Final answer:
The amount of neurotransmitter released at the axon terminal of a sensory neuron is determined by the amount of calcium that enters the sensory receptor when voltage-gated Ca²⁺ channels open in response to an action potential.
Step-by-step explanation:
The amount of neurotransmitter released at the axon terminal of a sensory neuron is directly determined by the amount of calcium that enters the sensory receptor. This process is essential for initiating neurotransmitter release through exocytosis into the synaptic cleft between neurons, impacting synaptic transmission and ultimately influencing neural communication and the body's response to stimuli.
This influx of calcium causes neurotransmitter-containing vesicles to fuse with the presynaptic membrane and release their content into the synaptic cleft, where it can bind to receptors on the postsynaptic neuron. The strength or frequency of action potentials merely influences the number of times this release process occurs, while the depolarization at an interneuron's cell body is a subsequent event in a different neuron and does not directly affect the neurotransmitter release at the sensory neuron's axon terminal.