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Date November 2018 Marks available 4 Reference code 18N.3.SL.tz0.15
Level Standard Level Paper Paper 3 Time zone time zone 0
Command term Explain Question number 15 Adapted from N/A

Question

Describe two methods of monitoring the hydration status of athletes.

[2]
a.

Explain how antidiuretic hormone (ADH) helps conserve water when sweating during vigorous exercise.

[4]
b.

Markscheme

monitoring of urine colour: darker colour indicates dehydration ✔

urine osmolarity measures the concentration of urine, which is affected by hydration ✔

variation in body mass loss/weight may be indicative of change in hydration ✔

a hydrometer measures the specific gravity of urine ✔

Award [1 max] for list.

a.

sweating leads to reduced blood plasma ✔

loss of blood plasma results in increased blood osmolality ✔

increased blood osmolality stimulates the hypothalamus ✔

hypothalamus sends neural signal to the pituitary gland ✔

pituitary gland secretes ADH into the blood ✔

ADH acts on the kidneys, increasing water permeability of the renal tubules and collecting ducts ✔

ADH acting on the kidneys leads to increased reabsorption of water ✔

b.

Examiners report

Straightforward, well prepared.

a.

Reasonably well prepared, though sometimes superficial.

b.

Syllabus sections

Option D: Nutrition for sports, exercise and health » D.2. Water and electrolyte balance » D.2.5. Explain the roles of the loop of Henlé, medulla, collecting duct and ADH in maintaining the water balance of the blood.
Option D: Nutrition for sports, exercise and health » D.2. Water and electrolyte balance
Option D: Nutrition for sports, exercise and health

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