A climber attempts an assault on a high mountain in the Andes and reaches an altitude of 5000 meters (16,400 ft) above sea level. What will happen to his arterial PCO2 and pH?

Correct Answer: B

Rationale: At high altitude (5000 m), low oxygen partial pressure triggers hyperventilation, reducing arterial PCOâ‚‚ (hypocapnia). Per Henderson-Hasselbalch, lower PCOâ‚‚ increases pH (respiratory alkalosis). Exertion may raise COâ‚‚ briefly, but hypoxia-driven ventilation dominates, ruling out C and D. A is close but less precise than B's directional clarity.

Correct Answer: A

Rationale: Elevated parathyroid hormone increases calcium reabsorption, contributing to kidney stones (A), a correct pathological effect. Hypothyroidism slows metabolism (B), nephrotic syndrome loses proteins into urine (C), and acute kidney injury reduces output (D), making A the accurate understanding.

Correct Answer: A

Rationale: The RAAS involves liver angiotensinogen, renal renin, and endothelial ACE (A, true), but angiotensin II, not just aldosterone, stimulates thirst/appetite (B is false), and AII increases sodium reabsorption (C, true). Only A is unequivocally correct—system components are accurate—while B is wrong and C is partial, making A the answer.

Correct Answer: D

Rationale: Keeping the drainage tubing and bag below the bladder (D) uses gravity to ensure continuous urine flow, preventing reflux and infection, a universal Foley care principle. Level positioning (A) hinders drainage, Neosporin irrigation (B) isn't routine and risks resistance, and clamping (C) disrupts flow and bladder function, making D the primary, evidence-based intervention.

Correct Answer: D

Rationale: The PCT has simple cuboidal epithelium (D) with microvilli for reabsorption. Stratified squamous (A) is in skin, transitional (B) in bladder, and ciliated columnar (C) in airways, making D correct.