| REST | Raynaud's phenomenon, esophageal motor dysfunction, sclerodactyly, and telangiectasia [syndrome]; re... |
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| RP | radial pulse; radiopharmaceutical; rapid processing [of film]; Raynaud phenomenon; reactive protein;... |
| SSP | Sanarelli-Shwartzman phenomenon; subacute sclerosing panencephalitis; slice sensitivity profile; sub... |
| TRAP | carpal tunnel syndrome, Raynaud phenomenon, aching muscles, proximal muscle weakness [rheumatic diso... |
| CST | Contraction Stress Test |
| ectoplasmic tube contraction | <cell biology> Model for amoeboid movement in which it is proposed that protrusion of a pseudopod is brought about by contraction of the sub plasmalemmal region everywhere else in the cell thus squeesing the central cytoplasm forwards. See: frontal zone contraction theory. (18 Nov 1997) |
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| tonic contraction | Sustained contraction of a muscle, as employed in the maintenance of posture. (05 Mar 2000) |
| escape contraction | Escaped beat, an automatic beat, usually arising from the A-V junction or ventricle, occurring after the next expected normal beat has defaulted; it is therefore always a late beat, terminating a longer cycle than the normal. Synonym: escape contraction. (05 Mar 2000) |
| escape ventricular contraction | An escape beat arising in the ventricle. (05 Mar 2000) |
| excitation contraction coupling | <physiology> Name given to the chain of processes coupling excitation of a muscle by the arrival of a nervous impulse at the motor end plate to the contraction of the filaments of the sarcomere. The crucial link is the release of calcium from the sarcoplasmic reticulum and the analogy is often drawn between this and stimulus secretion coupling, that also involves calcium release into the cytoplasm. (18 Nov 1997) |
| uterine contraction | Contraction of the uterine muscle. (12 Dec 1998) |
| frontal zone contraction theory | Model proposed to account for the movement of giant amoebae in which cytoplasmic contraction at the front of the leading pseudopod (fountain zone) pulls viscoelastic cytoplasm forward in the centre of the cell and forms a tube of more rigid cytoplasm immediately below the plasma membrane behind the active region. The peripheral contracted cytoplasm relaxes into a weaker gel at the rear and is pulled forward in its turn. Contrasts with the ectoplasmic tube contraction model. (18 Nov 1997) |
| front-tap contraction | Contraction of the calf muscles when the anterior surface of the leg is struck. Synonym: Gowers' contraction. (05 Mar 2000) |
| adhesion phenomenon | A phenomenon manifested by the adherence of antigen-antibody-complement complex to "indicator cells" (microorganisms, platelets, leukocytes, or erythrocytes), the reaction being sensitive and specific for the antigen and antibody in the complex. Synonym: erythrocyte adherence phenomenon, immune adherence phenomenon, red cell adherence phenomenon. (05 Mar 2000) |
| AFORMED phenomenon | As induced pulsus alternans progresses, a state in which alternating heart depolarisations fail to eject any blood, thus allowing longer diastolic filling; the subsequent beat is then able to produce a significant ejection; at high rates the cardiac minute volume and blood pressure may appear normal. Origin: Alternating, failure of response, mechanical, to electrical depolarisation (05 Mar 2000) |
| all-or-nothing phenomenon | <physiology> Refers to the phenomenon where the strength of a nerve impulse is not dependent on the strength of the stimulus. Instead, there is a threshold level of stimulus strength that must be reached before the nerve will fire an impulse (at full capacity). Below the threshold, the nerve will not fire at all. <cardiology> It also refers to the same phenomenon observed in the heart muscle, which will either contract fully or not at all. <psychology> In studies of behaviour, it refers to the same phenomenon where a behavioural stimulus will either produce a complete response or no response at all. Also called all-or-nothing principle, all-or-none law, all-or-none responsiveness, etc. (15 Nov 1997) |
| Anrep phenomenon | Homeometric autoregulation of the heart whereby cardiac performance improves as the afterload (aortic pressure) is increased. (05 Mar 2000) |
| aqueous influx phenomenon | The filling of the aqueous vein, which normally carries blood and aqueous, with aqueous, when the junction of the aqueous vein and the recipient vein is partially occluded. Synonym: Ascher's aqueous influx phenomenon. (05 Mar 2000) |
| Arias-Stella phenomenon | Focal, unusual, decidual changes in endometrial epithelium, consisting of intraluminal budding, and nuclear enlargement and hyperchromatism with cytoplasmic swelling and vacuolation; may be associated with ectopic or uterine pregnancy. Synonym: Arias-Stella effect, Arias-Stella reaction. (05 Mar 2000) |
| arm phenomenon | In tetany, spasm both of the extensor muscles of the knee and of the calf muscles when the extended leg is flexed at the hip. Synonym: leg phenomenon, Pool-Schlesinger sign, Schlesinger's sign. In tetany, contraction of the arm muscles following the stretching of the brachial plexus by elevation of the arm above the head with the forearm extended, resembles the contraction resulting from stimulation of the ulnar nerve. Synonym: arm phenomenon. (05 Mar 2000) |