The integumentary system protects the body, regulates temperature and functions in water transfer. It is also an important sensory organ that transmits information about the surrounding world.
The skin, a major component of the integumentary system, is the body's largest organ. One of the chief functions of the integumentary system is protection. The skin protects sensitive internal structures from damage and from sudden temperature changes. It also provides a barrier against disease agents, such as bacteria, parasites and fungi.
Melanin in the skin provides a natural sunscreen; increases in melanin production protect the body and the skin itself from ultraviolet radiation damage. The skin also uses ultraviolet light to produce vitamin D.
The integumentary system is essential in maintaining homeostasis, a state of stability across factors like temperature and hydration, in the body. The integumentary system stores water and prevents dehydration as well as producing sweat to regulate temperature and rid the body of waste products.
Running throughout the integumentary system are a series of blood vessels and nerve cells. The skin is extremely sensitive to factors like temperature and pressure. This allows an individual to perceive pain and take measures to end or prevent uncomfortable or potentially harmful situations. Sensitivity to temperature allows one to determine whether conditions are too hot or too cold to be safe.