Uni Week 1 to 4 Quiz

Question 1

Which of the following best describes the mechanism of glomerulotubular balance?
a. Increased reabsorption of sodium and water in the distal tubule in response to increased GFR
b. Decreased secretion of sodium and water in the proximal tubule in response to decreased GFR
c. Proportional reabsorption of sodium and water in the proximal tubule to match the filtered load
d. Decreased secretion of renin in response to increased sodium load
e. Increased secretion of aldosterone in response to increased GFR

Answer 1

c. Proportional reabsorption of sodium and water in the proximal tubule to match the filtered load

Question 2

Which renal mechanism is primarily responsible for the compensation for the acid base disturbance in this patient?
a. Increased reabsorption of chloride in the distal tubule
b. Increased reabsorption of bicarbonate in the proximal tubule
c. Decreased secretion of hydrogen ions in the distal tubule
d. Decreased reabsorption of bicarbonate in the proximal tubule
e. Increased secretion of hydrogen ions in the distal tubule

Answer 2

d. Decreased reabsorption of bicarbonate in the proximal tubule

Question 3

Which of the following conditions is most likely associated with the patient’s decreased calcium excretion?
a. Hypoparathyroidism
b. Primary hyperparathyroidism
c. Metabolic acidosis
d. Low plasma phosphate concentration
e. High blood pressure

Answer 3

b. Primary hyperparathyroidism

Question 4

Which of the following renal mechanisms is primarily responsible for compensating for this patient’s acid-base imbalance?
a. Decreased excretion of hydrogen ions as titratable acids (e.g., H2PO4-)
b. Increased excretion of bicarbonate in the urine
c. Decreased production of ammonia in the proximal tubule
d. Increased reabsorption of filtered bicarbonate in the proximal tubule
e. Decreased reabsorption of sodium in the collecting duct

Answer 4

d. Increased reabsorption of filtered bicarbonate in the proximal tubule

Question 5

Which of the following mechanisms is most likely contributing to the patient’s hypokalemia?
a. Increased potassium reabsorption in the proximal tubule
b. Acidosis leading to intracellular potassium shift
c. Decreased aldosterone secretion
d. Increased insulin secretion leading to intracellular potassium shift
e. Increased potassium reabsorption in the distal tubule

Answer 5

d. Increased insulin secretion leading to intracellular potassium shift

Question 6

Which of the following mechanisms is primarily responsible for handling the increased sodium intake?
a. Increased release of aldosterone
b. Increased sympathetic activity
c. Increased reabsorption of sodium in the proximal tubule
d. Decreased release of atrial natriuretic peptide (ANP)
e. Increased glomerular filtration rate (GFR)

Answer 6

e. Increased glomerular filtration rate (GFR)

Question 7

A patient presents with small cell lung cancer, oliguria, and hypotension. Her serum sodium is markedly low. Which of the following is the most likely diagnosis?
a. Diabetes insipidus (DI)
b. Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
c. Adrenal insufficiency (Addison’s disease)
d. Psychogenic polydipsia
e. Primary hyperaldosteronism (Conn’s syndrome)

Answer 7

b. Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Question 8

Which of the following best describes the role of principal cells in maintaining potassium concentrations?
a. Principal cells decrease potassium secretion in response to high serum sodium levels
b. Principal cells secrete potassium into the tubular lumen in response to aldosterone
c. Principal cells reabsorb potassium in the distal convoluted tubule
d. Principal cells increase potassium reabsorption in the proximal tubule
e. Principal cells are involved in the reabsorption of sodium and bicarbonate

Answer 8

b. Principal cells secrete potassium into the tubular lumen in response to aldosterone

Question 9

A person’s arterial blood pH is 7.25, PCO2 is 24 mm Hg, and HCO3− is 10.2 mEq/L. Which of the following might cause this pattern?
a. Obstructive pulmonary disease
b. Renal failure
c. Diuretics
d. Diarrhea
e. Vomiting

Answer 9

d. Diarrhea

Question 10

Arterial blood gas analysis revealed: pH 7.25, PaCO2 25 mmHg, HCO3- 12 mEq/L. Which of the following conditions is most likely responsible for the patient’s high anion gap metabolic acidosis?
a. Diarrhea-induced bicarbonate loss
b. Hyperchloremic acidosis
c. Diabetic ketoacidosis
d. Acute respiratory acidosis
e. Renal tubular acidosis

Answer 10

c. Diabetic ketoacidosis

Question 11

Which of the following renal mechanisms contributes to potassium excretion in the distal nephron?
a. Decreased sodium delivery to the distal tubule
b. Increased activity of Na+/K+ ATPase in principal cells
c. Increased potassium reabsorption in the thick ascending limb
d. Decreased aldosterone secretion
e. Decreased flow rate in the distal nephron

Answer 11

b. Increased activity of Na+/K+ ATPase in principal cells

Question 12

Which of the following changes would most likely occur in response to chronic respiratory acidosis?
a. Decreased renal ammoniagenesis
b. Decreased reabsorption of bicarbonate
c. Increased excretion of titratable acids
d. Increased bicarbonate excretion
e. Decreased hydrogen ion secretion

Answer 12

c. Increased excretion of titratable acids

Question 13

Which of the following is the most appropriate explanation for the patient’s laboratory findings of metabolic alkalosis with hypokalemia?
a. Diarrhea leading to loss of bicarbonate
b. Excessive intake of sodium bicarbonate
c. Loop diuretic use causing loss of potassium and hydrogen ions
d. Renal tubular acidosis type 1
e. Respiratory compensation for metabolic acidosis

Answer 13

c. Loop diuretic use causing loss of potassium and hydrogen ions

Question 14

Which of the following is the best explanation for the patient’s presentation and laboratory results showing metabolic acidosis with hyperkalemia and a normal anion gap?
a. Diabetic ketoacidosis
b. Lactic acidosis
c. Renal tubular acidosis type IV
d. Vomiting
e. Chronic respiratory acidosis

Answer 14

c. Renal tubular acidosis type IV

Question 15

Which of the following laboratory findings would be most consistent with metabolic alkalosis due to vomiting?
a. Low pH, low HCO3-, low PaCO2
b. High pH, high HCO3-, high PaCO2
c. Low pH, high HCO3-, high PaCO2
d. High pH, low HCO3-, low PaCO2
e. Low pH, high HCO3-, low PaCO2

Answer 15

b. High pH, high HCO3-, high PaCO2

Question 16

A patient with chronic renal failure has serum HCO3- of 14 mEq/L and arterial pH of 7.29. Which of the following is the most likely acid-base disorder?
a. Respiratory acidosis
b. Respiratory alkalosis
c. Metabolic acidosis
d. Metabolic alkalosis
e. Mixed acid-base disorder

Answer 16

c. Metabolic acidosis

Question 17

Which of the following best explains the hypokalemia in a patient receiving thiazide diuretics?
a. Increased potassium secretion in the proximal tubule
b. Increased sodium reabsorption in the proximal tubule
c. Increased sodium delivery to the distal tubule enhances potassium secretion
d. Decreased aldosterone secretion
e. Decreased flow to the distal nephron

Answer 17

c. Increased sodium delivery to the distal tubule enhances potassium secretion

Question 18

Which of the following changes would most likely be observed in a patient with chronic vomiting?
a. Hyperkalemia and metabolic acidosis
b. Hypokalemia and metabolic alkalosis
c. Hypernatremia and respiratory acidosis
d. Hyponatremia and metabolic acidosis
e. Hyperkalemia and respiratory alkalosis

Answer 18

b. Hypokalemia and metabolic alkalosis

Question 19

Which of the following mechanisms explains the metabolic alkalosis observed in the patient?
a. Loss of bicarbonate due to diarrhea
b. Increased bicarbonate reabsorption due to volume contraction
c. Decreased aldosterone secretion
d. Increased reabsorption of chloride in the proximal tubule
e. Decreased reabsorption of sodium in the distal tubule

Answer 19

b. Increased bicarbonate reabsorption due to volume contraction

Question 20

Which of the following would most likely lead to a normal anion gap metabolic acidosis?
a. Lactic acidosis
b. Diabetic ketoacidosis
c. Chronic renal failure
d. Diarrhea
e. Salicylate poisoning

Answer 20

d. Diarrhea

Question 21

Which type of potassium-sparing diuretic is most likely prescribed for this patient
a. Aldosterone receptor antagonist
b. Sodium-glucose cotransporter 2 (SGLT2) inhibitor
c. Loop diuretic
d. Carbonic anhydrase inhibitor
e. Thiazide diuretic

Answer 21

Aldosterone receptor antagonist

Question 22

Which of the following best describes the mechanism of action of loop diuretics like furosemide in this patient?
a.Blockade of sodium reabsorption in the distal convoluted tubule
b.Inhibition of sodium-potassium-chloride cotransport in the thick ascending limb of the loop of Henle
c.Stimulation of sodium reabsorption in the collecting ducts
d.Inhibition of carbonic anhydrase in the proximal convoluted tubule
e.Inhibition of aldosterone synthesis

Answer 22

Inhibition of sodium-potassium-chloride cotransport in the thick ascending limb of the loop of Henle

Question 23

What is the primary mechanism of action of an ACE inhibitor in lowering blood pressure?
a.Blocking the conversion of angiotensin I to angiotensin II
b.Inhibiting the breakdown of bradykinin, a potent vasodilator
c.Increasing the heart rate and cardiac output
d.Increasing the reabsorption of sodium and water in the kidneys
e.Stimulating the release of aldosterone from the adrenal glands

Answer 23

Blocking the conversion of angiotensin I to angiotensin II

Question 24

Which of the following best describes the role of countercurrent exchange in renal physiology?
a.Increases filtration pressure across the glomerulus.
b.Maintains the osmotic gradient in the renal medulla for concentrating urine.
c.Enhances secretion of potassium ions in the distal convoluted tubule.
d.Facilitates reabsorption of glucose and amino acids in the proximal tubule.
e.Regulates acid-base balance in the collecting ducts.?

Answer 24

Maintains the osmotic gradient in the renal medulla for concentrating urine.

Question 25

Which of the following statements best describes a difference between loop diuretics and thiazide diuretics in the management of this patient's condition? a.Loop diuretics increase calcium excretion, while thiazide diuretics decrease calcium excretion. b.Thiazide diuretics primarily act on the thick ascending limb of the loop of Henle. c.Thiazide diuretics are more potent in inducing diuresis than loop diuretics. d.Loop diuretics have a longer duration of action compared to thiazide diuretics. e.Loop diuretics are more effective in patients with renal impairment.

Answer 25

Loop diuretics increase calcium excretion, while thiazide diuretics decrease calcium excretion.

Question 26

Which of the following potassium-sparing diuretics would be most appropriate to add to her regimen to prevent further potassium loss with minimal antiandrogenic effects? a. Amiloride - Potassium-sparing ENaC blocker, but not as effective in heart failure and lacks aldosterone antagonism. b. Spironolactone - Effective but has notable antiandrogenic effects (e.g. gynecomastia, menstrual irregularities) c. Triamterene - Similar to amiloride; less effective in heart failure and may cause kidney stones d. Hydrochlorothiazide e. Eplerenone - - Eplerenone is a potassium-sparing diuretic and a selective aldosterone receptor antagonist.

Answer 26

Eplerenone - - Eplerenone is a potassium-sparing diuretic and a selective aldosterone receptor antagonist.

Question 27

Which of the following best describes how the body responds to dehydration in this patient? Question 7Answer a.Inhibition of the RAAS to decrease blood pressure. b.Activation of the renin-angiotensin-aldosterone system (RAAS) to decrease blood pressure. c.Activation of the sympathetic nervous system to decrease heart rate and blood pressure. d.Increased secretion ADH to decrease water reabsorption in the kidneys. e.Increased secretion of antidiuretic hormone (ADH) to increase water reabsorption in the kidneys.

Answer 27

Increased secretion of antidiuretic hormone (ADH) to increase water reabsorption in the kidneys.

Question 28

Which of the following best describes the role of antidiuretic hormone (ADH) in regulating osmolarity? a.ADH decreases sodium reabsorption in the distal convoluted tubule, raising serum osmolarity. b.ADH increases sodium reabsorption in the proximal tubule, raising serum osmolarity. c.ADH decreases water reabsorption in the collecting ducts, lowering serum osmolarity. d.ADH increases water reabsorption in the collecting ducts, increasing serum osmolarity. e.ADH increases water reabsorption in the collecting ducts, lowering serum osmolarity.

Answer 28

ADH increases water reabsorption in the collecting ducts, lowering serum osmolarity.

Question 29

Which of the following mechanisms primarily underlies the formation of dilute urine? a.Increased water reabsorption in the collecting ducts b.Increased aldosterone secretion c.Decreased antidiuretic hormone (ADH) secretion d.Decreased glomerular filtration rate (GFR) e.Increased reabsorption of sodium in the proximal convoluted tubule

Answer 29

Decreased antidiuretic hormone (ADH) secretion

Question 30

Which of the following best defines the process of countercurrent multiplication within the nephron? a.Reabsorption of water in the collecting duct under the influence of antidiuretic hormone (ADH). b.Secretion of hydrogen ions in the distal convoluted tubule for acid-base balance. c.Active transport of sodium and chloride ions out of the thick ascending limb of the loop of Henle, creating a concentration gradient. d.Passive movement of water from the descending limb of the loop of Henle into the hypertonic medullary interstitium. e.Selective reabsorption of glucose and amino acids in the proximal convoluted tubul

Answer 30

Active transport of sodium and chloride ions out of the thick ascending limb of the loop of Henle, creating a concentration gradient.

Question 31

Q4  Which of the following best describes the mechanism of glomerulotubular balance? a.  Increased reabsorption of sodium and water in the distal tubule in response to increased GFR b.  Decreased secretion of sodium and water in the proximal tubule in response to decreased GFR c.  Proportional reabsorption of sodium and water in the proximal tubule to match the filtered load d.  Decreased secretion of renin in response to increased sodium load e.  Increased secretion of aldosterone in response to increased GFR

Answer 31

Proportional reabsorption of sodium and water in the proximal tubule to match the filtered load

Question 32

Which renal mechanism is primarily responsible for the compensation for the acid base disturbance in this patient? a.  Increased reabsorption of chloride in the distal tubule b.  Increased reabsorption of bicarbonate in the proximal tubule c.  Decreased secretion of hydrogen ions in the distal tubule d.  Decreased reabsorption of bicarbonate in the proximal tubule e.  Increased secretion of hydrogen ions in the distal tubule

Answer 32

Decreased reabsorption of bicarbonate in the proximal tubule

Question 33

Which of the following conditions is most likely associated with the patient's decreased calcium excretion? a.  Hypoparathyroidism b.  Primary hyperparathyroidism c.  Metabolic acidosis d.  Low plasma phosphate concentration e.  High blood pressure

Answer 33

Primary hyperparathyroidism

Question 34

Which of the following renal mechanisms is primarily responsible for compensating for this patient's acid-base imbalance? a.  Decreased excretion of hydrogen ions as titratable acids (e.g., H2PO4-) b.  Increased excretion of bicarbonate in the urine c.  Decreased production of ammonia in the proximal tubule d.  Increased reabsorption of filtered bicarbonate in the proximal tubule e.  Decreased reabsorption of sodium in the collecting duct

Question 35

Which of the following mechanisms is most likely contributing to the patient's hypokalemia? a.  Increased potassium reabsorption in the proximal tubule b.  Acidosis leading to intracellular potassium shift c.  Decreased aldosterone secretion d.  Increased insulin secretion leading to intracellular potassium shift e.  Increased potassium reabsorption in the distal tubule

Answer 35

Increased insulin secretion leading to intracellular potassium shift

Question 36

Which of the following mechanisms is primarily responsible for handling the increased sodium intake? a.  Increased release of aldosterone b.  Increased sympathetic activity c.  Increased reabsorption of sodium in the proximal tubule d.  Decreased release of atrial natriuretic peptide (ANP) e.  Increased glomerular filtration rate (GFR)

Answer 36

Increased glomerular filtration rate (GFR)

Question 37

small cell lung cancer, oliguria (decreased urine output), and hypotension. Her serum sodium level is markedly low. Given the patient's history and clinical presentation, which of the following conditions is the most likely diagnosis? a.  Diabetes insipidus (DI) b.  Syndrome of inappropriate antidiuretic hormone secretion (SIADH) c.  Adrenal insufficiency (Addison's disease) d.  Psychogenic polydipsia e.  Primary hyperaldosteronism (Conn's syndrome)

Answer 37

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Question 38

Which of the following best describes the role of principal cells in maintaining potassium concentrations? a.  Principal cells decrease potassium secretion in response to high serum sodium levels b.  Principal cells secrete potassium into the tubular lumen in response to aldosterone c.  Principal cells reabsorb potassium in the distal convoluted tubule d.  Principal cells increase potassium reabsorption in the proximal tubule e.  Principal cells are involved in the reabsorption of sodium and bicarbonate

Answer 38

Principal cells secrete potassium into the tubular lumen in response to aldosterone

Question 39

A person’s arterial blood pH is 7.25 (normal: 7.35-7.45), PCO2 is 24 mm H (normal: 35-45 mm Hg), and HCO3− is 10.2 mEq/L (normal: 22-28 mEq/L). Which of the following might cause this pattern? Question 9 Answer a.  Obstructive pulmonary disease. b.  Renal failure. c.  Diuretics. d.  Diarrhea. e.  Vomiting.

Answer 39

Diarrhea.

Question 40

Arterial blood gas analysis revealed: pH 7.25, PaCO2 25 mmHg, HCO3- 12 mEq/L. Which of the following conditions is most likely responsible for the patient's high anion gap metabolic acidosis? Question 10 Answer a.  Diarrhea-induced bicarbonate loss b.  Hyperchloremic acidosis c.  Diabetic ketoacidosis d. Acute respiratory acidosis e. Renal tubular acidosis

Answer 40

Diabetic ketoacidosis

Question 41

Which of the following structures are typically found in the renal hilum? a.Renal pyramids and renal papilla b.Renal cortex and renal medulla c.Renal artery, renal vein, and ureter d.Glomerulus and Bowman's capsule e.Loop of Henle and collecting duct

Answer 41

Renal artery, renal vein, and ureter

Question 42

Which of the following statements best describes the histological structure of Bowman's capsule? a.It consists of a single layer of squamous epithelial cells. b.It contains fenestrated capillaries surrounded by simple cuboidal epithelium. c.It connects directly to the renal tubules via tight junctions. d.It is devoid of any cellular structures, consisting only of collagen fibers. e.It is lined by podocytes with interdigitating foot processes.

Answer 42

It is lined by podocytes with interdigitating foot processes.

Question 43

A 28-year-old female presents to the ED with complaints of flank pain. On examination, she has CVA tenderness, and her BP is 157/94 mm Hg. She says her dad died of chronic kidney disease. An abdominal ultrasound reveals multiple cysts located on the cortical surface of both the kidneys. You suspect cystic kidney disease with autosomal dominant form of inheritance. The cyst in this condition arises from a.All parts of nephron b.Collecting ducts c.Distal convoluted tubule d.Proximal convoluted tubule e.Glomerulus

Answer 43

All parts of nephron

Question 44

During routine prenatal ultrasound at 20 weeks, a pregnant woman is found to have a fetus with a suspected urogenital anomaly. Further imaging reveals a condition where the urogenital sinus is not properly separated from the rectum. Which of the following structures is primarily affected due to the failure of urorectal septum development? a.Renal pelvis b.Urethra c.Bladder d.Kidneys e.Ureter

Answer 44

Bladder

Question 45

During routine prenatal ultrasound screening, a 32-week pregnant woman is found to have bilateral renal agenesis in the fetus. The absence of both kidneys indicates a lack of ureteric bud formation. Which of the following structures, derived from the ureteric buds during normal development, would be absent in this condition? a.Nephron b.Bowman's capsule c.Collecting duct d.Renal cortex e.Glomerulus

Answer 45

Collecting duct

Question 46

A 15-year-old patient presents with complaints of abdominal pain. On examination, she has pain in the right upper quadrant of the abdomen. Which organ is located anterior to the right kidney? a.Liver b.Stomach c.Pancreas d.Diaphragm e.Duodenum

Answer 46

Liver

Question 47

A 45-year-old male presents with recurrent episodes of flank pain and urinary tract infections. Imaging studies reveal a Horseshoe kidney. Which of the following morphological changes is characteristic of this condition? a.Bilateral renal agenesis b.Presence of multiple renal arteries c.Fusion of the lower poles of the kidneys d.Absence of renal papillae e.Excessive branching of the renal pelvis

Answer 47

Fusion of the lower poles of the kidneys

Question 48

A 45-year-old man presents with complaints of right flank pain radiating to the groin and red colored urine. Ultrasound of the right kidney shows a branched calculus in the renal pelvis. Which of the following structures opens into the renal pelvis? a.Minor calyx b.Collecting ducts c.Renal papillae d.Major calyx

Answer 48

Major calyx

Question 49

During mammalian kidney development, which of the following embryonic structures gives rise to mature nephrons? a.Wolffian duct b.Ureteric bud c.Glomerular mesangium d.Pronephros e.Metanephric blastema

Answer 49

Metanephric blastema

Question 50

A one-year-old is brought in for routine checkup. On examination, the child’s blood pressure is elevated, and urinalysis shows proteinuria. Imaging studies show left renal agenesis. The contralateral kidney in this condition will show a.Dysplastic change b.Glomerulosclerosis c.Multiple cysts d.Hypertrophy e.Hydronephrosis

Answer 50

Hypertrophy

Question 51

A 6-year-old boy is brought to the pediatric clinic by his parents due to concerns about his poor growth and frequent episodes of dehydration. On examination, the child appears pale and has signs of rickets. Laboratory tests reveal glucosuria, aminoaciduria, and phosphaturia, despite normal blood glucose levels. Further tests show metabolic acidosis and hypokalemia. The pediatrician suspects Fanconi syndrome. Which of the following is a common pathogenesis of Fanconi syndrome in this patient? a.Immune-mediated destruction of the renal tubules b.Overproduction of uric acid leading to distal tubular damage c.Excessive activation of the renin-angiotensin-aldosterone system d.Defective renal tubular reabsorption due to heavy metal toxicity e.Impaired glomerular filtration due to autoimmune glomerulonephritis

Answer 51

Defective renal tubular reabsorption due to heavy metal toxicity

Question 52

A 10-year-old girl is brought to the pediatric clinic by her parents due to poor growth and frequent muscle cramps. The parents report that she has had episodes of dehydration despite adequate fluid intake. Physical examination reveals a thin, frail child with normal blood pressure. Urinary studies reveal increased calcium excretion. The pediatrician suspects Bartter syndrome. Which of the following is a typical clinical feature of Bartter syndrome? a.Hypokalemia and metabolic alkalosis b.Hyponatremia and metabolic acidosis c.Hyperkalemia and metabolic acidosis d.Hypertension and hyperkalemia e.Hypercalcemia and hypotension

Answer 52

Hypokalemia and metabolic alkalosis

Question 53

In the thick ascending limb of the nephron loop, the Na+-K+-2Cl- symporter plays a crucial role in renal function. Which of the following best describes the intricate actions and implications of this symporter? a.It selectively reabsorbs sodium and potassium ions from the tubular lumen, while chloride ions are left behind, thus influencing the ionic composition of the filtrate. b.It simultaneously reabsorbs sodium, potassium, and chloride ions from the tubular lumen into the interstitial fluid, significantly contributing to the establishment of a hyperosmolar gradient in the renal medulla essential for water reabsorption. c.It promotes the active secretion of sodium, potassium, and chloride ions into the tubular lumen, which aids in the regulation of electrolyte balance and urine concentration. d.It selectively reabsorbs sodium and chloride ions from the tubular lumen while facilitating the secretion of potassium ions into the lumen, thereby maintaining ionic balance. e.It assists in the reabsorption of sodium and chloride ions into the interstitial fluid while potassium ions are secreted into the interstitial fluid, contributing to the regulation of potassium homeostasis.

Answer 53

It simultaneously reabsorbs sodium, potassium, and chloride ions from the tubular lumen into the interstitial fluid, significantly contributing to the establishment of a hyperosmolar gradient in the renal medulla essential for water reabsorption.

Question 54

Which of the following best describes the actions of Antidiuretic Hormone (ADH)? a.Increases calcium reabsorption in the ascending limb of the nephron loop. b.Increases urine output by promoting sodium reabsorption in the distal convoluted tubule. c.Decreases blood pressure by promoting the secretion of renin from the juxtaglomerular apparatus. d.Stimulates the reabsorption of water in the collecting ducts of the nephron, leading to concentrated urine. e.Stimulates the release of aldosterone from the adrenal cortex, enhancing potassium excretion.

Answer 54

Stimulates the reabsorption of water in the collecting ducts of the nephron, leading to concentrated urine.

Question 55

A 60-year-old female presents to the emergency department with severe dehydration following a bout of gastroenteritis. She reports significant vomiting and diarrhea over the past 48 hours. On examination, her blood pressure is 85/50 mm Hg, and her heart rate is 110 beats per minute. The attending physician explains that the kidneys are trying to maintain an adequate glomerular filtration rate (GFR) despite the low blood pressure. Which of the following best describes a mechanism of autoregulation that helps maintain GFR in this patient’s condition? a.The tubuloglomerular feedback mechanism, which involves the macula densa sensing low sodium chloride levels and triggering afferent arteriole constriction. b.The myogenic mechanism, which involves constriction of the afferent arteriole in response to decreased blood pressure. c.The myogenic mechanism, which involves dilation of the afferent arteriole in response to decreased blood pressure. d.The myogenic mechanism, which involves constriction of the efferent arteriole in response to increased blood pressure. e.The tubuloglomerular feedback mechanism, which involves the macula densa sensing high sodium chloride levels and triggering renin release.

Answer 55

The myogenic mechanism, which involves dilation of the afferent arteriole in response to decreased blood pressure.

Question 56

Active tubular reabsorption involves the movement of substances across the tubular epithelium against their concentration gradient. Which of the following is a primary active transport mechanism involved in tubular reabsorption? a.Facilitated diffusion b.Aquaporin channels c.Osmosis d.Na-K ATPase pump e.Simple diffusion

Answer 56

Na-K ATPase pump

Question 57

A 55-year-old male presents to the clinic with complaints of muscle weakness and frequent urination. He has a history of hypertension and has been prescribed medications for several years. On examination, his blood pressure is elevated, and laboratory tests show hypokalemia and metabolic alkalosis. The physician suspects an issue with aldosterone regulation. Which of the following best describes the action of aldosterone on principal cells in the renal collecting duct? a.Aldosterone has no direct effect on sodium or potassium transport. b.Aldosterone inhibits sodium reabsorption and potassium secretion. c.Aldosterone decreases water reabsorption by principal cells. d.Aldosterone inhibits both sodium and potassium reabsorption. e.Aldosterone promotes sodium reabsorption and potassium secretion.

Answer 57

Aldosterone promotes sodium reabsorption and potassium secretion.

Question 58

Which of the following best describes the normal histology of the Distal Convoluted Tubule (DCT) and Collecting Duct? a.Both the DCT and collecting duct are lined with cuboidal cells, with the DCT having more prominent microvilli compared to the collecting duct. b.Both the DCT and collecting duct are lined with squamous cells, with the collecting duct having a thicker epithelial layer compared to the DCT. c.The DCT is lined with columnar cells and contains numerous microvilli, while the collecting duct is lined with cuboidal cells and lacks microvilli. d.The DCT is lined with squamous cells and is relatively featureless, while the collecting duct is lined with cuboidal cells and has prominent microvilli. e.The DCT is lined with cuboidal cells and lacks microvilli, while the collecting duct is lined with columnar cells and contains numerous microvilli.

Answer 58

Both the DCT and collecting duct are lined with cuboidal cells, with the DCT having more prominent microvilli compared to the collecting duct.

Question 59

A 55-year-old male with a history of hypertension and type 2 diabetes mellitus presents to the clinic with symptoms of fatigue, muscle weakness, and episodes of confusion. Laboratory tests reveal metabolic acidosis with a low serum bicarbonate level. The attending physician suspects that the patient's proximal convoluted tubule (PCT) function may be compromised, particularly the mechanism involving Na+-H+ antiporters. Which of the following best describes the mechanism of action of the Na+-H+ antiporters in the cells of the PCT? a.They use the sodium gradient to actively secrete sodium into the tubular lumen in exchange for hydrogen ions. b.They use the hydrogen ion gradient to actively reabsorb hydrogen ions in exchange for sodium ions. c.They facilitate the passive diffusion of sodium and hydrogen ions across the tubular membrane. d.They facilitate the active secretion of bicarbonate into the tubular lumen in exchange for sodium ions. e.They use the sodium gradient to actively reabsorb sodium from the tubular lumen in exchange for hydrogen ions.

Answer 59

They use the sodium gradient to actively reabsorb sodium from the tubular lumen in exchange for hydrogen ions.

Question 60

A 45-year-old male presents to the clinic with complaints of persistent fatigue and dizziness over the past few months. His blood pressure is recorded as 95/60 mm Hg. Laboratory results show a significant decrease in serum sodium levels and increased potassium levels. The physician suspects an issue with the patient's juxtaglomerular apparatus (JGA) function and orders a series of tests. Which of the following best explains the function of the JGA in the context of the patient’s condition? a.The JGA increases glomerular filtration rate (GFR) by constricting the afferent arteriole in response to high blood pressure. b.The JGA senses decreased sodium chloride concentration in the distal tubule and releases renin to increase blood pressure. c.The JGA directly monitors and adjusts blood glucose levels through the secretion of insulin. d.The JGA inhibits the release of aldosterone in response to increased blood potassium levels. e.The JGA releases antidiuretic hormone (ADH) in response to decreased blood volume.

Answer 60

The JGA senses decreased sodium chloride concentration in the distal tubule and releases renin to increase blood pressure.