Question 1

Which of the following best describes the primary function of the urinary system?

Accepted Answer

To filter waste products and excess water from the blood, producing urine and maintaining homeostasis.

Question 2

Which structures together form the renal corpuscle?

Accepted Answer

Bowman's capsule and glomerulus

Question 3

What is the main role of the proximal convoluted tubule (PCT) in nephron function?

Accepted Answer

It reabsorbs the majority of water, ions, and all glucose and amino acids from the filtrate.

Question 4

Which of the following best explains why red blood cells are not filtered into Bowman’s capsule during glomerular filtration?

Accepted Answer

Red blood cells are too large to pass through the fenestrations and filtration slits of the glomerular capillaries.

Question 5

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

Accepted Answer

Aldosterone; increases Na+ reabsorption in the distal convoluted tubule and collecting duct.

Question 6

Which of the following equations correctly represents the conversion of bicarbonate in the proximal convoluted tubule?

Accepted Answer

$$\mathrm{$$HCO_3$$^-} + \mathrm{H^+} \rightarrow \mathrm{H_2CO_3} \rightarrow \mathrm{CO_2$} + \mathrm{H_2O}$$

Question 7

Which segment of the nephron is impermeable to water but actively transports sodium and chloride ions out of the filtrate?

Accepted Answer

Thick ascending limb of the loop of Henle

Question 8

A patient with diabetes mellitus has glucose present in their urine. What is the most likely explanation for this finding?

Accepted Answer

The glucose transporters in the proximal convoluted tubule are saturated due to high blood glucose levels.

Question 9

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

Accepted Answer

It creates a hyperosmotic medullary environment by actively transporting salt out of the ascending limb, promoting water reabsorption in the descending limb.

Question 10

Which cell type in the juxtaglomerular apparatus acts as a baroreceptor and releases renin in response to low blood pressure?

Accepted Answer

Juxtaglomerular cell

Question 11

What is the effect of antidiuretic hormone (ADH) on the collecting duct?

Accepted Answer

It increases the number of aquaporins, enhancing water reabsorption and concentrating urine.

Question 12

Which of the following best describes the role of the macula densa in regulating glomerular filtration rate (GFR)?

Accepted Answer

It senses NaCl concentration in the distal convoluted tubule and signals afferent arteriole constriction or dilation.

Question 13

Which of the following is the correct sequence for the Renin-Angiotensin-Aldosterone System (RAAS) activation?

Accepted Answer

Low blood pressure → Renin release → Angiotensinogen to Angiotensin I → ACE converts to Angiotensin II → Aldosterone release

Question 14

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

Accepted Answer

To increase hydrostatic pressure in the glomerulus, promoting filtration of plasma into Bowman’s capsule.

Question 15

Which of the following is the primary mechanism for water reabsorption in the proximal convoluted tubule?

Accepted Answer

Osmosis through aquaporin channels

Question 16

A patient’s blood pH is measured at 7.30 (below normal). Which cell type in the collecting duct will be most active, and what will it secrete?

Accepted Answer

Alpha-intercalated cells; secrete protons (H+)

Question 17

Which of the following best describes the fate of most of the filtrate produced by the kidneys each day?

Accepted Answer

99% is reabsorbed, with only 1-2 liters excreted as urine.

Question 18

Which of the following is a direct effect of angiotensin II?

Accepted Answer

Vasoconstriction of blood vessels, increasing blood pressure

Question 19

Which of the following best describes the function of podocytes in the glomerulus?

Accepted Answer

They form filtration slits that allow passage of water and small solutes but block large proteins and cells.

Urinary System: Structure and Physiology

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