Explain (HT only) how thyroxine levels are controlled by negative feedback.

In the subtopic Feedback systems (HT only), this learning objective focuses on explain (HT only) how thyroxine levels are controlled by negative feedback. Within Hormonal coordination in humans, students should explain this idea in the exact curriculum context rather than as an isolated fact. Approved keywords for this objective include HT only, negative feedback, and thyroxine. thyroxine means a hormone produced by the thyroid gland that regulates metabolism and is involved in growth and development. Avoid students often confuse the role of thyroxine in metabolism with its regulation by negative feedback, thinking it only increases metabolism without understanding the feedback mechanism; instead to fix this, students should focus on how thyroxine levels are monitored by the hypothalamus and pituitary gland, and how an increase in thyroxine leads to a decrease in TSH production, illustrating the negative feedback loop. For exam answers, focus on explaining how thyroxine levels are regulated through negative feedback. Use diagrams to illustrate the process.