Final answer:
The statement is true; an action potential reaching the axon terminal triggers the release of neurotransmitter into the synaptic cleft due to the influx of Ca2+ ions which facilitate the fusion of neurotransmitter vesicles with the presynaptic membrane.
Step-by-step explanation:
The statement that when an action potential reaches the axon terminal, a quick burst of neurotransmitter is released into the synaptic cleft is true. During the transmission of a nerve impulse, when the action potential arrives at the axon terminal, it causes the opening of voltage-gated Ca2+ channels. This results in an influx of Ca2+ ions into the neuron's synapse.
Inside the end bulb or terminal button, the increased concentration of Ca2+ plays a crucial role in neurotransmitter release. The Ca2+ ions bind to proteins that are associated with synaptic vesicles, which contain the neurotransmitter. This binding helps vesicles to fuse with the presynaptic membrane, resulting in the release of their neurotransmitter contents through a process known as exocytosis. Released neurotransmitter molecules then travel across the synaptic cleft and can bind to receptors on the membrane of the receiving cell, potentially initiating another action potential.