A volunteer rests in a room where the air is cooler than the volunteer's skin. Researchers use a heated blanket to raise the volunteer's core body temperature. They measure skin blood flow before warming and immediately after the blanket is removed.
| Core body temperature | Blood flow in the forearm in arbitrary units | Blood flow in the lower leg in arbitrary units |
|---|---|---|
| 37.0 ∘C37.0\ ^\circ\mathrm{C}37.0 ∘C | 24 | 16 |
| 38.0 ∘C38.0\ ^\circ\mathrm{C}38.0 ∘C | 66 | 34 |
Calculate the percentage increase in the combined blood flow in the two regions when core body temperature increases from 37.0 ∘C37.0\ ^\circ\mathrm{C}37.0 ∘C to 38.0 ∘C38.0\ ^\circ\mathrm{C}38.0 ∘C.
Explain how the change in blood flow shown in the table helps the volunteer's core body temperature return towards normal.
78 exam-style questions on Edexcel GCSE Biology 7.3 Homeostasis and thermoregulation, covering 7.3.1 Importance of a constant internal environment, 7.3.2 Importance of homeostasis, 7.3.3a Thermoregulation via the skin and hypothalamus, and 7.3.3b Vasoconstriction and vasodilation in thermoregulation. Each one has a worked solution and a mark scheme showing where the marks go.