Which statement best describes neurotransmitters and neurohormones?

Which statement best describes neurotransmitters and neurohormones?

• A. Neurotransmitters act locally at synapses; neurohormones travel through the bloodstream
• B. Neurotransmitters travel through the bloodstream; neurohormones act at synapses
• C. Neurotransmitters are produced by the brain; neurohormones are produced by the liver
• D. Neurotransmitters act globally; neurohormones act in the nervous system

Answer: (A)

Neurotransmitters are released from a neuron into the tiny gap at a synapse and act on local, nearby cells, producing fast, targeted responses. Neurohormones, on the other hand, are released into the bloodstream by neurosecretory cells and travel to distant targets throughout the body, producing slower but more widespread effects. This distinction—local, rapid signaling versus bloodstream-based, systemic signaling—is what the statement captures best. For example, acetylcholine at neuromuscular junctions works right where it’s released, while hormones like oxytocin or vasopressin travel through the blood to influence distant organs. The other options blur these routes or distance patterns (traveling in bloodstream vs acting at synapses, brain vs liver origin, or signaling as global vs nervous-system confined), so they don’t fit as accurately.

Neurotransmitters are released from a neuron into the tiny gap at a synapse and act on local, nearby cells, producing fast, targeted responses. Neurohormones, on the other hand, are released into the bloodstream by neurosecretory cells and travel to distant targets throughout the body, producing slower but more widespread effects. This distinction—local, rapid signaling versus bloodstream-based, systemic signaling—is what the statement captures best. For example, acetylcholine at neuromuscular junctions works right where it’s released, while hormones like oxytocin or vasopressin travel through the blood to influence distant organs. The other options blur these routes or distance patterns (traveling in bloodstream vs acting at synapses, brain vs liver origin, or signaling as global vs nervous-system confined), so they don’t fit as accurately.