A neurophysiologist is investigating reflexes in two different animals: a crab and a fish. Action potentials are found to pass more rapidly along the fish's neurons. What is a likely explanation?
A) The fish's axons are smaller in diameter than the axons in the crab.
B) The fish's axons are myelinated. The crab's axons are not myelinated.
C) The fish's axons are not myelinated. The crab's axons are myelinated.
D) There is a higher percentage of ion channels in the axons of the crab compared with the percentage of ion channels in fish axons.

Question

Quizplus · Accepted Answer

Myelination significantly increases the speed of action potential propagation along axons. The presence of myelinated axons in the fish would explain the faster transmission of action potentials compared to the crab, which has unmyelinated axons.

A Neurophysiologist Is Investigating Reflexes in Two Different Animals: a Crab