The primary function of the nervous system in regulating body functions is to facilitate communication between different body parts and the environment. It consists of the central nervous system (CNS) and peripheral nervous system (PNS), which work together to process sensory information, coordinate responses, and maintain homeostasis. Through complex networks of neurons, the nervous system controls voluntary and involuntary actions, regulates vital functions such as heart rate and digestion, and allows for cognitive processing and coordination. Its proper functioning is essential for overall health and well-being.