What is the primary function of neurotransmitters in the nervous system?

The primary function of neurotransmitters in the nervous system is to transmit signals across synapses between neurons. Neurotransmitters are chemical messengers that facilitate communication between neurons by crossing the synaptic cleft, which is the small gap between the terminal of one neuron and the receptor sites on another neuron. When an electrical impulse reaches the end of a neuron, neurotransmitters are released into the synapse and bind to receptors on the neighboring neuron, allowing the signal to continue.

This process is essential for numerous physiological activities, including muscle contraction, reflexes, mood regulation, and cognitive functions like learning and memory. The release and binding of neurotransmitters can either excite or inhibit the receiving neuron, thus playing a critical role in the overall functioning of the nervous system. Understanding this mechanism is fundamental to fields such as neuroscience, psychology, and medicine, as it underpins many aspects of how we think and behave.