ATI RN
Urinary System Questions Questions
Question 1 of 5
What percentage renal function can be lost but still have a creatinine in the normal range?
Correct Answer: D
Rationale: ~60% renal function (GFR) can be lost with normal creatinine compensatory hypertrophy masks decline (e.g., GFR 120 to 50 mL/min), nonlinear rise. 20-50% underestimates creatinine lags. 60% distinguishes it, critical for early CKD detection, unlike lower estimates.
Question 2 of 5
A 60-year-old male with history of benign prostatic hypertrophy presents complaining of nausea and vomiting. Laboratory values include serum Na of 145 mmol/L, blood urea nitrogen (BUN) of 45 mg/dL, creatinine of 2.0 mg/dL, urine Na of 10, and urine creatinine of 80. Which of the following is the MOST likely diagnosis?
Correct Answer: A
Rationale: Prerenal failure fits BUN:creatinine >20:1 (22.5), urine Na <20 (10), high urine:serum creatinine (>40:1), dehydration from vomiting/BPH obstruction. ATN shows FENa >1, urine Na >40 tubular damage. Glomerulonephritis has casts absent here. Postrenal (BPH) raises creatinine more obstruction incomplete. Prerenal markers distinguish it, key to hypoperfusion diagnosis, unlike intrinsic or obstructive patterns.
Question 3 of 5
All of the following substances cause urinary retention EXCEPT
Correct Answer: D
Rationale: Beta-blockers don't cause retention may relax detrusor (e.g., opposite alpha-agonists), unlike methamphetamines/ephedrine (sympathomimetic, sphincter tone) and cogentin (anticholinergic, detrusor inhibition). Lack of retention distinguishes beta-blockers, key to drug effects, unlike obstructive agents.
Question 4 of 5
Juxtaglomerular cells are:
Correct Answer: D
Rationale: Juxtaglomerular (JG) cells secrete renin, not mesangial (support), phagocytic, lacis (extraglomerular), or Na-sensitive (macula densa). This identifies JG cells' role in RAAS, critical for blood pressure regulation, contrasting with other glomerular components' functions.
Question 5 of 5
All the following are true about Proteus sp. EXCEPT:
Correct Answer: B
Rationale: Proteus causes UTI, is urease positive, and swarms, but is Gram-negative not Gram-positive. This corrects bacteriology, key for infection treatment, contrasting with Gram-positive misidentification.