Scientists investigate how intensive exercise affects blood flow to different organs and tissues in the human body. The table below shows the average rate of blood flow to these parts at rest and during intensive exercise:
| Organ / Tissue | Rate of blood flow (mL per minute) at Rest | Rate of blood flow (mL per minute) during Exercise |
|---|---|---|
| Brain | 700 | 700 |
| Heart muscle | 300 | 1200 |
| Skeletal muscles | 1200 | 22500 |
| Skin | 500 | 1800 |
| Other organs | 2100 | 800 |
| Total | 4800 | 27000 |
By how many times has the total blood flow increased during exercise? Give your answer to the nearest whole number.
Explain the changes in blood flow rate to the skeletal muscles and other organs during exercise.
194 exam-style questions on OCR GCSE Biology 2.1 Supplying the cell, covering 2.1.1 Transport across cell membranes, 2.1.2 Mitosis and the cell cycle, 2.1.3 Importance of cell differentiation, and 2.1.4 Stem cells. Each one has a worked solution and a mark scheme showing where the marks go.