Myasthenia Gravis Is a Collection of Muscle Disorders That Cause

question 72

Multiple Choice

Myasthenia gravis is a collection of muscle disorders that cause muscle fatigue and weakness. What is the major mechanism?

• A) overproduction of acetylcholinesterase
• B) autoimmune destruction of nicotinic acetylcholine receptors
• C) demyelination of axons in motor pathways
• D) autoimmune destruction of L-type Ca²⁺ channels.
• E) a tumor that overproduces acetylcholine

---

Definitions:

Secondary Receptors

Protein molecules located on cell surfaces or within cells that bind to external signaling molecules after they have interacted with primary receptors, often amplifying the cellular response.

Chemoreceptors

Sensory receptors that respond to chemical stimuli, such as taste, smell, or changes in the blood's chemical composition.

Brainstem

The lower extension of the brain, connecting the cerebrum with the spinal cord, and controlling vital functions such as breathing and heart rate.

Cranial Nerves

Twelve pairs of nerves that are connected directly to the brain or brainstem and are responsible for motor and sensory functions of the head and neck.