Scientists investigate collecting duct tissue from a healthy person and from a person with a kidney condition.
Equal-sized samples of tissue are placed in apparatus in which water can move from a filtrate-like solution, through the tissue, into a surrounding solution. The scientists repeat the investigation using different concentrations of ADH.
| ADH concentration / pg cm−3\mathrm{pg\,cm^{-3}}pgcm−3 | Volume of water moved through healthy tissue in 30 minutes / cm3\mathrm{cm^3}cm3 | Volume of water moved through the person's tissue in 30 minutes / cm3\mathrm{cm^3}cm3 |
|---|---|---|
| 0 | 0.10 | 0.11 |
| 2 | 0.42 | 0.12 |
| 6 | 0.78 | 0.13 |
Explain what the results show about the response of the person's collecting duct tissue to ADH.
The ADH concentration in the person's blood increases further.
Suggest and explain the effect on the volume and concentration of urine produced.
94 exam-style questions on Edexcel GCSE Biology 7.4 Blood glucose and the urinary system, covering 7.4.1 Insulin and blood glucose control, 7.4.2 Glucagon and blood glucose regulation, 7.4.3 Type 1 and type 2 diabetes, 7.4.4 Structure of the urinary system, 7.4.5 Structure and function of the nephron, 7.4.6 ADH and water regulation, 7.4.7 Treatments for kidney failure, and 7.4.8 Production of urea in the liver. Each one has a worked solution and a mark scheme showing where the marks go.