Which system includes all nervous system structures outside the CNS, including cranial and peripheral nerves?

• A. Peripheral nervous system
• B. Central nervous system
• C. Autonomic nervous system
• D. Somatic nervous system

Answer: (A)

Outside the brain and spinal cord lies the peripheral nervous system, which includes all nerves reaching the rest of the body, such as the cranial nerves from the brain and the spinal nerves from the spinal cord. This network connects the CNS to muscles and organs, carrying sensory information to the brain and motor commands outward. The central nervous system is the brain and spinal cord, not the peripheral nerves. Within the peripheral nervous system are the somatic and autonomic systems: the somatic handles voluntary movements and external sensory input, while the autonomic manages involuntary functions like heart rate and digestion. Since the description specifies all structures outside the CNS, including cranial and peripheral nerves, the peripheral nervous system fits perfectly.