Nerve Impulse Flashcards

What is a nerve impulse?

an electrical current that travels along dendrites or axons due to ions moving through voltage-gated channels in the neuron's plasma membrane.

What causes voltage-gated channels to open or close?

changes in electrical voltage/charge around them/ changes in electrical membrane potential

What maintains the charge difference when a neuron is at rest?

Active transport using sodium-potassium pumps maintains the resting charge difference.

How does the sodium-potassium pump work?

It pumps sodium ions out of the cell and potassium ions into the cell.

Why does the inside of a resting neuron have a net negative charge?

Potassium can leak out through channels, but sodium cannot easily return, leaving the inside negative and the outside positive.

What is the resting membrane potential?

The difference in charge between the interior and exterior of a neuron at rest.

What begins a nerve impulse?

A stimulus disturbs the plasma membrane on a dendrite, causing sodium channels to open and sodium ions to enter.

What is depolarization?

When sodium floods into a region of the cell, making the inside locally positive and the outside negative.

What is an action potential?

A moving depolarization along the membrane caused by the opening of voltage-gated sodium channels.

What happens behind the action potential to restore resting potential?

Voltage-gated sodium channels close and voltage-gated potassium channels open, allowing potassium to flow out and repolarize the membrane.

How is the resting membrane potential fully restored after repolarization?

Sodium-potassium pumps restore ion concentrations and return the membrane to its resting state.