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For a brief time after an action potential begins a muscle fiber or neuron cannot generate another action potential This time is called the?
five second silence
What is the period of time during which the neuron cannot generate another action potential called?
refractory period
What happens to the neuron after an action potential is fired?
After an action potential is fired, the neuron goes through a refractory period where it cannot fire another action potential immediately. During this time, the neuron resets its electrical charge and prepares for the next signal.
What is the absolute refractory period?
Absolute Refractory Period:It is the interval during which a second action potential absolutely cannot be initiated, no matter how large a stimulus is applied.ORAfter repolarization there is a period during which a second action potential cannot be initiated, no matter how large a stimulus current is applied to the neuron. This is called the absolute refractory period, and it is followed by a relative refractory period, during which another action potential can be generated
Why does regeneration of the action potential occur in one direction?
As the action potential passes an area on the axon, sodium channels are closed, preventing influx of more sodium ions. At the same time, voltage-sensitive potassium channels open, allowing the membrane potential to fall quickly. After this repolarization phase, membrane permeability to potassium remains high, allowing for the "afterhyperpolarization" phase. During this entire period, while the sodium ion channels are forced closed, another action potential cannot be generated except by a much larger input signal. This helps to prevent the action potential from moving backwards along the axon.
Are action potential and local potential reversible?
Under normal circumstances action potential will proceed unilaterally. An action potential cannot proceed down an axon and depolarize in the reverse direction on the same axon. It must carry information on one axon in one direction and then on another axon in a separate direction. In a lab you can depolarize neurons in the middle of an axon and it will depolarize bilaterally.
Absolute refractory period relative refractory period?
In absolute refractory period, none of channels are reconfigured, so that second active potential cannot be generated no matter how large the stimulus current is applied to the neuron. In contrast, in relative refractory period, some but not all of channels are reconfigured, another action potential can be generated but only by a greater stimulus current thatn that originally needed.
When can a second nerve impulse cannot be generated?
The generation of a second action in some neurons can only happen after a refractory period, when the membrane potential has returned it's base level or even more negative. This is because some types of Na+ channels inactivate at a positive potential and then require a negative potential to reset. Other neurons have other types of channels and can fire multiple action potentials to a single depolarization.
What happens during the refractory period?
The voltage-gated Na+ channels get deactivated, thus the sodium ions cannot diffuse into the cell and cause depolarisation and this also provides time for the membrane to prepare for its second action potential.
What is the hyperpolarization that occurs after repolarizing phase of action potential?
Hyperpolarization occurs because some of the K+ channels remain open to allow the Na+ channels to reset. This excessive amount of K+ causes hyperpolarization so the Na+ channels open to bring the potential back up to threshold.
Period of reploarization of the neuron during which it cannot respond to a second stimulus?
The absolute refractory period. This period occurs after the action potential has been initiated and is a result of inactivation of the sodium channels. These sodium channels would normally open up to allow sodium influx into the cell during an action potential. The absolute refractory period occurs during an ongoing action potential and is the period in which a subsequent action potential absolutely cannot be generated.This should not be confused with the relative refractory period which occurs immediately following the absolute refractory period (during membrane hyperpolarization). During this period a subsequent action potential is possible, but more difficult to attain.
What is the relationship between the absolute and relative refractory periods in the context of neuronal excitability?
The absolute refractory period is the time when a neuron cannot generate another action potential, regardless of the stimulus strength. The relative refractory period is the time when a neuron can generate another action potential, but only with a stronger stimulus. These periods help regulate neuronal excitability by ensuring that neurons fire in a controlled manner and prevent excessive firing.
