An Action Potential Is Regarded as an Example of a Positive

question 63

Multiple Choice

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) Potassium permeability is about 25 times greater than sodium ions.
• B) Voltage gated potassium ion channels open slowly and remain open long enough to cause hyperpolarization.
• C) 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) The sodium potassium pump consistently moves ions as long as ATP is available, and regardless of membrane potential changes.