the change in electrical potential that occurs between the inside and outside of a nerve or muscle fiber when it is stimulated, serving to transmit nerve signals.
a localized change in electrical potential, from about –70 mV to +30 mV and back again, that occurs across a nerve fibre during transmission of a nerve impulse
action potential n.
The change in membrane potential occurring in nerve, muscle, or other excitable tissue when excitation occurs.
A momentary change in electrical potential on the surface of a neuron or muscle cell. Nerve impulses are action potentials. They either stimulate a change in polarity in another neuron or cause a muscle cell to contract.
The rapid change in electric potential that parts of a nerve cell undergo when a nerve impulse is generated. Unlike ordinary electric current, which consists of the flow of electrons, the action potential involves the movement of sodium and potassium ions across the cell membrane.
- Action picture
noun See action photograph Contemporary Examples He was also reported to be starring in an action picture called Cancun, which has gone by the wayside. Is He Sabotaging His Career? Kim Masters March 8, 2010 Historical Examples In the action picture there is no adequate means for the development of any full grown personal passion. […]
- Action replay
. noun the rerunning of a small section of a television film or tape of a match or other sporting contest, often in slow motion US and Canadian name instant replay
- Action reporter
a news reporter who reports to the public on matters of special interest to the consumer.
- Action shot
noun See action photograph Historical Examples Commander O’Brine jumped up so fast that the action shot him to the ceiling. Rip Foster in Ride the Gray Planet Harold Leland Goodwin
- Action sport
noun See extreme sport Contemporary Examples How can plain ink-on-paper compete with reading as an action sport? Do Literary Gimmicks Work? Caryn James April 19, 2011