Question 1

Which of the following best describes the composition of normal urine?

Accepted Answer

95% water, with urea, creatinine, and various ions such as sodium, potassium, chloride, and calcium

Question 2

Which structure is responsible for the initial filtration of blood in the kidney?

Accepted Answer

Glomerulus

Question 3

What is the main driving force for glomerular filtration?

Accepted Answer

Hydrostatic pressure in the glomerular capillaries

Question 4

Which of the following is NOT a component of the filtration membrane in the renal corpuscle?

Accepted Answer

Parietal layer of glomerular capsule

Question 5

A patient presents with proteinuria. What does this indicate about their filtration membrane?

Accepted Answer

There is a problem with the filtration membrane, allowing proteins to pass into the filtrate

Question 6

Calculate the net filtration pressure (NFP) given the following values: $$HP_{gc} = 55\ mm\ Hg$$, $$HP_{cs} = 15\ mm\ Hg$$, $$OP_{gc} = 30\ mm\ Hg. $$Use the formula $$NFP = HP_{gc} - (HP_{cs} + OP_{gc}).$$

Accepted Answer

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

Question 7

Which process returns 99% of the filtrate back to the blood?

Accepted Answer

Tubular reabsorption

Question 8

Which hormone increases water reabsorption in the collecting ducts by inserting aquaporins?

Accepted Answer

Antidiuretic hormone (ADH)

Question 9

What is the effect of aldosterone on the distal convoluted tubule and collecting duct?

Accepted Answer

Increases sodium reabsorption and decreases potassium levels

Question 10

Which of the following is a function of tubular secretion?

Accepted Answer

Disposing of drugs and metabolites bound to plasma proteins

Question 11

If the glomerular filtration rate (GFR) increases, what happens to the sodium concentration in the filtrate and the afferent arteriole?

Accepted Answer

Sodium concentration increases; afferent arteriole constricts

Question 12

Which mechanism is responsible for maintaining a consistent GFR when mean arterial pressure (MAP) is between 80–180 mm Hg?

Accepted Answer

Renal autoregulation (intrinsic controls)

Question 13

Which cells in the juxtaglomerular complex respond to changes in sodium concentration in the filtrate?

Accepted Answer

Macula densa cells

Question 14

A patient with abnormally low urinary output (anuria) is most likely experiencing which of the following?

Accepted Answer

Nephrons have stopped functioning due to acute nephritis or crush injuries

Question 15

Which of the following substances is NOT normally reabsorbed in the proximal convoluted tubule?

Accepted Answer

Plasma proteins

Question 16

Which route of tubular reabsorption involves movement through the cytosol of tubule cells?

Accepted Answer

Transcellular route

Question 17

Which process is responsible for the elimination of excess potassium from the body?

Accepted Answer

Tubular secretion

Question 18

Which of the following would most likely lead to the formation of renal calculi (kidney stones)?

Accepted Answer

Crystallization of calcium, magnesium, or uric acid salts in the renal pelvis

Question 19

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

Accepted Answer

$$NFP = HP_{gc} - (HP_{cs} + OP_{gc})$$

Question 20

Which of the following is a consequence of sympathetic nervous system activation on the kidneys?

Accepted Answer

Constriction of afferent arterioles, decreased GFR, and increased blood volume and pressure

Renal Physiology: Filtration, Reabsorption, and Secretion in the Kidney

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