Answer: Tetany.
- A Simple goitre
- B Infant cretinism
- C Tetany
- D Diabetes mellitus
Correct answer: C. Tetany
Explanation: Low blood Ca<sup>2+</sup> (hypocalcaemia), often from parathyroid failure, causes tetany - involuntary sustained muscle contractions.
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.