Comparing the myelin sheath to the rubber coating of electrical wire

This is Science Today. Oftentimes when researchers describe the myelin sheath, which is the protective fatty coating around nerve fibers in the central nervous system, they use the analogy of the rubber coating over electrical wires.

“I think that’s a very useful analogy both because it helps people understand what the nerve cell is doing, but it also highlights the differences in between conduction in a biological tissue and conduction in an electrical wire.

Dr. Ari Green of the University of California, San Francisco explains that in conduction in an electrical wire, electrons flow down the wire at extremely fast rate; in biological tissues, it’s a much graded response, is much slower and is the result of the flow of charged particles across the surface of an axon.

“And in that way, myelin is kind of like the rubber in that it’s an insulating substance and so that’s the essential function of myelin is to preserve the speedy conduction of that electrical signal.”