ATI Pathophysiology Practice Exam

The primary pathological change observed in multiple sclerosis (MS) is demyelination of nerve fibers. In MS, the immune system mistakenly attacks the myelin sheath that insulates nerve fibers in the central nervous system. This demyelination disrupts the normal transmission of electrical impulses along the nerves, leading to a variety of neurological symptoms. As the myelin is damaged, it results in slowed or blocked communication between the brain and the rest of the body.

While inflammation of blood vessels does occur in MS and contributes to the demyelination process, it is not the primary pathological change. The formation of plaques in the brain refers to the areas of demyelination that appear as lesions in imaging studies, but it is the underlying demyelination of the nerve fibers that is central to the disease's pathology. Degeneration of muscle tissue is not a characteristic change associated with MS itself; rather, it may be a secondary effect due to disuse or neurological impairment resulting from demyelination.