-An action potential arrives at the presynaptic membrane-Ca2+ ion channels open-Ca2+ ions diffues into presynaptic knob-Acetylcholine/ neurotransmitter in vesicles-Vesicles move towards presynaptic membrane-Vesicles fuse with membrane-Acetylcholine released by exocytosis into synaptic cleft-Acetylcholine diffuses across synaptic cleft-Acetylcholine binds to receptors on the post synaptic membrane-Receptors cause Na+ channels to open-Na+ diffuses into post synaptic membrane-If threshold is reached an action potential is initiated