A heated garment covers a participant's torso but not their arms. Researchers investigate whether switching on the garment causes a thermoregulatory response.
The same participants complete a trial with the heating switched off and a trial with the heating switched on. The participants remain at rest during every trial.
The table shows the mean changes after 10 minutes.
| Investigation | Heating | Room temperature in °C | Change in core body temperature in °C | Change in blood flow through capillaries close to the forearm surface in cm³ min⁻¹ |
|---|---|---|---|---|
| 1 | off | 22 | 0.0 | +0.1 |
| 1 | on | 22 | +0.6 | +3.0 |
| 2 | off | 22 | 0.0 | 0.0 |
| 2 | on | 35 | +0.8 | +4.2 |
Evaluate the evidence for the conclusion that switching on the garment caused the increase in blood flow through the forearm capillaries.
Explain why the change in blood flow in investigation 1 would help return core body temperature towards the normal range.
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.