A veterinary scientist measures the thickness of the ventricular walls at matching positions in a sheep heart.
| Ventricle | Artery receiving blood from the ventricle | Wall thickness in mm\text{mm}mm |
|---|---|---|
| Left | Aorta | 12 |
| Right | Pulmonary artery | 4 |
Which statement explains the pressure expected in the two arteries when the ventricles contract?
The pulmonary artery receives blood at a higher pressure because lung capillaries need rapid blood flow for diffusion.
The aorta receives blood at a lower pressure because blood in the systemic circulation travels a greater distance.
The aorta receives blood at a higher pressure because the thicker left ventricular wall contracts more forcefully.
The two arteries receive blood at the same pressure because the right and left ventricles contract simultaneously.
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.