The membrane voltage level at which an action potential is triggered is termed the
A) refractory period.
B) hyperpolarization event.
C) threshold of excitation.
D) rate level.
E) equilibrium point.

Question

Quizplus · Accepted Answer

The threshold of excitation is the membrane voltage level at which an action potential is triggered. This is the point at which the membrane potential depolarizes enough to open voltage-gated ion channels and initiate the rapid depolarization phase of an action potential. The other options are not correct: 
A) refractory period refers to the time immediately after an action potential when the neuron is temporarily unable to fire another action potential 
B) hyperpolarization refers to a membrane potential that is more negative than the resting potential, making it harder for an action potential to be triggered 
D) rate level refers to the frequency of action potentials fired by a neuron 
E) equilibrium point is a term used in systems theory, and is not directly related to the biology of neurons.

The Membrane Voltage Level at Which an Action Potential Is