Human Urinary System

Biology, HSSC-Punjab Second Year. This chapter is split into 33 topics and has 759 practice questions. The topics covered are listed below, followed by 10 free sample questions from the chapter.

Topics in this chapter

1. Kidney transplant and its complications 25 questions
2. Regulation of urine concentration: counter-current mechanism 25 questions
3. Kidney failure and dialysis (haemodialysis and peritoneal) 25 questions
4. Kidney functioning: ultrafiltration 25 questions
5. Selective reabsorption and tubular secretion 25 questions
6. Urinary tract infections 25 questions
7. Kidney: external and internal structure 25 questions
8. Nephron: structure and parts 25 questions
9. Human urinary system: organs and overview 25 questions
10. Chapter review: urinary system (end-of-chapter exercise focus) 25 questions
11. Blood supply of the kidney 25 questions
12. Kidney stones 25 questions
13. Figures 14.1 and 14.2: labelled urinary system and kidney section 20 questions
14. Figure 14.3: labelled parts of a nephron and its blood vessels 22 questions
15. Figure 14.4: arrows of urine formation and counter-current mechanism 20 questions
16. Figures 14.5 and 14.6: lithotripsy diagrams 20 questions
17. Figures 14.7 and 14.8: haemodialysis and peritoneal dialysis diagrams 23 questions
18. Excretion, the three roles of the urinary system and the critical-thinking question 20 questions
19. Urine output, hydration and the osmoregulatory role of the kidneys 20 questions
20. ADH: osmoreceptors, thirst, diabetes insipidus and blood pressure 21 questions
21. Aldosterone, ADH tidbits and the hormonal control of the kidney 20 questions
22. Two capillary beds of the kidney: glomerular and peritubular compared 22 questions
23. Kidney numbers: filtration, reabsorption and nephron counts (calculations) 23 questions
24. Cortical and juxtamedullary nephrons and the loop of Henle: applied reasoning 22 questions
25. Reading urine and blood findings: clinical interpretation of kidney function 24 questions
26. Kidney failure: chronic and acute causes 22 questions
27. Dialysis applied: haemodialysis reasoning and peritoneal dialysis calculations 28 questions
28. Problems associated with dialysis: causes and consequences 20 questions
29. Kidney transplant applied: donor categories, matching and complications 24 questions
30. Kidney donation and transplant centres in Pakistan (information and inquisitive items) 21 questions
31. Kidney stones applied: types, causes, terms and numbers 24 questions
32. Differentiate between paired terms of the urinary system chapter 23 questions
33. Disorders of the urinary tract: classification and applied reasoning 20 questions

Sample questions: Human Urinary System

10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.

Q1. Which of the following correctly pairs a cause with the type of kidney failure it produces?

• A. Blockage of urinary tract by kidney stones - acute kidney failure(correct answer)
• B. High blood pressure - acute kidney failure
• C. Diabetes - acute kidney failure
• D. NSAIDs - chronic kidney failure

Answer: A.Blockage in the urinary tract (due to kidney stones, bladder cancer, or enlarged prostate) can cause acute kidney failure, whereas diabetes and high blood pressure cause chronic kidney failure, and NSAIDs are listed among the causes of acute, not chronic, kidney failure.

Q2. Which of the following statements about the nephron is CORRECT?

• A. The proximal convoluted tubule is the last portion of the renal tubule and opens into the collecting duct.
• B. Cortical nephrons make the majority of nephrons (about 85%) and possess relatively short loops of Henle.(correct answer)
• C. The ascending limb of the loop of Henle opens into the collecting duct.
• D. In juxtamedullary nephrons, the loops of Henle are relatively short and remain within the renal cortex.

Answer: B.Cortical nephrons make the majority of nephrons (about 85%) and possess relatively short loops of Henle. The ascending limb actually opens into the distal convoluted tubule, and the proximal convoluted tubule is the beginning portion of the renal tubule, not the last.

Q3. Assertion (A): The glomerulus is a capillary network derived from an afferent renal arteriole. Reason (R): The renal corpuscle consists of two associated structures, the glomerulus and Bowman's capsule.

• A. A is false but R is true
• B. A is true but R is false
• C. Both A and R are true, but R does not explain A(correct answer)
• D. Both A and R are true, and R correctly explains A

Answer: C.Both statements are true: the glomerulus is a capillary network derived from an afferent renal arteriole, and the renal corpuscle consists of the glomerulus and Bowman's capsule. However, the composition of the renal corpuscle does not explain the origin of the glomerulus from an afferent arteriole.

Q4. Assertion (A): The distal convoluted tubules of multiple nephrons drain into a single collecting duct. Reason (R): As collecting ducts descend through the medulla, they merge to form larger papillary ducts, which ultimately discharge into the renal pelvis.

• A. A is true but R is false
• B. Both A and R are true, but R does not explain A(correct answer)
• C. A is false but R is true
• D. Both A and R are true, and R correctly explains A

Answer: B.Both statements are stated in the text: multiple distal convoluted tubules drain into a single collecting duct, and collecting ducts merge into papillary ducts discharging into the renal pelvis. However, R describes the later course of the collecting duct and does not explain why several distal convoluted tubules share one collecting duct.

Q5. The peritubular capillaries form a dense network around which structures of the kidney?

• A. The loops of Henle in the renal medulla
• B. The collecting ducts in the renal pelvis
• C. The Bowman's capsules in the renal medulla
• D. The proximal and distal convoluted tubules in the renal cortex(correct answer)

Answer: D.The efferent arteriole branches into peritubular capillaries, which form a dense network around the proximal and distal convoluted tubules in the renal cortex. It is the vasa recta, not peritubular capillaries, that run through the medulla parallel to the loops of Henle.

Q6. Assertion (A): Unlike most capillary beds in the body, the glomerular capillaries drain into an efferent arteriole. Reason (R): The efferent arteriole is narrower than the afferent arteriole, which keeps the blood in the glomerular capillaries under relatively high pressure.

• A. A is true but R is false
• B. A is false but R is true
• C. Both A and R are true, but R does not explain A(correct answer)
• D. Both A and R are true, and R correctly explains A

Answer: C.Both statements are true: the glomerular capillaries drain into an efferent arteriole, and the narrower efferent arteriole keeps glomerular blood under high pressure. However, the diameter difference accounts for the high glomerular pressure, not for the fact that the capillaries drain into an arteriole instead of a venule.

Q7. Which statement correctly distinguishes the peritubular capillaries from the glomerular capillaries?

• A. Peritubular capillaries lie within the Bowman's capsule and operate under high blood pressure for filtration
• B. Peritubular capillaries surround the renal tubules and operate under low hydrostatic pressure, carrying out reabsorption and secretion(correct answer)
• C. Peritubular capillaries operate under high hydrostatic pressure so that toxins can be forced into the nephron
• D. Glomerular capillaries pull glucose and water back into the bloodstream while peritubular capillaries perform filtration

Answer: B.Peritubular capillaries surround the renal tubules, work at low hydrostatic pressure, pull essential nutrients and water back into the blood, and secrete specific toxins into the tubule; glomerular capillaries instead sit in the Bowman's capsule and filter under high pressure.

Q8. Which option correctly orders the key events of the counter-current mechanism?

• A. Ascending limb: water is reabsorbed → Descending limb: salts are actively transported out → Collecting duct: salts are reabsorbed into blood
• B. Descending limb: water is reabsorbed → Ascending limb: sodium and chloride are actively transported out → Collecting duct: water moves out by osmosis and enters blood via the vasa recta(correct answer)
• C. Collecting duct: water enters by osmosis → Descending limb: water is reabsorbed → Ascending limb: salts are transported out
• D. Descending limb: salts are actively transported out → Ascending limb: water is reabsorbed → Collecting duct: water moves out by osmosis into the salty fluid

Answer: B.Water is first reabsorbed from the descending limb, the ascending limb then actively transports sodium (with chloride following) out of the tubule, and finally water leaves the collecting duct by osmosis into the salty fluid and enters blood via the vasa recta.

Q9. Assertion (A): A person who cannot produce enough ADH due to pituitary damage constantly excretes a large volume of dilute urine. Reason (R): ADH acts on the walls of the collecting ducts and makes them more permeable to water.

• A. Both A and R are true, but R does not explain A
• B. A is false but R is true
• C. Both A and R are true, and R correctly explains A(correct answer)
• D. A is true but R is false

Answer: C.The assertion describes diabetes insipidus caused by pituitary damage; it occurs because ADH normally makes the collecting ducts more permeable to water so that more water moves from the filtrate into the blood, and without enough ADH a large volume of dilute urine is lost.

Q10. Assertion (A): Continuous dehydration in the body increases the chances of kidney stone formation. Reason (R): High concentration of cysteine and phosphates in urine also cause kidney stones.

• A. A is false but R is true
• B. A is true but R is false
• C. Both A and R are true, but R does not explain A(correct answer)
• D. Both A and R are true, and R correctly explains A

Answer: C.Both statements are given in the text: continuous dehydration raises the chances of stone formation, and high cysteine and phosphate concentrations are additional causes; the reason is a separate cause and does not explain why dehydration increases stone formation.