Animation of neurons firing in the brain. Neurons (nerve cells) are responsible for producing and receiving messages in the nervous system. Each cell has a body that receives messages from numerous dendrites, long processes that connect to other nerve cells. These signals are passed on to the dendrites of other nerve cells through a long axon. Connections between nerve cells are made at junctions called synapses, which feature a narrow gap across which chemical messengers called neurotransmitters carry the signal to the next nerve cell.