Chapter 39, Problem 7TYK

Which of the following does not contribute to propagation of action potentials?

a. As the area outside the membrane becomes negative, itattracts ions from adjacent regions; as the inside of the membrane becomes positive, it attracts negative ions from nearby in the cytoplasm. These events depolarize nearby regions of the axon membrane.

b. The refractory period allows the impulse to travel in only one direction.

c. Each segment of the axon prevents the adjacent segments from firing.

d. The magnitude of the action potential stays the same as it travels down the axon.

e. Up to a limit, increasing the intensity of the stimulus increases the number of action potentials.