When membrane potential changes, we use the terms depolarization, hyperpolarization, and repolarization
Explain what is happening to the membrane potential in relation to the extracellular fluid during depolarization and hyperpolarization and how each phase could be achieved by negatively charged ions. Next, explain how it is possible for the membrane to be in both hyperpolarization and repolarization at the same time.
What will be an ideal response?
Answer: The terms depolarization and hyperpolarization describe the relationship in the potential difference between the intracellular and extracellular fluid. The intracellular fluid is typically negatively charged compared to the extracellular fluid when the cell is at rest. If that potential difference becomes greater (i.e., more negative), the cell is hyperpolarizing. This can be achieved when negatively charged ions move into the cell. When the potential difference decreases, (i.e., becomes less negative), the cell is depolarizing. This occurs when negatively charged ions leave the cell. The term repolarization is used when the cell membrane potential is returning to the resting membrane potential. Thus, after a depolarization, the membrane must hyperpolarize to return to the resting membrane potential (repolarization).
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