A young woman is found comatose, having taken an unknown number of sleeping pills an unknown time before. An arterial blood sample yields the following values: pH - 6.90, HCO3- 13 meq/liter, PaCO2 68 mmHg. This patient's acid-base status is most accurately described as

Correct Answer: C

Rationale: A pH of 6.90 (severe acidosis), HCO₃⁻ of 13 mEq/L (low), and PaCO₂ of 68 mmHg (high) indicate combined metabolic acidosis (low HCO₃⁻ from overdose, e.g., lactic acid) and respiratory acidosis (high PCO₂ from hypoventilation due to sedation). No compensation is evident (HCO₃⁻ isn't rising), ruling out A, B, D, making C correct.

Correct Answer: C

Rationale: Bladder training for impaired urinary elimination (e.g., incontinence) focuses on strengthening pelvic floor muscles (C) via exercises (e.g., Kegels) and scheduled voiding to improve control. Fluid balance (A) is secondary, catheterization (B) is invasive, and urodynamic testing (D) is diagnostic, making C the primary focus.

Correct Answer: D

Rationale: Na/H and Cl/HCO₃ antiports regulate volume in hypertonic conditions (A), water efflux precedes KCl in hypertonic states (B is partial), and KCl efflux adjusts hypotonic swelling (C). A and C are true—antiports for shrinkage, KCl for swelling—while B is incomplete, making D (A and C are correct) the answer.

Correct Answer: A

Rationale: Net filtration pressure (NFP) = Glomerular hydrostatic pressure (75 mm Hg) - (Capsular hydrostatic pressure (15 mm Hg) + Glomerular osmotic pressure (25 mm Hg)) = 75 - (15 + 25) = 35 mm Hg (A). This drives filtration; 85 (B), 65 (C), and 115 (D) miscalculate, making A correct.

Correct Answer: B

Rationale: In females, the urethral orifice is anterior to the vaginal orifice (B), not posterior, due to anatomical positioning (urethra above vagina). True (A) reverses this, making B correct.