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.

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Definitions:

Brain Plasticity

The capacity of the nervous system to change its structure and function in response to experience or damage.

Proportions

The relationship in size, amount, degree, or number between two or more things; often involves mathematical ratio.

Presbyopia

A natural age-related decline in the eye's ability to focus on close objects, usually becoming noticeable in early to mid-adulthood.

Near Vision

The ability to see objects clearly at a close range.