The speed at which an action potential could travel down the length of an axon would
A)increase,if the axon's diameter were increased.
B)decrease,if the neuron's cell body volume were decreased.
C)increase,if the myelin sheath were removed from the axon.
D)decrease,if the concentration of extracellular sodium were increased.

Question

Quizplus · Accepted Answer

The speed at which an action potential could travel down the length of an axon would increase if the axon's diameter were increased. This is because a larger diameter allows for less resistance to the flow of ions, which increases the speed of the action potential.

Answer: C 
 The speed at which an action potential could travel down the length of an axon would increase if the myelin sheath were removed from the axon. This is because the myelin sheath helps to insulate the axon and speeds up the transmission of the action potential. Removing the myelin sheath would slow down the transmission of the action potential.

The other options (B and D) are incorrect. Decreasing the neuron's cell body volume would not have a direct impact on the speed of an action potential, and increasing the concentration of extracellular sodium would actually increase the speed of the action potential, not decrease it.

The Speed at Which an Action Potential Could Travel Down