What enables rapid communication through neuroelectrical circuitry?

• A. Blood flow
• B. Myelin sheath
• C. Neurotransmitters
• D. Hormones

Answer: (C)

Neurotransmitters provide the fast chemical bridge that makes communication in neural circuits rapid. When an action potential arrives at the presynaptic terminal, voltage-gated calcium channels open and vesicles containing neurotransmitters fuse with the membrane to release their contents into the synaptic cleft. The chemicals diffuse across the tiny gap in a fraction of a second and bind to receptors on the postsynaptic neuron, opening ion channels or triggering other signaling cascades that generate a new electrical response in the next neuron. This whole sequence happens in only a few milliseconds, allowing rapid transmission of signals through neural networks. While the myelin sheath speeds the electrical travel along axons and hormones or blood flow support overall function, it is the neurotransmitters that enable the immediate, rapid transfer of information between neurons at each synapse.