Related to the function of nerves and muscles, especially referring to the communal unit of a given nerve and all of the muscle fibers that it innervates.

Function

---

The neuromuscular junction is the connection between an efferent nerve and muscle fibers controlled by this nerve. Transmission is universally mediated by acetylcholine released from the presynaptic terminal by the arrival of an action potential. The release of this neurotransmitter is mediated by fusion proteins on the membrane, and appears to be dependent on an influx of calcium ions. Once the acetylcholine is released into the synaptic cleft, it rapidly diffuses to the postsynaptic membrane where it binds to acetylcholine receptors. These, in turn, trigger a rapid influx of calcium into the muscle cells (mediated by foot proteins), triggering muscle contraction. The remaining acetylcholine in the synaptic cleft is rapidly degraded by acetylcholinesterase to prevent desensitization of the synapse.

Neuromuscular Disorders

---

Neuromuscular diseases are disorders where upper motor neurons lose ultimate control over muscles, causing eventual muscle atrophy or spasticity. These diseasease can can affect either:

1) The lower motor neuron leading to the muscle

2) The neuromuscular junction, also known as the synapse

3) The postsynaptic muscle