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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 Outline Question number 2 Adapted from N/A

Question

Outline how the body maintains a stable core temperature when the external environment cools.

[2]
a.

Explain why swimming in cold water is a challenge to the thermoregulation process.

[2]
b.

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]

a.

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]

b.

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.

a.

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.

b.

Syllabus sections

Option A: Optimizing physiological performance » A.2. Environmental factors and physical performance » A.2.11. Outline the principal means by which the body maintains core temperature in cold environments.
Option A: Optimizing physiological performance » A.2. Environmental factors and physical performance
Option A: Optimizing physiological performance

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