Fig. 1 shows part of the skin of a runner near the end of a 10 km race on a warm day. Her body temperature has increased above 37 degrees C. Blood vessels c...
Question 1 Report
Fig. 1 shows part of the skin of a runner near the end of a 10 km race on a warm day. Her body temperature has increased above 37 degrees C. Blood vessels close to the skin surface are shown, together with a sweat gland. The person drinks water after the race.
(a) Describe two changes in the skin shown in Fig. 1 that help the runner lose heat. [2]
(b) Explain how evaporation of sweat from the skin can lower body temperature. [2]
(c) Use the information about the runner to give two reasons why drinking water is important after the race. [2]
Answer Details
(a) The blood vessels near the skin dilate or become wider. [1] Sweat is released onto the skin surface. [1]
(b) Sweat needs thermal energy to evaporate. [1] It takes this energy from the skin and body, lowering body temperature. [1]
(c) Drinking water replaces water lost in sweat. [1] It also helps prevent dehydration and maintains blood volume for circulation. [1]
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