Repolarization

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Repolarization

Repolarization (/riːˌpoʊləraɪˈzeɪʃən/) is a stage of the cardiac cycle when the heart's electrical conduction system recharges itself after a heartbeat. It is an essential process that allows the heart to prepare for the next heartbeat.

Etymology

The term "repolarization" is derived from the prefix 're-', meaning 'again', and 'polarization'. In this context, it refers to the restoration of the electrical potential of a cell membrane after a depolarization event.

Process

During repolarization, potassium ions (K+) move out of the cardiomyocytes (heart muscle cells), while sodium ions (Na+) and calcium ions (Ca2+) stay mostly outside. This ion movement is facilitated by ion channels in the cell membrane, specifically the potassium channels. The outflow of potassium ions restores the negative charge inside the cell, returning the membrane potential to its resting state and preparing the cell for the next depolarization.

Related Terms

  • Depolarization: The process that immediately precedes repolarization, where the membrane potential of a cell rapidly moves from negative to positive.
  • Hyperpolarization: A state where the membrane potential is more negative than the normal resting potential.
  • Action potential: The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.
  • Refractory period: The period of time during which a cell is incapable of repeating an action potential.

See Also

External links

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