Which system in the body regulates hormones?

The endocrine system is the primary regulator of hormones in the body. It is a network of glands that produce and secrete hormones directly into the bloodstream. These hormones act as chemical messengers that influence various physiological processes, including metabolism, growth, and mood regulation, among others. The glands that are part of the endocrine system include the pituitary gland, thyroid gland, adrenal glands, and pancreas, each responsible for producing specific hormones that target various organs and tissues.

In contrast, while the nervous system does play a role in regulating bodily functions and can influence hormonal activity through neurotransmitters, it primarily facilitates rapid communication and response rather than the slower, sustained regulation provided by hormones. The circulatory system, while essential for transporting hormones throughout the body, does not produce or regulate them. Similarly, the respiratory system is involved in gas exchange and does not have a direct role in hormone regulation. Thus, the endocrine system is the correct answer, as it is the specialized system focused on the production and regulation of hormones.