Question

Explain how thyroxine controls metabolic rate as an example of negative feedback, including;

A) Low levels of thyroxine stimulates production of TRH in hypothalamus
B) This causes the release of TSH from the pituitary gland
C) TSH acts on the thyroid to produce thyroxine
D) When thyroxine levels are normal thyroxine inhibited the release of TRH and the production of TSH

NOTE - the above letters are NOT answers, they are separate points that need clarifying. PLEASE HELP!

Answer 1

Step-by-step explanation:

The question is self-explanatory and asking about negative feedback. It is a mechanism with which something increases, it will cause a chain reaction leading it being brought back down or vice versa.

In this case, when thyroxine is at low level, it stimulates hypothalamus to produce more TRH which in turn cause the pituitary gland to release more TSH. TSH will cause the thyroid to make more thyroxine; bringing its level back to normal. Thyroxine will inhibit further release and production of TRH and TSH.