1. Loosening, lengthening, or lessening of tension in a muscle. 2. In nuclear magnetic resonance, r. is the decay in magnetization of protons after the direction of the surrounding magnetic field is changed; the different rates of r. for individual nuclei and tissues are used to provide contrast in imaging. [L. relaxatio (see relax)]
- cardioesophageal r. r. of the lower esophageal sphincter, which can allow reflux of acidic gastric contents into the lower esophagus, producing esophagitis.
- isometric r. decrease in tension of a muscle while the length remains constant because of fixation of the ends.
- isovolumic r. that part of the cardiac cycle between the time of aortic valve closure and mitral opening, during which the ventricular muscle decreases its tension without lengthening so that ventricular volume remains unaltered; the heart is never precisely isovolumetric (vs. isovolumic) except during long diastoles with a midiastolic period of diastasis. SYN: isovolumetric r..
- longitudinal r. in nuclear magnetic resonance, the return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90°; varies in rate in different tissues, taking up to 15 s for water. See TI. SYN: spin- lattice r., spin-spin r..
- spin- lattice r. SYN: longitudinal r..
- spin-spin r. SYN: longitudinal r..
- transverse r. in nuclear magnetic resonance, the decay of the nuclear magnetization vector at right angles to the magnetic field after the 90° pulse is turned off; the signal is called free induction decay. See T2. Cf.:longitudinal r..

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re·lax·ation .rē-.lak-'sā-shən, ri-.lak-, esp Brit .rel-ək- n
1) the act of relaxing or state of being relaxed <maximal abdominal \relaxation was not evident until at least five minutes after the injection (Lancet)>
2) the reduction of contractile force in a muscle or muscle fiber esp the lengthening that typically characterizes inactive muscles or muscle fibers

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(in physiology) the diminution of tension in a muscle, which occurs when it ceases to contract: the state of a resting muscle.

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re·lax·a·tion (re″lak-saґshən) 1. a lessening of tension. 2. a mitigation of pain.

Medical dictionary. 2011.

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  • RELAXATION — RELAXATI Détente psychosomatique contrôlée. Déjà en latin relaxatio signifiait relâchement d’un prisonnier et détente, repos. Le vieux français garda les deux sens, faisant de relaxation un doublet un peu pédant de relâchement (H. de Mondeville,… …   Encyclopédie Universelle

  • Relaxation — may refer to: *Human relaxation is the art and science of doing nothing regardless of the outer activity including physical and/or mental tension. A human condition of flowing vital energy binging about a state of improved health and well being.… …   Wikipedia

  • Relaxation — Re lax*a tion (r? l?ks ? sh?n;277), n. [L. relaxatio; cf. F. relaxation.] 1. The act or process of relaxing, or the state of being relaxed; as, relaxation of the muscles; relaxation of a law. [1913 Webster] 2. Remission from attention and effort; …   The Collaborative International Dictionary of English

  • Relaxation — (zum Teil synonym auch Relaxierung) bezeichnet in den Naturwissenschaften (insbesondere in Physik, Chemie, Materialwissenschaften) den Übergang eines Systems in seinen Grundzustand oder in einen Gleichgewichtszustand (häufig nach einer Anregung) …   Deutsch Wikipedia

  • Relaxation — (Таланг,Таиланд) Категория отеля: 2 звездочный отель Адрес: 92/2 Moo 2 T. Srisoonthorn, A …   Каталог отелей

  • relaxation — Relaxation. s. f. Terme de Droit Canon, qui n a guere d usage que dans cette phrase. Relaxation des peines Canoniques, qui signifie Diminution, ou entiere remission des peines Canoniques. On appelle, Relaxation de nerfs, La foiblesse qui survient …   Dictionnaire de l'Académie française

  • relaxation — relaxation. См. релаксация. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Relaxation — (lat.), Erschlaffung der Gewebe …   Meyers Großes Konversations-Lexikon

  • relaxation — index enjoyment (pleasure), informality, leave (absence), mitigation, mollification, pause, remis …   Law dictionary

  • relaxation — 1520s, “remission of a burden or penalty,” L. relaxationem (nom. relaxatio), noun of action from pp. stem of relaxare (see RELAX (Cf. relax)). Meaning “relief from hard work or ordinary cares” is from 1540s …   Etymology dictionary

  • relaxation — *rest, repose, leisure, ease, comfort Analogous words: amusement, diversion, recreation (see under AMUSE vb): relieving or relief, assuagement, alleviation, mitigation (see corresponding verbs at RELIEVE) …   New Dictionary of Synonyms

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