Renal and Urinary Anatomy and Physiology Practice Questions

25 multiple-choice questions on Renal and urinary anatomy and physiology for paramedic and EMT students, from Chapter 22 (Genitourinary and Renal Emergencies). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. Glucose begins to spill into the urine when the blood glucose rises above about:

   1. A. 70 mg/dL
   2. B. 100 mg/dL
   3. C. 600 mg/dL or higher
   4. D. 180 mg/dL
   Show answer

   Answer: D. 180 mg/dL

   The kidney tubules reabsorb all filtered glucose until their capacity is exceeded at roughly 180 mg/dL, after which glucose appears in the urine and pulls water with it, causing polyuria. Normal fasting glucose (70 to 100) does not cause glycosuria.

2. A 6-year-old has a puffy face and swollen legs, and his parents say his urine looks foamy. The foam most likely reflects:

   1. A. Sugar from a sweet drink
   2. B. Air from a urinary infection
   3. C. Protein leaking into the urine
   4. D. Normal urine after a long hot bath
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   Answer: C. Protein leaking into the urine

   Foamy urine with generalized edema suggests nephrotic syndrome, in which damaged glomeruli leak large amounts of albumin. Low blood albumin lets fluid leak into the tissues. Sugar and infection do not typically cause persistent foam with edema.

3. Two weeks after strep throat, a 7-year-old has cola-colored urine, a puffy face, and high blood pressure. You should suspect:

   1. A. Post-strep glomerulonephritis
   2. B. A kidney stone in the ureter
   3. C. Simple dehydration
   4. D. A lower urinary tract infection
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   Answer: A. Post-strep glomerulonephritis

   An immune reaction 1 to 3 weeks after group A strep infection inflames the glomeruli, causing dark (tea or cola) urine, edema, and hypertension. A UTI causes dysuria and frequency, and a stone causes colicky pain.

4. A 42-year-old with polycystic kidney disease has a sudden, severe headache. His kidney disease matters because it:

   1. A. Causes headaches from low sodium
   2. B. Raises the risk of a brain aneurysm
   3. C. Protects against high blood pressure
   4. D. Is linked to migraine headaches
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   Answer: B. Raises the risk of a brain aneurysm

   Autosomal dominant polycystic kidney disease is associated with intracranial aneurysms, so a thunderclap headache in these patients should be treated as a possible subarachnoid hemorrhage. The disease also causes hypertension rather than protecting against it.

5. A patient in atrial fibrillation who stopped his anticoagulant has sudden flank pain and blood in the urine, with no stone history. You should consider:

   1. A. Cystitis from a new partner
   2. B. A clot blocking a renal artery
   3. C. A muscle strain from heavy lifting
   4. D. A normal effect of the AF
   Show answer

   Answer: B. A clot blocking a renal artery

   Atrial fibrillation can throw emboli to the kidney, causing renal infarction with flank pain and hematuria that is often mistaken for a stone. Like mesenteric ischemia, it is a time-sensitive embolic event.

6. Narrowing of one renal artery can cause high blood pressure because the kidney beyond it:

   1. A. Stops making any urine at all
   2. B. Releases aldosterone directly
   3. C. Senses low flow and releases renin
   4. D. Excretes more sodium and water into urine
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   Answer: C. Senses low flow and releases renin

   In renal artery stenosis, the kidney perceives low perfusion and activates the renin-angiotensin-aldosterone system, causing vasoconstriction and salt retention. Aldosterone comes from the adrenal cortex, not the kidney, the kidney holds on to sodium and water rather than excreting more, and it continues to make urine.

7. A worried patient has red urine the morning after eating a large serving of beets. A dipstick shows no blood. The most likely cause is:

   1. A. Pigment from the food
   2. B. A bleeding kidney stone
   3. C. Muscle breakdown
   4. D. Bladder cancer
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   Answer: A. Pigment from the food

   Beets, some berries, and drugs such as rifampin and phenazopyridine can color urine red or orange without blood. Rhabdomyolysis gives a positive dipstick for blood (myoglobin), and a bleeding stone or cancer would also test positive.

8. Hydronephrosis means:

   1. A. A kidney cyst filled with blood
   2. B. Kidney infection that has spread to the blood
   3. C. Normal kidney growth in children
   4. D. Swelling of the kidney from blocked urine
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   Answer: D. Swelling of the kidney from blocked urine

   When urine cannot drain (from a stone, an enlarged prostate, or a tumor), the renal pelvis and calyces dilate. Prolonged hydronephrosis damages the kidney and, if infected, becomes an emergency.

9. A transplanted kidney is usually placed in the:

   1. A. Flank, just beside the old kidney
   2. B. Lower abdomen near the pelvis
   3. C. Chest, behind the heart
   4. D. Upper back near the spine
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   Answer: B. Lower abdomen near the pelvis

   Transplant kidneys are usually placed in the iliac fossa, where they connect to the iliac vessels and bladder. Pain, tenderness, or trauma over the lower abdomen in a transplant patient may involve the graft.

10. A 70-kg septic patient's urinary catheter has collected 60 mL over 3 hours. This output is:

    1. A. Normal for an adult of this size
    2. B. High, suggesting fluid overload
    3. C. Normal whenever a catheter is in place
    4. D. Low, suggesting poor kidney perfusion
    Show answer

    Answer: D. Low, suggesting poor kidney perfusion

    60 mL over 3 hours is 20 mL/h, or about 0.3 mL/kg/h, below the 0.5 mL/kg/h threshold that signals poor kidney perfusion and possible AKI. The presence of a catheter does not change what normal output is.

11. As a kidney stone travels down the ureter, it most often becomes stuck at the:

    1. A. Ureterovesical junction
    2. B. Dome of the bladder
    3. C. Renal artery
    4. D. Tip of the urethra in the penis
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    Answer: A. Ureterovesical junction

    The ureterovesical junction is the narrowest point of the ureter, so stones often lodge there, causing urgency, frequency, and pain referred to the groin or genitals. Stones do not travel through the renal artery.

12. In the hospital, a creatinine level is used to estimate the:

    1. A. Degree of liver function
    2. B. Rate of red cell breakdown
    3. C. Glomerular filtration rate
    4. D. Concentration of the urine
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    Answer: C. Glomerular filtration rate

    Creatinine, a muscle waste product, is filtered by the glomeruli, so the blood level is used with age and sex to calculate an estimated GFR (eGFR), the main measure of kidney function. A rising creatinine signals falling filtration. Liver function is judged by other tests, red cell breakdown by bilirubin, and urine concentration by specific gravity.

13. Kidney blood flow falls sharply when a septic adult's mean arterial pressure drops below about:

    1. A. 95 mmHg
    2. B. 110 mmHg
    3. C. 40 mmHg
    4. D. 65 mmHg
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    Answer: D. 65 mmHg

    Kidneys autoregulate their flow over a range of pressures, but below a MAP of about 65 mmHg their perfusion falls, which is why sepsis guidelines target a MAP of at least 65 mmHg. Waiting until 40 mmHg would cause severe ischemia.

14. Repeated kidney infections in a young child are often linked to:

    1. A. Too much water intake each day
    2. B. Urine flowing back up the ureters
    3. C. Swallowing bath water
    4. D. Wearing diapers too long at night
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    Answer: B. Urine flowing back up the ureters

    Vesicoureteral reflux lets bladder urine flow back toward the kidneys, carrying bacteria and causing recurrent pyelonephritis and scarring. It is a common finding in children with febrile UTIs.

15. A urine dipstick that is positive for nitrites suggests:

    1. A. Bacteria in the urine
    2. B. Too much protein in the diet
    3. C. A high blood glucose level
    4. D. Recent heavy exercise
    Show answer

    Answer: A. Bacteria in the urine

    Many urinary pathogens, such as E. coli, convert nitrate to nitrite, so a positive nitrite test supports a bacterial UTI. A negative test does not rule one out. Glucose and protein have their own dipstick pads.

16. Fractures of the lowest posterior ribs (11th and 12th) should raise concern for injury to the:

    1. A. Heart
    2. B. Bladder
    3. C. Kidney
    4. D. Appendix
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    Answer: C. Kidney

    The upper kidneys lie under the 11th and 12th ribs, so fractures there can injure the kidney; check for hematuria and flank tenderness. The heart lies under the upper anterior ribs, and the bladder and appendix are in the pelvis.

17. Which structure stores urine until it is released?

    1. A. Urinary bladder
    2. B. Renal pelvis
    3. C. Proximal ureter
    4. D. Prostatic urethra
    Show answer

    Answer: A. Urinary bladder

    The bladder is a muscular sac that can hold roughly 500 mL in adults. A distended bladder may be palpable above the pubic bone.

18. White, powdery crystals on the skin of a patient with untreated end-stage kidney failure are called:

    1. A. Diabetic dermopathy
    2. B. Contact dermatitis
    3. C. Heat rash
    4. D. Uremic frost
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    Answer: D. Uremic frost

    In severe uremia, urea in sweat dries to leave a fine white crust (uremic frost). It is a rare, late sign of very high urea and needs urgent dialysis. It is not an allergic or heat rash.

19. Most drugs and their metabolites that are not cleared by the liver are removed by the:

    1. A. Lungs
    2. B. Spleen
    3. C. Kidneys
    4. D. Sweat glands
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    Answer: C. Kidneys

    Patients with kidney failure may accumulate drugs such as some antibiotics and morphine metabolites, causing toxicity at normal doses.

20. Waste products measured to assess kidney function include:

    1. A. Troponin and CK-MB
    2. B. BUN and creatinine
    3. C. Lipase and amylase
    4. D. AST and ALT
    Show answer

    Answer: B. BUN and creatinine

    Blood urea nitrogen and creatinine rise when filtration falls. Troponin is cardiac, lipase is pancreatic, and AST/ALT reflect the liver.

21. A urine dipstick is strongly positive for blood, but the lab sees no red cells under the microscope. This suggests:

    1. A. A urinary tract infection
    2. B. Myoglobin from muscle breakdown
    3. C. A urine sample that is too dilute
    4. D. Normal urine after eating
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    Answer: B. Myoglobin from muscle breakdown

    The dipstick blood pad reacts to both hemoglobin and myoglobin. A positive dipstick without red cells points to myoglobinuria from rhabdomyolysis (or hemoglobinuria from hemolysis), both of which can injure the kidneys.

22. Normal urine output in an infant is about:

    1. A. 0.1 mL/kg per hour
    2. B. 5 to 10 mL/kg per hour
    3. C. 20 mL/kg per hour
    4. D. 1 to 2 mL/kg per hour
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    Answer: D. 1 to 2 mL/kg per hour

    Infants and young children make more urine per kilogram than adults: about 1 to 2 mL/kg/h, compared with 0.5 to 1 mL/kg/h in adults. Fewer wet diapers is an early sign of dehydration.

23. The renal arteries arise directly from the:

    1. A. Inferior vena cava
    2. B. Celiac trunk
    3. C. Abdominal aorta
    4. D. Iliac veins
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    Answer: C. Abdominal aorta

    Because renal arteries branch off the aorta, an AAA or aortic dissection can reduce kidney blood flow.

24. A dialysis patient started gabapentin a week ago and is now very drowsy and unsteady. The most likely cause is:

    1. A. The kidneys cannot clear the drug
    2. B. Gabapentin is a stimulant
    3. C. Dialysis removes his sodium
    4. D. He has developed a drug allergy to it
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    Answer: A. The kidneys cannot clear the drug

    Gabapentin and pregabalin are cleared by the kidneys and accumulate in kidney failure, causing sedation, ataxia, and confusion unless the dose is reduced. Gabapentin is not a stimulant, and drowsiness is not an allergic reaction.

25. Which finding would you expect in a patient with urinary retention?

    1. A. Distended, tender suprapubic area
    2. B. Frequent passage of large volumes
    3. C. Flank bruising after a fall
    4. D. Pain relieved by urination
    Show answer

    Answer: A. Distended, tender suprapubic area

    A full, firm bladder is often felt above the pubic bone, with an urge to urinate but inability to void.