What are neurotransmitters?

Neurotransmitters are indeed chemical messengers utilized by neurons to communicate with each other and with other types of cells. When a neuron sends an impulse, it releases neurotransmitters into the synaptic cleft, which is the gap between neurons. These chemicals bind to specific receptors on the receiving neuron, leading to various outcomes depending on the type of neurotransmitter and receptor involved. This process is crucial for the functioning of the nervous system, allowing for rapid communication and coordination of bodily functions, such as movement, mood regulation, and sensory perception.

Other options describe different biological substances or functions. Hormones, for example, are involved in regulating metabolism and other bodily functions but operate through the endocrine system, not the nervous system. Proteins associated with muscle contraction play roles in the muscular system rather than in neural communication. Cells that defend against pathogens pertain to the immune system, which is separate from the functions of neurotransmitters. Understanding the role of neurotransmitters is fundamental to comprehending how the nervous system coordinates and controls various physiological processes.