What system of the body is responsible for hormone regulation?

The endocrine system is primarily responsible for hormone regulation in the body. This system comprises glands that secrete hormones directly into the bloodstream, where they travel to target organs and tissues to elicit various physiological responses. Hormones play crucial roles in regulating processes such as metabolism, growth, mood, immune function, and reproduction.

In contrast, the nervous system primarily communicates through nerve impulses and neurotransmitters for rapid responses, rather than hormonal signals. The digestive system is involved in the breakdown and absorption of food, and while it does interact with hormones (like insulin for glucose management), it is not the system that regulates them. The respiratory system focuses on gas exchange and is unrelated to hormonal regulation as its main function. This distinction clarifies why the endocrine system is the correct answer regarding hormone regulation.