Which of the following describes the subdivisions of the autonomic nervous system?

• A. Somatic nervous system
• B. Central nervous system
• C. Sympathetic and Parasympathetic
• D. Peripheral nervous system

Answer: (C)

The autonomic nervous system is organized into two main divisions that balance how the body operates involuntarily. These two parts are the sympathetic and the parasympathetic systems. They typically have opposite effects to keep the body in balance: the sympathetic division readies the body for action—heart rate increases, airways widen, and blood is directed toward muscles—while the parasympathetic division promotes restoration and energy conservation—heart rate slows, digestion is stimulated, and activities that heal or restore are encouraged. The other options refer to larger parts of the nervous system rather than subdivisions within the autonomic system: the somatic nervous system handles voluntary movement and sensory input; the central nervous system comprises the brain and spinal cord; the peripheral nervous system includes all nerves outside the CNS and contains the autonomic system but isn’t itself the subdivision in question.