Answer: Catecholamines.
- A Steroid hormones
- B Peptide hormones
- C Simple fatty acids
- D Catecholamines
Correct answer: D. Catecholamines
Explanation: Adrenaline and noradrenaline are catecholamines - amino-acid (tyrosine) derivatives from the adrenal medulla.
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.