Action Potentials

Front

What is an action potential?

Back

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

Front

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

Back

The sodium-potassium pump uses ATP to move sodium ions out of the cell and potassium ions into the cell, maintaining the resting membrane potential.

Front

What happens during depolarization?

Back

During depolarization, the membrane potential becomes less negative (more positive) due to the influx of sodium ions through sodium channels.

Front

What is repolarization in the context of action potentials?

Back

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

Front

Define polarity in the context of neurons.

Back

Polarity refers to the difference in charge across the neuronal membrane, with the inside being negatively charged relative to the outside.

Front

What is the significance of the threshold potential?

Back

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

Front

What occurs during the refractory period?

Back

During the refractory period, a neuron cannot fire another action potential, ensuring that signals only travel in one direction.

Front

How do sodium channels contribute to action potentials?

Back

Sodium channels open in response to depolarization, allowing sodium ions to rush into the cell, further depolarizing the membrane.

Front

What is the function of potassium channels during an action potential?

Back

Potassium channels open after depolarization, allowing potassium ions to exit the cell, which helps to repolarize the membrane.

Front

Explain the all-or-nothing principle of action potentials.

Back

The all-or-nothing principle states that once the threshold is reached, an action potential will occur fully; it cannot be partial.