What organ system is primarily responsible for regulating metabolism?

The endocrine system is primarily responsible for regulating metabolism through the secretion of hormones. Hormones are chemical messengers that travel throughout the body to target specific organs and tissues, guiding a variety of physiological processes, including metabolism. For example, hormones such as insulin and glucagon regulate glucose levels in the blood, while thyroid hormones influence the rate of metabolic processes and energy expenditure.

Other organ systems also play significant roles in different bodily functions, but they do not primarily focus on metabolic regulation. The nervous system is more involved in response to stimuli and coordination of voluntary and involuntary actions. The immune system's main function is to protect the body against pathogens and diseases. The digestive system is crucial for breaking down food and nutrient absorption, but it does not directly regulate metabolism on a systemic level. Thus, the endocrine system's specific function of hormone production and regulation aligns it directly with the management of metabolic processes.