Explain how a synapse between two neurons functions

When impulse arrives at pre-synaptic terminal, the depolarisation opens the voltage-gated Ca2+ ion channels. This causes Ca2+ to enter synapse due to differences in concentration. This causes the vesicles to bind to the membrane, open, and release the neurotransmitters into the cleft. Neurotransmitters diffuse across cleft to the post-synaptic membrane. They bind to receptors on ligand-gated ion channels. When acetylcholine is the neurotransmitter, it opens Na+ ion channels. The influx of Na+ ions in post synaptic neuron depolarises the membrane and causes a new action potential to form. This is an excitatory response. Neurotransmitter detaches from receptor, is broken down by enzymes, and is reabsorbed back into pre-synaptic membrane.