Describe the synaptic transmission of a nerve impulse

-action potential arrives at the axon terminal 

-voltage gated calcium ion channels open (due to the influx of sodium),

-calcium ions diffuse into the synaptic knob

-synaptic vesicles containing the neurotranmitter, fuse to the pre synaptic membrane (example Ach)

-exocytosis of neurotransmitter into the synpatic cleft

-neurotransmitter diffuses across synpatic cleft, which binds to receptors

-if sufficient have bound to receptors and action potential is produced, traveling along the second neurone