The function of neurotransmitters is to transmit signals across synapses between neurons in the nervous system. These chemical messengers are released from the presynaptic neuron and bind to specific receptors on the postsynaptic neuron, facilitating communication within the brain and throughout the body. Neurotransmitters play crucial roles in regulating a range of physiological processes, including mood, sleep, appetite, and cognition. Imbalances in neurotransmitter levels can lead to various disorders, highlighting their importance in maintaining homeostasis and ensuring proper functioning of the nervous system.