Here is a picture of the living pulp tissue extending out from a broken tooth. This is the artery, vein & nerve which is what extends down the root of the tooth. This is what is removed during a root canal, also known as endodontic therapy.
This is a image of the pulp chamber of a tooth showing how difficult root canal therapy is. A root canal is also known as endodontic therapy. Dentaltown Online Endodontic Continuing Education: Root Canal Anatomy Dictates Treatment Objectives by Dr.