Spec 1BI0
Revise Edexcel GCSE Biology 7.1.3 Thyroxine and negative feedback with the question bank, lessons, revision guides, and flashcards.
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 release of TSH from the pituitary gland • c TSH acts on the thyroid to produce thyroxine • d when thyroxine levels are normal thyroxine inhibits the release of TRH and the production of TSH
