat glands, oil glands, blood vessels, lymph vessels, nerves, and muscles.