Neurotransmitters released by neurons play a key role in the nervous system by relaying messages from one cell to another. Neurotransmitters are crucial for brain function and regulating all bodily functions, ranging from breathing and heart rate to reproduction. These chemicals also coordinate cognitive processes that enable us to focus on important information within the constant barrage of stimuli the brain receives from the external environment, otherwise known as our attention span.Two neur. Sign in to read more..