Which part of the nervous system includes both sympathetic and parasympathetic divisions?

The correct answer is the autonomic division of the nervous system, which includes both the sympathetic and parasympathetic divisions. This part of the nervous system is responsible for regulating involuntary physiological functions, such as heart rate, digestion, and respiratory rate.

The sympathetic division prepares the body for stressful or emergency situations, often referred to as the "fight or flight" response. It increases heart rate, dilates pupils, and redirects blood flow to essential organs needed for immediate physical activity.

In contrast, the parasympathetic division promotes a state of relaxation and conserves energy by slowing the heart rate and stimulating digestive processes, often termed the "rest and digest" response. Together, these two divisions work to maintain homeostasis in the body, effectively balancing the body's responses to stress and relaxation.

Understanding this organization helps clarify how the autonomic nervous system manages various bodily functions without conscious effort, distinguishing it from the somatic nervous system, which controls voluntary movements and sensory information or the central nervous system, which comprises the brain and spinal cord. The peripheral nervous system encompasses both autonomic and somatic components, but it is the autonomic aspect that specifically includes the sympathetic and parasympathetic divisions.