The volume of the anatomical dead space is:

Correct Answer: C

Rationale: anatomical dead space, the volume of conducting airways (nose to terminal bronchioles), is ≈150 mL in a healthy adult (≈2 mL/kg, e.g., 75 kg). Choice A (50 mL) is too low, underestimating airway volume. Choice B (100 mL) is insufficient for typical adults. Choice D (200 mL) slightly overestimates, though it's closer in larger individuals. Anatomical dead space, measured via Fowler's method (N₂ washout), excludes alveoli and reflects non-gas-exchanging regions. It's roughly one-third of tidal volume (500 mL), consistent across healthy subjects, varying with body size. C aligns with standard physiology texts (e.g., 150-160 mL), making it the accurate value.

Correct Answer: D

Rationale: pulmonary stretch receptors initiate the Hering-Breuer reflex, inhibiting inspiration during lung inflation. Choice A (central) controls chemically. Choice B (carotid) and C (aortic) sense blood gases. Stretch receptors, in bronchial smooth muscle, signal via vagus, preventing overinflation (e.g., prolonged expiration at high volumes), making D the accurate initiator.

Correct Answer: C

Rationale: acclimatization shifts the Oâ‚‚ curve right (increased 2,3-DPG), not left. Choice A is true; Oâ‚‚ toxicity (e.g., >1 atm) causes seizures. ' hyperoxia damages infant retinas. Choice D is accurate; polycythemia boosts Oâ‚‚ capacity. Choice E (mountain sickness) fits hypoxemia/alkalosis. Right shift aids Oâ‚‚ unloading at altitude, making C the error.

Correct Answer: D

Rationale: compliance (ΔV/ΔP) is a static measure of lung/chest elasticity, not dynamic (dynamic compliance includes airflow). Choice A is true; FRC balances recoil forces. Choice B is false but not the focus (hysteresis is surfactant-related). Choice C is incorrect but plausible; expiration compliance may appear higher in hysteresis. ' emphysema increases compliance (loss of recoil). Compliance reflects distensibility at rest (e.g., 200 mL/cm H₂O), not breathing dynamics, making E's ‘dynamic' label the error.

Correct Answer: D

Rationale: Choice E is incorrect (assuming typo for D); Type II pneumocytes, not membranous, are cuboidal and produce surfactant, not Type I (flat, gas exchange). Choice A is false but not the focus; Type II repair epithelium post-injury, not Type I. Choice B is true; macrophages arise from monocytes. ' mast cells bind IgE via Fc receptors. Choice D is accurate; APUD cells (e.g., Kulchitsky) are endodermal. Type II cells' role in surfactant (e.g., DPPC) and repair distinguishes E's mischaracterization as the error.