Nerve Impulse and Action Potential Quiz

What is a nerve impulse primarily composed of?

• Flow of electrons

• Movement of charged particles

• Movement of neutrons

• Flow of protons

What ions are in high concentration outside the cell membrane when a neuron is at rest?

• Calcium ions

• Chlorine ions

• Potassium ions

• Sodium ions

What is the overall internal charge of a neuron at rest?

• Negative 55 millivolts

• Zero millivolts

• Negative 70 millivolts

• Positive 70 millivolts

What happens during depolarization?

• Calcium ions rush out of the cell

• Chlorine ions rush out of the cell

• Sodium ions rush into the cell

• Potassium ions rush into the cell

What triggers the opening of the potassium gate during an action potential?

• Influx of sodium ions

• Influx of potassium ions

• Efflux of potassium ions

• Efflux of sodium ions

What is the role of the sodium-potassium pump during the refractory period?

• Move potassium ions out of the cell

• Move sodium ions into the cell

• Move three sodium ions out and two potassium ions into the cell

• Move three potassium ions out and two sodium ions into the cell

What is the role of ATP in the sodium-potassium pump?

• To close potassium gates

• To open sodium gates

• To provide energy for moving ions against their concentration gradient

• To move ions down their concentration gradient

In which direction do action potentials move?

• From axon terminals to dendrites

• In both directions

• They do not move

• From dendrites to axon terminals

What is the local current in the context of nerve impulses?

• The flow of protons

• The flow of ions in a wave-like pattern

• The flow of electrons

• The flow of neutrons

What is the threshold potential for an action potential to begin?

• 55 millivolts

• -70 millivolts

• 0 millivolts

• -55 millivolts