The most common cause for acute renal failure is

Correct Answer: A

Rationale: Acute tubular necrosis (ATN) is the top cause of acute renal failure ischemia/toxins (e.g., sepsis) damage tubules, impairing filtration. Glomerulonephritis (immune) is less frequent chronic more common. Vasculitis (e.g., ANCA) is rare systemic. Tubulointerstitial nephritis (drugs) occurs but trails ATN less acute. ATN's prevalence distinguishes it, critical for ARF etiology, unlike glomerular or interstitial causes.

Correct Answer: D

Rationale: Sickle cell disease tops pediatric priapism sickling blocks penile outflow (ischemic), prevalent in affected populations. Idiopathic is less defined residual category. Trauma causes high-flow rarer. Leukemia clogs vessels significant but less common. Sickle cell's dominance distinguishes it, key to pediatric etiology, unlike trauma or hematologic alternatives.

Correct Answer: C

Rationale: Alpha1c isn't a recognized receptor misnomer; Alpha1a, Alpha1b, and Alpha1d mediate LUTS (e.g., BPH). Alpha1a dominates prostate/bladder neck obstruction. Alpha1d affects detrusor irritative. Alpha1b is vascular less LUTS-specific. Non-existent Alpha1c distinguishes it, key to receptor pharmacology, unlike active mediators.

Correct Answer: A

Rationale: The nephron ends at the collecting duct, which drains into the renal papilla, unlike the distal convoluted tubule (preceding), glomerulus (start), or papilla (not part). This distinguishes the nephron's final segment, critical for urine concentration, contrasting with earlier structures.

Correct Answer: B

Rationale: GFR averages 180 L/day (125 mL/min × 1440 min), not 10 L, 1.5 L, or 1 mL/min (misunits). This quantifies filtration capacity, critical for renal function assessment, contrasting with incorrect scales.