Question 1

Which of the following best describes the primary function of the nephron in the kidney?

Accepted Answer

To filter blood plasma, reabsorb useful substances, and eliminate waste as urine

Question 2

A patient presents with a blood pressure of 180/110 mmHg and is later diagnosed with glomerular damage. Which mechanism best explains how hypertension can lead to kidney damage?

Accepted Answer

High blood pressure causes rupture and scarring of glomerular capillaries, leading to decreased filtration.

Question 3

Which of the following substances is NOT normally found in significant amounts in the urine of a healthy individual?

Accepted Answer

Glucose

Question 4

The glomerular filtration rate (GFR) is approximately 125 mL/min in males. If a patient’s GFR drops to 50 mL/min, what is the most likely consequence?

Accepted Answer

Decreased urine output and accumulation of nitrogenous wastes

Question 5

Which hormone is released in response to dehydration and acts to increase water reabsorption in the collecting duct?

Accepted Answer

Antidiuretic hormone (ADH)

Question 6

A person stranded at sea drinks salt water. Which physiological principle explains why this is dangerous?

Accepted Answer

Salt water increases the osmolarity of body fluids, causing the kidneys to excrete more water than is ingested.

Question 7

Which of the following best describes the effect of aldosterone on the distal convoluted tubule (DCT)?

Accepted Answer

It increases sodium reabsorption and water retention, decreasing urine volume.

Question 8

Which of the following equations correctly represents the calculation of net filtration pressure (NFP) in the glomerulus?

Accepted Answer

$$NFP = (HP_g) - (OP_g + HP_c)$$

Question 9

Which of the following is a correct sequence for the flow of filtrate through the nephron?

Accepted Answer

Glomerular capsule → PCT → nephron loop → DCT → collecting duct

Question 10

A patient with chronic kidney disease has a blood urea nitrogen (BUN) level that is significantly elevated. What does this indicate?

Accepted Answer

The kidneys are failing to adequately remove nitrogenous wastes from the blood.

Question 11

Which of the following best explains why the afferent arteriole is wider than the efferent arteriole in the glomerulus?

Accepted Answer

To maintain a high hydrostatic pressure that favors filtration

Question 12

Which of the following is a function of the peritubular capillaries?

Accepted Answer

They reabsorb water and solutes from the renal tubule back into the blood.

Question 13

Which of the following is a likely result of diabetes insipidus?

Accepted Answer

Polyuria due to lack of ADH

Question 14

Which of the following best describes the role of the macula densa in the juxtaglomerular apparatus?

Accepted Answer

It senses sodium concentration in the distal convoluted tubule and signals to adjust GFR.

Question 15

Which of the following is a correct description of the countercurrent multiplier system in the nephron loop?

Accepted Answer

It creates a salinity gradient in the medulla, allowing the collecting duct to concentrate urine.

Question 16

A patient’s urinalysis reveals hematuria and proteinuria after a car accident. What is the most likely explanation?

Accepted Answer

The patient has suffered trauma to the kidneys, causing glomerular damage.

Question 17

Which of the following best explains why females are more prone to urinary tract infections (UTIs) than males?

Accepted Answer

Females have a shorter urethra, making it easier for bacteria to reach the bladder.

Question 18

Which of the following is a likely effect of a diuretic such as caffeine on the urinary system?

Accepted Answer

It increases GFR by dilating the afferent arteriole, leading to increased urine output.

Question 19

Which of the following is the correct formula for calculating the amount of urine excreted per day, given GFR and the percentage reabsorbed?

Accepted Answer

$$Urine\ Volume = GFR 	imes (1 - 	ext{Fraction\ Reabsorbed})$$

The Urinary System: Structure, Function, and Clinical Relevance

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