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 in relation to heat. [L. potentia, power, potency]
- action p. the change in membrane p. occurring in nerve, muscle, or other excitable tissue when excitation occurs.
- after-p. afterpotential.
- bioelectric p. electrical potentials occurring in living organisms.
- biotic p. a theoretical measurement of the capacity of a species to survive or to compete successfully.
- brain p. the electrical charge of the brain as compared to a point on the body; the p. may be steady (DC p.) or may fluctuate at specific frequencies when recorded against time, giving rise to the electroencephalogram.
- brainstem auditory evoked p. responses triggered by click stimuli, which are generated in the acoustic nerve and brainstem auditory pathways; recorded over the scalp.
- chemical p. (μ) a measure of how the Gibbs free energy of a phase depends on any change in the composition of that phase.
- compound action p. the combined potentials resulting from activation of the auditory division of the eighth cranial nerve.
- demarcation p. the difference in p. recorded when one electrode is placed on intact nerve fibers or muscle fibers and the other electrode is placed on the injured ends of the same fibers; the intact portion is positive with reference to the injured portion. SYN: injury p..
- early receptor p. (ERP) a voltage arising across the eye from a charge displacement within photoreceptor pigment, in response to an intense flash of light.
- endocochlear p. the standing direct current p. in the endolymph relative to the perilymph, measuring positive 80 mV.
- evoked p. an event-related p., elicited by, and time-locked to, a stimulus. SEE ALSO: evoked response.
- excitatory junction p. (EJP) discrete partial depolarization of smooth muscle produced by stimulation of excitatory nerves; similar to small end-plate potentials. summate with repeated stimuli.
- excitatory postsynaptic p. (EPSP) the change in p. that is produced in the membrane of the next neuron when an impulse that has an excitatory influence arrives at the synapse; it is a local change in the direction of depolarization; summation of these potentials can lead to discharge of an impulse by the neuron.
- generator p. local depolarization of the membrane p. at the end of a sensory neurone in graded response to the strength of a stimulus applied to the associated receptor organ, e.g., a pacinian corpuscle; if the generator p. becomes large enough (because the stimulus is at least of threshold strength), it causes excitation at the nearest node of Ranvier and a propagated action p..
- inhibitory junction p. (IJP) hyperpolarization of smooth muscle produced by stimulation of inhibitory nerves.
- inhibitory postsynaptic p. (IPSP) the change in p. produced in the membrane of the next neuron when an impulse that has an inhibitory influence arrives at the synapse; it is a local change in the direction of hyperpolarization; the frequency of discharge of a given neuron is determined by the extent to which impulses that lead to excitatory postsynaptic potentials predominate over those that cause inhibitory postsynaptic potentials.
- injury p. SYN: demarcation p..
- membrane p. the p. inside a cell membrane, measured relative to the fluid just outside; it is negative under resting conditions and becomes positive during an action p.. SYN: transmembrane p..
- oscillatory p. the variable voltage in the positive deflection of the electroretinogram (β-wave) of the dark-adapted eye arising from amacrine cells.
- Ottoson p. SYN: electroolfactogram.
- oxidation-reduction p. (E0+) the p. in volts of an inert metallic electrode measured in a system of an arbitrarily chosen ratio of [oxidant] to [reductant] and referred to the normal hydrogen electrode at absolute temperature; it is calculated from the following equation; where R is the gas constant expressed in electrical units, T the absolute temperature (Kelvin), n the number of electrons transferred, F the faraday, and E0 the normal symbol for the p. of the system at pH 0; for biologic systems, E0′ is often used (in which pH = 7). Cf.:Nernst equation. SYN: redox p..
- S p. prolonged, slow, depolarizing or hyperpolarizing responses to illumination; initiated between the photoreceptor and ganglion cell layers of the retina.
- somatosensory evoked p. the computer-averaged cortical and subcortical responses to repetitive stimulation of peripheral nerve sensory fibers.
- spike p. the main wave in the action p. of a nerve; it is followed by negative and positive afterpotentials.
- thermodynamic p. free energy.
- transmembrane p. SYN: membrane p..
- ventricular late p. high-frequency microvolt electrocardiogram signals at the end of the QRS complex.
- visual evoked p. voltage fluctuations that may be recorded from the occipital area of the scalp as the result of retinal stimulation by a light flashing at 14-s intervals; commonly summated and averaged by computer.
- zeta p. the degree of negative charge on the surface of a red blood cell; i.e., the p. difference between the negative charges on the red cell and the cation in the fluid portion of the blood.
- zoonotic p. the p. for infections of subhuman animals to be transmissible to humans.
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po·ten·tial pə-'ten-chəl adj existing in possibility: capable of development into actuality
po·ten·tial·ly -'tench-(ə-)lē adv
potential n
1) something that can develop or become actual
2 a) any of various functions from which the intensity or the velocity at any point in a field may be readily calculated specif ELECTRICAL POTENTIAL
b) POTENTIAL DIFFERENCE
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po·ten·tial (po-tenґshəl) [L. potentia power] 1. existing and ready for action but not yet active. 2. the work per unit charge necessary to move a charged body in an electric field from a reference point (usually infinity) to another point, measured in volts. The difference in potential between two points is measured by the work necessary to move a unit positive charge from one to the other.Medical dictionary. 2011.