Knowledge Tree
depolarization
Also known as: depolarization, depolarizations
Facts (21)
Sources
Action potential: Definition, Steps, Phases | Kenhub kenhub.com 10 facts
claimA new action potential cannot be generated during the depolarization phase of a neuron because all voltage-gated sodium channels are already opened or are opening at their maximum speed.
claimAn action potential consists of three phases: depolarization, overshoot, and repolarization.
claimAction potentials propagate along the axon cell membrane until reaching the terminal button, where depolarization triggers the release of neurotransmitters into the synaptic cleft.
claimMyelin increases the speed of action potential propagation by increasing the thickness of the fiber and enabling saltatory conduction, where depolarization occurs only at the nodes of Ranvier.
claimAn action potential propagates along the neuronal membrane by sequentially depolarizing adjacent segments of the membrane, effectively causing a new action potential in each subsequent segment rather than moving as a single entity.
claimIn unmyelinated fibers, action potential propagation is significantly slower because every part of the axonal membrane must undergo depolarization.
claimThe absolute refractoriness subphase overlaps the depolarization phase and approximately two-thirds of the repolarization phase.
claimAn action potential consists of three primary phases: depolarization, overshoot, and repolarization.
claimHypopolarization is the initial increase of the membrane potential to the value of the threshold potential, which precedes depolarization.
claimDuring the depolarization phase, the threshold potential opens voltage-gated sodium channels, causing a large influx of sodium ions and making the inside of the cell more electropositive.
Neuroanatomy, Neuron Action Potential - StatPearls - NCBI Bookshelf ncbi.nlm.nih.gov 7 facts
claimThe speed of action potential propagation along an axon is primarily determined by the extent to which initial local currents spread before creating further depolarizations.
claimDepolarization occurs when the resting membrane potential becomes less negative, while hyperpolarization occurs when the resting membrane potential becomes more negative.
claimA neuronal action potential is generated when the negative inside potential of the neuron reaches a less negative threshold, which opens voltage-gated sodium channels and results in depolarization.
claimThe rapid depolarization or upstroke of the neuronal action potential is caused by the opening of voltage-gated sodium channels.
claimNeuronal action potentials reach the axonal terminal and cause depolarization of neighboring cells through synapses, facilitating synaptic transmission.
claimAction potential propagation along a neuron's axon occurs when local currents created by depolarization are strong enough to depolarize neighboring segments of the membrane to the threshold.
procedureThe generation of an action potential occurs in three stages: (1) depolarization, which changes the membrane potential from -60 mV to +40 mV primarily through sodium influx; (2) repolarization, which returns the membrane to its resting potential primarily through potassium efflux; and (3) after-hyperpolarization, which involves recovery from a slight overshoot of the repolarization phase.
Thinking about the action potential: the nerve signal as a window to ... frontiersin.org 4 facts
claimExperimental data indicates that the cell membrane of excitable plant cells sequentially condenses (freezes) and melts (relaxes-rarefaction) during the depolarization and repolarization phases of an action potential, respectively, which aligns with Kaufmann’s thermodynamic theory.
claimAxonal swelling and contraction coincide with the depolarization and repolarization phases of the action potential, respectively, and are associated with fluctuations in intracellular pressure.
claimTerakawa (1985) proposed that depolarization causes electrostriction, defined as the mechanical deformation of a dielectric insulator in the presence of an electric field, which underlies changes in membrane thickness and tension.
claimBishop (1956) described the change in membrane potential during action potential generation as a conveniently recorded sign of cell excitation, while suggesting that metabolic and electrochemical events behind depolarization may be more essential activities.