In humans, the integumentary system comprises the skin, hair, nails, and exocrine glands, acting to protect the body from various kinds of damage. The integumentary system is essential for maintaining thermoregulation while providing a water or abrasion barrier from outside. Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different.
Exocrine glands produce and secrete substances onto an epithelial surface by way of a duct. Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, and mucous.