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Questions and Answers
During which phase of the cardiac action potential do the Na+ channels close, preventing further action potential production?
During which phase of the cardiac action potential do the Na+ channels close, preventing further action potential production?
Which phase of the cardiac action potential is referred to as the 'absolute refractory period'?
Which phase of the cardiac action potential is referred to as the 'absolute refractory period'?
What is a characteristic of the 'relative refractory period' in the cardiac action potential?
What is a characteristic of the 'relative refractory period' in the cardiac action potential?
Which phase of the cardiac action potential marks the transition from depolarization to repolarization?
Which phase of the cardiac action potential marks the transition from depolarization to repolarization?
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What happens to the Na+ channels during the plateau phase of the cardiac action potential?
What happens to the Na+ channels during the plateau phase of the cardiac action potential?
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In which phase of the cardiac action potential does repolarization occur?
In which phase of the cardiac action potential does repolarization occur?
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What characterizes phase 0 of the cardiac action potential?
What characterizes phase 0 of the cardiac action potential?
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Which phase of the cardiac action potential is characterized by a hundred-fold increase in sodium permeability?
Which phase of the cardiac action potential is characterized by a hundred-fold increase in sodium permeability?
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What is the defining feature of phase 1 in the cardiac action potential?
What is the defining feature of phase 1 in the cardiac action potential?
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During which phase of the cardiac action potential does the plateau phase occur?
During which phase of the cardiac action potential does the plateau phase occur?
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Which phase marks the complete repolarization in the cardiac action potential?
Which phase marks the complete repolarization in the cardiac action potential?
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At what membrane potential does the resting phase (phase 4) occur in cardiac myocytes?
At what membrane potential does the resting phase (phase 4) occur in cardiac myocytes?
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During which phase of the cardiac action potential does Na+ influx take place down its electrochemical gradient?
During which phase of the cardiac action potential does Na+ influx take place down its electrochemical gradient?
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Which phase is characterized by the membrane potential rising to between +20 and +30 mV?
Which phase is characterized by the membrane potential rising to between +20 and +30 mV?
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What causes the membrane potential to fall to a value close to the potassium equilibrium potential in phase 3?
What causes the membrane potential to fall to a value close to the potassium equilibrium potential in phase 3?
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Which event causes the release of a larger quantity of Ca++ from the sarcoplasmic reticulum in the cardiac action potential cycle?
Which event causes the release of a larger quantity of Ca++ from the sarcoplasmic reticulum in the cardiac action potential cycle?
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Which phase is characterized by K+ permeability beginning to increase and K+ leaving the cell at an increased rate?
Which phase is characterized by K+ permeability beginning to increase and K+ leaving the cell at an increased rate?
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At which stage of the cardiac action potential cycle does the membrane potential begin again from the resting potential?
At which stage of the cardiac action potential cycle does the membrane potential begin again from the resting potential?
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