Scientists kept an isolated liver and an isolated kidney functioning outside the body. Artificial plasma containing excess amino acids was pumped through the liver. The plasma leaving the liver was then pumped through the kidney.
| Measurement | Concentration before passing through the organ (mmol dm−3\mathrm{mmol\,dm^{-3}}mmoldm−3) | Concentration after passing through the organ (mmol dm−3\mathrm{mmol\,dm^{-3}}mmoldm−3) |
|---|---|---|
| excess amino acids in plasma passing through the liver | 8.0 | 3.0 |
| urea in plasma passing through the liver | 0.5 | 3.0 |
| urea in plasma passing through the kidney | 3.0 | 1.1 |
Urea was detected in the liquid formed by the kidney.
Explain the changes in the concentrations as the plasma passes through the liver and the kidney, including how urea enters the nephron.
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.