Answer:
Excitation is the process in which action potentials in the nerve fiber lead to action potentials in the muscle fiber. There is then a rapid fluctuation in membrane voltage at the motor end plate, called the end-plate potential. Areas of the sarcolemma near the motor plate have gates that open, moving ions, which causes the action potential that excites the muscle fiber. The process begins with a nerve signal stimulating a voltage-gated calcium ion channel to open, allowing the ions to enter the axon terminal. The ions stimulate the release of acetylcholine into the synaptic cleft.