importance of osmoregulation in organisms
EXCRETION AND HOMEOSTASIS
PAST K.C.S.E QUESTIONS ON THE TOPIC
1. In an investigation the pancreatic duct of a mammal was blocked. It was found that the
blood sugar regulation remained normal while food digestion was impaired. Explain
these observations. ( 2 marks)
2. (a) Explain why the body temperature of a healthy human being must rise up
to 390c on a humid day. (2 marks)
(b) In an experiment a piece of brain was removed from rat. It was found that
the rat had large fluctuations of body temperatures suggest the part of the brain
that had been removed. ( 1 mark)
3. (a) Explain why sweat accumulates on a person’s skin in a hot humid
Environment. (2 marks)
(b) Name the specific part of the brain that triggers sweating.
( 1 marks)
4. Explain why some desert animals excrete uric acid rather than ammonia.
(2 marks)
5. State the role of the following hormones in the body
(a) Insulin (3 marks)
(b) Antidiuretic Hormone (3 marks)
6. What osmoregulatory changes would take place in a marine amoeba if it was transferred
to a freshwater environment?
7. Name two components of blood that are not present in the glomerular filtrate.
( 2 marks)
8. How would one find out from a sample of urine whether a person is suffering from
diabetes mellitus? (2 marks)
9. When is glycogen, which is stored in the liver, converted into glucose and released into
the blood? ( 2 marks)
10. A person was found to pass out large volumes of dilute urine frequently. Name the
(a) Diseases the person was suffering from (1 marks)
(b) Hormone that was deficient (1 mark)
11. State the importance of osmoregulation in organisms ( 2 marks)
12. What happens to excess fatty acids and glycerol in the body? (2 marks)
13. Give reasons for each of the following
(a) Constant body temperature is maintained in mammals ( 1 mark)
(b) Low blood sugar level is harmful to the body ( 2 marks)
14. The temperature of a person taken before during and after taking a cold bath. The results
are shown in the graph
(a) Explain why the temperature fell during the bath ( 2 marks)
(b) What changes appeared in the skin that enabled the body temperature to return to
normal. (2 marks)
15. (a) Name the fluid that is produced by sebaceous glands (1 mark)
(b) What is the role of sweat on the human skin? ( 2 marks)
16. State the role of insulin in the human body? ( 1 mark)
17. Describe how the human kidney functions. ( 20 marks)
18. (a) What is the meaning of the following terms:
(i) Homeostasis ( 1 mark)
(ii) Osmoregulation ( 1 mark)
19. (a) Explain what happens to excess amino acids in the liver of humans.
( 3 marks)
(b) Which portions of the human nephrons are only found in the cortex?
( 3 marks)
(c) (i) What would happen if a person produced less antidiuretic hormone?
( 1 mark)
(ii) What term is given to the condition described in (c) (i) above?
( 1 mark)
20. Define the following terms
(a) Excretion
(b) Secretion
(c) Egestion ( 3 marks)
21. Name the components of blood that do not enter the renal tubule in mammals
(2 marks)
22. The table below shows the approximate percent concentration of various components in
blood plasma entering the kidney glomerular filtrate and urine of a healthy human being.
