Which of the following body systems is primarily responsible for hormonal regulation?

The endocrine system is primarily responsible for hormonal regulation within the body. This system consists of a network of glands that produce and secrete hormones directly into the bloodstream. Hormones are biochemical messengers that travel throughout the body to regulate various physiological processes, including metabolism, growth and development, tissue function, and mood.

The glands of the endocrine system—such as the pituitary, thyroid, adrenal glands, and pancreas—play a key role in maintaining homeostasis by releasing hormones in response to internal and external stimuli. For instance, insulin from the pancreas helps regulate blood sugar levels, while thyroid hormones influence metabolic rate.

While the nervous system does play a role in regulating various bodily functions through nerve impulses and neurotransmitters, it does not primarily handle hormonal regulation. Similarly, the integumentary system, which includes the skin, hair, and nails, is mainly involved in protection, sensation, and thermoregulation, but not in hormone production. The muscular system is focused on movement and posture control, and does not involve hormonal functions. Therefore, the endocrine system is unequivocally the correct answer as it is the central element in the hormonal regulatory processes of the body.