How many divisions make up the nervous system?

How many divisions make up the nervous system?

• A. 2
• B. 3
• C. 4
• D. 5

Answer: (B)

Think of the nervous system in terms of its main structural divisions. The central nervous system is the processing center, consisting of the brain and spinal cord. The peripheral nervous system includes all nerves that connect the CNS to the body, carrying signals to and from the brain and spinal cord. The autonomic nervous system is the part that governs involuntary functions—like heart rate, digestion, and breathing—and is often taught as its own division. When you count these as three distinct divisions, you get three in total. Some curricula only use two divisions (CNS and PNS) or add other subdivisions, but within this framework three divisions is the standard answer.

Think of the nervous system in terms of its main structural divisions. The central nervous system is the processing center, consisting of the brain and spinal cord. The peripheral nervous system includes all nerves that connect the CNS to the body, carrying signals to and from the brain and spinal cord. The autonomic nervous system is the part that governs involuntary functions—like heart rate, digestion, and breathing—and is often taught as its own division. When you count these as three distinct divisions, you get three in total. Some curricula only use two divisions (CNS and PNS) or add other subdivisions, but within this framework three divisions is the standard answer.