Question 1

Which of the following best describes the main function of the glomerulus in urine formation?

Accepted Answer

Nonselective filtration of blood plasma to produce a protein-free filtrate

Question 2

A patient presents with a blood pressure of 90/60 mmHg and decreased blood volume. Which hormonal system will be activated to restore homeostasis, and what is its primary effect?

Accepted Answer

Renin-Angiotensin-Aldosterone System (RAAS); increases sodium and water reabsorption

Question 3

Which equation correctly represents Net Filtration Pressure (NFP) in the glomerulus?

Accepted Answer

$$NFP = GBHP - (CHP + BCOP)$$

Question 4

If the afferent arteriole constricts, what is the expected effect on glomerular filtration rate (GFR) and why?

Accepted Answer

GFR decreases because glomerular blood hydrostatic pressure falls

Question 5

Which of the following mechanisms is responsible for the majority of glucose reabsorption in the proximal convoluted tubule (PCT)?

Accepted Answer

Secondary active transport via Na+-glucose symporter

Question 6

A patient with diabetes mellitus has a fasting plasma glucose concentration of 180 mg/dL. What is the likely consequence in terms of renal handling of glucose?

Accepted Answer

Glucose transporters will be saturated, and glucose will appear in urine

Question 7

Which of the following best explains the role of the countercurrent multiplier in the nephron loop?

Accepted Answer

It actively creates an osmotic gradient in the medulla to concentrate urine

Question 8

Which hormone increases water reabsorption in the late distal convoluted tubule and collecting duct by inserting aquaporins into the cell membranes?

Accepted Answer

Anti-diuretic hormone (ADH)

Question 9

During severe dehydration, which of the following changes would you expect in urine concentration and volume?

Accepted Answer

Urine becomes more concentrated and volume decreases

Question 10

Which of the following is a primary function of tubular secretion in the nephron?

Accepted Answer

Removal of excess hydrogen ions and drug metabolites from blood

Question 11

A patient is given a drug that blocks the action of aldosterone. What effect would this have on renal function?

Accepted Answer

Decreased sodium reabsorption and increased potassium retention

Question 12

Which of the following best describes the effect of sympathetic nervous system activation on glomerular filtration rate (GFR) during intense exercise?

Accepted Answer

GFR decreases due to vasoconstriction of afferent arterioles

Question 13

Which of the following substances is primarily reabsorbed in the thick ascending limb of the nephron loop?

Accepted Answer

Sodium and chloride via active transport

Question 14

Which process is responsible for the movement of water from the filtrate into the blood in the proximal convoluted tubule?

Accepted Answer

Osmosis through aquaporins

Question 15

A patient with elevated blood urea nitrogen (BUN) may be experiencing which of the following conditions?

Accepted Answer

Renal insufficiency or dehydration

Question 16

Which of the following is the correct sequence of events in the Renin-Angiotensin-Aldosterone System (RAAS) following a drop in blood pressure?

Accepted Answer

Renin release → Angiotensinogen conversion → Angiotensin I → Angiotensin II → Aldosterone release

Question 17

Which of the following would most likely result in an increase in glomerular filtration rate (GFR)?

Accepted Answer

Constriction of the efferent arteriole

Question 18

Which of the following is a direct effect of Anti-diuretic Hormone (ADH) on the renal tubules?

Accepted Answer

Inserts aquaporins into the collecting duct cells to increase water reabsorption

Question 19

Which of the following best describes the role of the vasa recta in the kidney?

Accepted Answer

Serves as a countercurrent exchanger to preserve the medullary osmotic gradient

Urinary System Physiology: Filtration, Reabsorption, and Regulation of Urine Formation

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