There is no single answer to this question because the central nervous system (CNS) is not comprised of five separate systems. The CNS is actually a single, unified system made up of two main parts: the brain and the spinal cord.
While the brain itself is a complex organ with many distinct regions and structures that perform specialized functions (such as the cerebrum, cerebellum, and brainstem as noted in sources like KidsHealth), it does not have separate, independent "systems" working in parallel. Similarly, the spinal cord, which acts as a vital communication pathway between the brain and the rest of the body, is also a single, continuous structure.
The references provided emphasize this point: they discuss the CNS as a whole, focusing on its function as the body's primary processing center responsible for awareness, movement, thought, speech, and senses. The references also mention studies and classifications of CNS tumors, further highlighting that the CNS is a single anatomical and functional unit. Therefore, the concept of "5 central nervous systems" is inaccurate.
