What body system primarily regulates hormones?

The endocrine system is primarily responsible for regulating hormones in the body. This system consists of various glands, such as the pituitary, thyroid, adrenal, and pancreas, which produce and secrete hormones directly into the bloodstream. These hormones serve as chemical messengers that regulate processes like metabolism, growth and development, mood, and the body's response to stress and injury.

The endocrine system operates alongside the nervous system, but it focuses specifically on slow and sustained body regulation through hormone signaling, as opposed to the rapid transmission of signals seen in the nervous system. While the reproductive system has a role in hormone regulation, particularly regarding sexual and reproductive functions, it is not the primary system responsible for overall hormonal control. The musculoskeletal system, which supports and maintains body movement, does not regulate hormones. Thus, the endocrine system is the correct answer for its crucial role in hormone regulation throughout the body.