Which part of a tooth contains nerves and blood vessels?

The pulp is the part in the center of a tooth made up of living connective tissue and cells called odontoblasts (cells of neural crest origin). The pulp is a part of the dentin–pulp complex (endodontium). The vitality of the dentin-pulp complex, both during health and after injury, depends on pulp cell activity and the signaling processes that regulate the cell's behavior.

The pulp is the neurovascular bundle central to each tooth, permanent or primary. It comprises a central pulp chamber, pulp horns, and radicular canals. The large mass of pulp is contained within the pulp chamber, which is contained in and mimics the overall shape of the crown of the tooth. Because of the continuous deposition of dentine, the pulp chamber becomes smaller with age. This is not uniform throughout the coronal pulp but progresses faster on the floor than on the roof or sidewalls.