What is the role of a neurotransmitter?

A neurotransmitter plays a crucial role in the communication between nerve cells, also known as neurons. When a nerve impulse reaches the end of a neuron, neurotransmitters are released into the synaptic cleft, which is the gap between neurons. These chemical messengers travel across this gap to bind to receptors on the adjacent neuron, facilitating the transmission of the signal. This process is essential for various functions in the nervous system, including muscle contraction, regulation of mood, and the processing of information.

The other choices do not capture the function of neurotransmitters accurately. While generating electrical impulses is a function of nerve cells themselves in their signaling process, neurotransmitters specifically are responsible for bridging the communication gap between neurons rather than generating electrical signals. Similarly, while the transportation of nutrients to nerve cells is vital for cellular health, it is not the role of neurotransmitters. Coating nerve fibers is also unrelated to neurotransmitter function; this is typically the role of myelin, which insulates nerve fibers to enhance signal conduction. Thus, the correct answer effectively highlights the primary purpose of neurotransmitters in the nervous system.