Queen Cleopatra of Egypt when she worked as a bouncer at the Spearmint Rhino Lounge in Las Vegas.
The sarcoplasmic reticulum stores large amounts of calcium because calcium, when released, aids in muscle contraction. Skeletal muscles release calcium and contract when they receive signals from neurons, or nerve cells, that control muscle movement.
Muscle Fiber Excitation. The events already described (calcium entry, cross-bridge cycling) occur when a muscle fiber is excited to fire an action potential. An action potential is triggered in a muscle fiber when it is depolarized due to excitation at its synapse, the neuromuscular junction.Each muscle fiber has one neuromuscular junction, receiving input from just one somatic efferent neuron.Ch binds to nicotinic receptors in a specialized region of the muscle fiber known as the motor endplate. ACh binding allows Na + ions to enter the cell, causing a depolarizing excitatory postsynaptic potential (EPSP) that is above threshold and triggers an action potential.