Answer: pituitary gland.
- A pituitary gland
- B thyroid gland
- C adrenal gland
- D the pancreas
Correct answer: A. pituitary gland
Explanation: The pituitary controls many other endocrine glands, so it is the master gland.
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.