(Redirected from Sweat)'Perspiration' (also called sweating or sometimes
transpiration) is the production and evaporation of a fluid, consisting primarily of
water as well as a smaller amount of
sodium chloride (the main constituent of "
table salt"), that is excreted by the sweat
glands in the
skin of
mammals. Sweat also contains the chemicals or
odorants
2-methylphenol (''o''-cresol) and
4-methylphenol (''p''-cresol).
In
humans, sweating is primarily a means of
thermoregulation, although it has been proposed that components of male sweat can act as
pheromonal cues
[1].
Evaporation of sweat from the skin surface has a cooling effect due to the
latent heat of evaporation of water. Hence, in
hot weather, or when the individual's muscles heat up due to exertion, more sweat is produced. Sweating is increased by nervousness and
nausea and decreased by cold. Animals with few sweat glands, such as
dogs, accomplish similar temperature regulation results by panting, which evaporates water from the moist lining of the oral cavity and
pharynx. Primates and horses have armpits that sweat similarly to those of humans.
How sweat glands operate
There are two kinds of
sweat glands, and they differ greatly in both the composition of the sweat and its purpose:
★ '
Eccrine sweat glands' are distributed over the entire body surface, but are particularly abundant on the palms of hands, soles of feet, and on the forehead. These produce sweat that is composed chiefly of water with various salts. These glands are used for body temperature regulation.
★ '
Apocrine sweat glands' produce sweat that contains fatty materials. These glands are mainly present in the armpits and around the genital area and their activity is the main cause of sweat odor, due to the bacteria that break down the organic compounds in the sweat from these glands.
See also
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Diaphoresis
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Hyperhidrosis
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Anhidrosis
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Hyponatremia
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Hyperthermia
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Body odor
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Hidradenitis suppurativa
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Pheromones
References
1. Smelling a single component of male sweat alters levels of cortisol in women", C. Wyart et. al., ''Journal of Neuroscience'', February 7, 2006
External links
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Sweating treatments, Causes and Information
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Male sweat boosts women's hormone levels -- from
UC Berkeley, February 2007
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The Effect of Male Sweat on Women's Hormone Levels -- from Science Daily, February 2007
★ K. Sato et. al.,
"Biology of sweat glands and their disorders", ''Journal of the American Academy of Dermatology'', April 1989
Further reading
★ Ferner S, Koszmagk R, Lehmann A, Heilmann W., ''Z Erkr Atmungsorgane''. 1990;175(2):70-5. 'Reference values of Na(+) and Cl(-) concentrations in adult sweat'
★ E. R. Nadel, R. W. Bullard, and J. A. Stolwijk, "Importance of skin temperature in the regulation of sweating", ''Journal of Applied Physiology'', Vol. 31, Issue 1, 80-87, July 1, 1971