Which statement best describes the Peripheral Nervous System?

• A. The brain and spinal cord
• B. The sensory and motor neurons that connect the CNS to the rest of the body
• C. Autonomic subdivisions only
• D. Nerves outside the brain and spinal cord

Answer: (B)

The Peripheral Nervous System is made up of the nerves and supporting tissues that extend from the brain and spinal cord to the rest of the body, carrying information between the CNS and every organ, muscle, and sensation. The best description emphasizes the two main kinds of signals that travel through these pathways: sensory signals going from the body to the CNS and motor signals traveling from the CNS to the body. This captures both the structure (neurons that connect the CNS to the rest of the body) and the function (communication back and forth).

The brain and spinal cord form the Central Nervous System, so describing the PNS as including only those would be inaccurate. Autonomic subdivisions are indeed part of the PNS, but they’re just subdivisions rather than the whole system. And while nerves outside the brain and spinal cord reflect a big part of the PNS, the term also encompasses the ganglia and the broad network that enables communication between the CNS and the body.