The Arkansas Railroad Museum preserves the last steam-powered locomotive built in Arkansas and includes various artifacts of Arkansasâs railroad heritage. The Pine Bluff/Jefferson County Historical Museum opened in 1980 in the restored 1907 Union Pacific train depot.
myasthenia gravis. An autoimmune disease affecting neuromuscular junctions characterized by muscle weakness and fatigability. It is due to a destruction of acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction.
Terminology [edit]. In the United States the term motor neuron disease is often used interchangeably with amyotrophic lateral sclerosis. The other four motor neuron diseases are: primary lateral sclerosis, progressive muscular atrophy, progressive bulbar palsy and pseudobulbar palsy.n the United States the term motor neuron disease is often used interchangeably with amyotrophic lateral sclerosis.