Question 1

Which of the following best describes the main function of the juxtamedullary nephron compared to the cortical nephron?

Accepted Answer

It plays a key role in establishing the osmotic gradient necessary for concentrating urine.

Question 2

A patient presents with high blood pressure and low blood potassium. Which hormone is most likely elevated, and what is its effect on the nephron?

Accepted Answer

Aldosterone; increases Na+ reabsorption and K+ secretion in the distal convoluted tubule.

Question 3

Which of the following equations correctly represents the calculation of Net Filtration Pressure (NFP) in the glomerulus?

Accepted Answer

$$NFP = Glomerular\ hydrostatic\ pressure - (Colloid\ osmotic\ pressure + Capsular\ hydrostatic\ pressure)$$

Question 4

If the glomerular hydrostatic pressure is 55 mm Hg, the colloid osmotic pressure is 30 mm Hg, and the capsular hydrostatic pressure is 15 mm Hg, what is the Net Filtration Pressure (NFP)?

Accepted Answer

$$NFP = 55\ mm\ Hg - (30\ mm\ Hg + 15\ mm\ Hg) = 10\ mm\ Hg$$

Question 5

Which of the following changes would most likely decrease the Glomerular Filtration Rate (GFR)?

Accepted Answer

Constriction of the afferent arteriole

Question 6

A patient with diabetes mellitus has glucose present in their urine. Which concept best explains this finding?

Accepted Answer

The tubular maximum for glucose reabsorption has been exceeded.

Question 7

Which part of the nephron is impermeable to water but actively transports Na+ and Cl- out of the filtrate?

Accepted Answer

Thick ascending limb of the loop of Henle

Question 8

Which of the following best describes the effect of antidiuretic hormone (ADH) on the nephron?

Accepted Answer

It increases water permeability in the distal convoluted tubule and collecting duct, leading to more concentrated urine.

Question 9

Which of the following substances is NOT significantly reabsorbed in the nephron and is commonly used to estimate glomerular filtration rate (GFR)?

Accepted Answer

Creatinine

Question 10

A patient is given a drug that inhibits aldosterone. What is the expected effect on urine composition?

Accepted Answer

Increased Na+ in urine and decreased K+ in urine

Question 11

Which of the following best explains why the vasa recta is essential for the kidney's ability to concentrate urine?

Accepted Answer

It maintains the osmotic gradient in the medulla by allowing passive exchange of water and NaCl.

Question 12

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

Accepted Answer

Elimination of drugs and excess K+ from the blood into the urine

Question 13

Which hormone is released by the heart in response to increased blood volume and inhibits Na+ reabsorption in the nephron?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 14

Which of the following best describes the countercurrent multiplier system in the loop of Henle?

Accepted Answer

It establishes an osmotic gradient in the renal medulla, allowing the kidney to concentrate urine.

Question 15

If a patient is dehydrated, which of the following changes would you expect in their urine and hormone levels?

Accepted Answer

Increased ADH secretion and more concentrated urine

Question 16

Which of the following is TRUE regarding the movement of water and solutes in the thin descending limb of the loop of Henle?

Accepted Answer

It is permeable to water but impermeable to Na+ and Cl-.

Question 17

Which of the following best explains why plasma proteins are not normally found in the urine?

Accepted Answer

The filtration membrane restricts passage of large proteins and podocytes trap any that slip through.

Question 18

A patient with chronic kidney disease has a decreased glomerular filtration rate (GFR). Which of the following is a likely consequence?

Accepted Answer

Accumulation of nitrogenous wastes such as urea and creatinine in the blood

Question 19

Which of the following best describes the effect of increased colloid osmotic pressure in the glomerular capillaries?

Accepted Answer

It decreases the net filtration pressure and reduces GFR.

Question 20

Which of the following is the correct sequence of urine flow from the nephron to the outside of the body?

Accepted Answer

Collecting duct → Minor calyx → Major calyx → Renal pelvis → Ureter → Bladder → Urethra

Chapter 25 The Urinary System: Structure, Function, and Physiology

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