Quick Facts
Sweat is the liquid secreted by the sweat glands, having a salty taste and a pH that varies from 4.5 to 7.5. That produced by the eccrine sweat glands is clear with a faint characteristic odor, and contains water, sodium chloride, and traces of albumin, urea, and other compounds; its composition varies according to factors such as fluid intake, external temperature and humidity, and some hormonal activity. Sweat produced by the larger, deeper, apocrine sweat glands of the axillae contains, in addition, organic material that on bacterial decomposition produces a strong odor (Dorland, 2011).
Related parts of the anatomy
Structure/Morphology
Sweat is produced by both apocrine and eccrine glands of the skin. The type of sweat that is produced in each gland differs as the cellular composition and function of the cells of the glands is different.
Sweat produced by eccrine glands is primarily composed of water (approximately 99-99.5%) and both inorganic and organic solutes, including electrolytes such as chloride and sodium (Freinkel and Woodley, 2001). Eccrine sweat is odorless and colorless with a similar viscosity to water.
Sweat produced by apocrine glands is composed of water, electrolytes, lipids, and steroids and appears as a cloudy, viscous secretion. Although the secretion is initially odorless, bacteria found on the skin can produce odoriferous compounds.
Function
Sweating is an important function that regulates body temperature. The viscous watery sweat is secreted to the surface of the epidermis. As it evaporates, it dissipates thermal energy, or heat, from the skin, hence, why humans sweat more during exercise or in hot temperatures. The sweat glands are also excretory organs, eliminating a variety of organic compounds in addition to heavy metals out of the body.
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Freinkel, R. K. and Woodley, D. T. (2001) The Biology of the Skin. Taylor & Francis.
