Repolarization Health Dictionary

Repolarization: From 1 Different Sources


n. the process in which the membrane of a nerve cell returns to its normal electrically charged state after a nerve impulse has passed. During the passage of a nerve impulse a temporary change in the molecular structure of the membrane allows a surge of ions across the membrane (see action potential). During repolarization ions diffuse back to restore the charge and the nerve becomes ready to transmit further impulses. See refractory period.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Nerve Impulse

the electrical activity in the membrane of a *neuron that – by its rapid spread from one region to the next – is the means by which information is transmitted within the nervous system along the axons of the neurons. The membrane of a resting nerve is charged (polarized) because of the different concentrations of ions inside and outside the cell. When a nerve impulse is triggered, a wave of *depolarization spreads, and ions flow across the membrane (see action potential). Until the nerve has undergone *repolarization no further nerve impulses can pass.... nerve impulse

Q–t Interval

the interval on an *electrocardiogram between the beginning of ventricular depolarization (*Q wave) and the beginning of *repolarization (the T wave). See also long QT syndrome.... q–t interval

Refractory Period

(in neurology) the time of recovery needed for a nerve cell that has just transmitted a nerve impulse or for a muscle fibre that has just contracted. During the refractory period a normal stimulus will not bring about excitation of the cell, which is undergoing *repolarization.... refractory period

R On T Phenomenon

(in *electrocardiography) the superimposition of an R wave (ventricular *depolarization) on the T wave (ventricular *repolarization) of the preceding heartbeat. It may trigger ventricular fibrillation. See QRS complex; Q–T interval; S–T segment.... r on t phenomenon

S–t Segment

the segment on an *electrocardiogram that represents the interval between the end of ventricular *depolarization (QRS complex) and the beginning of ventricular *repolarization (T wave). The S–T segment is usually depressed by *ischaemia of the heart muscle but raised in the initial phase of myocardial infarction. It is therefore very useful for diagnosis in patients presenting with chest pain.... s–t segment



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