释义 |
refractory period
refractory period n (Physiology) a period during which a nerve or muscle is incapable of responding to stimulation, esp immediately following a previous stimulation. In an absolute refractory period there is a total inability to respond; in an effective or relative refractory period there is a response to very large stimuli ThesaurusNoun | 1. | refractory period - (neurology) the time after a neuron fires or a muscle fiber contracts during which a stimulus will not evoke a responseneurology - the branch of medical science that deals with the nervous systembiological time - the time of various biological processes |
Refractory Period
refractory period[ri′frak·trē ‚pir·ē·əd] (neuroscience) A brief period of time following the stimulation of a nerve during which the nerve will not respond to a second stimulus. Refractory Period a brief period of disappearance or decrease in the excitability of nervous or muscle tissue. The refractory period begins immediately after the tissue’s reaction to a stimulus. refractory period
period [pēr´e-od] an interval or division of time; the time for the regular recurrence of a phenomenon.absolute refractory period the part of the period" >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 systole" >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.latency period 1. latent period.2. stage" >latency stage.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 (period" >absolute refractory period), the nerve or muscle fiber cannot respond to a second stimulus, whereas during the period" >relative refractory period it can respond only to a strong stimulus.relative refractory period the part of the period" >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 potential" >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.Wenckebach's period a usually repetitive sequence seen in partial heart block, marked by progressive lengthening of the interval" >P–R interval; see also beat" >dropped beat.re·frac·to·ry pe·ri·od1. 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. refractory period A 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 period Cardiac 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 period The 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 period the 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.AcronymsSeerepeaterrefractory period Related to refractory period: Relative refractory period, Absolute refractory periodWords related to refractory periodnoun (neurology) the time after a neuron fires or a muscle fiber contracts during which a stimulus will not evoke a responseRelated Words |