ADH is a hormone released by the pituitary gland that plays a key role in maintaining water balance in the body by regulating how much water is reabsorbed from the renal tubules.
Table 1 shows the physiological effects of different plasma concentrations of ADH in a healthy adult male.
Table 1
| Plasma ADH concentration (ng/dm3\text{ng/dm}^3ng/dm3) | Concentration of dissolved solutes in urine (mOsm/kg\text{mOsm/kg}mOsm/kg) | Rate of urine production (cm3/minute\text{cm}^3/\text{minute}cm3/minute) |
|---|---|---|
| 0.8 | 250 | 15.0 |
| 1.6 | 500 | 9.5 |
| 2.4 | 800 | 5.2 |
| 3.2 | 1100 | 2.1 |
| 4.8 | 1300 | 0.8 |
During a physiological study, the participant's plasma ADH concentration increased from 1.6 ng/dm31.6\text{ ng/dm}^31.6 ng/dm3 to 3.2 ng/dm33.2\text{ ng/dm}^33.2 ng/dm3.
Explain how this increase in the concentration of ADH causes the changes to the urine shown in Table 1.
62 exam-style questions on AQA GCSE Biology 5.3 Hormonal coordination in humans, covering 5.3.1 Human endocrine system, 5.3.2 Control of blood glucose concentration, 5.3.3 Maintaining water and nitrogen balance in the body, 5.3.4 Hormones in human reproduction, 5.3.5 Contraception, 5.3.6 The use of hormones to treat infertility (HT only), and 5.3.7 Negative feedback (HT only). Each one has a worked solution and a mark scheme showing where the marks go.