Action Potential Review

True/False: When the cellular membrane is at its resting potential, there are more sodium (Na+) ions inside the cell and more potassium ions (K+) outside of the cell.

• True

• False

True/False: At rest, a cellular membrane's potential is negative inside the cell and positive outside the cell.

• True

• False

What is the role of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

• It pumps sodium ions out and potassium ions into the neuron, against their concentration gradients.

• It allows sodium and potassium ions to flow down their concentration gradients.

• It equalizes the concentrations of sodium and potassium ions inside and outside the neuron.

• It generates action potentials by rapidly changing the permeability of the membrane to sodium and potassium.

During an action potential, what causes depolarization?

• K+ ions flowing out of the cell

• Na+ ions flowing into the cell

• Cl- ions flowing into the cell

• Ca2+ ions flowing out of the cell

Depolarization of a region of the cellular membrane causes ___-gated Na+ channels to open, allowing the influx of Na+ ions.

Briefly describe the mechanism by which Na+ ion influx in a region of the cellular membrane is able to depolarize neighboring regions.

What is the primary role of the Na+/K+ pump in action potential dynamics?

• To depolarize the membrane

• To depolarize the membrane

• To restore ion concentration gradients after an action potential

• To initiate the action potential

What is the significance of the refractory period during an action potential?

• It allows the neuron to fire action potentials more rapidly

• It prevents the backward propagation of an action potential

• It increases the membrane potential beyond the threshold level

• It decreases the duration of the action potential

What is the relationship between stimulus amplitude and response amplitude during an action potential? Select all that apply.

• Stimulus and response amplitude are positively correlated in a neuron

• Response amplitude in a neuron is the same regardless of stimulus amplitude, as long as the stimulus is above a certain threshold

• Stimulus and response amplitude are positively correlated in a nerve, up until a certain point

• Response amplitude in a nerve is the same regardless of stimulus amplitude, as long as the stimulus is above a certain threshold

Membrane depolarization at axon terminals causes synaptic vesicles to release ___, which bind to receptors on the post-synaptic cell.