In normal individual, regarding gas exchange across pulmonary capillaries during mild exercise, which of the following statements is TRUE?

Correct Answer: A

Rationale: CO2 diffuses easier than O2 (A). CO2's solubility (0.57 mL/mmHg/dL) outstrips O2's (0.024), 20x faster despite O2's gradient (60 vs. 6 mmHg, Q20). O2's diffusing capacity (B, false) is lower (21 vs. 400 mL/min/mmHg) due to binding limits. Exercise shortens equilibrium time (C, true), but not length capillaries stay 0.75 s. ABGs hold (D, false, PaO2 ~95 mmHg). A's ease unlike B's reversal fits Fick's law, per physiology.

Correct Answer: D

Rationale: Average vital capacity (VC) total air exhaled after maximal inhalation is 4-5 liters (D) in healthy adults (e.g., ~4.8 L men, 3.2 L women), varying by age, sex, height. Options 600 cc (A) and 300 cc (B) are tidal volumes or fractions far too low. 10-20 liters (C) exceeds human lung capacity (total ~6 L). 2.5-3 liters underestimates normal VC, closer to inspiratory reserve. VC, measured via spirometry, reflects lung function; 4-5 L aligns with physiologic norms, key in assessing restrictive (low VC) versus obstructive diseases in pulmonary diagnostics.

Correct Answer: B

Rationale: Markedly decreased diffusion capacity for CO (DLCO) (B) indicates non-operability in lung cancer poor gas exchange (e.g., DLCO <40% predicted) predicts post-resection respiratory failure. Decreased compliance (A), V/Q mismatch (C), hypoventilation (D), or pulmonary hypertension impair function but aren't primary surgical contraindications DLCO directly assesses alveolar-capillary integrity. Low DLCO, from tumor or emphysema, limits resection tolerance, key in preoperative pulmonary function testing for surgical planning in chest oncology.

Correct Answer: B

Rationale: Thalassemia minor mild β-thalassemia raises hemoglobin A₂ (B) (e.g., 3.5-7%) from compensatory δ-chain production, detected via electrophoresis. Hemoglobin A (A) dominates but is reduced. HbS (C) is sickle cell, unrelated. HbF (D) rises in severe forms, not minor. All' overstates. A₂ elevation reflects β-chain defect, key in nursing for genetic counseling and distinguishing from iron deficiency.

Correct Answer: C

Rationale: Chronic lymphocytic leukemia (CLL) features skin lesions, positive Coombs test, and hypogammaglobulinemia (C) lymphocyte proliferation causes autoimmune hemolysis (Coombs), infections (low IgG), and rare cutaneous infiltration. B12 (A) rises from binding protein, not universal. Philadelphia chromosome (B) is CML. Uric acid (D) ties to turnover, not specific. Pelger-Huet is congenital. C's triad reflects CLL's immune dysfunction, key in nursing for infection prophylaxis and anemia management.