During physiology class, the instructor asks students to explain the pathology behind development of multiple sclerosis. Which student gave the most accurate description?

Question

A) The demyelination and subsequent degeneration of nerve fibers and decreased oligodendrocytes, which interfere with nerve conduction
B) Muscle necrosis with resultant increase in fat/connective tissue replacing the muscle fibers
C) Atherosclerotic destruction of circulation to the brain resulting in lactic acid buildup that affects nerve transmission
D) Autoimmune disease where antibody loss of acetylcholine receptors at the neuromuscular junction causes decrease motor response

Answer 1

Ans: A
Feedback:
Multiple sclerosis (MS) is an immune-mediated disorder that occurs in genetically susceptible individuals. The pathophysiology of MS involves demyelination and subsequent degeneration of nerve fibers in the central nervous system (CNS), marked by prominent lymphocytic invasion in the lesion. The infiltrate in nerve fiber (rather than vascular) sclerotic plaques contains CD8+ and CD4+ T cells as well as macrophages, which are thought to induce oligodendrocyte injury. With muscular dystrophy, the muscle undergoes necrosis, and fat and connective tissue replace the muscle fibers, which increases muscle size and results in muscle weakness. Now recognized as an autoimmune disease, myasthenia gravis is caused by an antibody-mediated loss of acetylcholine receptors in the neuromuscular junction.