Excretion and Homeostasis: Kidneys, Skin, Liver, Negative Feedback and Blood Glucose Control

1. Which substance is excreted by the kidneys as a nitrogenous waste product formed in the liver?

A glucose
B urea
C glycogen
D bile

2. Which process converts excess amino acids into urea?

A assimilation
B deamination
C ultrafiltration
D translocation

3. Which row correctly matches organ and excretory product?

A lungs: urea
B kidneys: carbon dioxide
C skin: water and salts
D liver: oxygen

4. Which statement correctly distinguishes excretion from egestion?

A excretion removes undigested food; egestion removes metabolic waste
B excretion removes metabolic waste; egestion removes undigested food
C both remove only carbon dioxide
D both occur only through kidneys

5. Which substances are normally present in glomerular filtrate but not normally present in urine of a healthy person?

A urea and excess salts
B glucose and amino acids
C water and urea
D excess water and drugs

6. Which substance is too large to pass through the glomerular filter in a healthy kidney?

A glucose
B urea
C plasma protein
D water

7. What causes ultrafiltration in the Bowman’s capsule?

A active transport of glucose from blood into filtrate
B high blood pressure in the glomerulus
C diffusion of urea from filtrate into blood
D osmosis of water from urine into blood

8. Which blood vessel carries blood into the glomerulus?

A renal vein
B efferent arteriole
C afferent arteriole
D ureter

9. The afferent arteriole is wider than the efferent arteriole.
   What is the effect?

A lower pressure in glomerulus, reducing filtration
B higher pressure in glomerulus, increasing filtration
C no filtration because blood flows backwards
D glucose is actively pumped into urine

10. Which row correctly compares renal artery and renal vein?

A renal artery: less urea, less oxygen; renal vein: more urea, more oxygen
B renal artery: more urea, more oxygen; renal vein: less urea, less oxygen
C renal artery: more carbon dioxide, less glucose; renal vein: less carbon dioxide, more glucose
D renal artery: no urea; renal vein: all urea

11. Which part of the nephron is mainly responsible for selective reabsorption of all glucose in a healthy person?

A Bowman’s capsule
B proximal convoluted tubule
C collecting duct
D renal pelvis

12. Which process is used to reabsorb glucose from the filtrate into blood?

A diffusion only
B active transport
C evaporation
D emulsification

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

13. A person has glucose in their urine.
    Which explanation is most likely?

A blood glucose concentration exceeded the kidney’s reabsorption capacity
B the glomerulus blocked all glucose from entering filtrate
C the liver converted all glucose to urea
D ADH caused glucose to evaporate from blood

14. Which hormone increases water reabsorption by the kidneys?

A insulin
B glucagon
C ADH
D adrenaline

15. ADH acts mainly on which part of the nephron?

A collecting duct
B glomerulus
C renal artery
D bladder

16. A person drinks very little water and sweats heavily.
    Which change is most likely?

A less ADH released and more dilute urine produced
B more ADH released and more concentrated urine produced
C less ADH released and more concentrated urine produced
D no ADH released and no urine produced

17. Which statement about osmoregulation is correct?

A it keeps blood glucose constant only
B it controls the water potential of blood
C it controls the oxygen content of air
D it removes faeces from the rectum

18. If blood water potential becomes too low, what is the negative feedback response?

A pituitary releases less ADH, collecting ducts become less permeable
B pituitary releases more ADH, collecting ducts become more permeable
C pancreas releases insulin, liver stores glycogen
D liver releases bile, fats are emulsified

19. Which row correctly shows the effect of ADH?

A more ADH → less water reabsorbed → more dilute urine
B more ADH → more water reabsorbed → less urine
C less ADH → more water reabsorbed → less urine
D less ADH → collecting ducts become completely impermeable to urea only

20. A student drinks 1.5 dm³ of water quickly.
    Which effect is most likely after a short time?

A more ADH and concentrated urine
B less ADH and dilute urine
C more insulin and no urine
D more glucagon and dark urine

21. Which statement about the bladder is correct?

A it produces urine from blood plasma
B it stores urine before urination
C it filters urea from blood
D it reabsorbs all glucose

22. Which sequence correctly shows urine movement after formation?

A kidney → ureter → bladder → urethra
B kidney → urethra → bladder → ureter
C bladder → ureter → kidney → urethra
D ureter → kidney → bladder → urethra

23. Which substance is normally reabsorbed completely from filtrate in a healthy kidney?

A glucose
B urea
C excess salt
D excess water

24. Which statement about urea formation is correct?

A urea is formed in the kidney from glucose
B urea is formed in the liver from excess amino acids
C urea is formed in the lungs from carbon dioxide
D urea is formed in the pancreas from insulin

25. What happens to the carbon skeleton left after deamination?

A it may be used in respiration or converted to carbohydrate/fat
B it must be excreted unchanged in urine
C it becomes haemoglobin directly in the bladder
D it is converted into bile in the nephron

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

26. Which organ stores glycogen and converts it back into glucose when blood glucose falls?

A kidney
B liver
C lung
D skin

27. Which hormone lowers blood glucose concentration?

A glucagon
B insulin
C ADH
D thyroxine

28. Which hormone raises blood glucose concentration?

A insulin
B glucagon
C ADH
D oestrogen

29. After a meal rich in carbohydrate, which response occurs in a healthy person?

A pancreas releases insulin and liver converts glucose to glycogen
B pancreas releases glucagon and liver converts glycogen to glucose
C pituitary releases ADH and kidney excretes glucose
D liver releases insulin and pancreas stores glycogen

30. During fasting, blood glucose concentration falls.
    Which response is most likely?

A insulin increases and glucose is converted to glycogen
B glucagon increases and glycogen is converted to glucose
C ADH decreases and glucose enters urine
D bile increases and amino acids become glucose in the bladder

31. Which statement best describes negative feedback?

A a change is increased until the body becomes unstable
B a change from normal triggers responses that reverse the change
C a hormone is released only once and never stops
D every organ responds in the same direction to all stimuli

32. A person with untreated type 1 diabetes has high blood glucose and glucose in urine.
    Which hormone is deficient?

A insulin
B glucagon
C ADH
D adrenaline

33. Why can untreated diabetes cause excessive urination?

A glucose in filtrate lowers water potential, reducing water reabsorption
B insulin converts all water into glycogen
C glucagon blocks the ureter completely
D urea becomes too large to filter

34. Which statement about type 1 diabetes is correct?

A body cells are unable to respond to insulin because of obesity only
B pancreas produces little or no insulin
C kidneys produce too much insulin
D liver cannot produce bile

35. Which statement about type 2 diabetes is correct?

A it always starts in early childhood and requires no diet control
B body cells become less responsive to insulin
C no insulin receptors are ever present in the body
D it is caused by ADH deficiency only

36. Which treatment is most directly needed for many people with type 1 diabetes?

A insulin injections
B antibiotics
C dialysis only
D extra bile salts

37. Which action helps control type 2 diabetes?

A regular exercise and controlled carbohydrate intake
B avoiding all water
C increasing saturated fat intake only
D removing both kidneys

38. Which organ detects blood glucose concentration and releases insulin or glucagon?

A pancreas
B bladder
C skin
D lungs

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

39. Which statement about skin in temperature regulation is correct?

A sweat glands produce urine
B skin blood vessels can dilate or constrict to alter heat loss
C hairs always lie flat to trap more insulating air
D shivering occurs in sweat glands

40. What happens during vasodilation in the skin?

A arterioles near the skin surface widen, increasing heat loss
B arterioles near the skin surface narrow, reducing heat loss
C sweat glands stop producing sweat completely
D skeletal muscles contract rapidly to generate heat

41. What happens during vasoconstriction in the skin?

A more blood flows near the skin surface
B less blood flows near the skin surface
C sweat evaporates faster because arterioles widen
D blood glucose rises because insulin increases

42. Which response helps cool the body?

A shivering
B sweating and vasodilation
C vasoconstriction and hair erection
D glucagon release only

43. Why does sweating cool the body?

A sweat absorbs heat when it evaporates
B sweat digests glucose on the skin
C sweat prevents all water loss from the body
D sweat is converted into oxygen by skin cells

44. Which response helps increase body temperature when cold?

A sweating and vasodilation
B vasoconstriction and shivering
C increased ADH and dilute urine
D insulin release and glycogen storage

45. Which statement about shivering is correct?

A it is rapid muscle contraction that releases heat from respiration
B it is evaporation of sweat from skin
C it is filtration of blood in glomeruli
D it is conversion of glucose into glycogen

46. Which part of the brain monitors body temperature and coordinates responses?

A hypothalamus
B cerebellum
C retina
D medulla only

47. Which row correctly matches stimulus and response?

A high body temperature → vasoconstriction
B low body temperature → sweating
C high body temperature → vasodilation
D low body temperature → hairs lie flat and sweat increases

48. Which statement about homeostasis is correct?

A it keeps the internal environment constant within narrow limits
B it stops all external changes from happening
C it controls only body temperature, not glucose or water
D it occurs only in plants

49. Which pair of responses both reduce heat loss?

A sweating and vasodilation
B vasoconstriction and hair erection
C sweating and hair flattening
D vasodilation and increased blood flow to skin

50. A person’s blood glucose rises above normal. Which sequence shows the correct negative feedback response?

A pancreas detects rise → insulin released → liver converts glucose to glycogen → blood glucose falls
B pancreas detects fall → glucagon released → liver converts glucose to glycogen → blood glucose rises
C kidney detects rise → ADH released → glucose leaves in sweat → blood glucose falls
D liver detects rise → bile released → glucose becomes urea → blood glucose falls

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

1. Answer: B
   A is wrong because glucose is normally reabsorbed and is not a nitrogenous waste.
   B is correct because urea is a nitrogenous waste made in the liver and excreted by the kidneys.
   C is wrong because glycogen is a storage carbohydrate.
   D is wrong because bile is involved in fat emulsification and pigment excretion, but urea is the main nitrogenous waste in urine.

2. Answer: B
   A is wrong because assimilation is using absorbed molecules in cells.
   B is correct because deamination removes the nitrogen-containing part of excess amino acids and forms urea.
   C is wrong because ultrafiltration occurs in the kidney.
   D is wrong because translocation is movement of sucrose/amino acids in phloem.

3. Answer: C
   A is wrong because lungs excrete carbon dioxide and water vapour, not urea.
   B is wrong because kidneys excrete urea, excess water and salts, not carbon dioxide mainly.
   C is correct because skin excretes water and salts in sweat.
   D is wrong because oxygen is not an excretory product of the liver.

4. Answer: B
   A is wrong because it reverses the definitions.
   B is correct because excretion removes metabolic waste, while egestion removes undigested food from the alimentary canal.
   C is wrong because excretion includes urea, carbon dioxide, water and salts.
   D is wrong because excretion involves several organs, and egestion occurs through the anus.

5. Answer: B
   A is wrong because urea and excess salts are normally present in urine.
   B is correct because glucose and amino acids enter the filtrate but are normally fully reabsorbed in a healthy person.
   C is wrong because water and urea are normally present in urine.
   D is wrong because excess water and some drugs may be excreted in urine.

6. Answer: C
   A is wrong because glucose is small enough to enter the filtrate.
   B is wrong because urea is small and passes through the filter.
   C is correct because plasma proteins are too large to pass through the glomerular filter.
   D is wrong because water passes into the filtrate.

7. Answer: B
   A is wrong because glucose reabsorption occurs later, not during ultrafiltration.
   B is correct because high blood pressure in the glomerulus forces small molecules into Bowman’s capsule.
   C is wrong because urea is filtered into the filtrate, not mainly diffused back at this stage.
   D is wrong because osmosis from urine into blood is not ultrafiltration.

8. Answer: C
   A is wrong because the renal vein carries blood away from the kidney.
   B is wrong because the efferent arteriole carries blood away from the glomerulus.
   C is correct because the afferent arteriole carries blood into the glomerulus.
   D is wrong because the ureter carries urine, not blood.

9. Answer: B
   A is wrong because a wider afferent and narrower efferent arteriole increase pressure, not lower it.
   B is correct because this creates high pressure in the glomerulus, increasing ultrafiltration.
   C is wrong because blood does not normally flow backwards.
   D is wrong because glucose is not actively pumped into urine.

10. Answer: B
    A is wrong because the renal artery has more urea and more oxygen than the renal vein.
    B is correct because blood entering the kidney has more oxygen and urea; blood leaving has less urea and less oxygen.
    C is wrong because renal vein usually has more carbon dioxide after kidney respiration.
    D is wrong because renal artery does contain urea.

11. Answer: B
    A is wrong because Bowman’s capsule receives filtrate; it is not the main site of glucose reabsorption.
    B is correct because the proximal convoluted tubule selectively reabsorbs all glucose in a healthy person.
    C is wrong because the collecting duct mainly controls water reabsorption under ADH.
    D is wrong because the renal pelvis collects urine.

12. Answer: B
    A is wrong because glucose reabsorption is not by diffusion only.
    B is correct because glucose is reabsorbed by active transport from filtrate into blood.
    C is wrong because evaporation is not involved in kidney reabsorption.
    D is wrong because emulsification occurs in fat digestion.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

13. Answer: A
    A is correct because glucose appears in urine when blood glucose is too high and the kidney cannot reabsorb it all.
    B is wrong because glucose normally enters the filtrate and is then reabsorbed.
    C is wrong because the liver does not convert all glucose to urea.
    D is wrong because ADH controls water reabsorption, not glucose evaporation.

14. Answer: C
    A is wrong because insulin lowers blood glucose.
    B is wrong because glucagon raises blood glucose.
    C is correct because ADH increases water reabsorption by the kidneys.
    D is wrong because adrenaline prepares the body for action.

15. Answer: A
    A is correct because ADH mainly acts on the collecting ducts, making them more permeable to water.
    B is wrong because the glomerulus is for ultrafiltration.
    C is wrong because the renal artery carries blood to the kidney.
    D is wrong because the bladder stores urine.

16. Answer: B
    A is wrong because little water/heavy sweating causes more ADH, not less.
    B is correct because more ADH increases water reabsorption, producing more concentrated urine.
    C is wrong because less ADH would produce dilute urine.
    D is wrong because urine production does not stop completely.

17. Answer: B
    A is wrong because blood glucose control is not osmoregulation.
    B is correct because osmoregulation controls the water potential of blood.
    C is wrong because oxygen content of air is not controlled by osmoregulation.
    D is wrong because faeces removal is egestion.

18. Answer: B
    A is wrong because less ADH would reduce water reabsorption and worsen low water potential.
    B is correct because more ADH makes collecting ducts more permeable, so more water is reabsorbed.
    C is wrong because insulin controls blood glucose, not blood water potential.
    D is wrong because bile emulsifies fats in digestion.

19. Answer: B
    A is wrong because more ADH causes more, not less, water reabsorption.
    B is correct because more ADH increases water reabsorption, producing less urine.
    C is wrong because less ADH causes less water reabsorption and more dilute urine.
    D is wrong because ADH mainly affects water permeability, not “urea only.”

20. Answer: B
    A is wrong because after drinking lots of water, ADH secretion decreases.
    B is correct because less ADH causes less water reabsorption and more dilute urine.
    C is wrong because insulin is not the main response to drinking water.
    D is wrong because glucagon controls blood glucose, not water balance.

21. Answer: B
    A is wrong because urine is produced in the kidneys.
    B is correct because the bladder stores urine before urination.
    C is wrong because blood is filtered in nephrons, not the bladder.
    D is wrong because glucose reabsorption occurs in the kidney tubules.

22. Answer: A
    A is correct because urine moves kidney → ureter → bladder → urethra.
    B is wrong because urethra comes after bladder.
    C is wrong because urine does not move from bladder back to kidney.
    D is wrong because urine forms in the kidney before entering the ureter.

23. Answer: A
    A is correct because glucose is normally completely reabsorbed from filtrate in a healthy kidney.
    B is wrong because urea is not completely reabsorbed; much is excreted.
    C is wrong because excess salt may be excreted.
    D is wrong because excess water is excreted depending on ADH levels.

24. Answer: B
    A is wrong because urea is not formed in the kidney from glucose.
    B is correct because urea is formed in the liver from excess amino acids after deamination.
    C is wrong because lungs remove carbon dioxide; they do not form urea.
    D is wrong because the pancreas makes insulin/glucagon, not urea.

25. Answer: A
    A is correct because the remaining carbon skeleton may be used in respiration or converted into carbohydrate/fat.
    B is wrong because it is not excreted unchanged in urine.
    C is wrong because it does not become haemoglobin in the bladder.
    D is wrong because it is not converted into bile in the nephron.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

26. Answer: B
    A is wrong because kidneys filter blood and regulate water/salt balance.
    B is correct because the liver stores glucose as glycogen and converts glycogen back to glucose when blood glucose falls.
    C is wrong because lungs are for gas exchange.
    D is wrong because skin helps temperature regulation and excretes sweat.

27. Answer: B
    A is wrong because glucagon raises blood glucose.
    B is correct because insulin lowers blood glucose concentration.
    C is wrong because ADH controls water reabsorption.
    D is wrong because thyroxine affects metabolic rate.

28. Answer: B
    A is wrong because insulin lowers blood glucose.
    B is correct because glucagon raises blood glucose concentration.
    C is wrong because ADH controls water balance.
    D is wrong because oestrogen is involved in the menstrual cycle.

29. Answer: A
    A is correct because after a carbohydrate-rich meal, insulin is released and the liver converts glucose to glycogen.
    B is wrong because glucagon is released when blood glucose falls.
    C is wrong because ADH controls water, not post-meal glucose storage.
    D is wrong because insulin is released by the pancreas, not the liver.

30. Answer: B
    A is wrong because insulin would lower glucose further.
    B is correct because glucagon increases and stimulates glycogen breakdown into glucose.
    C is wrong because ADH controls water balance.
    D is wrong because bile is digestive, and glucose regulation does not occur in the bladder.

31. Answer: B
    A is wrong because negative feedback does not increase the original change.
    B is correct because negative feedback detects a change and triggers responses that reverse it.
    C is wrong because hormones can stop being released once normal levels are restored.
    D is wrong because organs do not all respond the same way to every stimulus.

32. Answer: A
    A is correct because type 1 diabetes involves little or no insulin production.
    B is wrong because glucagon raises blood glucose.
    C is wrong because ADH controls water reabsorption.
    D is wrong because adrenaline is not the deficient hormone in type 1 diabetes.

33. Answer: A
    A is correct because glucose in filtrate lowers water potential, reducing water reabsorption and causing more urine.
    B is wrong because insulin does not convert water into glycogen.
    C is wrong because glucagon does not block the ureter.
    D is wrong because urea size is not the issue.

34. Answer: B
    A is wrong because reduced response to insulin is more typical of type 2 diabetes.
    B is correct because type 1 diabetes occurs when the pancreas produces little or no insulin.
    C is wrong because kidneys do not produce insulin.
    D is wrong because liver bile production is unrelated.

35. Answer: B
    A is wrong because type 2 diabetes does not always start in childhood and often requires diet/exercise control.
    B is correct because body cells become less responsive to insulin.
    C is wrong because insulin receptors are not necessarily completely absent.
    D is wrong because ADH deficiency causes diabetes insipidus, not type 2 diabetes.

36. Answer: A
    A is correct because many people with type 1 diabetes need insulin injections.
    B is wrong because antibiotics treat bacterial infections.
    C is wrong because dialysis treats kidney failure, not insulin deficiency.
    D is wrong because bile salts are for lipid digestion.

37. Answer: A
    A is correct because exercise and controlled carbohydrate intake help control blood glucose in type 2 diabetes.
    B is wrong because avoiding all water is dangerous and unrelated.
    C is wrong because increasing saturated fat intake worsens health risks.
    D is wrong because removing kidneys is not a treatment for type 2 diabetes.

38. Answer: A
    A is correct because the pancreas detects blood glucose and releases insulin or glucagon.
    B is wrong because the bladder stores urine.
    C is wrong because skin regulates temperature.
    D is wrong because lungs exchange gases.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

39. Answer: B
    A is wrong because sweat glands produce sweat, not urine.
    B is correct because skin blood vessels dilate or constrict to alter heat loss.
    C is wrong because hairs lie flat to reduce insulation, not trap more air.
    D is wrong because shivering occurs in skeletal muscles.

40. Answer: A
    A is correct because vasodilation widens arterioles near the skin surface, increasing heat loss.
    B is wrong because narrowing arterioles is vasoconstriction.
    C is wrong because vasodilation is not the same as stopping sweat.
    D is wrong because rapid skeletal muscle contraction is shivering.

41. Answer: B
    A is wrong because vasoconstriction reduces blood flow near the skin surface.
    B is correct because less blood flows near the skin surface, reducing heat loss.
    C is wrong because arterioles narrow, not widen.
    D is wrong because vasoconstriction is not a blood glucose response.

42. Answer: B
    A is wrong because shivering warms the body.
    B is correct because sweating and vasodilation increase heat loss and cool the body.
    C is wrong because vasoconstriction and hair erection reduce heat loss.
    D is wrong because glucagon mainly affects blood glucose.

43. Answer: A
    A is correct because evaporation of sweat absorbs heat from the skin.
    B is wrong because sweat does not digest glucose.
    C is wrong because sweating increases water loss.
    D is wrong because sweat is not converted into oxygen.

44. Answer: B
    A is wrong because sweating and vasodilation cool the body.
    B is correct because vasoconstriction reduces heat loss and shivering generates heat.
    C is wrong because increased ADH affects water balance, not direct warming.
    D is wrong because insulin and glycogen storage lower blood glucose.

45. Answer: A
    A is correct because shivering is rapid muscle contraction; respiration in muscles releases heat.
    B is wrong because evaporation of sweat cools the body.
    C is wrong because filtration occurs in kidneys.
    D is wrong because conversion of glucose to glycogen is blood glucose regulation.

46. Answer: A
    A is correct because the hypothalamus monitors body temperature and coordinates responses.
    B is wrong because the cerebellum coordinates movement and balance.
    C is wrong because the retina detects light.
    D is wrong because the medulla controls processes such as breathing and heart rate, not the main temperature centre.

47. Answer: C
    A is wrong because high body temperature causes vasodilation, not vasoconstriction.
    B is wrong because low body temperature reduces sweating.
    C is correct because high body temperature causes vasodilation to increase heat loss.
    D is wrong because low temperature causes hair erection and reduced sweating, not hairs flat and more sweat.

48. Answer: A
    A is correct because homeostasis keeps internal conditions constant within narrow limits.
    B is wrong because it cannot stop all external changes.
    C is wrong because homeostasis controls temperature, glucose, water and more.
    D is wrong because homeostasis occurs in animals and plants.

49. Answer: B
    A is wrong because sweating and vasodilation increase heat loss.
    B is correct because vasoconstriction reduces blood flow near skin and hair erection traps insulating air.
    C is wrong because sweating increases heat loss and hair flattening reduces insulation.
    D is wrong because vasodilation and increased blood flow to skin increase heat loss.

50. Answer: A
    A is correct because high blood glucose is detected by the pancreas, insulin is released, the liver converts glucose to glycogen, and blood glucose falls.
    B is wrong because glucagon is released when glucose falls and it converts glycogen to glucose.
    C is wrong because ADH controls water balance, not glucose in sweat.
    D is wrong because bile does not convert glucose to urea.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.