What is affected by myasthenia gravis?

Myasthenia gravis primarily affects the neuromuscular junction, which is the site where nerve cells communicate with muscle fibers to initiate movement. In this condition, antibodies disrupt the normal communication between the nerve and the muscle, leading to varying degrees of muscle weakness and fatigue.

The underlying problem is the autoimmune response where the body's immune system mistakenly attacks the acetylcholine receptors at the neuromuscular junction. This results in a reduced ability for muscles to contract effectively, particularly after sustained use. The symptoms often fluctuate throughout the day, worsening with activity and improving with rest, highlighting the direct impact on neuromuscular transmission.

Understanding myasthenia gravis in terms of its effect on the neuromuscular junction is crucial as it differentiates this disorder from those that would affect the brain, muscle fibers directly, or bone marrow, which are not the primary sites of impact in myasthenia gravis.