sweat

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Related to sweat blood: hematidrosis

sweat

or

perspiration,

fluid secreted by the sweat glands of mammalian skin and containing water, salts, and waste products of body metabolism such as urea. The dissolved solid content of sweat is only one eighth that of an equal volume of urine, the body's main vehicle of salt excretion; however, excessive sweating may produce severe salt loss (see heat exhaustionheat exhaustion,
condition caused by overexposure to sunlight or another heat source and resulting in dehydration and salt depletion, also known as heat prostration. The symptoms are severe headaches, weakness, dizziness, blurred vision, and sometimes unconsciousness.
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). Human sweat glands are of two types, eccrine and apocrine. The eccrine glands, found everywhere on the body surface, are vital to the regulation of body temperature. Evaporation of the sweat secreted by the eccrines cools the body, dissipating the heat generated by metabolic processes. The release of such sweat is usually imperceptible; yet even in cool weather an individual will lose from 1 pt to 3 qt of fluid per day. Only when environmental conditions are especially hot or humid, or during periods of exercise or emotional stress, does the output of sweat exceed the rate of evaporation, so that noticeable beads of moisture appear on the skin. When such conditions are extreme, the body may lose up to 20 qt of fluid per day. Production of sweat is controlled by the temperature-regulating center of the hypothalamus. The apocrine glands, which occur only in the armpits and about the ears, nipples, navel, and anogenital region, are scent glands. They function in response to stress or sexual stimulation, playing no part in temperature regulation. The apocrines exude a sticky fluid quite different from the watery sweat of the eccrines. Apocrine fluid is rich in organic substances that are odorless when fresh but are quickly degraded by bacteria on the skin to produce characteristic odors. Copious sweating in the armpits comes not from the apocrines but from the eccrines interspersed among them.

Sweat

 

a colorless, slightly opalescent fluid secreted by the sweat glands.

Human sweat contains 98 to 99 percent water, about 0.1 percent urea, uric acid, creatinine, serine, fats, volatile fatty acids, cholesterol, and alkaline metal salts, including chlorides (NaCl predominates— about 0.3 percent), phosphates, and sulfates, as well as sulfuric acid esters and aromatic oxygen acids. The secretion of the sebaceous glands is always mixed with the sweat that gathers on the skin surface. The composition of sweat depends on the condition of the body, the intensity of sweat excretion, and the presence of various substances in the blood. Sweat may be acid, with a pH of 3.8–6.2, or alkaline, when there is decomposition of urea and production of ammonia. In man from 0.5 to 10 liters of sweat or more per day are excreted, depending on intensity of muscle work, temperature of the external environment, and the quantity of water imbibed. Thus, with heavy muscle work, sweat contains a significant quantity of lactic acid and nitrogenous substances. In pathological states, sweat may contain glucose (sugar diabetes), bile pigments, cystine (cystinuria), and sometimes erythrocytes (bloody sweat).

sweat

[swet]
(chemistry)
Exudation of nitroglycerin from dynamite due to separation of nitroglycerin from its adsorbent.
(metallurgy)
Exudate of low-melting-point constituents from a metal on solidification.
(physiology)
The secretion of the sweat glands. Also known as perspiration.
(science and technology)
Formation of moisture beads on a surface as a result of concentration.

sweat

1. the secretion from the sweat glands, esp when profuse and visible, as during strenuous activity, from excessive heat, etc.; commonly also called perspiration
2. Chiefly US an exercise gallop given to a horse, esp on the day of a race
References in periodicals archive ?
You need to get a good group of players together who are prepared to gel as a team, sweat blood for the cause and squeeze out those extra yards on the pitch.
And not only will Moyes sweat blood but so will his players.
We sweat blood for the NHS - I've lost count of the hours of overtime that I haven't claimed for.
I expect," he concludes, "that those Jesuits who pushed for this statement had to sweat blood, and will receive their well-earned service medals in the world to come.
Disappointed boss Ronnie Moore said: "What I expect is for them to sweat blood and that didn't happen today.
And, faced with the knowledge of his approaching demise, it is conceivable Jesus's emotional state caused him to sweat blood.
He's not match-fit yet after that thigh injury but you can't beat his willingness to sweat blood for the cause.
Brothers Tato (Garcia Bernal) and Beto (Luna) sweat blood and tears on the banana plantations to keep a roof above the head of their mama (Dolores Heredia).
The three leads sweat blood and tears, literally, to wring out every last chortle from the set-ups.
Whatever Boro's deficiencies this season, there's no doubting the desire of players like Redcar's own David Wheater to sweat blood for the cause.
I would much rather have our players at St Andrew's, who will sweat blood and tears for my club, than any over-rated prima-donna who is quite obviously looking for an easy meal ticket.
Aberdeen finished sixth last year after a late charge to make the top half before the split but Calderwood has warned his side must do better and they are set to sweat blood to achieve his aims.