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.
A neuromuscular junction is a chemical synapse formed by the contact between a motor neuron and a muscle fiber. It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction. Muscles require innervation to functionâand even just to maintain muscle tone, avoiding atrophy. Synaptic transmission at the neuromuscular junction begins when an action potential reaches the presynaptic terminal of a motor neuron, which activates ...