What is depolarization?

What is depolarization?

• A. Membrane remains at baseline
• B. Membrane returns to negative
• C. Membrane becomes more positive
• D. Membrane becomes more negative

Answer: (C)

Depolarization is when the neuron's membrane potential becomes less negative than its resting value, i.e., the inside of the cell becomes more positive. At rest, the inside is negatively charged relative to the outside. When depolarization occurs, voltage-gated Na+ channels open and Na+ rushes into the cell, reducing the polarity difference and making the interior more positive. This rising, more-positive state is what triggers the action potential if the threshold is reached. That’s why the correct description is that the membrane becomes more positive. The other statements describe other states: staying at baseline means no change, returning to negative refers to repolarization after the spike, and becoming more negative describes hyperpolarization.

Depolarization is when the neuron's membrane potential becomes less negative than its resting value, i.e., the inside of the cell becomes more positive. At rest, the inside is negatively charged relative to the outside. When depolarization occurs, voltage-gated Na+ channels open and Na+ rushes into the cell, reducing the polarity difference and making the interior more positive. This rising, more-positive state is what triggers the action potential if the threshold is reached.

That’s why the correct description is that the membrane becomes more positive. The other statements describe other states: staying at baseline means no change, returning to negative refers to repolarization after the spike, and becoming more negative describes hyperpolarization.