A synapse is a space between two neurons that serves as a junction through which nervous impulses pass in order for cellular communication to occur. The word synapse comes from the Greek term synaptein, meaning "to join."
Synapses are tiny regions of empty space through which nerve cells are able to transmit information to other cells. This occurs when a nerve impulse reaches the terminal point of a neuron, stimulating the nerve cell and causing the release of neurotransmitter molecules such as adrenaline, norepinephrine or dopamine.
Once neurotransmitters are activated by the nerve impulse, they are then released by the presynaptic membrane into the synaptic gap between nerve cells. The released neurotransmitters are then diffused through the synaptic gap, where they remain until they find a postsynaptic membrane to which they can bind themselves. After the neurotransmitters bind themselves to a receptor site, the information contained within the nervous impulse is then able to continue being transmitted until it reaches its destination. Through this process, the brain is able to communicate with the cells and tissues of the entire body via the electrical impulses of the nervous system. Synapses therefore serve a crucial function in transferring this information throughout the body.