Autonomic nervous system Somatic nervous system Central Nervous System (CNS) Sympathetic nervous system Peripheral Nervous System (PNS) 1. Brain and spinal cord 2. Relays signals between the CNS and the rest of the body 3. Part of the PNS associated with the voluntary control of body movements via skeletal muscles. 4. Part of the PNS that regulates involuntary physiological processes including heart rate, blood pressure, respiration, digestion, and sexual arousal. 5. A division of the autonomic system that directs the body's rapid involuntary response to dangerous or stressful situations. A flash flood of hormones boosts the body's alertness and heart rate, sending extra blood to the muscles.