A local depolarization of a muscle fiber sarcolemma due to an initial influx of sodium is called a(n) ___.

a. End plate potential
b. action potential
c. refraction
d. repolarization


Answer is a. End plate potential  Binding of ACh molecules to ACh receptors at neuromuscular junction opens (ligand) gated ion channels that allow Na+ and K+ to pass; More Na+ diffuses in then K+ diffuses out and interior of sarcolemma becomes less negative (depolarization [local electrical event called, end plate potential)

Anatomy & Physiology

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