Which statement is true regarding how neurotransmitters influence neural impulses?

Neurotransmitters play a crucial role in communication within the nervous system. When released from a neuron, they travel across the synapse to bind with receptors on the surface of the receiving neuron. This binding can have various effects, primarily influencing whether or not the receiving neuron will generate an action potential and thus "fire."

The variability in the effects of neurotransmitters is what allows for complex signaling within the brain and nervous system. Some neurotransmitters can have excitatory effects, making it more likely for the neuron to fire, while others may have inhibitory effects, making it less likely to fire. Therefore, the statement that neurotransmitters can influence whether the neuron fires based on their binding is accurate and captures the essence of how these chemical messengers operate in neuronal communication.

In contrast, the other options do not accurately describe the full range of neurotransmitter functions. Neurotransmitters do not always inhibit receiving neurons; they do not exclusively trigger muscle contractions, as many also play roles in mood, cognition, and other processes; and they are not limited to acting only as signaling compounds in the blood, but rather in the context of synaptic transmission in the nervous system.