Home > Encyclopedia of Science > Integumentary System

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The human integumentary system is made up of the skin, hair, nails, and associated glands. Its main function is to protect the body. It prevents excessive water loss, keeps out microorganisms that could cause illness, and shields the underlying tissues from external damage.

The skin helps to regulate body temperature. If heat builds up in the body, sweat glands in the skin produce sweat, which evaporates and cools the skin. When the body overheats, blood vessels in the skin expand and bring more warm blood to the surface, where it cools. When the body gets too cold, the blood vessels in the skin contract, leaving less blood at the body surface, and its heat is conserved.

In addition to temperature regulation, the skin serves as a...