Final answer:
Neurotransmitters are stored in vesicles within axon terminals of neurons, and are released into the synaptic cleft to transmit signals to the next cell.
Step-by-step explanation:
Neurotransmitters are stored in vesicles within the axon terminals of presynaptic neurons. These vesicles contain molecules such as dopamine, which play a critical role in transmitting signals across the synaptic cleft during the process of neurotransmission.
When an action potential reaches the axon terminal, it triggers the opening of channels that allow calcium to enter.
This influx of calcium ions then causes the synaptic vesicles to fuse with the presynaptic membrane, releasing neurotransmitters into the synaptic cleft where they can bind to receptors on the postsynaptic cell.