| Nervous System | The telephone communication center of the body. All information from outside the body and from inside the body must pass through this system. The two parts of the nervous system include the Central and Peripheral Nervous systems. |
| Nerves | The extensions which branch off of the brain and spinal cord and carry information to all parts of the body. |
| Neural Canal | The opening in the spine through which the spinal cord passes. |
| Neurological | Pertaining to the nervous system. |
| Nucleus pulposus | The gelatinous mass in the center of the intervertebral disc. |