Q:Which of the following holds true regarding action potentials?
A
Irrespective of the magnitude of the stimulus, the magnitude of the action potential remains constant.
B
Axons are responsible for conduction of action potentials towards the nerve cell body.
C
Action potentials only occur in nervous cells in the human body.
D
An action potential is typically generated before the membrane depolarizes to the threshold potential.
The correct answer is A and the key to this question is to recall that no matter how strong a stimulus, as long as it passes the depolarization threshold, the resulting action potential will be the same magnitude. Answer B is incorrect because dendrites conduct action potentials towards the soma and axons conduct them away from the cell body. Answer C is incorrect because action potentials can be generated in muscle cells and even some plant cells. The muscle counterexample should stand out because it’s integral to how muscles work. Answer D is incorrect because the threshold potential must be crossed for depolarization to occur.
