Typically hovering around -70 millivatts, this negative charge inside the cell relative to the outside is not arbitrary. Repolarization and the Refractory Period Following the peak of depolarization, the cell cannot remain excited indefinitely.
How Depolarization Alters Cell Function and Electrical State
In neurons, the change in voltage at one point on the axon triggers the opening of adjacent voltage-gated sodium channels. Phase Ion Movement Channel State Resulting Voltage Resting High K+ out, Low Na+ in K+ channels open, Na+ channels closed -70 mV Depolarization High Na+ in Voltage-gated Na+ channels open +30 to +40 mV Repolarization High K+ out Voltage-gated K+ channels open -70 mV.
This sequential opening creates a domino effect, allowing the action potential to travel long distances without degradation. This polarized state ensures the cell is ready to respond to stimuli with precision and speed.
How Depolarization Alters Cell Function and Electrical State
The sodium-potassium pump then works to rebalance the ions, and the cell enters a refractory period—a brief window where it cannot fire again, ensuring action potentials move in one direction and preventing signal overlap. At its core, membrane depolarization represents a fundamental shift in the electrical state of a cell, moving the membrane potential toward a less negative value.
More About Membrane depolarization
Looking at Membrane depolarization from another angle can help expand the discussion and give readers a second clear paragraph under the same section.
More perspective on Membrane depolarization can make the topic easier to follow by connecting earlier points with a few simple takeaways.
