22. Myelin is basically the insulators of the axons. Myelin insures that the electrical signal along an axon is conserved and not lost to the environment around it. Much like the rubber around a copper wire. The patient has blurred vision because of inflammation of the optic nerve which is a common MS symptom.
23. Myelinated nerve fibers possess the fastest speed of propagation because as explained above, the impulse is insulated from the environment.