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Guilherme Mazui

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What is the Difference Between Depolarization and Repolarization?

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Depolarization and repolarization are processes that occur during the transmission of nerve impulses in cells, such as neurons and heart cells. They involve the changes in membrane potential, which are regulated by the opening and closing of ion channels. Here are the main differences between depolarization and repolarization:

  • Depolarization:
  • The movement of a cell's membrane potential to a more positive value.
  • Caused by the opening of voltage-gated sodium channels, allowing positively charged sodium ions to enter the cell.
  • Increases the membrane potential, making the inside of the cell less negative.
  • Facilitates the firing of an action potential.
  • Repolarization:
  • The change in membrane potential from a positive to a negative value.
  • Caused by the closing of sodium ion channels and the opening of potassium ion channels, allowing positively charged potassium ions to exit the cell.
  • Decreases the membrane potential and restores the resting membrane potential.
  • Prevents the firing of an action potential.

In the context of the heart, depolarization of heart cells leads to contraction, while repolarization leads to relaxation. The process of depolarization and repolarization creates the electrocardiogram (ECG) reading, which is caused by the electrical conduction system of the heart.

On this page
  • What is the Difference Between Depolarization and Repolarization?
  • Comparative Table: Depolarization vs Repolarization

    • Comparative Table: Depolarization vs Repolarization

    Here is a table comparing the differences between depolarization and repolarization:

    Feature Depolarization Repolarization
    Definition Depolarization is the process that causes an action potential due to the influx of Na+ ions into the neuron. Repolarization is the change in membrane potential that returns to its negative value, preventing the firing of an action potential.
    Membrane Potential Increases the membrane potential. Decreases the membrane potential and restores the resting membrane potential.
    Ion Channels Involved Caused by the opening of voltage-gated sodium channels. Caused by the closing of sodium ion channels and the opening of potassium ion channels.
    Effect on Action Potential Facilitates the firing of an action potential. Prevents the firing of an action potential.
    Polarity Change Causes the membrane potential to become more positive. Causes the membrane potential to become more negative.
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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.