Question

Multiple sclerosis is a debilitating autoimmune disease that results in the loss of the insulation around neuron axons. What cell type is the immune system attacking, and how does this disrupt the transfer of messages by the nervous system?

Short answer

Immune system attacks the oligodendrocytes results in the loss of the insulating sheath around the axon of the neurons.

Step-by-step solution

Step1. Introduction   

A demyelinating disease is any condition that causes damage to the protective covering (myelin sheath) that surrounds nerve fibers in your brain, the nerves leading to the eyes (optic nerves) and spinal cord.

Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system. In this disorder, immune system attacks the myelin sheath or the cells that produce and maintain it.

Explanation 

In multiple sclerosis, the immune system attacks the oligodendrocytes.

The death of oligodendrocytes results in the loss of the insulating sheath around the axon of the neurons.

When the sheath is gone, the electrical impulses travel much more slowly down the length of the axon.