The action potential travels down the presynaptic neuron, depolarising the membraneCauses voltage-gated calcium channels to openCalcium ions cause the neurotransmitter to fuse with the membraneThe neurotransmitter is released into the synaptic cleft by exocytosisIt then binds to receptors on the post-synaptic neuronEnzymes then break down the neurotransmitter so it only produced a discreet signalThe action potential is carried along by causing depolarisation in the post-synaptic knob