isometric contraction period |
The time between closure of the atrioventricular valves and opening of the semilunar valves.
(05 Mar 2000) |
isotonic contraction |
Contraction of a muscle, the tension remaining constant. Since the contractile force is proportional to the overlap of the filaments and the overlap is varying, the numbers of active cross bridges must be changing.
(18 Nov 1997) |
opening contraction |
A contraction produced at the time of opening the circuit when using direct current to stimulate the muscle or a motor nerve.
(05 Mar 2000) |
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) |
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) |