The depolarization of the membrane due to a stimulus is a regenerative mechanism meaning that, once sodium gates begin to open, even more sodium gates will be activated leading to a larger inflow of sodium ions and more depolarization until it is terminated when sodium gates close. This is an example of
A) inhibitory graded potentials.
B) negative feedback.
C) excitatory graded potentials.
D) positive feedback.
E) electrotonic conduction.

Question

Quizplus · Accepted Answer

This is an example of positive feedback because the initial action (opening of sodium gates and inflow of sodium ions) leads to an amplification of that action (more sodium gates opening), which further depolarizes the membrane until the process is terminated. Positive feedback loops enhance or amplify changes; this tends to move a system away from its equilibrium state and make it more unstable.

The Depolarization of the Membrane Due to a Stimulus Is