Describe how an action potential is transmitted across a synapse

The arrival of an action potential at the end of the presynaptic neurone causes Ca2+ protein channels to open Ca2+ ions diffuse into the synaptic knob by facilitated diffusionCa2+ ions cause synaptic vesicles to fuse with the presynaptic membrane - releasing ACh inot the synaptic cleftACh molecules diffuse across the synaptic cleft and bind to Na+ ion channels on the presynaptic neuroneThis opens the Na+ ion channels, casuing Na+ to diffuse rapidly into the post synaptic neuroneThe influx of Na+ depolarises the post synaptic neurone - generating a new action potentialAcetylcholinesterase hydrolyses ACh into acetyl and choline. These diffuse back across into the presynaptic cleftATP released by mitochondria is used to recobine the choline and acetyl in the presynaptic cleft. This is then stored in vesicles for future use

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