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7.1 Hormones and coordination

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Question 10

A medicine prevents TSH from acting on the thyroid gland. It does not affect the hypothalamus or the pituitary gland. Before taking the medicine, the concentrations of TSH and thyroxine are within their normal ranges.

Which statement explains the changes caused by the medicine?

[1]
A

Rising TSH strengthens inhibition of the pituitary, so less thyroxine is released, while the thyroid releases additional TSH.

B

Falling thyroxine weakens inhibition of the pituitary, so more TSH is released, but the blocked thyroid cannot restore thyroxine to normal.

C

Falling thyroxine strengthens inhibition of the pituitary, so less TSH is released, and the thyroid continues to reduce thyroxine release.

D

Rising thyroxine weakens inhibition of the pituitary, so more TSH is released, although the thyroid cannot respond to the hormone.

Markscheme

7.1 Hormones and coordination Questions

  1. GCSE
  2. /Biology
  3. /7.1 Hormones and coordination

89 exam-style questions on Edexcel GCSE Biology 7.1 Hormones and coordination, covering 7.1.1 Endocrine glands and hormone transport, 7.1.2 Adrenalin and fight or flight, and 7.1.3 Thyroxine and negative feedback. Each one has a worked solution and a mark scheme showing where the marks go.

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