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Is the influx of sodium into the cell during depolarization greater than repolarization?
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What ion is rapidly moving into the cell during the depolarization period of an action potential?
Sodium.A positive ion (cation) that enters the cell (influx) rapidly when the membrane threshold is reached and the voltage gated sodium channels open.This occurs during the rising phase of an action potential, i.e. membrane depolarization beyond the threshold for activation.
Why can't an action potential be generated during the absolute refractory period?
Action potentials cannot be generated during the absolute refractory period, as not enough ion channels are able to respond to the stimulus, no matter how large it is. Using Na+ fast channels as an example, during depolarization the "gate" of the channel is opened, allowing for Na+ influx into the cell. However, during the repolarization phase, a second "gate" marks the closure of the cell, preventing any further movement of ions into the cell. However, this also means that the channel is unable to open again until the second gate is removed, and the first gate returns back into place.
What ion flows into a nerve cell when an axon's membrane depolarizes?
During the depolarization phase, sodium ions enter the cell through the open ion-channels (Na+ influx).
Is creation of an action potential part of the procsee of nerve conduction along an axon?
Indeed. You have saltatory conduction because of the presence of myelin in peripheral nerves, laid by Schwann cells. How AP is generated is via the following: WHen threshold potential is reached , voltage gated Na+ channels open, allowing huge Na+ influx. THis is called rapid depolarization. This is followed by a plateau phase, where the membrane potential is relatively flat because slow Ca2+ influx equalizes K+ efflux. The last thing is repolarization which is going to a negative membrane potential because more K+ channels open, Ca2+ channels closing and Na/K+ pump (Na+ pumped out, K+ in)
What is the primary action during depolarization of an action potential?
Sodium ions flow into the neuron via voltage-gated sodium ion channels, driving the membrane potential into the positive. Beyond the threshold, more sodium ion channels are opened, causing the influx of sodium further downstream, and the process repeats, propagating the action potential down the axon.
The greater influx of sodium ions results in what of the membrane?
depolarization
Describe the action of depolarization and repolarization?
Depolarization is due to the influx of Na+ which causes the cell's internal membrane to become more positive, leading to an action potential. Repolarization occurs when K+ leaves the cell causing the interior of the cell to become negative again.
What is the reversal of the resting potential owing to an influx of sodium ions called?
Is called depolarization.
The interior of the cell becomes less negative due to an influx of sodium ions?
Depolarization
What ion is rapidly moving into the cell during the depolarization period of an action potential?
Sodium.A positive ion (cation) that enters the cell (influx) rapidly when the membrane threshold is reached and the voltage gated sodium channels open.This occurs during the rising phase of an action potential, i.e. membrane depolarization beyond the threshold for activation.
What part of an ecg do atria contract?
Atrial depolarization occurs at the P wave. The atrial contraction occurs at the peak of the wave at the influx of calcium ions to prolong depolarization.
Binding of the neurotransmitters with muscle membrane receptors causes the membrane to become permeable to sodium resulting in the influx of sodium ions an what of the membrane?
depolarization
Why can't an action potential be generated during the absolute refractory period?
Action potentials cannot be generated during the absolute refractory period, as not enough ion channels are able to respond to the stimulus, no matter how large it is. Using Na+ fast channels as an example, during depolarization the "gate" of the channel is opened, allowing for Na+ influx into the cell. However, during the repolarization phase, a second "gate" marks the closure of the cell, preventing any further movement of ions into the cell. However, this also means that the channel is unable to open again until the second gate is removed, and the first gate returns back into place.
What ion flows into a nerve cell when an axon's membrane depolarizes?
During the depolarization phase, sodium ions enter the cell through the open ion-channels (Na+ influx).
When under what conditions will a local depolarization not lead to the action potential?
If ion pumps open to hyperpolarize the neuron (chloride ions flowing into the neuron) elsewhere, leading to a net polarization/hyperpolarization, then the action potential will not be created.In order for the AP to be induced, a NET depolarization (influx of cations) must be created above the membrane threshold.
Is creation of an action potential part of the procsee of nerve conduction along an axon?
Indeed. You have saltatory conduction because of the presence of myelin in peripheral nerves, laid by Schwann cells. How AP is generated is via the following: WHen threshold potential is reached , voltage gated Na+ channels open, allowing huge Na+ influx. THis is called rapid depolarization. This is followed by a plateau phase, where the membrane potential is relatively flat because slow Ca2+ influx equalizes K+ efflux. The last thing is repolarization which is going to a negative membrane potential because more K+ channels open, Ca2+ channels closing and Na/K+ pump (Na+ pumped out, K+ in)
What causes depolarisation of sarcolemma of muscle fibre?
An incoming action potential to an alpha motor neuron causes acetylcholine (Ach)release at the end plate, Ach binds to Ach receptors on the sarcolemma causing a sodium influx which causes depolarization.
