How do neurotransmitters transmit action potentials across synapses?

The process can be broken down into 3 main stages. 1 - An Action Potential triggers Calcium Influx: when the action potential arrives at the synaptic knob of the presynaptic neurone, it stimulates voltage-gated calcium ion channels to open, causing an influx of calcium ions into the synaptic knob. 2 - Calcium Influx causes Neurotransmitter Release: the influx of calcium ions causes synaptic vesicles to move towards the presynaptic membrane and fuse with it, releasing neurotransmitters into the synaptic cleft by exocytosis. 3 - Neurotransmitters trigger an Action Potential in the Postsynaptic Neurone: neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the postsynaptic membrane, which causes sodium ion channels to open, causing an influx of sodium in the postsynaptic membrane. The influx of sodium causes depolarisation, and if the level of depolarisation reaches the threshold voltage, an action potential is generated in the postsynaptic neurone.