What is the sequence of events in neuronal signaling when a nerve impulse is transmitted to the next neuron?

• A. Action potentials occur along the axon; at the synapse neurotransmitters are released and bind receptors on the next neuron.
• B. The neuron communicates only through chemical signals without electrical impulses.
• C. Dendrites generate action potentials and transmit directly to muscles.
• D. Neurotransmitters at the soma mediate signal without synaptic release.

Answer: (A)

Electrical signaling starts the process, with an action potential traveling along the axon to its terminal. When the impulse arrives, voltage-gated calcium channels open and calcium enters, triggering the release of neurotransmitter-filled vesicles into the synaptic cleft. The neurotransmitters diffuse across the gap and bind to receptors on the postsynaptic neuron, altering its membrane potential and potentially generating a new action potential if the signal is strong enough. This sequence—electrical signal along the axon, chemical release at the synapse, and receptor activation on the next neuron—is how the impulse is transmitted to the next neuron.

Other descriptions miss a key part of the process: signaling without an electrical impulse; dendrites not typically generating full action potentials that pass directly to muscles; or neurotransmitter action occurring at the soma without a synaptic release.