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1. 1995/I/4b

Below is a simplified diagram of a section of the human skin :

(i) (1) Name structures A and B. (2 marks)

(2) Explain how they help to speed up heat loss from the body when the body temperature rises.

(6 marks)

(ii) In a fire, a large area of C of a person was burnt. Give two reasons why this damage may endanger

his life. (2 marks)

2. 1996/I/4c

An experiment was performed to study the effect of environmental temperature on the skin temperature and

the body temperature of a person. During the experiment, the person was kept in a room with a constant

relative humidity of 65%. He was allowed to eat and move around freely but he was not allowed to change

the amount of clothing.

The results are shown in the graph below :

(i) (1) Describe the change in the skin temperature when the room temperature rose from 18

oC to

28oC. (1 mark)

(2) What physiological change in the skin may cause this change in skin temperature ? (2 marks)

(ii) When the room temperature rose from 38oC to 40

oC,

(1) describe the change in the body temperature. (1 mark)

(2) what was the main way by which the body heat was lost to the environment ? Explain how you

arrived at your answer. (3 marks)

(3) explain why the person's life might be endangered if the relative humidity of the room rose to

95%. (3 marks)

HKCEE BIOLOGY | 6.2 Regulation of body temperature | P.1

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3. 1999/I/2c

A person spent two hot days on a beach. He drank plenty of water to avoid the danger of dehydration. The

air temperature and the relative humidity at the beach on these two days are recorded in the table below :

Air temperature (oC) Relative humidity (%)

Day 1

Day 2

38

38

65

90

(i) Explain why heat loss from the person’s body was mainly effected through sweating on Day 1.

(4 marks)

(ii) Compared to Day 1, explain why it would be more dangerous for the person to carry out vigorous

exercise on the beach on Day 2. (5 marks)

4. 2001/I/4a

Simon went hiking in Sai Kung on a hot afternoon.

(i) After walking for half an hour, Simon’s face became red.

(1) Explain why his face became red. (3 marks)

(2) Why is this response important ? (2 marks)

(ii) After 4 hours of walking, he had drunk all the water he brought along and his sweat production

became greatly reduced. His body temperature increased significantly. This might lead to heatstroke.

Account for the increase in his body temperature. (2 marks)

(iii) The following table provides some information on the weather conditions in Sai Kung on three

afternoons :

Day Temperature (oC) Relative humidity (%) Ultra-violet light

intensity

Wind speed

(km h–1

)

1 32.8 90 medium 5

2 33.1 72 high 15

3 32.6 80 high 31

On which afternoon would a person have the highest risk of developing heatstroke if he went hiking in Sai

Kung ? Justify your answer by stating two special features of the weather of that afternoon as compared

with the other two afternoons. (3 marks)

HKCEE BIOLOGY | 6.2 Regulation of body temperature | P.2

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5. 2005/I/7

Jane spent a day on the beach in the summer. The graph below shows the changes in the air temperature on

the beach on that day:

(a) Draw a line on the graph to show the possible changes in Jane's body temperature on that day.

(1 mark)

(b) Referring to the change in air temperature from 0600 to 1000 hour, explain how the blood vessels in

Jane's skin are involved in the regulation of her body temperature during this period. (4 marks)

(c) What is the main way of heat loss from Jane's body at 1400 hour? Why do you think so? (3 marks)

6. 2008/I/10ai,ii

The table below shows the body temperature and the rate of urine formation of a person under two

conditions.

At rest During heavy exercise

Body temperature (oC) 37.05 37.45

Rate of urine formation

(cm3 per hour)

58 21

(i) Why does the body temperature increase during heavy exercise? (2 marks)

(ii) There is only a small rise in body temperature during heavy exercise. Other than the sweat gland,

describe how one structure of the skin helps to maintain a relatively constant body temperature

under such conditions. (3 marks)

HKCEE BIOLOGY | 6.2 Regulation of body temperature | P.3