Depolarization repolarization and polarization sodium potassium
Answers
After a cell has been depolarized, it undergoes one final change in internal charge. Following depolarization, the voltage-gated sodium ion channels that had been open while the cell was undergoing depolarization close again. The increased positive charge within the cell now causes the potassium channels to open.
DEPOLARIZATION;
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Depolarization is the change in the electric charge of a cell which makes the inside of the cell more positive than the outside of the cell.
The voltage gated ion channels of the cell open in response to electrical stimuli, that is, excitatory stimuli which increase the voltage in the cell.
Positive sodium ions rush into the cell from these ion channels and change the electric charge of the inside of the cell from negative to positive.
REPOLARIZATION;
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Repolarization follows depolarization.
Voltage gated sodium ion channels close and potassium channels open as a result of the increased positive charge inside the cell.
Positive potassium ions move out of the cell, making the inside of the cell more negative; even slightly more negative than the resting potential due to overshoot (excessive amount of potassium ions rushing out of the cell), a process called hyperpolarization.
The resting potential is later re-established through sodium potassium ion pump and the closing of the voltage gated ion channels.
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