Test 1
Lecture 1: Development of Urinary System
A neonate presents with bilateral renal agenesis, leading to oligohydramnios and Potter's sequence. Which developmental process is most likely to have failed in this patient?
- A. Reciprocal induction between ureteric bud and metanephric mesenchyme
- B. Formation of the mesonephros
- C. Formation of the pronephros
- D. Formation of the cloaca
Answer: A. Reciprocal induction between ureteric bud and metanephric mesenchyme
Explanation: Renal agenesis results from the failure of reciprocal induction between the ureteric bud and the metanephric mesenchyme. As described in the lecture, “WT1 required to form nephrons from this mesenchyme” is critical, and without it, the kidney cannot develop.
A 3-year-old boy presents with Wilms’ tumor (nephroblastoma). Which gene is most likely mutated in this patient?
- A. PAX2
- B. WT1
- C. FGF2
- D. BMP7
Answer: B. WT1
Explanation: Wilms’ tumor is commonly associated with mutations in the WT1 gene. As stated in the lecture, “WT1 mutations cause Nephroblastoma (Wilms' tumor)”.A 25-year-old patient is found to have a bifid ureter on imaging. This abnormality is most likely due to:
- A. Duplication of the metanephric blastema
- B. Early splitting of the ureteric bud
- C. Defective cloacal development
- D. Failure of reciprocal induction
Answer: B. Early splitting of the ureteric bud
Explanation: The lecture explains that a bifid ureter is caused by "early splitting of the ureteric bud," resulting in two ureters originating from one kidney.Which of the following congenital abnormalities is associated with oligohydramnios and lung hypoplasia in newborns?
- A. Horseshoe kidney
- B. Renal agenesis
- C. Polycystic kidney disease
- D. Ureteral duplication
Answer: B. Renal agenesis
Explanation: Bilateral renal agenesis results in oligohydramnios, leading to Potter’s syndrome, as noted in the lecture: “Causes Potter’s syndrome: Lung hypoplasia... Face abnormalities... Feet clubbed...”.
Lecture 2: Renal Histology
A 5-year-old boy is diagnosed with minimal change disease. What microscopic structure is primarily affected?
- A. Glomerular basement membrane
- B. Podocyte foot processes
- C. Mesangial cells
- D. Endothelial cells
Answer: B. Podocyte foot processes
Explanation: The lecture states that minimal change disease affects the podocyte foot processes, leading to proteinuria. The filtration barrier is described in detail, with podocytes playing a central role in selective permeability.A biopsy of a patient with rapidly progressive glomerulonephritis shows crescent formation. Which cell type is proliferating?
- A. Mesangial cells
- B. Parietal epithelial cells
- C. Podocytes
- D. Endothelial cells
Answer: B. Parietal epithelial cell
Explanation: Crescent formation in rapidly progressive glomerulonephritis occurs due to the proliferation of parietal epithelial cells, as explained in the histology of renal corpuscles.
Where in the nephron does most glucose reabsorption occur?
- A. Distal convoluted tubule
- B. Proximal convoluted tubule
- C. Thick ascending limb
- D. Collecting duct
Answer: B. Proximal convoluted tubule
Explanation: The lecture states that the proximal convoluted tubule (PCT) is responsible for reabsorbing "most of the nutrients including glucose, amino acids, and phosphate".Which of the following structures contains both afferent and efferent arterioles, playing a key role in glomerular filtration?
- A. Renal corpuscle
- B. Loop of Henle
- C. Collecting duct
- D. Vasa recta
Answer: A. Renal corpuscle
Explanation: The renal corpuscle, as described in the lecture, contains afferent and efferent arterioles and is the site of "glomerular filtration".
Lecture 3: Renal Physiology
A patient with GFR of 120 mL/min has a plasma creatinine level of 1.0 mg/dL. If the plasma creatinine rises to 2.0 mg/dL, what is the new estimated GFR?
- A. 60 mL/min
- B. 90 mL/min
- C. 30 mL/min
- D. 45 mL/min
Answer: A. 60 mL/min
Explanation: The relationship between GFR and plasma creatinine is inversely proportional. As noted in the lecture, “GFR is maintained at a homeostatic state by dilation/constriction of afferent and efferent arterioles”.In the nephron, which of the following segments reabsorbs the majority of water and solutes?
- A. Distal convoluted tubule
- B. Collecting duct
- C. Proximal convoluted tubule
- D. Thick ascending limb
Answer: C. Proximal convoluted tubule
Explanation: The lecture notes that "67% of Na⁺ and H₂O are reabsorbed in the PCT (proportional to Na)".Which of the following is the primary driving force for filtration at the glomerulus?
- A. Oncotic pressure in Bowman’s capsule
- B. Hydrostatic pressure in glomerular capillaries
- C. Plasma oncotic pressure
- D. Hydrostatic pressure in the peritubular capillaries
Answer: B. Hydrostatic pressure in glomerular capillaries
Explanation: The driving force of filtration is the “hydrostatic pressure in the glomerular capillaries,” as explained in the renal physiology overview.Which substance’s clearance is the gold standard for measuring GFR?
- A. Creatinine
- B. Urea
- C. Inulin
- D. Para-aminohippuric acid (PAH)
Answer: C. Inulin
Explanation: According to the lecture, "Inulin clearance represents GFR" because it is filtered but neither reabsorbed nor secreted.Lecture 4-5: Renal Blood Flow and GFR
A patient with high blood pressure is found to have decreased GFR. Which of the following is most likely contributing to the reduced GFR?
- A. Constriction of the afferent arteriole
- B. Dilation of the afferent arteriole
- C. Increased filtration coefficient (Kf)
- D. Increased oncotic pressure in Bowman’s space
Answer: A. Constriction of the afferent arteriole
Explanation: "Constriction of the afferent arteriole reduces renal blood flow (RBF) and glomerular filtration rate (GFR)." As noted in the lecture, "↑RA (afferent arteriole constriction) → ↓GFR".A patient is undergoing surgery, and anesthesia causes a drop in systemic blood pressure. How will the kidney attempt to maintain GFR?
- A. Constriction of efferent arteriole
- B. Dilation of afferent arteriole
- C. Dilation of efferent arteriole
- D. Constriction of afferent arteriole
Answer: A. Constriction of the efferent arteriole
Explanation: The body compensates for low blood pressure by constricting the efferent arteriole to maintain GFR. The lecture explains: "↑RE (efferent arteriole constriction) → ↑GFR despite ↓RBF".Which of the following mechanisms is responsible for autoregulation of renal blood flow and GFR in response to changes in systemic blood pressure?
- A. Myogenic reflex
- B. Sympathetic stimulation
- C. Aldosterone secretion
- D. Glucocorticoid release
Answer: A. Myogenic reflex
Explanation: Autoregulation of RBF and GFR occurs via the myogenic reflex and tubuloglomerular feedback. The myogenic response detects pressure changes in the afferent arteriole to maintain constant RBF and GFR. As the lecture explains: "↑ΔP → ↑stretch → ↑[Ca2+]i → ↑constrict → constant flow".In a healthy individual, what is the effect of increased efferent arteriole constriction on GFR and renal plasma flow (RPF)?
- A. Increased GFR, decreased RPF
- B. Decreased GFR, increased RPF
- C. Increased GFR, increased RPF
- D. Decreased GFR, decreased RPF
Answer: A. Increased GFR, decreased RPF
Explanation: "↑Efferent arteriole constriction leads to an increase in GFR and a decrease in renal plasma flow (RPF)," as discussed in the lecture. This is due to increased pressure in the glomerulus, which boosts filtration.
Lecture 6: Nephron Physiology
Which part of the nephron is responsible for the majority of sodium reabsorption?
- A. Proximal convoluted tubule
- B. Distal convoluted tubule
- C. Loop of Henle
- D. Collecting duct
Answer: A. Proximal convoluted tubule
Explanation: "The PCT is responsible for most reabsorption," where "67% of Na⁺ and H₂O are reabsorbed".A patient is given a drug that inhibits the Na⁺-K⁺-2Cl⁻ cotransporter in the thick ascending limb of the nephron. What is the expected effect on calcium reabsorption?
- A. Increased reabsorption
- B. Decreased reabsorption
- C. No change in reabsorption
- D. Increased calcium secretion
Answer: B. Decreased reabsorption
Explanation: "Loop diuretics (which block the Na⁺-K⁺-2Cl⁻ cotransporter) reduce Mg²⁺ and Ca²⁺ reabsorption" in the thick ascending limb, as the positive lumen charge decreases.Which part of the nephron is primarily responsible for concentrating urine in response to ADH?
- A. Proximal convoluted tubule
- B. Distal convoluted tubule
- C. Thick ascending limb
- D. Collecting duct
Answer: D. Collecting duct
Explanation: "ADH increases water reabsorption in the collecting duct by increasing the insertion of aquaporin channels in the apical membrane," leading to concentrated urine.A patient has a plasma glucose concentration of 400 mg/dL. Which of the following is most likely to occur in the nephron?
- A. All filtered glucose is reabsorbed
- B. Some filtered glucose is excreted
- C. Glucose is secreted into the tubular lumen
- D. Glucose is reabsorbed in the loop of Henle
Answer: B. Some filtered glucose is excreted
Explanation: Glucose transporters in the PCT can become saturated at high plasma glucose concentrations, leading to glucosuria. As described: "Filtered glucose above the transport maximum (Tmax) is excreted".
Lecture 7: Volume Control
A patient with central diabetes insipidus is given desmopressin. Which segment of the nephron will now become more permeable to water?
- A. Proximal convoluted tubule
- B. Thick ascending limb
- C. Distal convoluted tubule and collecting duct
- D. Glomerulus
Answer: C. Distal convoluted tubule and collecting duct
Explanation: ADH (or desmopressin, an analog) acts on the distal convoluted tubule and collecting duct to insert aquaporins, thereby increasing water reabsorption. "ADH → AQP insertion → water reabsorption".A 50-year-old man is severely dehydrated. Which hormone is primarily responsible for increasing water reabsorption in the kidneys?
- A. Aldosterone
- B. Renin
- C. ADH
- D. Angiotensin II
Answer: C. ADH
Explanation: ADH increases water reabsorption in the collecting duct, as described: "ADH (Anti-Diuretic Hormone) is secreted by the posterior pituitary in response to increased ECF osmolarity".Which of the following conditions will most likely lead to increased aldosterone secretion?
- A. High blood pressure
- B. Hyperkalemia
- C. Hypercalcemia
- D. Hypokalemia
Answer: B. Hyperkalemia
Explanation: Aldosterone is released in response to high potassium levels (hyperkalemia), as noted in the lecture: "Aldosterone → Na⁺ reabsorption, K⁺ secretion".A patient consumes a large amount of water quickly. What changes are most likely to occur in urine output and osmolarity?
- A. Increased urine output, decreased osmolarity
- B. Decreased urine output, increased osmolarity
- C. Increased urine output, increased osmolarity
- D. Decreased urine output, decreased osmolarity
Answer: A. Increased urine output, decreased osmolarity
Explanation: "After drinking 1 L of water... Urine flow rate (V): UP, Urine osmolarity (U): DOWN".Lecture 8: Diuretics
A patient with heart failure is started on a loop diuretic. What is the expected effect of this medication on calcium and magnesium reabsorption in the thick ascending limb?
- A. Increased calcium and magnesium reabsorption
- B. Decreased calcium and magnesium reabsorption
- C. No effect on calcium and magnesium reabsorption
- D. Increased potassium reabsorption
Answer: B. Decreased calcium and magnesium reabsorption
Explanation: Loop diuretics block the Na⁺-K⁺-2Cl⁻ cotransporter in the thick ascending limb, reducing the positive lumen potential that drives the reabsorption of calcium and magnesium. As noted in the lecture: "Loop diuretic: ↓Mg, ↓Ca".Which of the following diuretics primarily inhibits sodium reabsorption in the distal convoluted tubule and may cause hypercalcemia?
- A. Furosemide
- B. Acetazolamide
- C. Hydrochlorothiazide
- D. Spironolactone
Answer: C. Hydrochlorothiazide
Explanation: Thiazide diuretics inhibit the Na⁺-Cl⁻ cotransporter in the distal convoluted tubule and enhance calcium reabsorption. "Thiazide diuretics can cause hypercalcemia," according to the lecture.A patient with cirrhosis is being treated with spironolactone. Which of the following is a potential side effect of this medication?
- A. Hyperkalemia
- B. Hypokalemia
- C. Hypercalcemia
- D. Metabolic alkalosis
Answer: A. Hyperkalemia
Explanation: Spironolactone is a potassium-sparing diuretic that blocks aldosterone's effects, leading to decreased potassium secretion and the risk of hyperkalemia. "Serum: ↑K+, acidosis" is listed as a side effect in the lecture.A 67-year-old man with glaucoma is started on acetazolamide. What is the primary mechanism by which this drug causes diuresis?
- A. Inhibition of Na⁺-K⁺-2Cl⁻ cotransporter
- B. Inhibition of carbonic anhydrase
- C. Blockade of ENaC in the collecting duct
- D. Inhibition of Na⁺-Cl⁻ cotransporter in the distal tubule
Answer: B. Inhibition of carbonic anhydrase
Explanation: Acetazolamide is a carbonic anhydrase inhibitor, primarily acting in the proximal tubule, leading to increased bicarbonate excretion and diuresis. "CA inhibitors will keep HCO3⁻ in the urine," increasing urine output.
Lecture 9: Disorders of Potassium
A patient with hypokalemia is found to have low urinary potassium excretion. Which of the following is the most likely cause of the hypokalemia?
- A. Increased renal losses
- B. Increased GI losses
- C. Low dietary intake
- D. Use of loop diuretics
Answer: C. Low dietary intake
Explanation: In cases of hypokalemia with low urinary potassium (<20 mEq/d), a common cause is poor dietary potassium intake. As the lecture states, "Low urinary K⁺ loss typically <20 mEq/d is due to low K⁺ diet".A 56-year-old woman presents with vomiting and alkalemia. Her serum potassium is low, and her urinary potassium is high. What is the most likely cause of her hypokalemia?
- A. Renal tubular acidosis
- B. Diarrhea
- C. Vomiting
- D. Hyperventilation
Answer: C. Vomiting
Explanation: Vomiting leads to the loss of gastric acid (H⁺), resulting in metabolic alkalosis and hypokalemia. As described in the lecture, vomiting causes "volume loss, resulting in high aldosterone" and "higher renal K⁺ secretion from the collecting duct".Which of the following genetic conditions is associated with hypokalemia and involves a gain-of-function mutation in the ENaC channel?
- A. Liddle’s syndrome
- B. Bartter syndrome
- C. Gitelman syndrome
- D. Gordon’s syndrome
Answer: A. Liddle’s syndrome
Explanation: Liddle’s syndrome is caused by a gain-of-function mutation in the epithelial sodium channel (ENaC), leading to increased sodium reabsorption and potassium excretion, resulting in hypokalemia. "Liddle’s Syndrome (activating mutation of the ENaC) leads to excessive Na⁺ reabsorption and K⁺ excretion".A patient is started on a high-potassium diet. Which of the following is most likely to increase in response?
- A. Renal potassium secretion
- B. Renal potassium reabsorption
- C. Plasma aldosterone concentration
- D. Plasma sodium concentration
Answer: A. Renal potassium secretion
Explanation: A high-potassium diet increases potassium secretion in the collecting duct. As noted in the lecture, "The secretion of K⁺ by the collecting duct is increased by a high [K⁺] diet".
Lecture 10: Disorders of Calcium and Magnesium
A 65-year-old woman presents with bone pain and frequent kidney stones. Lab tests reveal hypercalcemia and a high parathyroid hormone (PTH) level. What is the most likely diagnosis?
- A. Hyperparathyroidism
- B. Malignancy-associated hypercalcemia
- C. Vitamin D toxicity
- D. Hypoparathyroidism
Answer: A. Hyperparathyroidism
Explanation: Hyperparathyroidism causes increased PTH secretion, leading to hypercalcemia, bone pain, and kidney stones. The lecture lists "Hyperparathyroidism" as a cause of hypercalcemia with symptoms of "stones, bones, groans, thrones, and psychiatric overtones".A patient presents with muscle cramps and tingling in the extremities. Lab results show low calcium and magnesium levels. What is the most appropriate next step in management?
- A. Replace calcium only
- B. Replace magnesium only
- C. Replace both calcium and magnesium
- D. Observe for spontaneous resolution
Answer: C. Replace both calcium and magnesium
Explanation: The lecture states, "Replace magnesium" when both calcium and magnesium are low, as hypomagnesemia can interfere with calcium homeostasis.Which of the following is a clinical sign associated with hypocalcemia and can be elicited by tapping the facial nerve?
- A. Trousseau's sign
- B. Chvostek's sign
- C. Babinski's sign
- D. Hoffmann's sign
Answer: B. Chvostek's sign
Explanation: Chvostek's sign is described in the lecture as a clinical feature of hypocalcemia: "Tap the skin over the facial nerve... Ipsilateral contraction of the facial muscles is a positive sign".A patient is diagnosed with hypocalcemia secondary to hypoparathyroidism. What is the primary treatment for this condition?
- A. Bisphosphonates
- B. IV calcium and vitamin D supplementation
- C. Loop diuretics
- D. Calcitonin
Answer: B. IV calcium and vitamin D supplementation
Explanation: The treatment for hypocalcemia, especially when associated with hypoparathyroidism, is "IV calcium" with "vitamin D" to promote calcium absorption. This is essential for correcting the underlying hypocalcemia.Lecture 12: Ventilation and PCO2
A patient is admitted with hyperventilation due to a panic attack. Arterial blood gas (ABG) shows a PaCO2 of 30 mm Hg. Which of the following compensatory changes would you expect?
- A. Increased renal excretion of H⁺
- B. Increased renal reabsorption of HCO3⁻
- C. Decreased renal reabsorption of HCO3⁻
- D. Increased secretion of ammonium (NH4⁺)
Answer: C. Decreased renal reabsorption of HCO3⁻
Explanation: During respiratory alkalosis (low PaCO2), the body compensates by decreasing renal HCO3⁻ reabsorption to lower the pH back towards normal. The lecture states: "Respiratory alkalosis... compensation: renal [HCO3⁻] reabsorption decreases".A patient is found to have hypoventilation with a PaCO2 of 55 mm Hg. Which of the following is the likely pH imbalance?
- A. Metabolic acidosis
- B. Respiratory acidosis
- C. Metabolic alkalosis
- D. Respiratory alkalosis
Answer: B. Respiratory acidosis
Explanation: Respiratory acidosis occurs when there is an increase in PaCO2 due to hypoventilation. As stated in the lecture: "Hypoventilation causes ↑ PaCO2 and respiratory acidosis".A patient on a ventilator has an alveolar ventilation rate of 2 L/min, significantly lower than normal. What effect will this have on PaCO2?
- A. PaCO2 will increase
- B. PaCO2 will decrease
- C. PaCO2 will remain unchanged
- D. PaCO2 will fluctuate randomly
Answer: A. PaCO2 will increase
Explanation: Reduced alveolar ventilation leads to increased PaCO2. "PaCO2 is inversely proportional to VA (alveolar ventilation). If ventilation decreases, PaCO2 increases".A patient with obesity hypoventilation syndrome presents with chronic hypercapnia (PaCO2 > 45 mm Hg). Which renal compensatory mechanism is most likely?
- A. Decreased renal reabsorption of bicarbonate
- B. Increased renal secretion of H⁺
- C. Increased renal excretion of ammonium (NH4⁺)
- D. Decreased renal reabsorption of chloride
Answer: B. Increased renal secretion of H⁺
Explanation: In chronic hypercapnia (respiratory acidosis), the kidneys compensate by increasing H⁺ secretion. "Respiratory acidosis... defense mechanism: increase renal H⁺ excretion".
Lecture 13: Acid-Base 1
A 40-year-old man with a history of chronic obstructive pulmonary disease (COPD) presents with an ABG showing a pH of 7.32, PaCO2 of 60 mm Hg, and HCO3⁻ of 29 mEq/L. What is the primary acid-base disturbance?
- A. Metabolic acidosis
- B. Respiratory acidosis
- C. Metabolic alkalosis
- D. Respiratory alkalosis
Answer: B. Respiratory acidosis
Explanation: This patient has a high PaCO2 and low pH, consistent with respiratory acidosis. The lecture explains: "Respiratory acidosis... primary disturbance is an increase in PCO2".A patient with diabetic ketoacidosis (DKA) has a pH of 7.28 and HCO3⁻ of 10 mEq/L. Which of the following is the compensatory response?
- A. Decreased renal excretion of H⁺
- B. Increased alveolar ventilation
- C. Increased renal reabsorption of bicarbonate
- D. Decreased production of ammonium (NH4⁺)
Answer: B. Increased alveolar ventilation
Explanation: In metabolic acidosis, the body compensates by increasing ventilation to decrease PaCO2. The lecture notes: "Metabolic acidosis... compensatory response: increased ventilation to lower PaCO2".Which of the following buffers accounts for the majority of non-bicarbonate buffering power in extracellular fluid (ECF)?
- A. Plasma proteins
- B. Hemoglobin
- C. Phosphate
- D. Bicarbonate
Answer: B. Hemoglobin
Explanation: Hemoglobin is responsible for "about 80% of non-bicarbonate buffering power in ECF," according to the lecture.A patient with a pH of 7.48, HCO3⁻ of 29 mEq/L, and PaCO2 of 48 mm Hg is likely compensating for which acid-base disorder?
- A. Metabolic acidosis
- B. Respiratory acidosis
- C. Metabolic alkalosis
- D. Respiratory alkalosis
Answer: C. Metabolic alkalosis
Explanation: This patient's high pH and HCO3⁻ indicate metabolic alkalosis. The elevated PaCO2 reflects compensation by the respiratory system, reducing ventilation to increase PaCO2.
Lecture 14: Acid-Base 2
In which part of the nephron is the majority of bicarbonate reabsorbed?
- A. Proximal tubule
- B. Thick ascending limb
- C. Distal convoluted tubule
- D. Collecting duct
Answer: A. Proximal tubule
Explanation: "Proximal tubule reabsorbs ~85% of filtered bicarbonate," making it the primary site of bicarbonate reabsorption.A patient has metabolic acidosis due to severe diarrhea. Which of the following is most likely to increase in the kidney to help regenerate bicarbonate?
- A. Chloride reabsorption
- B. Ammonium (NH4⁺) excretion
- C. Decreased hydrogen ion secretion
- D. Increased urine pH
Answer: B. Ammonium (NH4⁺) excretion
Explanation: In metabolic acidosis, the kidney compensates by increasing ammonium excretion to regenerate bicarbonate. "Most of the regenerated bicarbonate will be created by urinary excretion of ammonia".A 60-year-old patient with emphysema is found to have chronic hypercapnia (PaCO2 > 50 mm Hg) with a serum HCO3⁻ of 30 mEq/L. Which of the following processes is most likely upregulated in response to this chronic condition?
- A. Decreased bicarbonate reabsorption
- B. Increased secretion of ammonium (NH4⁺)
- C. Increased bicarbonate reabsorption
- D. Decreased H⁺ secretion
Answer: C. Increased bicarbonate reabsorption
Explanation: In response to chronic respiratory acidosis, the kidneys increase bicarbonate reabsorption. "In chronic hypercapnia... bicarbonate reabsorption increases".Which of the following conditions is associated with a normal anion gap metabolic acidosis?
- A. Diabetic ketoacidosis
- B. Aspirin overdose
- C. Diarrhea
- D. Lactic acidosis
Answer: C. Diarrhea
Explanation: Diarrhea is a common cause of normal anion gap metabolic acidosis, as it results in bicarbonate loss from the gut. "Non-renal causes of normal anion gap metabolic acidosis include diarrhea".Lecture 15: Renal Tubular Acidosis【60†source】
A patient with a history of autoimmune disease presents with severe acidosis and a urine pH of 6.0. Which type of renal tubular acidosis is most likely?
- A. Type I (distal RTA)
- B. Type II (proximal RTA)
- C. Type III (mixed RTA)
- D. Type IV (hyperkalemic RTA)
Answer: A. Type I (distal RTA)
Explanation: Type I RTA is characterized by severe acidosis and the inability to acidify the urine (pH > 5.5). "Distal RTA (Type I)... severe acidosis, urine pH > 5.5"【60†source】.Which renal tubular acidosis (RTA) type is most commonly associated with hyperkalemia?
- A. Type I RTA
- B. Type II RTA
- C. Type III RTA
- D. Type IV RTA
Answer: D. Type IV RTA
Explanation: Type IV RTA is associated with hyperkalemia due to aldosterone deficiency or resistance. "Type IV RTA (hyperkalemic RTA)... occurs with hypoaldosteronism"【60†source】.A patient with Fanconi syndrome is found to have mild acidosis with a urine pH of 5.0. Which renal tubular acidosis type is most likely?
- A. Type I (distal RTA)
- B. Type II (proximal RTA)
- C. Type III (mixed RTA)
- D. Type IV (hyperkalemic RTA)
Answer: B. Type II (proximal RTA)
Explanation: Fanconi syndrome is associated with Type II RTA, characterized by impaired bicarbonate reabsorption in the proximal tubule. "Proximal RTA (Type II)... associated with Fanconi syndrome"【60†source】.A patient has a negative urine anion gap and metabolic acidosis. Which of the following is the most likely diagnosis?
- A. Type I renal tubular acidosis
- B. Type II renal tubular acidosis
- C. Type IV renal tubular acidosis
- D. Diarrhea
Answer: D. Diarrhea
Explanation: A negative urine anion gap suggests non-renal causes of metabolic acidosis, such as diarrhea. "Negative UAG (urine anion gap) occurs with non-renal causes like diarrhea"【60†source】.
Test 2 -Slightly Easier
Lecture 1: Development of the Urinary System
Which embryonic germ layer gives rise to the nephrons (kidney)?
- A. Endoderm
- B. Mesoderm
- C. Ectoderm
- D. Neural crest cells
- Answer: B. Mesoderm
- Explanation: The nephrons of the kidney develop from intermediate mesoderm, specifically the metanephros.
What happens to the pronephros during development?
- A. It forms the permanent kidney
- B. It disappears after a few weeks
- C. It becomes part of the urethra
- D. It forms the collecting duct system
- Answer: B. It disappears after a few weeks
- Explanation: The pronephros is the earliest form of the kidney in development but regresses and disappears, playing no role in the formation of adult structures.
What congenital anomaly results from the failure of the ureteric bud to induce nephron formation?
- A. Renal agenesis
- B. Polycystic kidney disease
- C. Horseshoe kidney
- D. Pelvic kidney
- Answer: A. Renal agenesis
- Explanation: Renal agenesis occurs when the ureteric bud fails to induce the metanephric mesenchyme, preventing nephron formation.
Which of the following anomalies results in a kidney being positioned in the pelvis?
- A. Horseshoe kidney
- B. Pelvic kidney
- C. Bifid ureter
- D. Duplicated ureter
- Answer: B. Pelvic kidney
- Explanation: A pelvic kidney occurs when the kidney fails to ascend to its normal position in the abdomen during development.
Lecture 2: Renal Histology
Which cell type is responsible for producing erythropoietin in the kidney?
- A. Podocytes
- B. Macula densa cells
- C. Juxtaglomerular cells
- D. Peritubular fibroblasts
- Answer: D. Peritubular fibroblasts
- Explanation: Erythropoietin is produced by peritubular fibroblasts in response to hypoxia.
What is the main function of the proximal convoluted tubule (PCT)?
- A. Filtration of blood
- B. Secretion of potassium
- C. Reabsorption of glucose, water, and electrolytes
- D. Concentration of urine
- Answer: C. Reabsorption of glucose, water, and electrolytes
- Explanation: The PCT is responsible for reabsorbing most of the filtered substances such as water, glucose, and electrolytes.
Which structure is located at the urinary pole of a renal corpuscle?
- A. Proximal convoluted tubule
- B. Distal convoluted tubule
- C. Afferent arteriole
- D. Efferent arteriole
- Answer: A. Proximal convoluted tubule
- Explanation: The proximal convoluted tubule begins at the urinary pole of the renal corpuscle.
A patient presents with proteinuria and edema. Electron microscopy reveals loss of podocyte foot processes. What is the most likely diagnosis?
- A. Alport’s syndrome
- B. Minimal change disease
- C. Glomerulosclerosis
- D. Nephrolithiasis
- Answer: B. Minimal change disease
- Explanation: Minimal change disease is characterized by the loss of podocyte foot processes and leads to nephrotic syndrome with proteinuria.
Lecture 3: Renal Physiology
What is the primary driving force for glomerular filtration?
- A. Oncotic pressure in Bowman's capsule
- B. Hydrostatic pressure in the glomerular capillaries
- C. Oncotic pressure in the glomerular capillaries
- D. Hydrostatic pressure in the renal vein
- Answer: B. Hydrostatic pressure in the glomerular capillaries
- Explanation: The glomerular filtration rate (GFR) is mainly driven by the hydrostatic pressure in the glomerular capillaries.
Which of the following substances is used to measure renal plasma flow (RPF)?
- A. Inulin
- B. Creatinine
- C. Para-aminohippuric acid (PAH)
- D. Glucose
- Answer: C. Para-aminohippuric acid (PAH)
- Explanation: PAH is used to estimate renal plasma flow because it is both filtered and secreted, allowing nearly all PAH to be cleared from the plasma.
In which part of the nephron does aldosterone act to increase sodium reabsorption?
- A. Proximal convoluted tubule
- B. Thick ascending limb of the loop of Henle
- C. Distal convoluted tubule
- D. Collecting duct
- Answer: C. Distal convoluted tubule
- Explanation: Aldosterone increases sodium reabsorption in the distal convoluted tubule.
What is the formula for calculating the filtration fraction (FF)?
- A. GFR / RBF
- B. RPF / GFR
- C. GFR / RPF
- D. RBF / RPF
- Answer: C. GFR / RPF
- Explanation: The filtration fraction is the ratio of glomerular filtration rate (GFR) to renal plasma flow (RPF).
Lecture 4-5: Renal Blood Flow (RBF) and Glomerular Filtration Rate (GFR)
Which arteriole constriction leads to a decrease in both RBF and GFR?
- A. Afferent arteriole
- B. Efferent arteriole
- C. Renal artery
- D. Interlobar artery
- Answer: A. Afferent arteriole
- Explanation: Constriction of the afferent arteriole decreases both renal blood flow (RBF) and glomerular filtration rate (GFR).
How does angiotensin II affect the glomerular filtration rate (GFR)?
- A. It dilates the afferent arteriole
- B. It constricts the efferent arteriole
- C. It dilates the efferent arteriole
- D. It increases sodium excretion
- Answer: B. It constricts the efferent arteriole
- Explanation: Angiotensin II increases GFR by constricting the efferent arteriole.
Which feedback mechanism adjusts GFR in response to changes in sodium concentration at the macula densa?
- A. Myogenic reflex
- B. Tubuloglomerular feedback
- C. Renal autoregulation
- D. Juxtaglomerular feedback
- Answer: B. Tubuloglomerular feedback
- Explanation: Tubuloglomerular feedback adjusts GFR by detecting changes in sodium concentration at the macula densa.
Which substance's clearance is most commonly used to estimate GFR in clinical practice?
- A. PAH
- B. Inulin
- C. Creatinine
- D. Urea
- Answer: C. Creatinine
- Explanation: Creatinine clearance is commonly used to estimate GFR because it is freely filtered with minimal secretion.