Surfactant
A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue. In more technical terms, a surfactant is a surface active agent, the best known example being the lung surfactant that is produced shortly before birth and makes the alveolar surfaces hydrophobic and prevents the lung from filling with water.
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1. A surface-active agent, including substances commonly referred to as wetting agents, surface tension depressants, detergents, dispersing agents, emulsifiers, quaternary ammonium antiseptics, etc. 2. Those surface-active agents forming a monomolecular layer over pulmonary alveolar surfaces; lipoproteins that include lecithins and sphygomyelins that stabilize alveolar volume by reducing surface tension and altering the relationship between surface tension and surface area. [surface active agent]
- nonionic s. a s. without a charged moiety.
- zwitterionic s. a dipolar s..

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sur·fac·tant (.)sər-'fak-tənt, 'sər-. n a surface-active substance specif a surface-active lipoprotein mixture which coats the alveoli and which prevents collapse of the lungs by reducing the surface tension of pulmonary fluids
surfactant adj

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n.
a wetting agent. Pulmonary surfactant, secreted by type II pneumocyte, is a complex mixture of compounds (including lipids, protein, and carbohydrates) that prevents the air sacs (alveoli) of the lungs from collapsing by reducing surface tension. In its absence, as in the immature lungs of premature babies, atelectasis and respiratory distress syndrome will develop.

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sur·fac·tant (sər-fakґtənt) 1. surface-active agent. 2. in pulmonary physiology, a mixture of phospholipids (chiefly lecithin and sphingomyelin) secreted by the alveolar type II cells into the alveoli and respiratory air passages, which reduces the surface tension of pulmonary fluids and thus contributes to the elastic properties of pulmonary tissue.

Medical dictionary. 2011.

Look at other dictionaries:

  • Surfactant — ist ein englisches Kunstwort (surface active agent) und bedeutet „grenzflächenaktive Substanz“. Die englische Bezeichnung hat sich im Deutschen für eine spezielle, bedeutsame oberflächenaktive Substanz in der Lunge durchgesetzt. Von… …   Deutsch Wikipedia

  • surfactant — ● surfactant nom masculin (de surface et tensioactif) Molécule amphiphile qui, placée en solution diluée dans l eau, abaisse sa tension superficielle. Substance tapissant l intérieur des poumons. ● surfactant (synonymes) nom masculin (de surface… …   Encyclopédie Universelle

  • surfactant — [sʉr fak′tənt] n. [surf(ace) act(ive) a(ge)nt] any substance that is SURFACE ACTIVE …   English World dictionary

  • Surfactant — Surfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids. Etymology The term surfactant is a blend of surface acting agent . Surfactants are… …   Wikipedia

  • Surfactant — Sur|fac|tant [sə faektənt; engl. Kurzw. aus surface active agent = grenzflächenaktiver Stoff], das; s, s: 1) im dt. Sprachgebrauch unübliches Syn. für ↑ Tensid 2) in der Med. Bez. für ein die Innenfläche der Lunge auskleidendes System aus… …   Universal-Lexikon

  • surfactant — A surface active compound; the best known example of which is the lung surfactant that renders the alveolar surfaces hydrophobic and prevents the lung filling with water by capillary action. The lung surfactant is produced just at parturition,… …   Dictionary of molecular biology

  • Surfactant — Tensioactif Un tensioactif ou agent de surface est un composé qui modifie la tension superficielle entre deux surfaces. Les composés tensioactifs sont des molécules amphiphiles, c est à dire qu elles présentent deux parties de polarité différente …   Wikipédia en Français

  • surfactant — noun Etymology: surface active + ant Date: 1950 a surface active substance (as a detergent) • surfactant adjective …   New Collegiate Dictionary

  • surfactant — n. a wetting agent. Pulmonary surfactant, secreted by type II pneumocytes, is a complex mixture of compounds (including lipids, protein, and carbohydrates) that prevents the air sacs (alveoli) of the lungs from collapsing by reducing surface… …   The new mediacal dictionary

  • surfactant — ploviklis statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga teršalams šalinti nuo kietųjų paviršių. atitikmenys: angl. detergent; surfactant vok. Detergens, n; Detergent, n; synthetisches Reinigungsmittel,… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

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