Question 1
Paper 2Hard16 marksA healthy adult volunteer completed two separate 40-minute exposures in a climate chamber, one at 10°C and one at 34°C. Clothing and activity (seated) were the same in both exposures. Measurements and observations at the end of each exposure are shown.
| Air temperature / °C | Core temperature / °C | Skin blood-flow index / arbitrary units | Sweat production / g h⁻¹ | Shivering |
|---|---|---|---|---|
| 10 | 37.0 | 24 | 0 | observed |
| 34 | 37.1 | 72 | 360 | not observed |
A higher skin blood-flow index indicates greater blood flow near the skin.
Calculate the percentage increase in skin blood-flow index from 10°C to 34°C. State how core temperature changed.
Explain how vasoconstriction and shivering could help the volunteer at 10°C. State how hair erection could contribute to thermoregulation in humans.
In a separate 40-minute period at each temperature, the volunteer was free to act. At 10°C, the volunteer put on an insulated coat and moved into shelter. At 34°C, the volunteer moved into shade, removed an outer layer of clothing and rested. Core temperature at the end was 37.0°C at 10°C and 37.1°C at 34°C.
A research team concluded that these behavioural actions alone were sufficient to maintain core temperature, and that physiological responses were not important. Evaluate this conclusion using the table and the follow-up observations. Include physiological and behavioural responses, and one limitation of the evidence.