afterpotential

afterpotential
The small change in electrical potential in a stimulated nerve that follows the main, or spike, potential; it consists of an initial negative deflection followed by a positive deflection in the oscillograph record.
- diastolic a. in the heart, a transmembrane potential change following repolarization, which may reach threshold magnitude and cause a rhythm disturbance; often recorded in poisoning, as by digitalis overdosage.
- positive a. a spontaneous or inducible increase in transmembrane potential of a cardiac or nerve cell following the completion of repolarization. In the heart, this usually corresponds temporal to the electrocardiographic U wave.

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af·ter·po·ten·tial -pə-.ten-chəl n the sequence of electrical events that follows the action potential of nerve activity and that usu. takes the form of a negative followed by a positive potential with both being of much smaller amplitude than the action potential compare prepotential

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af·ter·po·ten·tial (af″tər-po-tenґshəl) the small action potential generated following termination of the spike or main potential; it has a negative and a positive phase.

Medical dictionary. 2011.

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  • afterpotential — noun A small, transitory electrical potential that follows, and is dependent upon the main potential produced when a nerve is stimulated; seen as a small positive or negative spike on an oscillograph output …   Wiktionary

  • afterpotential — ˈ ̷ ̷ ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷ noun Etymology: after (IV) + potential : the sequence of electrical events that follows the spike potential of nerve activity and that usually takes the form of a negative followed by a positive potential with both being of …   Useful english dictionary

  • positive afterpotential — the period following termination of the negative afterpotential, during which the potential of an excitable cell membrane is more negative than the resting potential. It is paradoxically called positive because it was first detected outside the… …   Medical dictionary

  • negative afterpotential — the period following termination of the spike potential during which there is a lag in the return of the potential of an excitable cell membrane to resting potential …   Medical dictionary

  • after-potential — afterpotential …   Medical dictionary

  • potential — 1. Capable of doing or being, although not yet doing or being; possible, but not actual. 2. A state of tension in an electric source enabling it to do work under suitable conditions; in relation to electricity, p. is analogous to the temperature… …   Medical dictionary

  • prepotential — A gradual rise in potential between action potentials as a phasic swing in electric activity of the cell membrane, which establishes its rate of automatic activity, as in the ureter or cardiac pacemaker. * * * pre·po·ten·tial pə ten chəl …   Medical dictionary

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