= Neuromuscular junction
A <neuromuscular junction> is the specialized <synapse> through which a somatic <motor neuron> excites a <skeletal muscle> fibre. Arrival of an <action potential> at the nerve terminal opens <voltage-gated calcium channels>; <calcium> entry triggers release of <acetylcholine>. Binding of <acetylcholine> to receptors on the muscle's motor end plate produces a local <depolarization> that normally triggers a <muscle> <action potential>.<Anatomy and Physiology 2e by J. Gordon Betts and others>[Section 10.3, Excitation-Contraction Coupling]{ref}
The electrical signal then initiates release of stored <calcium> within the <muscle> fibre, enabling contraction. Synaptic release and contraction are separate steps: the <acetylcholine> does not itself pull the contractile filaments. Breakdown of <acetylcholine> by <acetylcholinesterase> helps terminate the synaptic signal.<Anatomy and Physiology 2e by J. Gordon Betts and others>[Section 10.3, The Neuromuscular Junction and Sliding Filament Model]{ref}
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