Final answer:
Action potentials in a chemical synapse travel from the presynaptic terminal to the postsynaptic membrane, initiating neurotransmitter release which then affects the postsynaptic neuron.
Step-by-step explanation:
Action potentials at a chemical synapse travel from the presynaptic terminal to the postsynaptic membrane. The process begins when an action potential reaches the axon terminal, which then causes depolarization of the presynaptic membrane and opening of voltage-gated Na+ channels. This influx of Na+ ions leads to the opening of voltage-gated Ca2+ channels, and the resulting entry of calcium triggers the release of neurotransmitters stored in synaptic vesicles into the synaptic cleft.
The neurotransmitters then diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane. This can result in either excitation or inhibition of the postsynaptic neuron, depending on the nature of the neurotransmitter and receptors involved. Ultimately, the action potential is not physically transmitted across the synapse but rather prompts the release of neurotransmitters that bridge the gap to influence the postsynaptic cell.