In the disease myathenia gravis, the body makes, by mistake, antibodies to its own actylcholine receptors molecules. These antibodies bind to and inactivate acetylcholine receptors on the plasma membrane of muscle cells. The disease leads to a progressive weakening of the patients motor responses. Early on, they may have difficulty opening their eyelids, for example. As the disease progresses,, most muscles weaken, and patients have difficulty speaking and swallowing. Eventually, impaired breathing can cause death. Now, I need to explain which step of muscle funtion is affected.