Physiology: Action Potentials & Nerve Signaling

What is the typical resting membrane potential of a multipolar neuron?

-70 mV

Which ion has the highest membrane permeability at rest, primarily determining the resting potential?

Potassium (K+)

What term describes the phase of the action potential where the membrane potential becomes more positive?

Depolarization

What is the rapid jumping of an action potential from one Node of Ranvier to the next called?

Saltatory conduction

Which principle states that an action potential occurs at full strength or not at all?

All-or-none principle

How many sodium and potassium ions does the Na+/K+ ATPase pump move, and in what directions?

3 Na+ out and 2 K+ in

During which period is it impossible to trigger a second action potential regardless of stimulus strength?

Absolute refractory period

What specific ion influx triggers the exocytosis of neurotransmitters at the presynaptic terminal?

Calcium (Ca2+)

What is the specific membrane potential level that must be reached to trigger an action potential?

Threshold potential (typically -55 mV)

Which ion movement is primarily responsible for the repolarization phase of the action potential?

Efflux of Potassium (K+)