| Date | May 2019 | Marks available | 2 | Reference code | 19M.3.SL.tz0.2 |
| Level | Standard Level | Paper | Paper 3 | Time zone | time zone 0 |
| Command term | Explain | Question number | 2 | Adapted from | N/A |
Question
Outline how the body maintains a stable core temperature when the external environment cools.
Explain why swimming in cold water is a challenge to the thermoregulation process.
Markscheme
«peripheral» vasoconstriction to areas not being used or outside the core ✔
shivering which is involuntary contractions of skeletal muscles ✔
non-shivering thermogenesis occurs which is an increase in heat production due to increasing cellular metabolic rates ✔
reduction in sweat production ✔
[2 max]
in water heat is conducted away from the body faster than air ✔
heat loss in water is faster when the water is moving due to the convective heat loss «26x faster in water» ✔
swimming at high speeds may allow the metabolic rate to increase and compensate for the heat loss ✔
Award [1 max] for a list.
[2 max]
Examiners report
In this question, the students fully understood shivering as many answered the question with this as a response. Fewer students were able to identify vasoconstriction as a correct response. Very few students provided non-shivering thermogenesis as a response.
Most were able to provide either conduction or convection with fewer providing both as a response. The student’s difficulty here was with the reasoning and description of how either thermoregulating process would challenge a swimmer.
