The relative refractory period is where it is more difficult to fire another action potential for a period after the absolute refractory period ends. Which of the following is typically the largest contributor to the relative refractory period?Group of answer choicesThe membrane resistance on the axon is lower than at restThe voltage gated potassium channels are in a state where they cannot openThe membrane potential is more negative than restThe sodium concentration gradient has decreased due to the firing of the previous action potentialVoltage gate sodium channels are in a state where they cannot open
Question
The relative refractory period is where it is more difficult to fire another action potential for a period after the absolute refractory period ends. Which of the following is typically the largest contributor to the relative refractory period?Group of answer choicesThe membrane resistance on the axon is lower than at restThe voltage gated potassium channels are in a state where they cannot openThe membrane potential is more negative than restThe sodium concentration gradient has decreased due to the firing of the previous action potentialVoltage gate sodium channels are in a state where they cannot open
Solution
The largest contributor to the relative refractory period is typically the fact that "The voltage gated potassium channels are in a state where they cannot open."
Here's why:
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During an action potential, sodium channels open first, allowing sodium ions to rush into the neuron, which depolarizes the membrane.
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Shortly after, potassium channels open, allowing potassium ions to rush out of the neuron, which begins to repolarize the membrane.
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However, the potassium channels stay open a bit longer than necessary, which leads to an overshoot and the membrane potential becomes more negative than its resting state. This is known as hyperpolarization.
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During this hyperpolarized state, or the relative refractory period, it is more difficult (but not impossible) to initiate another action potential. This is because more positive charge (or a stronger stimulus) is needed to bring the membrane potential back to the threshold level to trigger another action potential.
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Therefore, the fact that the voltage gated potassium channels are still open and the membrane is hyperpolarized is the largest contributor to the relative refractory period.
Similar Questions
Which statement regarding refractory periods is true?Select one:Select the correct definitionThey allow neurons to fire an unlimited number of action potentials per unit of time.During the refractory period the cell requires a less intense stimulus to reach threshold.The refractory period arises in part due to the increase in sodium conductance across the membrane.The refractory period arises in part due to the decrease in potassium conductance across the membrane.The refractory period ends when the sodium channels are no longer inactivated
Which of the following helps create the refractory period for action potentials frequency in muscle and nerve cells?Group of answer choicesclosed activation gate on voltage gated sodium channelslag for restoration of resting membrane potential by sodium-potassium pumpinability to reach threshold potential for the cellclosed inactivation gate on voltage gated sodium channelsclosed gates on voltage gated potassium channels
What is a refractory period for a membrane?Multiple choice question.Initial part of an action potential when Na+ is rushing into the cell.Threshold potential needed to initiate an action potential.Period of time after an action potential when the membrane cannot send another action potential.
A refractory period is a time in which the plasma membrane becomes Blank______ to further stimulation.Multiple choice question.less sensitivemore sensitive
For a typical neuron, what limits the maximal frequency attainable of action potentials moving down an axon?Multiple ChoiceThe refractory periodThe types of ions contributing to the action potentialThe strength of each action potentialThe strengths of the graded potentials on the neuron cell body and/or dendrites
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