A comatose woman with pH 6.90, HCO₃⁻ 13 mEq/L, PaCO₂ 68 mmHg has what acid-base status?

Correct Answer: C

Rationale: Simultaneous respiratory (PCO₂ 68, high) and metabolic acidosis (HCO₃⁻ 13, low) match pH 6.90 severe drop (e.g., overdose hypoventilation, lactic acidosis). Uncompensated metabolic lacks PCO₂ rise partial. Uncompensated respiratory misses HCO₃⁻ drop sole. Renal compensation raises HCO₃⁻ not here. Dual acidosis distinguishes it, key to mixed disorder, unlike single or compensated states.

Correct Answer: A

Rationale: Normal urine pH is ~6.0 (slightly acidic) not neutral, alkaline, or strongly acidic (pathological). This defines typical acidity, critical for urinalysis, contrasting with abnormal ranges.

Correct Answer: C

Rationale: Normal urine output is 1-2 L/day not lower (oliguria) or higher (polyuria). This quantifies healthy production, critical for assessing function, contrasting with abnormal volumes.

Correct Answer: D

Rationale: Podocytes are visceral epithelial cells of Bowman's capsule, forming filtration slits not endothelial (capillaries), parietal (outer layer), or mesangial (support). This identifies their role in the filtration barrier, critical for GFR, contrasting with other glomerular cells.

Correct Answer: A

Rationale: Distal convoluted tubules (DCT) are simple cuboidal not brush border (PCT), lacking basement (false), or RER-rich (mitochondria-rich). This defines DCT structure, critical for fine-tuning, contrasting with PCT features.