Question 1

Which of the following best describes the structural difference between the afferent and efferent arterioles in the nephron, and how does this difference affect glomerular filtration?

Accepted Answer

The afferent arteriole is wider than the efferent arteriole, increasing glomerular hydrostatic pressure and promoting filtration.

Question 2

Which of the following substances is normally filtered at the glomerulus and enters the proximal tubule, but is almost completely reabsorbed under normal conditions?

Accepted Answer

Glucose

Question 3

A patient is experiencing severe dehydration. Which of the following changes would you expect in their glomerular filtration rate (GFR)?

Accepted Answer

Decreased GFR due to decreased renal blood flow and increased colloid oncotic pressure

Question 4

Which of the following best explains the effect of constricting the efferent arteriole on renal blood flow (RBF) and glomerular filtration rate (GFR)?

Accepted Answer

RBF decreases, but GFR increases

Question 5

Which of the following is a direct stimulus for the release of renin from the juxtaglomerular cells of the kidney?

Accepted Answer

Decreased blood volume

Question 6

Which hormone is secreted by the heart in response to increased blood volume and atrial stretch, and what is its primary effect on the kidneys?

Accepted Answer

Atrial natriuretic peptide (ANP); increases sodium and water excretion

Question 7

Which of the following best describes the three layers of the glomerular filtration membrane and their roles in filtration?

Accepted Answer

Fenestrated endothelium (size barrier), basement membrane (charge barrier), podocyte slit diaphragm (size and charge barrier)

Question 8

Which of the following substances is secreted from the peritubular capillaries into the distal convoluted tubule for excretion?

Accepted Answer

Potassium ions (K\^+)

Question 9

A patient with high levels of antidiuretic hormone (ADH) would be expected to have which of the following changes in urine composition?

Accepted Answer

Decreased urine volume and increased urine osmolality

Question 10

Where does countercurrent multiplication primarily occur in the nephron, and what is its main physiological importance?

Accepted Answer

In the loop of Henle; to create a hyperosmotic medullary gradient for water reabsorption

Question 11

Which of the following changes would most likely decrease glomerular filtration rate (GFR)?

Accepted Answer

Constriction of the afferent arteriole

Question 12

Which of the following best describes the effect of increased capsular hydrostatic pressure on glomerular filtration?

Accepted Answer

It decreases GFR by opposing filtration

Question 13

Which of the following is a normal component of urine?

Accepted Answer

Urea

Question 14

Which part of the nephron is primarily responsible for hormonally regulated water reabsorption, and which hormones are involved?

Accepted Answer

Distal convoluted tubule and collecting duct; aldosterone and ADH

Question 15

During the micturition reflex, which of the following events occurs as the bladder fills and voiding is initiated?

Accepted Answer

Detrusor muscle contracts, internal sphincter relaxes, external sphincter relaxes

Question 16

Which of the following best describes the effect of sympathetic nervous system activation on renal blood flow and GFR?

Accepted Answer

Vasoconstriction of afferent arterioles, decreased RBF and GFR

Question 17

Which of the following best explains why albumin is not normally found in urine?

Accepted Answer

Albumin is negatively charged and repelled by the basement membrane of the filtration barrier

Question 18

Which of the following best describes the difference between the descending and ascending limbs of the loop of Henle in the countercurrent multiplier system?

Accepted Answer

Descending limb is permeable to water but not to solutes, ascending limb is impermeable to water but actively transports NaCl

Question 19

A patient with a mutation that prevents the production of antidiuretic hormone (ADH) would most likely present with which of the following symptoms?

Accepted Answer

Large volumes of dilute urine and risk of dehydration

Question 20

Which of the following best describes the pathway of renal blood flow from the renal artery to the peritubular capillaries?

Accepted Answer

Renal artery → segmental artery → interlobar artery → arcuate artery → cortical radiate artery → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries

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