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Difference Between Depolarization and Repolarization

Main Difference

The main difference between Depolarization and Repolarization is that Depolarization is the loss of resting membrane potential because of the conversion of the polarization of the cell membrane, whereas Repolarization is the reestablishment of the resting membrane potential after each depolarization occurrence.

Depolarization vs. Repolarization

Depolarization is the changing of the potential of the cell membrane to an extra positive value; on the other hand, repolarization is the conversion in membrane potential by recurring to the negative value. The cell membrane consists of positive charges in depolarization, while the cell membrane has a negative charge in repolarization. During depolarization, the inner membrane becomes less negative and more positive, whereas, during repolarization, the negative charge on inner membrane returns.

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Depolarization is used to increase the membrane potential; on the other hand, repolarization is the process to restore the resting membrane potential by decreases the membrane potential. The depolarization assists in the boost of an action potential in the cell membrane; on the contrary, repolarization avoids the boost of an action potential. Sodium “m” voltage-gated channels are used in the depolarization; on the flip side, potassium “n” voltage-gated channels and various other potassium channels (A-type channels, delayed rectifiers, and Ca2+ activated K+ channels) are used in repolarization.

Depolarization is produced by the opening of sodium channels; conversely, repolarization is caused by the opening of potassium ion channels and the closing of the sodium channels. Depolarization generally results in exciting of effector organs, for example, muscular contractions; on the flip side, repolarization usually does not result in the prompt of the effector organ. There is present less polarity in the cell membrane in depolarization, whereas more polarity is present in the cell membrane in repolarization.

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Resting membrane potential does not get reestablished in depolarization; on the other hand, resting membrane potential brings back in repolarization. Depolarization generally activates a mechanical activity, while repolarization usually does not activate a mechanical activity. The value of membrane potential in depolarization in the cell membrane is -70mV; on the other hand, the value of membrane potential in repolarization in the cell membrane is+50mV.

Comparison Chart

DepolarizationRepolarization
Depolarization is considered as an activating method that takes place in the cell membrane that changes the polarization of it.Repolarization is the procedure of bringing back the cell membrane to the membrane resting potential.
Net Charge
Consists of positive charges in the cell membrane.The cell membrane has negative charges.
Change in the Membrane Potential
The inner membrane becomes less negative and more positive.The negative charge on inner membrane returns.
Membrane Potential
It used to increase membrane potential.The process to restore the resting membrane potential by decreases the membrane potential.
Action Potential
Assists in the boost of an action potential in the cell membraneAvoids the boost of an action potential
Channels Used
Sodium “m” voltage-gated channels are used.Potassium “n” voltage-gated channels and various other potassium channels are used.
Ion Channels
Caused by the opening of sodium channelsProduced by the opening of potassium ion channels and the closing of the sodium channels
Importance
Generally results in exciting effector organs, for example, muscular contractions.Usually does not result in the prompt of the effector organ.
Cell Membrane Potential
Present less polarity in the cell membrane.More polarity is present in the cell membrane.
Resting Membrane Potential
Resting membrane potential does not get reestablished.Resting membrane potential brings back.
Mechanical Activity
It generally activates a mechanical activity.Usually does not activate a mechanical activity.
Value of Potential
The value of the membrane potential in the cell membrane is -70mV.The value of the membrane potential in the cell membrane is +50mV.
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What is Depolarization?

The term depolarization defines as the depolarization is the loss of resting membrane potential because of the conversion of the polarization of the cell membrane. The resting membrane potential is considered as the potential through the cell membrane at rest, which is usually -70 mV. Hence, it proves that the interior of the cell is more negatively charged than the charge present outside the cell.

There is present less polarity in the cell membrane in depolarization, and it generally activates a mechanical activity of the cell membrane. Action potentials usually occur when protein channels of the neuron are releases in its membrane. Sodium “m” voltage-gated channels are used in the depolarization.

A depolarization current is produced by the opening of sodium channels when an action potential needs to speed up; this allows more sodium ions to enter into the cell. When more sodium ions enter into the cell; this usually results in the decrease of the negative charges present in the inside of the cell. The action potential generally speeds up when the resting membrane potential reaches -55 mV.

The membrane potential when across the cell membrane reaches +30 mV; this results in the transmission of nerve impulse in the method of an action potential. Depolarization generally results in exciting of effector organs, for example, muscular contractions. The whole depolarization-to-repolarization occurrence occurs in approximately two milliseconds, which allow neurons to a vigor action potential in fast rushes by allowing neuronal communication.

The Resting Membrane Potential Conserves By

  • The constant dispersion of potassium ions exterior to the cell
  • The accomplishment of the sodium-potassium pump, which drives three sodium ions exterior to the cell whereas taking two potassium ions into the cell
  • The presence of more negatively charged ions, for instance, phosphate ions and proteins in the inside of the cell

What is Repolarization?

The term repolarization defines as the restoration of the resting membrane potential after each depolarization occurrence. Repolarization is generally the occurrence by which membrane potential is recharged into its original resting membrane potential through the depolarization in the cell membrane.

The sodium channels that cause the less negative charge inside the cell membrane in depolarization, and excited the resting membrane potential to the action potential, are closed and now having opened potassium channels because of the presence of more positive ions inside the cell membrane which results in the transportation of potassium ions out of the cell by causing the interior of the cell more negative. Now, at last, the process of repolarization restores the resting membrane potential.

A cell usually brings back this form, or generally repolarizes the situation, through opening a protein push in the membrane, which is known as the sodium-potassium pump. In this pump, for every three sodium ions, it pumps in two potassium ones. The pumps continue doing this until the appropriate charge inside of a cell is gotten.

Unlike the depolarization occurrence, repolarization usually does not activate any mechanical activity through the prompt of the effector organ such as muscles. Though, repolarization is necessary for the transmission of the second nerve impulse through the depolarizing the second time by making the cell membrane ready.

The repolarization eventually results in the hyperpolarization stage in which the membrane potential develops extra negatively charged as compared to the resting potential before. The hyperpolarization is caused normally because of the diffusion of K+ ions from K+ channels outside the cell membrane or influx of Cl– ions from Cl– channels.

Key Differences

  1. Depolarization is known as the altering of the potential of the cell membrane to an extra positive value, while repolarization is known as the change in the membrane potential through the frequent negative value.
  2. In depolarization, the cell membrane contains positive charges, while in repolarization, the cell membrane contains a negative charge.
  3. The inner membrane turns into less negative and more positive during depolarization, whereas during repolarization, the negative charge on inner membrane revenues.
  4. The membrane potential is usually increased by the depolarization process; on the other hand, repolarization is used to reestablish the resting membrane potential by drops the membrane potential.
  5. In depolarization, the value of membrane potential is -70mV in the cell membrane; on the other hand, in repolarization, the value of membrane potential is +50mV in the cell membrane.
  6. In depolarization, there is existing minimum polarity in the cell membrane, whereas in repolarization, there is present maximum polarity in the cell membrane.
  7. The action potential in the cell membrane is enhanced by the help of the depolarization process; on the contrary, repolarization avoids the development of an action potential.
  8. In the depolarization, the channels which are used are usually sodium “m” voltage-gated channels; on the flip side, in repolarization, channels which are used are generally the potassium “n” voltage-gated channels and many other potassium channels.
  9. By the opening of sodium channels, the depolarization is produced; conversely, by the opening of potassium ion channels and the closing of the sodium channels, the repolarization is formed.
  10. Depolarization usually affects the excitement of many effector organs such as muscular contractions; on the flip side, repolarization generally does not result in the swiftness of the effector organ.
  11. In depolarization, the resting membrane potential does not get regenerated; on the other hand, in repolarization, the resting membrane potential regenerates.
  12. Depolarization triggers a mechanical action, while repolarization usually does not start a mechanical action.

Conclusion

The above discussion concludes that the cell membrane consists of positive charges in depolarization, while the cell membrane has a negative charge in repolarization. During depolarization, the inner membrane becomes less negative and more positive, whereas, during repolarization, the negative charge on inner membrane returns.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

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