Question 1

Which of the following best describes the main function of the glomerulus within the nephron?

Accepted Answer

It filters blood plasma to form filtrate, initiating urine formation.

Question 2

A patient presents with glucose in their urine (glycosuria). Which of the following best explains why this occurs in uncontrolled diabetes mellitus?

Accepted Answer

The transport proteins responsible for glucose reabsorption become saturated due to high plasma glucose levels.

Question 3

Which of the following equations correctly calculates the net filtration pressure (NFP) at the glomerulus?

Accepted Answer

$$\mathrm{NFP} = \mathrm{GHP} - (\mathrm{GCOP} + \mathrm{CHP})$$

Question 4

A drug causes constriction of the afferent arteriole in the kidney. What is the most likely effect on glomerular hydrostatic pressure (GHP) and glomerular filtration rate (GFR)?

Accepted Answer

GHP will decrease and GFR will decrease.

Question 5

Which of the following best describes the role of the juxtaglomerular apparatus (JGA) in regulating GFR?

Accepted Answer

It senses NaCl concentration in the distal tubule and releases renin to activate the RAAS pathway.

Question 6

Which of the following statements about the medullary osmotic gradient is correct?

Accepted Answer

It is necessary for the formation of concentrated urine by allowing water reabsorption in the collecting duct.

Question 7

A patient with chronic renal failure has a GFR that is significantly below normal. Which of the following is a likely consequence?

Accepted Answer

Accumulation of nitrogenous wastes in the blood, leading to uremia.

Question 8

Which of the following best explains why water reabsorption in the proximal tubule is considered 'obligatory'?

Accepted Answer

It is driven by the osmotic gradient created by solute reabsorption and does not depend on hormone levels.

Question 9

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

Accepted Answer

Glomerular capsule → proximal tubule → nephron loop → distal tubule → collecting duct → renal pelvis

Question 10

Which of the following best describes the effect of atrial natriuretic peptide (ANP) on the kidneys?

Accepted Answer

It dilates the afferent arteriole and constricts the efferent arteriole, increasing GFR.

Question 11

Which of the following is true regarding the difference between secretion and excretion in the nephron?

Accepted Answer

Secretion is the movement of substances from the blood into the filtrate, while excretion is the elimination of substances from the body in urine.

Question 12

A patient is severely dehydrated. Which hormone will be elevated to promote water reabsorption, and what is its mechanism?

Accepted Answer

ADH; increases aquaporin insertion in the collecting duct.

Question 13

Which of the following best describes the effect of high levels of sympathetic nervous system stimulation on GFR?

Accepted Answer

It causes vasoconstriction of both afferent and efferent arterioles, significantly decreasing GFR.

Question 14

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

Accepted Answer

They reabsorb water and solutes from the filtrate back into the blood.

Question 15

Which of the following best explains why the glomerular filtration membrane has a slight negative charge?

Accepted Answer

To repel most plasma proteins, preventing their filtration into the filtrate.

Question 16

Which of the following best describes the difference between cortical and juxtamedullary nephrons?

Accepted Answer

Juxtamedullary nephrons have longer nephron loops and are essential for concentrating urine.

Question 17

Which of the following best describes the mechanism of bicarbonate ion reabsorption in the proximal tubule?

Accepted Answer

Bicarbonate ions combine with hydrogen ions to form carbonic acid, which is converted to CO$$_2$$ and H$$_2O by $$carbonic anhydrase; CO$$_2$$ diffuses into the cell and is reconverted to bicarbonate for reabsorption.

Question 18

A urine sample is dark yellow with a high specific gravity. What does this indicate about the urine?

Accepted Answer

It is concentrated and produced in small volume.

Question 19

Which of the following best describes the involuntary component of micturition?

Accepted Answer

It is initiated by stretch receptors in the bladder wall, leading to contraction of the detrusor muscle and relaxation of the internal urethral sphincter via parasympathetic neurons.

Question 20

Which of the following would most likely be found in the urine of a patient with glomerulonephritis, and why?

Accepted Answer

Large plasma proteins, due to increased permeability of the filtration membrane.

The Urinary System: Structure, Function, and Regulation

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