Which respiratory principle is INCORRECT?

Correct Answer: D

Rationale: the chloride shift moves HCO₃⁻ out of the RBC (not in) and Cl⁻ in, maintaining neutrality as CO₂ forms HCO₃⁻. Choice A is true (Fick's law: V ∝ A/T). Choice B is correct (Bohr effect: PCO₂ → H⁺ → right shift). Choice C is accurate (Henry's law). Choice E is true (Haldane effect). D reverses ion directions; HCO₃⁻ exits via band 3 exchanger, Cl⁻ enters, supporting CO₂ transport, making it the error.

Correct Answer: A

Rationale: diffusion capacity (Dₗ) depends on partial pressure gradient (P1-P2) driving gas transfer (Fick's law: V = D·A·ΔP/T). Choice B (area), C (thickness), and D (constant) are factors, but Dₗ integrates them with ΔP as the flux determinant. Choice E (all) is too broad. Dₗ (e.g., 25 mL/min/mmHg for O₂) measures transfer rate per pressure difference, making A the key variable.

Correct Answer: A

Rationale: breathing's energy cost rises to ≈2-5% in exercise (not 10%), though it can reach 10-15% in respiratory disease. Choice B is true; ventilation increases 20x (6 to 120 L/min). ' VO₂ rises ≈15-20x (0.25 to 4-5 L/min in fit adults). Choice D is plausible; VCO₂ can increase disproportionately (e.g., 20-40x) with anaerobic metabolism (RQ > 1). Choice E (P₅₀ up) is true. Normal exercise elevates respiratory work modestly (≈0.5 to 5 kcal/min), not 10% of total (≈50-100 kcal/min), making A overstated and false.

Correct Answer: B

Rationale: phosphate deficiency decreases 2,3-DPG synthesis, as phosphate is a substrate in glycolysis (1,3-BPG to 2,3-DPG via mutase). Choice A (growth hormone), C (thyroid hormone), D (exercise), and E (androgens) increase 2,3-DPG by boosting metabolism or hypoxia response, shifting the O₂ curve right (P₅₀ up). In hypoxia (e.g., altitude, exercise), 2,3-DPG rises (e.g., 15 to 20 µmol/g Hb) to aid O₂ unloading. Phosphate scarcity impairs this, reducing levels (e.g., in hypophosphatemia), distinguishing B as the non-stimulator among metabolic enhancers.

Correct Answer: C

Rationale: Zanamivir is an inhaled antiviral used for influenza but is contraindicated in clients with COPD because it can cause bronchospasm, worsening airway obstruction and potentially leading to respiratory distress. For an older client with COPD and sickle cell disease, this risk is amplified, as both conditions compromise oxygen delivery COPD via lung function and sickle cell via reduced blood oxygenation. Oseltamivir (also known as Tamiflu) is an oral antiviral safe for such clients, making it a better choice. Xanax, an anti-anxiety drug, isn't an antiviral and is irrelevant here. The nurse must notify the prescriber about Zanamivir due to its potential to exacerbate the client's respiratory condition, requiring an alternative like Oseltamivir. This decision reflects the nurse's duty to assess medication appropriateness based on the client's comorbidities, preventing harm and ensuring treatment aligns with the client's fragile health status.