Activity at an axon terminal: Neuron A is transmitting a signal at the axon terminal to neuron B (receiving). Features: 1.Mitochondrion. 2.synaptic vesicle with neurotransmitters. 3. Autoreceptor. 4.Synapse with neurotransmitter released (serotonin). 5. Postsynaptic receptors activated by neurotransmitter (induction of a postsynaptic potential). 6.Calcium channel. 7. Exocytosis of a vesicle. 8. Recaptured neurotransmitter.