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What characterize repolarization the second phase of the action potential?
Wiki User
∙ 11y ago
Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.
Wiki User
∙ 11y ago
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What characterizes repolarization the second phase of the action potential?
Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.
What is the process called when sodium NA is pumped out of a nerve cell?
during action potentials, sodium and potassium cross the membrane of the synapse after the threshold of membrane potential is reached. There, sodium leaves the synapse and the membrane potential is now positive. this is known as depolarization. then during repolarization, the sodium channels close and the potassium channels open to stabilize the membrane potential. during this time, a second action potential cannot occur and this is an evolutionary advantage because it allows rest in the nerve cells and it allows the membrane potential to equalize.
What is synaptic facilitation?
an action will happen cause of axo-axonal syanapse,which can facilitate the nerve impulse transmitting from presynaptic membrane to post synaptic membrane. In the axo-axonal synapse one axon is secreting serotonin which can influence to close some of K+ channels in the other neuron to maintain a prolonged action potential by slowing down the repolarization. as long as action potential is there it can stimulate the presynaptic membrane to release neurotransmitters towards postsyanptic membrane so prolonged action potential will help to stimulate more the Post synaptic membrane and give a strong impulse this is called presynaptic facilitation
Generation of Action Potential?
1. Resting potential: all voltage-gates are closed. 2. At threshold, Sodium activation gate opens and Sodium permeability rises. 3. Sodium enters the cell (influx), causing an explosive depolarization to +30 mV, which generation the rising phase of action potential. 4. At peak of action potential, sodium activation gate closes and sodium permeability falls, which reduces the net movement of sodium into the cell. At the same time potassium activation gate opens and potassium permeability rises. . 5. Potassium leaves the cell (efflux), causing the repolarization to resting potential, which generates the falling phase of action potential. 6. On return to resting potential, sodium activation gates closes and inactivation gates opens, resetting channel for another depolarizing triggering event. 7. Further outward movement of potassium through still open potassium channels briefly hyperpolarize membrane, 8. Potassium activation gate closes and membrane returns to resting potential
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 characterizes repolarization the second phase of the action potential?
Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.
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
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
2 Define refractory period and differentiate between absolute and relative refractory periods?
refractory period is the interval between action potential , the absolute refractory period is the period in which second action potential can not be initiated but in relative refractory period the second action potential can be initiated by the more strong stimulus.
What is the cause of the relative refractory period?
The Refractory period is when a second action potential is possible, but unlikely; second action potential only if the stimulus is sufficiently strong. The refractory period helps to prevent backflow of Sodium.
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 are the advances in technology that characterize the in second generation in computer?
transistors
What is the process called when sodium NA is pumped out of a nerve cell?
during action potentials, sodium and potassium cross the membrane of the synapse after the threshold of membrane potential is reached. There, sodium leaves the synapse and the membrane potential is now positive. this is known as depolarization. then during repolarization, the sodium channels close and the potassium channels open to stabilize the membrane potential. during this time, a second action potential cannot occur and this is an evolutionary advantage because it allows rest in the nerve cells and it allows the membrane potential to equalize.
During which period can a second action potential be initiated by a larger than normal stimulus?
This the relative refractory period.
What is synaptic facilitation?
an action will happen cause of axo-axonal syanapse,which can facilitate the nerve impulse transmitting from presynaptic membrane to post synaptic membrane. In the axo-axonal synapse one axon is secreting serotonin which can influence to close some of K+ channels in the other neuron to maintain a prolonged action potential by slowing down the repolarization. as long as action potential is there it can stimulate the presynaptic membrane to release neurotransmitters towards postsyanptic membrane so prolonged action potential will help to stimulate more the Post synaptic membrane and give a strong impulse this is called presynaptic facilitation
Generation of Action Potential?
1. Resting potential: all voltage-gates are closed. 2. At threshold, Sodium activation gate opens and Sodium permeability rises. 3. Sodium enters the cell (influx), causing an explosive depolarization to +30 mV, which generation the rising phase of action potential. 4. At peak of action potential, sodium activation gate closes and sodium permeability falls, which reduces the net movement of sodium into the cell. At the same time potassium activation gate opens and potassium permeability rises. . 5. Potassium leaves the cell (efflux), causing the repolarization to resting potential, which generates the falling phase of action potential. 6. On return to resting potential, sodium activation gates closes and inactivation gates opens, resetting channel for another depolarizing triggering event. 7. Further outward movement of potassium through still open potassium channels briefly hyperpolarize membrane, 8. Potassium activation gate closes and membrane returns to resting potential
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.
