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The following diagram shows the regulation of thyroxine secretion - VCE - SSCE Biology - Question 14 - 2003 - Paper 1
Question 14
The following diagram shows the regulation of thyroxine secretion. A person who lacks sufficient iodine in the diet is unable to manufacture thyroxine. This is beca... show full transcript
Worked Solution & Example Answer:The following diagram shows the regulation of thyroxine secretion - VCE - SSCE Biology - Question 14 - 2003 - Paper 1
Step 1
C. the negative feedbacks would cease to operate.
Answer
When a person lacks sufficient iodine, the thyroid gland cannot produce thyroxine effectively. This deficiency leads to a decrease in thyroxine levels, which would reduce the feedback inhibition on the hypothalamus and anterior pituitary. As a result, the negative feedback mechanism, which normally regulates hormone production, would be disrupted. This means that TRH and TSH might be produced in greater quantities, as there isn’t enough thyroxine to signal the feedback loop.