Which group of organs releases hormones?

• A. Endocrine glands
• B. Target cells
• C. Hormones
• D. Pheromones

Answer: (A)

Endocrine glands are the organs that release hormones into the bloodstream. They produce chemical messengers that travel through the blood to distant target cells, where receptors convert the signal into a physiological response, helping regulate processes like metabolism, growth, and stress. For example, the pituitary gland releases hormones that control other glands, and adrenal glands release adrenaline during stress. Target cells are the recipients of these signals, not the producers. Hormones are the signaling molecules themselves, not the organs that release them. Pheromones are chemical signals used for communication between individuals, not internal endocrine signaling.