Which of the following statements are false in regard to Hodgkin's disease:

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Functional residual capacity (FRC) is the volume of air in the lungs at the end of a normal, quiet expiration, typically around 2.5-3 liters in adults. It's the resting state where the inward elastic recoil of the lungs balances the outward recoil of the chest wall, with no active muscle effort. Residual volume (RV) is the air left after maximal expiration (~1-1.5 L), not quiet expiration. Expiratory reserve volume (ERV) is the additional air that can be forcibly exhaled after a normal expiration (~1-1.5 L), not the resting volume itself. Inspiratory reserve volume (IRV) is the extra air inhaled beyond a normal breath (~2-3 L), relevant during inspiration, not expiration. Total lung capacity (TLC) is all lung volumes combined (~6 L), far exceeding the resting state. FRC represents the equilibrium point before inspiration begins, maintaining alveolar patency and efficient gas exchange, distinguishing it from other volumes tied to maximal efforts or different respiratory phases.

Correct Answer: C

Rationale: At the end of quiet expiration, respiratory muscles (diaphragm, intercostals) relax, and the lungs reach functional residual capacity (FRC), typically 2.5-3 liters. FRC is the resting volume where lung inward recoil balances chest wall outward recoil, maintaining equilibrium without active effort. Residual volume (RV, ~1-1.5 L) is the air left after maximal expiration, not quiet breathing. Expiratory reserve volume (ERV, ~1-1.5 L) is the extra air forcibly exhaled beyond quiet expiration, not present at rest. Inspiratory reserve volume (IRV, ~2-3 L) is additional air inhaled beyond a normal breath, irrelevant post-expiration. Total lung capacity (TLC, ~6 L) includes all volumes, not the resting state. FRC's role as the baseline volume after passive expiration reflects the natural relaxation point, critical for continuous gas exchange, distinguishing it from volumes tied to forced maneuvers or inspiration.

Correct Answer: C

Rationale: Residual volume (RV) is the air left after maximal expiration, not measurable by spirometry but calculable via helium dilution. Here, a 12 L spirometer with 10% helium (C1 = 0.1) equilibrates with lung volume (initially FRC). Post-equilibration, expired gas is 6.67% helium (C2 = 0.0667). Using V1C1 = V2C2 (helium conservation), V1 = 12 L, C1 = 0.1, C2 = 0.0667: 12 × 0.1 = V2 × 0.0667, so 1.2 = V2 × 0.0667, V2 = 1.2 / 0.0667 ≈ 18 L. V2 is total gas volume (spirometer + FRC). FRC = V2 - V1 = 18 - 12 = 6 L. FRC = ERV + RV, and ERV = 4.2 L, so RV = FRC - ERV = 6 - 4.2 = 1.8 L = 1800 ml. This assumes equilibration at FRC (post-normal expiration), common in such problems. The 1800 ml matches helium dilution principles, where dilution reflects unexpired lung volume, confirming RV amidst the options.

Correct Answer: D

Rationale: Normal inhalation follows a mechanical sequence. (5) Contraction of the diaphragm and external intercostals starts it, expanding the thoracic cavity. (1) This lowers intrapleural pressure (IPP) from -4 mmHg (756 mmHg) to -6 mmHg (754 mmHg), increasing transpulmonary pressure. (3) Lung size increases as the lungs expand with the chest wall. (4) Intra-alveolar pressure drops to 759 mmHg (-1 mmHg) as volume rises (Boyle's law), creating a gradient from atmospheric pressure (760 mmHg). (2) Air flows in from higher to lower pressure. The order 5,1,3,4,2 reflects causality: muscle action lowers IPP, expands lungs, drops alveolar pressure, and drives airflow. Alternatives disrupt this: 5,2,3,4,1 puts flow before pressure changes; 1,3,4,5,2 starts with IPP drop without muscle action; 5,4,3,2,1 misplaces alveolar pressure before lung expansion. The correct sequence mirrors respiratory physiology's step-by-step process.