Neuron Action Potentials

Front

What is an action potential?

Back

An electrical impulse that travels along the axon of a neuron, caused by the rapid influx and efflux of ions, leading to a change in membrane potential.

Front

What occurs when a neuron reaches its threshold?

Back

The neuron receives enough stimulation to trigger the opening of voltage-gated sodium channels, leading to depolarization.

Front

What role do sodium ions (Na+) play in action potentials?

Back

Sodium ions diffuse into the neuron when sodium channels open, causing depolarization and the initiation of an action potential.

Front

What happens during repolarization of a neuron?

Back

Potassium channels open, allowing K+ ions to diffuse out of the neuron, restoring the negative charge inside the cell.

Front

What is the resting potential of a neuron?

Back

The electrical charge difference across the neuron's membrane when it is not actively transmitting an impulse, typically around -70 mV.

Front

What is the function of the sodium-potassium pump?

Back

To maintain the resting potential by pumping 3 Na+ ions out of the neuron and 2 K+ ions into the neuron.

Front

What is depolarization?

Back

The process during an action potential where the inside of the neuron becomes more positive due to the influx of Na+ ions.

Front

What is hyperpolarization?

Back

A state where the inside of the neuron becomes more negative than the resting potential, often due to excessive K+ efflux.

Front

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

Back

Once the threshold is reached, an action potential will occur fully; it cannot be partially triggered.

Front

What is the role of voltage-gated channels in action potentials?

Back

They open in response to changes in membrane potential, allowing specific ions to flow in or out, which is crucial for the propagation of action potentials.