Which organ system transports hormones to target organs?

• A. Endocrine system
• B. Nervous system
• C. Digestive system
• D. Circulatory system

Answer: (A)

Hormones are chemical messengers released by glands of the endocrine system into the bloodstream. The circulatory system, with its network of blood vessels and the heart, serves as the transport highway that carries those hormones throughout the body to distant target organs. When hormones arrive, target cells with the appropriate receptors respond, enabling regulation of processes like metabolism, growth, and reproduction. So the endocrine system provides the hormones, but the circulatory system is what actually delivers them to where they need to act. The nervous system can influence hormone release, but it does not serve as the long-distance transport route itself, and the digestive system isn’t involved in carrying hormones to distant sites.