A scanning electron microscope picture of a nerve ending. It has been broken open to reveal vesicles (yellow and blue) containing chemicals used to pass messages in the nervous system. A nerve is an enclosed, cable-like bundle of axons (the long, slender projections of neurons) in the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons to peripheral organs. Vesicles are a basic tool used by the cell for organizing cellular substances. Vesicles are involved in metabolism, transport, and enzyme storage. They can also act as chemical reaction chambers.