refractory period(redirected from Refractory periods)
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an interval or division of time; the time for the regular recurrence of a phenomenon.
absolute refractory period the part of the refractory period from phase 0 to approximately −60 mV during phase 3; during this time it is impossible for the myocardium to respond with a propagated action potential, even with a strong stimulus. Called also effective refractory period.
blanking period a period of time during and after a pacemaker stimulus when the unstimulated chamber is insensitive to avoid sensing the electronic event in the stimulated chamber.
effective refractory period absolute refractory period.
ejection period the second phase of ventricular systole (0.21 to 0.30 sec), between the opening and closing of the semilunar valves, while the blood is discharged into the aorta and pulmonary artery. Called also sphygmic period.
gestation period see gestation period.
incubation period see incubation period.
isoelectric period the moment in muscular contraction when no deflection of the galvanometer is produced.
latent period a seemingly inactive period, as that between exposure to an infection and the onset of illness (incubation period) or that between the instant of stimulation and the beginning of response (latency, def. 2).
refractory period the period of depolarization and repolarization of the cell membrane after excitation; during the first portion (absolute refractory period), the nerve or muscle fiber cannot respond to a second stimulus, whereas during the relative refractory period it can respond only to a strong stimulus.
relative refractory period the part of the refractory period from approximately −60 mV during phase 3 to the end of phase 3; during this time a depressed response to a strong stimulus is possible.
safe period the period during the menstrual cycle when conception is considered least likely to occur; it comprises approximately the ten days after menstruation begins and the ten days preceding menstruation. See the section on fertility awareness methods, under contraception.
sphygmic period ejection period.
supernormal period in electrocardiography, a period at the end of phase 3 of the action potential during which activation can be initiated with a milder stimulus than is required at maximal repolarization, because at this time the cell is excitable and closer to threshold than at maximal diastolic potential.
vulnerable period that time at the peak of the T wave during which serious arrhythmias are likely to result if a stimulus occurs.
1. the period following effective stimulation, during which excitable tissue such as heart muscle and nerve fails to respond to a stimulus of threshold intensity (that is, excitability is depressed);
2. a period of temporary psychophysiologic resistance to further sexual stimulation that occurs immediately following orgasm.
the time from phase 0 to the end of phase 3 of the action potential, divided into effective and relative. In pacing terminology, the period during which a pulse generator is unresponsive to an input signal of specified amplitude. The effective refractory period is from phase 0 to approximately -60 mV during phase 3 of the action potential, a time during which it is impossible for the myocardium to respond with a propagated action potential, or even to a strong stimulus. The relative refractory period is from approximately -60 mV during phase 3 to the end of phase 3 of the action potential, the time during which a depressed response is possible to a strong stimulus. Also called refractory phase, refractory state.
refractory periodA component of the resolution phase, the fourth and final phase of Masters and Johnson’s four-stage model of physiological responses to sexual stimulation, which follows the orgasmic phase. During the refractory period, it is typically physiologically impossible for males to have additional orgasms: the male is sexually satiated physically, and the penis is flaccid and unerectable. Further stimulation of the now hypersensitive penis may even be painful. As further orgasm may be achieved by females following the first, they typically do not have a refractory period.
refractory periodCardiac pacing The time during which a pacemaker's sensing mechanism is nonresponsive–in full or in part to cardiac activity–eg, to a retrograde P-wave in a DDD pacemaker. See Pacemaker Sexuality A post-orgasm recovery period lasting from mins to hrs during which the penis is unerectable. See Erection.
re·frac·to·ry pe·ri·od(rĕ-frak'tŏr-ē pēr'ē-ŏd)
1. The time following effective stimulation, during which excitable tissue such as heart muscle and nerve fails to respond to a stimulus of threshold intensity (i.e., excitability is depressed).
2. A period of temporary psychophysiologic resistance to further sexual stimulation, which occurs immediately following orgasm.
refractory periodThe period immediately following the passage of a nerve impulse or the contraction of a muscle fibre during which a stimulus, normally capable of promoting a response, has no effect.
refractory periodthe period of inexcitability, that normally lasts about three milliseconds, during which the AXON recovers after it has transmitted an impulse. During the refractory period it is impossible for the axon to transmit another impulse, because the membrane is being repolarized by ionic movements at this time. During the absolute refractory period no NERVE IMPULSE can be transmitted, but during the relative refractory period an impulse can be transmitted providing the stimulus is strong.
re·frac·to·ry pe·ri·od(rē-frak'tŏr-ē pēr'ē-ŏd)
Duration following effective stimulation, during which excitable tissue fails to respond to a stimulus.
not readily yielding to treatment.
the period of depolarization and repolarization of the cell membrane after excitation; during the first portion (absolute refractory period), the nerve or muscle fiber cannot respond to a second stimulus, whereas during the relative refractory period, it can respond only to a strong stimulus.
myocardial refractory state
the myocardium is refractory to stimulation during the action potential period, excitability returning in the repolarization phase; initially there is a period of supernormality.