What are chemical messengers that traverse the synaptic gaps between neurons?

• A. Endocrine System
• B. Adrenal Glands
• C. Hormones
• D. Neurotransmitters

Answer: (D)

Neurotransmission uses chemical messengers that cross the tiny space between neurons to relay signals. When a nerve impulse arrives at the end of a neuron, neurotransmitters are released into the synaptic cleft. They travel across that gap and bind to receptors on the next neuron, either exciting or inhibiting it to continue the signal. This is fast, targeted communication that happens right where one neuron meets another.

The endocrine system, by contrast, operates through hormones released into the bloodstream by glands such as the adrenal glands. Hormones travel throughout the body and tend to produce slower, widespread effects on distant targets rather than signaling across a single synapse. That’s why hormones and the endocrine system are not the messengers responsible for crossing synapses. The chemical messengers that do cross synaptic gaps are neurotransmitters.