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Hormonal disorders sheet
4-mark answer frame

Explain the disorders caused by too little and too much thyroxine.

How to lay out the answer. Follow the frame, then write it in your own words.

  1. 1 · Open. The thyroid makes thyroxine, which controls BMR, growth and brain development. Too little or too much causes disorders.
  2. 2 · Too little (hyposecretion).
    • Simple goitre: lack of iodine; swollen thyroid.
    • Cretinism (children): stunted growth, slow mental development.
    • Myxoedema (adults): low BMR, puffy skin, tiredness.
  3. 3 · Too much (hypersecretion). Exophthalmic goitre (Graves' disease): bulging eyes, high BMR, fast heartbeat, weight loss.
  4. 4 · Link to daily life. Iodised salt prevents simple goitre and cretinism.
  5. 5 · Close. So the right amount of thyroxine is needed for normal growth and energy.

Scoring tip: Sort the disorders under two headings, too little and too much. It shows the examiner you understand the cause.