Function of Neuromuscular Junction
When the action potential arrives at the motor neuron terminus, calcium ions enter the motor neuron to stimulate the release of Ach from the synaptic vesicles.
ACh diffuses across the synaptic cleft to the motor end plate of the muscle fiber.
ACh binds to receptors on the motor end plate, triggering ion channels to open (by increasing membrane permeability).
Sodium ions flow through the open channels to enter the muscle cell, which initiates action potentials in the muscle cell.
Acetylcholinesterase breaks down the receptor-bound ACh.