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At the end of a marathon race a runner’s body is dehydrated - HSC - SSCE Biology - Question 14 - 2007 - Paper 1
Question 14
At the end of a marathon race a runner’s body is dehydrated. How does the body control the two hormones, ADH and aldosterone, to help re-establish normal water bala... show full transcript
Worked Solution & Example Answer:At the end of a marathon race a runner’s body is dehydrated - HSC - SSCE Biology - Question 14 - 2007 - Paper 1
Step 1
How does the body control the two hormones, ADH and aldosterone, to help re-establish normal water balance?
Answer
To address dehydration, the body primarily increases the release of both ADH (antidiuretic hormone) and aldosterone.
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ADH Release: ADH is secreted from the posterior pituitary gland in response to increased osmolarity of the blood and reduced blood volume. It acts on the kidneys to promote water reabsorption, thereby reducing urine output and helping to conserve body water.
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Aldosterone Release: Aldosterone is released from the adrenal glands in response to signals such as low blood pressure and volume. It promotes the reabsorption of sodium ions in the kidneys, which in turn helps to retain water through osmosis.
Both hormones work synergistically to counteract dehydration, increase blood volume, and restore normal fluid balance in the body.
Thus, the correct answer is (C) Both ADH and aldosterone are released.