Quiz on Action Potential Generation

What opens the voltage-gated Na+ channels?

• Hyperpolarization

• K+ efflux

• Resting potential

• Presence of stimulus

What is the threshold level for depolarization in many neurons?

• -70mV

• -55mV

• -40mV

• -30mV

What happens to the membrane potential when Na+ diffuses into the axon?

• It becomes more negative

• It hyperpolarizes

• It becomes slightly depolarized

• It remains unchanged

What is the action potential value generated?

• +10mV

• -55mV

• -70mV

• +30 or +35mV

What happens during the falling phase of the action potential?

• Membrane depolarizes

• K+ channels open

• Na+ channels open

• Resting potential is established

What maintains the resting potential?

• Sodium-potassium pump

• Voltage-gated Na+ channels

• Both sodium-potassium pump and passive ion channels

• Passive ion channels

What causes the inside of the membrane to become negative during repolarization?

• Cl- influx

• Ca2+ influx

• K+ efflux

• Na+ influx

What is the resting potential of the axon?

• -40mV

• -55mV

• -70mV

• -90mV

What happens to voltage-gated Na+ channels during the action potential?

• They remain open

• They become inactive

• They close immediately

• They open slowly

What is the phase called when the membrane potential becomes more negative than the resting potential?

• Repolarization

• Resting state

• Depolarization

• Undershoot (Hyperpolarization)