| isometric contraction | Muscular contractions characterised by increase in tension without change in length. (12 Dec 1998) |
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| isometric contraction period | The time between closure of the atrioventricular valves and opening of the semilunar valves. (05 Mar 2000) |
| isometric | 1. Of equal dimensions. 2. In physiology, denoting the condition when the ends of a contracting muscle are held fixed so that contraction produces increased tension at a constant overall length. Compare: auxotonic, isotonic, isovolumic. Origin: iso-+ G. Metron, measure (05 Mar 2000) |
| isometric chart | A chart or graph that displays three dimensions on a plane surface. (05 Mar 2000) |
| isometric exercise | Exercise consisting of muscular contractions without movement of the involved parts of the body. (05 Mar 2000) |
| isometric period of cardiac cycle | That period in which the muscle fibres do not shorten although the cardiac muscle is excited and the pressure in the ventricles rises, extending from the closure of the atrioventricular valves to the opening of the semilunar valves (isovolumic constriction) or the reverse (isovolumic relaxation). (05 Mar 2000) |
| isometric relaxation | Decrease in tension of a muscle while the length remains constant due to fixation of the ends. (05 Mar 2000) |
| isometric relaxation period | Early ventricular diastole beginning with closure of the aortic and pulmonic valves and preceding opening of the atrioventricular valves. (05 Mar 2000) |
| isometric ruler | A calibrated scale for eliminating distortion in the measurement of plane surfaces. (05 Mar 2000) |
| isometric tension | Tension generated in a muscle without contraction occurring: cross bridges are being re formed with the same site on the thin filament and the tension (in striated muscle) is proportional to the overlap between thick and thin filaments. (18 Nov 1997) |
| isometric traction | Traction in which the length of the limb does not change. (05 Mar 2000) |
| anodal closure contraction | An obsolete term for the momentary contraction of a muscle under the influence of the positive pole when the electrical circuit is established. (05 Mar 2000) |
| anodal opening contraction | An obsolete term for the momentary contraction of a muscle under the influence of the positive pole when the circuit is broken. (05 Mar 2000) |
| atrial premature contraction | <cardiology> An premature heartbeat of atrial origin. Generally nonserious and typically exacerbated by stimulant use (for example alcohol, decongestants, caffeine, nicotine). (27 Sep 1997) |
| automatic contraction | In contrast to forced beat, an ectopic beat that arises de novo and is not precipitated by the preceding beat; thus escaped and parasystolic beat's are automatic. Synonym: automatic contraction. (05 Mar 2000) |