Answer: brain.
- A brain
- B heart
- C kidney
- D stomach
Correct answer: A. brain
Explanation: The pituitary hangs from the base of the brain.
The hypothalamus releases hormones that direct the pituitary, which releases its own trophic hormone to a target gland; that gland's hormone output then feeds back (dashed lines) to suppress both the pituitary and hypothalamus once levels are sufficient - a self-correcting loop running the entire endocrine system.
Concept context
The endocrine glands, hormone classification and mechanism of action, and negative feedback regulation.