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1. 1990/I/2c

The diagram below shows the human urinary system :

(i) Name structures A and B. Give ONE function for each. (4 marks)

(ii) The table below shows the concentration of certain components of two fluids (X and Y) collected

from two different regions of the urinary system :

Concentration (g 100 cm3

)

Fluid X Fluid Y

Protein

Glucose

Urea

0.0

0.0

2.0

8.0

0.1

0.03

(1) Using the letters in the diagram, state the respective regions from which fluids X and Y were

collected. (2 marks)

(2) Explain why fluids X and Y differ in their concentrations of :

(I) protein

(II) glucose

(III) urea (6 marks)

2. 1991/I/2b

An experiment was performed to study the effect of the removal of the liver on the blood urea concentration

of a mammal. The blood urea concentration of this mammal was measured from 07:00 to 20:00 hours. The

animal's liver was removed at 08:00 hours. The results were as follows:

Time of day (hours) Blood urea concentration (mg per 100 cm3blood)

07:00

08:00 (liver removed)

11:00

14:00

17:00

20:00

7.0

7.0

3.6

2.6

2.0

1.6

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(i) Plot a graph to show how the blood urea concentration varies with time. (3 marks)

(ii) Explain the change in the blood urea concentration after 08:00 hours. (3 marks)

(iii) Describe and explain the changes in the blood urea concentration if the kidneys instead of the liver

of the mammal were removed at 08:00 hours. (3 marks)

(iv) State ONE other function of the liver. (1 mark)

3. 1993/I/2b

The bar chart below shows the amount of water lost by a man on two consecutive days. On the first day, he

was completely at rest and on the second day, he performed vigorous exercises.

(i) (1) How much morewater was lost by the man on the second day ? (2 marks)

(2) Why was this excessive water loss unavoidable ? (5 marks)

(ii) Explain the decrease in water loss in urine on the second day. (3 marks)

4. 1993/I/3aiv

Regulation of the blood glucose level is an example of the feedback mechanism in the body. State another

example. What is the importance of the feedback mechanism to the body ? (2 marks)

5. 1996/I/3b

Patients with kidney failure will die if they do not receive proper treatment. One method of treatment is to

use a kidney machine.The diagram below shows the workings of a kidney machine :

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(i) Urea is found in the solution passing out of the kidney machine. Account for this. (2 marks)

(ii) Give a reason for each of the following :

(1) Each treatment takes a long time (about 6 hours). (1 mark)

(2) The treatment needs to be repeated at regular intervals (about 2-3 times a week). (1 mark)

(iii) Both the human kidney and the kidney machine are able to retain useful substances in the blood.

Explain how this is achieved by

(1) the human kidney, (1 mark)

(2) the kidney machine. (2 marks)

(iv) Another method of treating kidney failure is to transplant a healthy kidney into the patient. Suggest

tworeasons why only a small number of such patients can receive this treatment in Hong Kong.

(2 marks)

6. 1997/I/3a

In humans, the normal ranges of glucose concentration in the blood plasma is between 70 and 110 mg per

100 cm3. As the concentration of glucose in the blood plasma changes, both the rate of filtering glucose

from the glomerulus and the rate of excreting glucose in the urine also change. The table below shows the

variation of the two rates with the glucose concentration in the blood plasma :

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Concentration of glucose in

blood plasma (mg per 100cm3)

Rate of filtering glucose from

glomerulus (mg min-1

)

Rate of excreting glucose

in urine (mg min-1

)

70

100

150200

250

300

350

400

95

135

203270

338

405

473

540

0

0

07

18

40

75

130

(i) Using the same x and y axes, present the above data in the form of a graph. (4 marks)

(ii) (1) When the concentration of glucose in the blood plasma is 90 mg per 100 cm3,

(I) what is the rate of filtering glucose from the glomerulus ?(II) what is the rate of excreting glucose in the urine ? (1 mark)

(2) With reference to the function of the kidney tubule, explain your answer in (II) above.

(2 marks)

(iii) Explain onesituation which leads to the excretion of glucose in the urine of a healthy person.

(3 marks)

7. 2000/I/4c

The table below shows the rates of water loss in different ways from a persons body under two conditions :

Rate of water loss (mL h1

)Condition

Sweat Urine Exhaled air

At rest 4 58 15

During heavy exercise 208 21 27

(i) Compare the rate of sweat production of the person under the two conditions. Explain why there was

such a difference. (3 marks)

(ii) Account for the decrease in the rate of urine production of the person during heavy exercise.

(3 marks)

(iii) (1) Explain how exhalation may lead to water loss from the body. (2 marks)

(2) Why did the rate of water loss through exhalation increase during heavy exercise ? (2 marks)

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8. 2001/I/1b

The graphs below show the concentration of three substances in the renal artery, and the changes in their

concentration along the nephron and the collecting duct :

(i) Explain the difference in the concentration of protein between the blood plasma and the fluid in the

nephron. (2 marks)

(ii) What process causes the increase in urea concentration along the collecting duct ? (1 mark)

(iii) (1) What may substance X be ? (1 mark)

(2) Explain the change in the concentration of substance X along the nephron. (3 marks)

(iv) If a person eats a lot of beans, how would the amount of urea excreted be affected ? Explain your

answer. (4 marks)

9. 2004/I/3b

The diagram below shows the structure of a nephron and its associated blood vessels :

(i) Name the fluid found in X. Explain how this fluid is formed. (4 marks)

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(ii) Describe twoways in which glucose in vessel A may reach vessel B. Your answer should include the

routes and the mechanisms involved. (4 marks)

(iii) Coffee contains a chemical called caffeine which cause dilation of vessel A. Explain how the

presence of caffeine in the blood may increase the rate of urine production. (3 marks)

10. 2006/I/9a

The table below shows some information about the composition of the plasma, glomerular filtrate and urine

of a healthy person:

Content (g per 100 mL fluid)Component

Plasma Glomerular filtrate Urine

Water 90-93 97-99 96

Plasma proteins 7-9 0 0

Glucose 0.10 0.10 0.00Chloride 0.37 0.37 0.60

Urea 0.03 0.03 2.00

Others