Myasthenia Gravis. Myasthenia gravis (MG) was first described by Thomas Willis in 1672. It is an acquired autoimmune disease with antibodies against the nicotinic acetylcholine receptor (AChR) at the neuromuscular junction or muscle-specific tyrosine kinase (MuSK). This leads to muscular weakness with easy 'fatiguability', which is worse on exercise and improves with rest. (read more here)
This video discusses the concept of the neuromuscular junction. This is the beginning of muscular contraction (the excitation steps) where ACh (acetylcholine) is the neurotransmitter of muscle contraction.