Part of the nervous system, myelin is a membrane of adipose tissue that surrounds nerve fibers along their length to protect and insulate neurons.
This creates a kind of “cable” that allows electrical current to pass from one nerve to another, thus transmitting data.
When myelin is destroyed, the process leads to many problematic health conditions, including multiple sclerosis.
Nerves are like an electric wire. The message must travel along the nerve pathway to successfully get from point A to point B (e.g., from the brain to the fingertip). Electricity must be transported without being damaged, mixed, shared or diverted from its proper course. Therefore, myelin is like a layer of plastic insulation that surrounds an inner wire, the nerve. In addition, myelin speeds up conduction. So it’s also analogous to having a secondary coating on the wire, which reduces the resistance it faces to the electric current. The inner wire represents the series of axons and nerve cells that carry the electrical stimulus.
Myelin is made up of protein lipids, but it works slightly differently depending on where our nervous system is busy. Our body has a peripheral nervous system that branches off the spine and transmits information about sensory inputs, while the central nervous system determines how to respond to those inputs. Each of these systems synthesizes myelin in different ways, so complications can arise.
A dysfunction in the myelin of the nerve fibers causes the smooth transmission of information to be interrupted. Either the nerve impulses can be slowed down, so that we can’t pull our hand away in time, say, when there’s a burn in the pan, or they can be confused, say, when we can’t tell if the pan is hot. It’s almost as if our pet chewed on a wire, causing the device that the wire belongs to to malfunction. When problems occur in the nerves of the peripheral nervous system, they can lead to neuropathy, and when the damage affects the nerves of the central nervous system, multiple sclerosis is often diagnosed.
This serious disease (multiple sclerosis) leads to demyelination. Demyelination is an autoimmune reaction in which our body attacks its own healthy myelin, damaging and scarring its important covering. In later stages, the cells that produce myelin in the central nervous system, the oligodendrocytes, become so destroyed that they cannot be replaced, permanently weakening the entire nerve.