the stage in action potential that immediately follows depolarization is known as the refractory period.
the stage in action potential that immediately follows depolarization is known as the refractory period.
the stage in action potential that immediately follows depolarization is known as?
the refractory period
once an action potential has occurred at a patch of membrane, the membrane patch needs time to recover before it can fire again. at the molecular level, this "absolute refractory period" corresponds to the time required for the voltage-activated sodium channels to recover from inactivation, i.e., to return to their closed state. there are many types of voltage-activated potassium channels in neurons. some of them inactivate fast (a-type currents) and some of them inactivate slowly or not inactivate at all; this variability guarantees that there will be always an available source of current for repolarization, even if some of the potassium channels are inactivated because of preceding depolarization. on the other hand, all neuronal voltage-activated sodium channels inactivate within several milliseconds during strong depolarization, thus making following depolarization impossible until a substantial fraction of sodium channels have returned to their closed state. although it limits the frequency of firing, the absolute refractory period ensures that the action potential moves in only one direction along an axon. the currents flowing in due to an action potential spread out in both directions along the axon. however, only the unfired part of the axon can respond with an action potential; the part that has just fired is unresponsive until the action potential is safely out of range and cannot restimulate that part. in the usual orthodromic conduction, the action potential propagates from the axon hillock towards the synaptic knobs (the axonal termini); propagation in the opposite direction—known as antidromic conduction—is very rare. however, if a laboratory axon is stimulated in its middle, both halves of the axon are "fresh", i.e., unfired; then two action potentials will be generated, one traveling towards the axon hillock and the other traveling towards the synaptic knobs.
action potential
the surge of depolarization traveling from the axon hillock to the axon terminal is known as an action potential. action potentials reach the axon terminal, where the action potential triggers the release of neurotransmitters from the neuron. the neurotransmitters that are released from the axon continue on to stimulate other cells such as other neurons or muscle cells. after an action potential travels down the axon of a neuron, the resting membrane potential of the axon must be restored before another action potential can travel the axon. this is known as the recovery period of the neuron, during which the neuron cannot transmit another action potential.
depolarization