ADH is a hormone made by the pituitary gland that regulates the water balance in the body.
ADH controls how much water is reabsorbed from the kidney tubules.
Table 1 shows the effects of different blood concentrations of ADH.
Table 1
| Concentration of ADH in the blood in ng/dm3\text{ng/dm}^3ng/dm3 | Concentration of dissolved substances in urine in arbitrary units | Rate of urine production in cm3/minute\text{cm}^3/\text{minute}cm3/minute |
|---|---|---|
| 0.5 | 300 | 12.0 |
| 1.0 | 600 | 8.0 |
| 2.0 | 850 | 4.8 |
| 3.0 | 1050 | 2.5 |
| 4.0 | 1150 | 1.2 |
A woman's blood ADH concentration increased from 1.0 ng/dm31.0\text{ ng/dm}^31.0 ng/dm3 to 3.0 ng/dm33.0\text{ ng/dm}^33.0 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.