Ch. 25 Urinary System

Question 1

Diabetes insipidus or diabetes mellitus would most likely be indicated by (BLANK).

A) Anuria
B) Polyuria
C) Oliguria
D) None of the above

Answer 1

B) Polyuria.

Explanation: Polyuria is the excessive production or passage of urine. Diabetes insipidus and diabetes mellitus cause excessive urination due to either failure to reabsorb water (ADH issue) or osmotic diuresis from high blood glucose levels.

Incorrect Answers:
A) Anuria: Very little or no urine output, not excessive.
C) Oliguria: Abnormally low urine output, not high.
D) None of the above: Incorrect because polyuria is the correct answer.

Question 2

The color of urine is determined mainly by (BLANK).

A) Diet
B) Filtration rate
C) Byproducts of red blood cell breakdown
D) Filtration efficiency

Answer 2

C) Byproducts of red blood cell breakdown.

Explanation: Urochrome, from the breakdown of hemoglobin in red blood cells, gives urine its characteristic yellow color.

Incorrect Answers:
A) Diet: Can cause temporary color changes, but not the main determinant.
B) Filtration rate: Affects urine volume, not color.
D) Filtration efficiency: Refers to how well waste is removed, not urine color.

Question 3

Production of less than 50 mL/day of urine is called (BLANK).

A) Normal
B) Polyuria
C) Oliguria
D) Anuria

Answer 3

D) Anuria.

Explanation:
Anuria is defined as urine output less than 50 mL per day.

Incorrect Answers:
A) Normal: Typically 1–2 liters per day.
B) Polyuria: Excessive urination, not decreased.
C) Oliguria: Reduced urine output (100–400 mL/day), but more than in anuria.

Question 4

Peristaltic contractions occur in the (BLANK).

A) Urethra
B) Bladder
C) Ureters
D) Urethra, bladder, and ureters

Answer 4

C) Ureters.

Explanation: Peristaltic waves in the ureters move urine from the kidneys to the bladder.

Incorrect Answers:
A) Urethra: Urine moves by sphincter control, not peristalsis.
B) Bladder: Contracts during urination but not through peristalsis.
D) Urethra, bladder, and ureters: Only the ureters utilize peristaltic contractions.

Question 5

Somatic motor neurons must be (BLANK) to relax the external urethral sphincter to allow urination.

A) Stimulated
B) Inhibited

Answer 5

B) Inhibited.

Explanation: Inhibiting somatic motor neurons causes the external urethral sphincter to relax, permitting urination.

Incorrect Answer:
A) Stimulated: Would contract the sphincter and prevent urination.

Question 6

Which part of the urinary system is not completely retroperitoneal?

A) Kidneys
B) Ureters
C) Bladder
D) Nephrons

Answer 6

C) Bladder.

Explanation: The bladder is subperitoneal (located below the peritoneum), not retroperitoneal.

Incorrect Answers:
A) Kidneys: Completely retroperitoneal.
B) Ureters: Completely retroperitoneal.
D) Nephrons: Located in the kidneys, which are retroperitoneal.

Question 7

The renal pyramids are separated from each other by extensions of the renal cortex called (BLANK).

A) Renal medulla
B) Minor calyces
C) Medullary cortices
D) Renal columns

Answer 7

D) Renal columns.

Explanation: Renal columns are extensions of cortical tissue that separate the renal pyramids.

Incorrect Answers:
A) Renal medulla: Contains pyramids but not the separating structures.
B) Minor calyces: Collect urine but do not separate pyramids.
C) Medullary cortices: Not an actual anatomical structure.

Question 8

The primary structure found within the medulla is the (BLANK).

A) Loop of Henle
B) Minor calyces
C) Portal system
D) Ureter

Answer 8

A) Loop of Henle.

Explanation: The loops of Henle dip into the renal medulla and are critical for concentrating urine.

Incorrect Answers:
B) Minor calyces: Found near the renal pelvis, not deep in the medulla.
C) Portal system: A blood vessel arrangement, not a medullary structure.
D) Ureter: Transports urine but is not located within the medulla.

Question 9

The right kidney is slightly lower because (BLANK).

A) It is displaced by the liver
B) It is displaced by the heart
C) It is slightly smaller
D) It needs protection of the lower ribs

Answer 9

A) It is displaced by the liver.

Explanation: The liver’s large size pushes the right kidney lower than the left.

Incorrect Answers:
B) Displaced by the heart: The heart does not influence kidney position.
C) Slightly smaller: Both kidneys are typically similar in size.
D) Protection of ribs: Both kidneys are partially protected by the lower ribs.

Question 10

Blood filtrate is captured in the lumen of the (BLANK).

A) Glomerulus
B) Bowman’s capsule
C) Calyces
D) Renal papillae

Answer 10

B) Bowman’s capsule.

Explanation: Bowman’s capsule surrounds the glomerulus and collects the filtrate.

Incorrect Answers:
A) Glomerulus: Performs filtration but doesn’t capture filtrate.
C) Calyces: Collect urine, not blood filtrate.
D) Renal papillae: Drain urine into the calyces from the pyramids.

Question 11

What are the names of the capillaries following the efferent arteriole?

A) Arcuate and medullary
B) Interlobar and interlobular
C) Peritubular and vasa recta
D) Peritubular and medullary

Answer 11

C) Peritubular and vasa recta.

Explanation: After the efferent arteriole, blood flows into peritubular capillaries (around cortical nephrons) and the vasa recta (around juxtamedullary nephrons).

Incorrect Answers:
A) Arcuate and medullary: Arcuate arteries are pre-filtration vessels; ‘medullary’ is not a capillary type.
B) Interlobar and interlobular: These are larger arteries/veins, not post-efferent capillary networks.
D) Peritubular and medullary: ‘Medullary’ refers to a region, not a capillary type.

Question 12

The functional unit of the kidney is called (BLANK).

A) The renal hilus
B) The renal corpuscle
C) The nephron
D) Bowman’s capsule

Answer 12

C) The nephron.

Explanation: The nephron is the microscopic functional unit that performs filtration, reabsorption, and secretion.

Incorrect Answers:
A) The renal hilus: Entry/exit site for vessels and ureter, not the functional unit.
B) The renal corpuscle: Part of the nephron (glomerulus + Bowman’s capsule), but not the whole unit.
D) Bowman’s capsule: Component of the corpuscle, not the entire nephron.

Question 13

(BLANK) pressure must be greater on the capillary side of the filtration membrane to achieve filtration.

A) Osmotic
B) Hydrostatic

Answer 13

B) Hydrostatic.

Explanation: Hydrostatic pressure in glomerular capillaries pushes fluid into the nephron, driving filtration.

Incorrect Answers:
A) Osmotic: Works in the opposite direction by drawing water back into capillaries, opposing filtration.

Question 14

Production of urine to modify plasma makeup is the result of (BLANK).

A) Filtration
B) Absorption
C) Secretion
D) Filtration, absorption, and secretion

Answer 14

D) Filtration, absorption, and secretion.

Explanation: All three processes are necessary to transform plasma into urine and regulate its composition.

Incorrect Answers:
A) Filtration: Initiates the process but doesn’t complete it.
B) Absorption: Reclaims substances but doesn’t form urine alone.
C) Secretion: Helps remove substances but is only one part of the process.

Question 15

Systemic blood pressure must stay above 60 so that the proper amount of filtration occurs.

A) True
B) False

Answer 15

A) True.

Explanation: Mean arterial pressure must stay above 60 mm Hg to sustain adequate glomerular filtration.

Incorrect Answers:

B) False: If pressure drops below this, filtration and kidney function are impaired.

Question 16

Aquaporin channels are only found in the collecting duct.

A) True
B) False

Answer 16

B) False.

Explanation: Aquaporins are found in both the proximal convoluted tubule and collecting duct. Their expression in the collecting duct is regulated by antidiuretic hormone (ADH).

Incorrect Answers:

A) True: Incorrect because they are also present in the proximal convoluted tubule.

Question 17

Most absorption and secretion occurs in this part of the nephron.

A) Proximal convoluted tubule
B) Descending loop of Henle
C) Ascending loop of Henle
D) Distal convoluted tubule
E) Collecting ducts

Answer 17

A) Proximal convoluted tubule.

Explanation: The PCT handles the majority of reabsorption (about 65–70%) and significant secretion.

Incorrect Answers:
B) Descending loop of Henle: Focuses mostly on water reabsorption.
C) Ascending loop of Henle: Reabsorbs ions but has limited total activity.
D) Distal convoluted tubule: Involved in selective reabsorption/secretion for fine-tuning.
E) Collecting ducts: Final stage of water reabsorption and urine concentration.

Question 18

The fine tuning of water recovery or disposal occurs in (BLANK).

A) The proximal convoluted tubule
B) The collecting ducts
C) The ascending loop of Henle
D) The distal convoluted tubule

Answer 18

B) The collecting ducts.

Explanation: The collecting ducts regulate water reabsorption under the influence of ADH, allowing fine control of urine concentration.

Incorrect Answers:
A) Proximal convoluted tubule: Performs bulk reabsorption, not precise water adjustments.
C) Ascending loop of Henle: Primarily reabsorbs sodium and chloride, not water.
D) Distal convoluted tubule: Primarily adjusts ion levels rather than water balance.

Question 19

(BLANK) is a protein-forming water channels through the lipid bilayer of the cell and allows water to cross.

A) Glycosuria
B) Aquaporin
C) Anuria
D) Medulla

Answer 19

B) Aquaporin.

Explanation: Aquaporins are protein channels that allow water to move rapidly through the cell membrane.

Incorrect Answers:
A) Glycosuria: The presence of glucose in urine, not a water channel.
C) Anuria: Absence of urine output, unrelated to water transport proteins.
D) Medulla: A region of the kidney, not a protein or channel.

Question 20

Vasodilation of blood vessels to the kidneys is due to (BLANK).

A) More frequent action potentials
B) Less frequent action potentials

Answer 20

B) Less frequent action potentials.

Explanation: Reduced sympathetic stimulation (fewer action potentials) leads to smooth muscle relaxation and vasodilation in renal vessels.

Incorrect Answers:
A) More frequent action potentials: Increases sympathetic tone, leading to vasoconstriction.

Question 21

When blood pressure increases, blood vessels supplying the kidney will (BLANK) to maintain a steady rate of filtration.

A) Contract
B) Relax

Answer 21

A) Contract.

Explanation: Afferent arterioles contract in response to increased pressure to maintain a stable glomerular filtration rate (autoregulation).

Incorrect Answers:
B) Relax: Would allow even more blood flow and increase pressure, risking damage to glomeruli.

Question 22

Which of these three paracrine chemicals cause vasodilation?

A) ATP
B) Adenosine
C) Nitric oxide

Answer 22

C) Nitric oxide.

Explanation: Nitric oxide is a powerful vasodilator released by endothelial cells to increase blood flow.

Incorrect Answers:
A) ATP: Usually causes vasoconstriction in the kidneys.
B) Adenosine: Promotes vasoconstriction in renal circulation.

Question 23

What hormone directly opposes the actions of natriuretic hormones?

A) Renin
B) Nitric oxide
C) Dopamine
D) Aldosterone

Answer 23

D) Aldosterone.

Explanation: Aldosterone promotes sodium and water retention, countering the effects of natriuretic peptides, which promote excretion.

Incorrect Answers:
A) Renin: Initiates RAAS but doesn’t directly oppose natriuretic hormones.
B) Nitric oxide: Primarily a vasodilator, not involved in sodium retention.
C) Dopamine: Can promote natriuresis, not oppose it.

Question 24

Which of these is a vasoconstrictor?

A) Nitric oxide
B) Natriuretic hormone
C) Bradykinin
D) Angiotensin II

Answer 24

D) Angiotensin II.

Explanation: Angiotensin II is a potent vasoconstrictor that raises blood pressure.

Incorrect Answers:
A) Nitric oxide: Causes vasodilation.
B) Natriuretic hormone: Promotes vasodilation and natriuresis.
C) Bradykinin: Causes vasodilation, especially in inflammation.

Question 25

What signal causes the heart to secrete atrial natriuretic hormone? A) Increased blood pressure B) Decreased blood pressure C) Increased Na⁺ levels D) Decreased Na⁺ levels

Answer 25

A) Increased blood pressure. Explanation: High blood pressure stretches atrial walls, stimulating ANH release, which promotes natriuresis and lowers blood pressure. Incorrect Answers: B) Decreased blood pressure: Would reduce ANH secretion. C) Increased Na⁺ levels: Indirect trigger; volume/stretch is the primary stimulus. D) Decreased Na⁺ levels: Would not promote ANH secretion.

Question 26

Which of these beverages does not have a diuretic effect? A) Tea B) Coffee C) Alcohol D) Milk

Answer 26

D) Milk. Explanation: Milk hydrates and provides electrolytes but doesn’t promote excess urination. Incorrect Answers: A) Tea: Contains caffeine, which has a diuretic effect. B) Coffee: Caffeinated; promotes urination. C) Alcohol: Inhibits ADH, increasing urine output.

Question 27

Progesterone can bind to receptors for which hormone that, when released, activates water retention? A) Aldosterone B) ADH C) PTH D) ANH

Answer 27

A) Aldosterone. Explanation: Progesterone can bind to aldosterone receptors and influence sodium/water retention. Incorrect Answers: B) ADH: Works via aquaporins, not aldosterone-type receptors. C) PTH: Regulates calcium, not water balance. D) ANH: Promotes sodium/water excretion, not retention.

Question 28

Renin is released in response to (BLANK). A) Increased blood pressure B) Decreased blood pressure C) ACE D) Diuretics

Answer 28

B) Decreased blood pressure. Explanation: Low blood pressure triggers renin release to activate the RAAS system and restore pressure. Incorrect Answers: A) Increased blood pressure: Inhibits renin. C) ACE: Works downstream of renin. D) Diuretics: Indirect effect; pressure drop is the actual trigger.

Question 29

Which step in vitamin D production does the kidney perform? A) Converts cholecalciferol into calcidiol B) Converts calcidiol into calcitriol C) Stores vitamin D D) None of these

Answer 29

B) Converts calcidiol into calcitriol. Explanation: The kidney converts calcidiol (from the liver) into calcitriol, the active form of vitamin D. Incorrect Answers: A) Converts cholecalciferol into calcidiol: Done in the liver. C) Stores vitamin D: Storage occurs in fat tissue. D) None of these: Incorrect; kidney is key in calcitriol formation.

Question 30

Which hormone does the kidney produce that stimulates red blood cell production? A) Thrombopoietin B) Vitamin D C) EPO D) Renin

Answer 30

C) EPO. Explanation: Erythropoietin (EPO) is produced by the kidney in response to low oxygen and stimulates RBC production in bone marrow. Incorrect Answers: A) Thrombopoietin: Made mainly in the liver; stimulates platelet production. B) Vitamin D: Involved in calcium metabolism. D) Renin: Regulates blood pressure, not red blood cell production.

Question 31

If there were no aquaporin channels in the collecting duct, (BLANK). A) You would develop systemic edema B) You would retain excess Na⁺ C) You would lose vitamins and electrolytes D) You would suffer severe dehydration

Answer 31

D) You would suffer severe dehydration. Explanation: Aquaporins allow water reabsorption in the collecting duct under the influence of ADH. Without them, water would remain in the filtrate and be excreted, leading to severe dehydration. Incorrect Answers: A) Edema: Involves water retention, not loss. B) Sodium: Its reabsorption is regulated independently of aquaporins. C) Electrolyte loss: May occur, but not as critically as water loss.

Question 32

The (BLANK) is the tuft of capillaries surrounded by Bowman’s capsule. Group of answer choices A) Medulla B) Glycosuria C) Loop of Henle D) Glomerulus

Answer 32

D) Glomerulus Explanation: The glomerulus is a tuft of capillaries located inside Bowman’s capsule, where blood filtration begins in the nephron. Incorrect: A) Medulla – Inner region of the kidney, not a capillary tuft. B) Glycosuria – Presence of glucose in urine; a condition, not a structure. C) Loop of Henle – Part of the nephron involved in concentration of urine, not involved in initial filtration.