An action potential is regarded as an example of a positive feedback. Which of the following examples below best illustrates the positive feedback aspect of an action potential?
A) The sodium potassium pump consistently moves ions as long as ATP is available, and regardless of membrane potential changes.
B) Potassium permeability is about 25 times greater than sodium ions.
C) Voltage gated potassium ion channels open slowly and remain open long enough to cause hyperpolarization.
D) A threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarizing stimulus. This stimulus will open still more voltage gated sodium ion channels.
D
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