Resting Potential

resting potential

[′rest·iŋ pə‚ten·chəl] (physiology) The potential difference between the interior cytoplasm and the external aqueous medium of the living cell.

Potential, Resting

a potential difference between the contents of a cell or fiber and the extracellular fluid; the difference in potential is localized on the surface membrane. The membrane’s inner surface is charged electronegatively with respect to the outer surface.

Resting potential results from unequal concentrations of Na⁺, K⁺, and Cl^- ions on both sides of the cell membrane and from the membrane’s unequal permeability to these ions. In nerve and muscle cells, resting potential helps keep the membrane’s molecular structure ready for excitation in response to stimulation. All influences on a cell causing a prolonged and stable decrease in action potential result in decreased cell excitability or in total loss of the cell’s capacity to generate action potential. Such influences include metabolic disturbance, increase in extracellular content of K⁺ ions, and the effect of a strong electric current.

B. I. KHODOROV

resting potential

potential

[po-ten´shal] existing and ready for action, but not active.electric tension or pressure.action potential see action potential.after-potential the period following termination of the potential" >spike potential.auditory evoked potential in electroencephalography, changes in waves in response to sound; see also potential" >brainstem auditory evoked potential.brainstem auditory evoked potential that portion of the potential" >auditory evoked potential that comes from the brainstem; abnormalities can be analyzed to evaluate comas, to support diagnosis of multiple sclerosis, and to detect early posterior fossa tumors.cognitive event--related p's a diagnostic study that uses electroencephalographic equipment and a computer dedicated to analyze brain wave P300; this wave is a measure of the brain's active cognitive processing of information. The patient is instructed to complete a task that requires attention and information processing. A recording of brain wave activity as well as information related to cognitive function is produced.diastolic potential the transmembrane potential of the cell during electrical diastole" >diastole.maximal diastolic potential the most negative level attained during the cycle" >cardiac cycle by the cell membrane of a fiber that does not have a constant resting potential, occurring at the end of phase 3 of the action potential. In pacemaker cells this is a point of hyperpolarization.membrane potential the electric potential that exists on the two sides of a membrane or across the wall of a cell.resting potential (resting membrane potential) the difference in potential across the membrane of a cell when it is at rest, i.e., fully repolarized. In cardiac physiology this occurs during electrical diastole in pacemaker cells and continuously in nonpacemaker cells.spike potential the initial, very large change in potential of the membrane of an excitable cell during excitation.threshold potential the transmembrane potential that must be achieved before a membrane channel can open; it differs among the various cardiac membrane channels.potential (omaha) in the omaha system, a modifier" >problem modifier on the third level of the problem classification scheme, defined as the presence of health patterns, behaviors, or risk factors that may preclude optimal health even though specific signs and symptoms are absent.