A red blood cell is carried from the capillaries of a kidney to the capillaries in the wall of the small intestine.
The table shows typical maximum blood pressures at three points in the circulation.
| Vessel and position | Typical maximum blood pressure (kPa) |
|---|---|
| Pulmonary artery, before the lung capillaries | 3.3 |
| Pulmonary vein, after the lung capillaries | 1.1 |
| Aorta | 16.0 |
Describe the route taken by the red blood cell from the kidney to the small intestine.
Use the data to explain why blood returns to the heart after passing through the lungs before it travels to the rest of the body.
114 exam-style questions on OCR GCSE Biology 2.2 The challenges of size, covering 2.2.1 Exchange surfaces and surface area : volume ratio, 2.2.2 Substances transported in organisms, 2.2.3 The human circulatory system, 2.2.4 The heart and blood vessels, 2.2.5 Red blood cells and plasma, 2.2.6 Uptake of water and mineral ions by plants, 2.2.7 Transpiration and translocation, 2.2.8 Xylem and phloem, 2.2.9 Environmental factors and water uptake, and 2.2.10 Using a potometer. Each one has a worked solution and a mark scheme showing where the marks go.