Cranial nerves and spinal nerves belong to which part of the nervous system?

• A. Endocrine system
• B. Lymphatic system
• C. Central nervous system
• D. Peripheral nervous system

Answer: (D)

The nervous system is organized into two main parts: the central nervous system and the peripheral nervous system. Cranial nerves and spinal nerves are part of the peripheral nervous system because they are outside the brain and spinal cord and connect the central nervous system to the rest of the body. They carry sensory information from the body to the brain and motor commands from the brain to muscles and glands. The central nervous system, by contrast, includes only the brain and spinal cord where information is processed. The other options refer to systems that aren’t about nerve pathways—endocrine uses hormones, lymphatic handles immunity and fluid balance—so they don’t describe where these nerves belong.