Final answer:
Neurotransmitters are stored and released from axon terminals and axon varicosities, which are crucial for neuronal communication by allowing neurotransmitters to bind to adjacent neurons.
Step-by-step explanation:
Neurotransmitters are stored and released from A) axon terminals and B) axon varicosities. These are specialized endings of axons where the neurotransmitters are held in synaptic vesicles. When an action potential reaches the axon terminal, it triggers the release of these neurotransmitters into the synaptic cleft. The released neurotransmitters then bind to receptors on the dendrite of the adjacent neuron, facilitating the transfer of the signal to the next cell. Axon varicosities are swellings found along the axon that can release neurotransmitters into the extracellular space, affecting nearby cells. This process is essential for communication between neurons, muscles, and glands.