Action Potential

Front

What is an action potential?

Back

An action potential is a rapid, temporary change in the membrane potential of a neuron, allowing it to transmit signals along the axon.

Front

What is depolarization?

Back

Depolarization is the process where the membrane potential becomes less negative (more positive), typically due to the influx of sodium ions (Na⁺).

Front

What role does the sodium-potassium pump play in neurons?

Back

The sodium-potassium pump exchanges sodium (Na⁺) and potassium (K⁺) ions across the cell membrane, helping to maintain the resting membrane potential.

Front

When are potassium channels open during an action potential?

Back

Potassium channels are open during repolarization, allowing potassium ions (K⁺) to exit the cell and restore the negative membrane potential.

Front

What happens when the membrane potential reaches +30mV?

Back

When the membrane potential reaches +30mV, sodium channels close, potassium channels open, and repolarization begins.

Front

What is hyperpolarization?

Back

Hyperpolarization is when the membrane potential becomes more negative than the resting potential, often due to the efflux of potassium ions (K⁺).

Front

What is the significance of the threshold potential?

Back

The threshold potential is the critical level to which a membrane must be depolarized to initiate an action potential.

Front

What is the all-or-nothing principle in action potentials?

Back

The all-or-nothing principle states that once the threshold is reached, an action potential will occur fully; if the threshold is not reached, no action potential occurs.

Front

What is repolarization?

Back

Repolarization is the process of returning the membrane potential to its resting state after depolarization, primarily through the opening of potassium channels.

Front

What ions are primarily involved in depolarization?

Back

Sodium ions (Na⁺) are primarily involved in depolarization, as they rush into the cell when sodium channels open.