Kidney Flashcards
The kidney is responsible for all of the following EXCEPT:
a. synthesis of renin.
b. acid–base balance.
c. reabsorption of electrolytes.
d. regulation of extracellular fluid.
e. release of angiotensin.
Correct Answer: e
Explanation: The kidney synthesizes and releases renin, which triggers a cascade that ultimately produces angiotensin, but the angiotensin itself is not directly released by the kidney. Angiotensin is primarily produced in the liver as angiotensinogen and then converted via renin and ACE enzymes.
Which of the following does NOT contribute to filtrate formation in the nephron?
a. capillary hydrostatic pressure.
b. positive charge of glomerular capillary wall.
c. hydraulic permeability of glomerular capillary wall.
d. colloid oncotic pressure.
e. size of filtration slits.
Correct Answer: b
Explanation: Filtration in the nephron is influenced by physical forces and structural barriers. While charge influences protein permeability, the positive charge of the glomerular capillary wall actually reduces filtration of negatively charged molecules and doesn’t directly enhance filtration volume. The other options reflect physical forces or pore size that determine filtrate flow.
Which of the following is NOT a characteristic of the loop of Henle?
a. There is reabsorption of filtered Na+ and K+.
b. Tubular fluid in the thin descending limb is iso-osmotic to the renal interstitium.
c. Water is freely permeable in the thin ascending limb.
d. Na+ and Cl− are reabsorbed in the thin ascending limb.
e. The thick ascending limb is impermeable to water
Which of the following is NOT a characteristic of the loop of Henle?
Correct answer (book): c. Water is freely permeable in the thin ascending limb
Explanation:
The thin ascending limb of the loop of Henle is impermeable to water, not freely permeable. Water is freely permeable in the thin descending limb. So option c is false, making it the correct answer to this “NOT” question.
The kidneys constitute 0.5% of total body mass and receive approximately how much of the
resting cardiac output?
a. 0.5% to 1 %.
b. 5%.
c. 10%.
d. 20% to 25%.
e. 50% to 60%
Correct Answer: d
Explanation: Despite being a small fraction of body weight, kidneys receive a disproportionately large share of cardiac output (~20–25%) due to their critical role in filtration and waste excretion.
Which of the following is most likely to occur after a toxic insult to the kidney?
a. GFR will decrease in the unaffected kidney.
b. Tight-junction integrity will increase in the nephron.
c. The unaffected cells will undergo atrophy and proliferation.
d. Clinical tests will likely show normal renal function.
e. Glomerulotubular balance is lost
Correct answer (book): d. Clinical tests will likely show normal renal function
Explanation:
In early or localized toxic injury, compensatory mechanisms can mask dysfunction in clinical tests, especially when the injury affects only some nephrons. Thus, renal function can appear normal in standard clinical tests.
Chronic renal failure does not typically result in:
a. decrease in GFR of viable nephrons.
b. glomerulosclerosis.
c. tubular atrophy.
d. increased glomerular pressures.
e. altered capillary permeability.
Correct answer (book): a. decrease in GFR of viable nephrons
Explanation:
The viable nephrons in chronic renal failure usually compensate by hyperfunctioning, so they maintain or even increase GFR, at least initially. Option a is correct because the remaining nephrons do not show decreased GFR—until very late stages.
All of the following statements regarding toxicity to the kidney are true EXCEPT:
a. Concentration of toxins in tubular fluid increase the likelihood that the toxin will diffuse
into tubular cells.
b. Drugs in the systemic circulation are delivered to the kidneys at relatively high
amounts.
c. The distal convoluted tubule is the most common site of toxicant-induced renal injury.
d. Immune complex deposition within the glomeruli can lead to glomerulonephritis.
e. Antibiotics and/or antifungal drugs affect the functioning of the nephron at multiple
locations.
Correct Answer: c
Explanation: The proximal tubule, not the distal convoluted tubule, is the primary site of toxicant-induced renal injury because it handles high concentrations of filtered substances and has high metabolic activity.
Which of the following test results is NOT correctly paired with the underlying kidney
problem?
a. increased urine volume—defect in ADH synthesis.
b. glucosuria—defect in reabsorption in the proximal convoluted tubule.
c. proteinuria—glomerular damage.
d. proteinuria—proximal tubular injury.
e. brush-border enzymuria—glomerulonephritis.
Correct answer (book): e. brush-border enzymuria—glomerulonephritis
Explanation:
Brush-border enzymes are typically released after proximal tubular damage, not glomerulonephritis. So option e is incorrectly paired, making it the correct answer for this “NOT” question.
Renal cell injury is NOT commonly mediated by which of the following mechanisms?
a. loss of membrane integrity.
b. impairment of mitochondrial function.
c. increased cytosolic Ca2+ concentration.
d. increased Na+,K+-ATPase activity.
e. caspase activation.
Correct Answer: d
Explanation: Renal cell injury is often associated with decreased Na+/K+-ATPase activity, not increased. Injury leads to ATP depletion, impaired pump function, and cellular swelling.
Which of the following statements is FALSE with respect to nephrotoxicants?
a. Mercury poisoning can lead to proximal tubular necrosis and acute renal failure.
b. Cisplatin may cause nephrotoxicity because of its ability to inhibit DNA synthesis.
c. Chronic consumption of NSAIDs results in nephrotoxicity that is reversible with time.
d. Amphotericin B nephrotoxicity can result in ADH-resistant polyuria.
e. Acetaminophen becomes nephrotoxic via activation by renal cytochrome P450.
Correct answer (book): c. Chronic NSAID use results in nephrotoxicity that is reversible with time
Explanation:
NSAID-related nephrotoxicity is not always reversible, especially with chronic exposure. It can cause interstitial nephritis, papillary necrosis, and irreversible damage. Therefore, option c is false, making it the correct answer.
