What is the role of neurotransmitters in the nervous system?

• A. To provide structural support to neurons
• B. To transmit signals across synapses between neurons
• C. To convert stimuli into nerve impulses
• D. To protect the brain from pathogens

Answer: (B)

Neurotransmitters play a crucial role in the nervous system by transmitting signals across synapses, which are the junctions between neurons. When an electrical impulse, or action potential, reaches the end of a neuron (the presynaptic terminal), it triggers the release of neurotransmitters stored in vesicles. These chemical messengers cross the synaptic cleft and bind to specific receptors on the surface of the adjacent neuron (the postsynaptic neuron). This binding can initiate a new electrical impulse in the receiving neuron, allowing the communication between neurons to continue. This process is essential for various functions in the nervous system, including muscle contraction, sensory perception, and the regulation of mood and behavior.

Structural support to neurons is provided by glial cells, neurons do not convert stimuli into nerve impulses directly, and the blood-brain barrier primarily protects the brain from pathogens, not neurotransmitters.