Which system regulates processes like digestion and heart function during relaxation?

The correct choice focuses on the role of the Parasympathetic Nervous System, which is responsible for regulating bodily functions when a person is at rest. This system is often referred to as the "rest and digest" system, as its main purpose is to conserve energy and promote maintenance activities in the body.

During periods of relaxation, the Parasympathetic Nervous System activates processes such as digestion, slowing the heart rate, and enhancing blood flow to the gastrointestinal tract. This is in direct contrast to the Sympathetic Nervous System, which prepares the body for "fight or flight" responses during stress, and is associated with elevated heart rates and suppressed digestive activity.

The Somatic Nervous System primarily controls voluntary movements of skeletal muscles, and while it plays a vital role in human movement, it does not regulate involuntary functions such as those involved in digestion or heart regulation during restful states. The Cerebral Cortex, while important for complex functions such as thinking, perception, and voluntary actions, does not directly manage internal organ functions like the heart and digestive system.

Thus, recognizing the function of the Parasympathetic Nervous System is crucial in understanding how the body maintains homeostasis during relaxation by managing essential involuntary processes.