Trivia: Which system releases hormones?
Urinary system
Muscular system
Endocrine system
Circulatory system
Correct Answer: Endocrine system
So why is this answer correct? : The endocrine system uses hormones as chemical messengers to tell specific organs what to do. Glands, such as the hypothalamus and thyroid, secrete hormones that travel through the bloodstream to the appropriate organ or tissue. The endocrine system controls vital functions, such as metabolism, growth, sexual function, heart rate, blood pressure, and sleep cycles.