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.
Explain how antidiuretic hormone (ADH) helps conserve water when sweating during vigorous exercise.
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.
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 ✔
Examiners report
Straightforward, well prepared.
Reasonably well prepared, though sometimes superficial.