Regarding pulmonary function, which of the following is NOT true?

Correct Answer: D

Rationale: Choice D is not true; inspiratory capacity (IC) in men is ≈3.3 L (TV + IRV, 0.5 + 2.8 L), not 4.8 L. ' FRC (≈2.4 L) equals ERV (≈1 L) + RV (≈1.4 L). Choice B is true; IRV is ≈3.3 L in men. Choice C is accurate; RV in women is ≈1.1 L. Choice E is correct; TLC is ≈6 L (men), 4.2 L (women). IC reflects maximal inspiratory volume from FRC; 4.8 L exceeds typical male values (closer to vital capacity). Standard lung volumes (e.g., 70 kg male) confirm D's overestimation, making it the false statement.

Correct Answer: A

Rationale: RQ nears 1.0 in exercise (e.g., 0.8 to 1.2) as metabolism shifts. Choice B is true but incomplete; PIO₂ = FiO₂ · (PB - PH₂O). Choice C is false; PACO₂ ≈ PaCO₂ (≈40 mmHg) in normals. Choice D is wrong; PAO₂ ≈ 100 mmHg (150 - 40/0.8), not 150. Exercise increases VCO₂ relative to VO₂, raising RQ, especially anaerobically. The equation (PAO₂ = PIO₂ - PACO₂/RQ) adjusts dynamically, making A the accurate statement.

Correct Answer: A

Rationale: central chemoreceptors (medulla) dominate minute-by-minute ventilation, sensing CSF pH (CO₂-driven, 70-80% of response). Choice B (carotid) and C (aortic) contribute <20% (O₂, CO₂, pH), critical in hypoxia. Choice D (stretch) fine-tunes via Hering-Breuer reflex. Central receptors adjust breathing rate/depth to maintain PaCO₂ ≈ 40 mmHg, responding within seconds to CO₂ shifts, making A the primary controller.

Correct Answer: C

Rationale: high altitude causes pulmonary vasoconstriction (hypoxic response), not vasodilation. Choice A is true; 2,3-DPG shifts the curve right. ' angiogenesis increases capillaries. Choice D is accurate; polycythemia boosts Hb. Choice E (breathing capacity) rises. Vasoconstriction matches V/Q, countering hypoxia, making C the exception.

Correct Answer: B

Rationale: Fick's law states gas diffusion rate (V) = (A · D · (P1-P2)) / T, where A is area, D is diffusion constant, P1-P2 is pressure gradient, and T is thickness. Choice A is the alveolar ventilation equation, not Fick's. Choice C is the pH definition, unrelated. Choice D is Boyle's law (gas volume-pressure). Choice E is a temperature ratio misstep. Fick's law governs O₂ and CO₂ transfer across the alveolar-capillary membrane, emphasizing area and gradient (e.g., DₗO₂ ≈ 25 mL/min/mmHg), inversely proportional to thickness. B accurately captures this principle, critical for lung gas exchange calculations.