Nervous tissue transmits, receives, and reacts to information about changes in our internal and external environment.

CNS and PNS
- CNS = Central nervous system = Nerve tissue in the cranial cavity and the spinal canal.
- This includes the brain and spinal cord.
- PNS = Peripheral nervous system = Nerve tissue outside of the cranial cavity and spinal canal.
- This includes all peripheral nerves, cranial nerves, ganglia, and plexuses.