Final answer:
Chemical messengers released from neurons that affect other neurons, muscle, or gland cells are called neurotransmitters. They are crucial for signal transmission in the central nervous system and play a role in many physiological and behavioral processes.
Step-by-step explanation:
Chemical messengers that are released from neurons onto other neurons, muscle cells, or gland cells are called neurotransmitters. Neurotransmitters are compounds that are released at the synapse of neurons to stimulate or suppress the actions of other cells. When a neuron is stimulated, it triggers the process of exocytosis, where vesicles containing neurotransmitters fuse with the neuronal membrane and release their contents into the synapse. The neurotransmitters then diffuse across this small gap and bind to receptors on the surface of the target cell.
Neurotransmitters play a crucial role in the transmission of signals within the central nervous system and can affect a wide range of bodily functions and behaviors. For example, dopamine, a well-studied neurotransmitter with the formula C8H11NO2, is involved in reward, motivation, and motor control. Abnormalities in dopamine signaling can lead to conditions such as Parkinson's disease and schizophrenia.