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"Sweat" redirects here. For other uses, see Sweat (disambiguation).

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. Transpiration is the Evaporation of water from the aerial parts of Plants especially leaves but also stems Flowers and Roots Water is a common Chemical substance that is essential for the survival of all known forms of Life. For sodium chloride in the diet see Salt. Sodium chloride, also known as common salt, table salt, or Halite, is a Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants The skin contains two different groups of sweat glands: Apocrine sweat glands and Merocrine sweat glands. The skin is the outer covering of living tissue of an animal (or plant Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Sweat also contains the chemicals or odorants 2-methylphenol (o-cresol) and 4-methylphenol (p-cresol). Cresols are Organic compounds which are methyl[[phenol]]s They are a widely occurring natural and manufactured group of Aromatic Organic compounds p -Cresol, also 4-methylphenol, is a Phenol, with formula (CH3C6H4(OH

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]. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Thermoregulation is the ability of an Organism to keep its body temperature within certain boundaries even when temperature surrounding is very different A pheromone (from Greek φέρω phero "to bear" + ‘ορμόνη " Hormone " is a Chemical that triggers a natural Evaporation of sweat from the skin surface has a cooling effect due to the latent heat of evaporation of water. Evaporation is the process by which Molecules in a Liquid state (e In Thermochemistry, latent heat is the amount of Energy in the form of Heat released or absorbed by a substance during a change of phase Hence, in hot weather, or when the individual's muscles heat up due to exertion, more sweat is produced. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Sweating is increased by nervousness and nausea and decreased by cold. Nausea ( Latin: Nausea, Greek:, " Sea-sickness " also called wamble) is the sensation of unease and discomfort 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. The dog ( Canis lupus familiaris) is a domesticated Subspecies of the gray wolf, a Mammal of the Canidae family of the order The pharynx (plural pharynges) is the part of the Neck and Throat situated immediately Posterior to (behind the Mouth and Nasal Primates and horses have armpits that sweat similarly to those of humans.

Contents

Mechanism

Sweating is controlled from a center in the preoptic & anterior regions of the hypothalamus where thermosensitive neurones are located. The heat regulatory function of the hypothalamus is also affected by inputs from temperature receptors in the skin. High skin temperature reduces the hypothalamic set point for sweating and increases the gain of the hypothalamic feedback system in response to variations in core temperature. Overall though, the sweating response to a rise in hypothalamic temperature (‘core temp’) is much larger than the response to the same increase in average skin temperature.

Sweat is not pure water; it always contains a small amount (0. 2 - 1%) of solute . When a person moves from a cold climate to a hot climate, adaptive changes occur in their sweating mechanism. These are referred to as acclimatisation: the maximum rate of sweating increases and its solute composition decreases. The daily water loss in sweat is very variable: from 100 to 8,000 mls/day. The solute loss can be as much as 350 mmols/day (or 90 mmols/day acclimatised) of sodium under the most extreme conditions. In a cool climate & in the absence of exercise, sodium loss can be very low (less than 5 mmols/day). [Na+] in sweat is 30-65 mmol/l depending on degree of acclimatisation.

Composition

Sweat contains mainly water. It also contains minerals, as well as lactate and urea. Mineral composition will vary with the individual, the acclimatisation to heat, exercise and sweating, the particular stress source (exercise, sauna, etc. ), the duration of sweating, and the composition of minerals in the body. An indication of the minerals content is is: sodium 0. 9 gram/liter, potassium 0. 2 gram/liter, calcium 0. 015 gram/liter, magnesium 0. 0013 gram/liter[2]. Also many other trace elements are excreted in sweat, again an indication of their concentration is (although measurements can vary fifteenfold): zinc (0. 4 mg/l), copper (0. 3 - 0. 8 mg/l), iron (1 mg/l), chromium (0. 1 mg/l), nickel (0. 05 mg/l), lead (0. 05 mg/l). [3] [4]. Probably many other less abundant trace minerals will leave the body through sweating with correspondingly lower concentrations. In humans sweat is hyposmotic relatively to the plasma [5].

See also

References

  1. ^ Smelling a single component of male sweat alters levels of cortisol in women", C. Diaphoresis is excessive sweating commonly associated with shock and other Medical emergency conditions Primary hyperhidrosis is the condition characterized by abnormally increased Perspiration, in excess of that required for regulation of Body temperature. Anhidrosis means lack of Sweating. It is also known by a number of other names including Adiaphoresis, Ischidrosis Hyponatremia ( British: hyponatraemia) is an Electrolyte disturbance (disturbance of the salts in the blood in which the Sodium ( Natrium Hyperthermia, in its advanced state referred to as heat stroke or sunstroke, is an acute condition which occurs when the Body produces or absorbs more Body odor (spelled body odour outside the United States often abbreviated as B Hidradenitis suppurativa or HS is a Skin disease that affects areas bearing Apocrine sweat glands and Hair follicles such as the underarms groin A pheromone (from Greek φέρω phero "to bear" + ‘ορμόνη " Hormone " is a Chemical that triggers a natural Sweat therapy is the combination of group counseling/ Psychotherapy with group sweating Wyart et al. , Journal of Neuroscience, February 7, 2006
  2. ^ Sweat mineral-element responses during 7 h of exer...[Int J Sport Nutr Exerc Metab. 2007] - PubMed Result
  3. ^ Cohn JR, Emmett EA, The excretion of trace metals in human sweat. , Ann Clin Lab Sci. 1978 Jul-Aug;8(4):270-5. , http://www.ncbi.nlm.nih.gov/pubmed/686643
  4. ^ Saraymen et al. , Sweat Copper, Zinc, Iron, Magnesium and Chomium levels in national westler. 1973
  5. ^ BRS Physiology 4th edition, Linda S. Constanzo, page155

External links

Further reading

Dictionary

perspiration

-noun

  1. the action or process of perspiring
  2. a saline fluid secreted by the sweat glands
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