The myelin on myelinated neurons can be degraded or destroyed in diseases such as multiple sclerosis-a process called demyelination. If a myelinated neuron was affected by demyelination, how would this affect action potentials in that neuron?

Explanation:

Myelination is the process of generating myelin in neurons. In CNS,  oligodendrocyte make the  myelin sheath.

The main function of myelin is to increase the speed of electrical impulses  along the myelinated fiber.

Myelinated fibers lack voltage-gated sodium channels along the myelinated internodes,  having them only at the nodes of Ranvier though which the molecules moves.

Demyelination is the loss of the myelin sheath,  result due to some neurodegenerative autoimmune diseases, resulting in the decrease of the speed of action potential propagation.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!