Describe what occurs at the neuronal synapse when the action potential reaches the axon terminal of the presynaptic neuron and a following EPSP. Use the following terms in your diagram or description: Depolarization, voltage gated calcium channel, axon, axon terminal, presynaptic membrane, post-synaptic membrane, synaptic cleft, vesicle, exocytosis, neurotransmitter, nonspecific cation channel.