Answer: Pituitary dwarfism, since long bone growth plates have not yet fused.
- A Acromegaly, due to continued action on already-fused bone ends
- B Goitre, from compensatory enlargement of the thyroid gland
- C Pituitary dwarfism, since long bone growth plates have not yet fused
- D Tetany, caused by a fall in blood calcium levels
Correct answer: C. Pituitary dwarfism, since long bone growth plates have not yet fused
Explanation: In children, growth hormone deficiency causes pituitary dwarfism because the epiphyseal plates are still open. In adults, deficiency does not affect height since growth plates have already fused.
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.