Which of the following statements are false:

Correct Answer: C

Rationale: Carcinoma of the stomach bleeding isn't usually massive (C false) it's chronic, occult (e.g., <100 mL/day), unlike varices. Red hematemesis (A) fits massive or achlorhydria true. Tarry melena (B) from distal gut true. Rare urinary bleeding (D) except TB true. C's overstatement is key, guiding nursing for endoscopy vs. acute bleed protocols.

Correct Answer: D

Rationale: Residual volume (RV) is the air remaining in the lungs after a maximal expiration, preventing complete collapse and maintaining alveolar stability. It's not just after tidal expiration (that's FRC), so that statement is imprecise. In COPD, an obstructive disease, air trapping increases RV due to impaired expiration from narrowed airways or loss of elastic recoil, not decreases it. In pulmonary fibrosis, a restrictive disease, RV decreases because stiff lungs limit all volumes, including the amount left after maximal effort. However, RV remains relatively constant throughout a healthy person's life, unaffected by aging alone in the absence of disease, as lung elasticity and structure don't drastically alter RV without pathology. While lung volumes like vital capacity may shift with age, RV's stability reflects its role as a fixed baseline, measured indirectly (e.g., helium dilution), and isn't subject to significant physiological variation over time in health. Thus, its consistency across a lifetime is the correct statement, distinguishing it from disease-specific changes.

Correct Answer: A

Rationale: Total lung capacity (TLC) is the maximum volume of air the lungs can hold after a maximal inspiration, encompassing all lung volumes: residual volume (RV, ~1-1.5 L), expiratory reserve volume (ERV, ~1-1.5 L), tidal volume (VT, ~0.5 L), and inspiratory reserve volume (IRV, ~2-3 L). In a normal adult, TLC averages around 6 liters (5-7 L, varying by age, sex, and size), widely accepted in physiology (e.g., Guyton, West). The 2 L option might confuse with FRC (~2.5-3 L), the resting volume after normal expiration. Four liters approximates vital capacity (VC, ~4-5 L), excluding RV. Nine liters exceeds typical human capacity, possibly a misestimate, and 15 L is implausible without pathology (e.g., hyperinflation). The 6 L value aligns with standard measurements (e.g., spirometry plus RV via helium dilution), reflecting the full extent of lung expansion in a healthy individual, making it the most accurate approximation.

Correct Answer: C

Rationale: Surfactant, from type II alveolar cells, reduces alveolar surface tension, aiding lung function. It causes hysteresis the difference in lung inflation vs. deflation pressure-volume curves by lowering tension more effectively as alveoli expand, a true property. It decreases, not increases, pulmonary resistance by easing expansion and reducing collapse tendency, so that's incorrect but not the queried option. Surfactant deficiency is common in preterm neonates (<37 weeks), causing respiratory distress syndrome (RDS), but in term neonates (≥37 weeks), surfactant production is typically mature, making commonly deficient in term-neonates' incorrect RDS is rare at term unless congenital defects exist. Surfactant prevents pulmonary edema indirectly by maintaining alveolar stability, reducing transudation pressure, though not its primary role. The term-neonate statement is the incorrect one, misaligning with developmental physiology where surfactant sufficiency is expected at full gestation.

Correct Answer: D

Rationale: Pulmonary function tests (PFTs) differentiate lung diseases. Obstructive diseases (e.g., COPD) reduce airflow, decreasing FEV1 (<80% predicted) due to airway narrowing, with increased residual volume (RV) and total lung capacity (TLC) from air trapping. Restrictive diseases (e.g., fibrosis) limit expansion, also reducing FEV1 (<80% predicted) due to lower volumes, but RV and TLC decrease. Decreased FEV1 is common to both obstructive from airflow limitation, restrictive from reduced capacity making it consistent across types. Decreased RV fits restriction, not obstruction (increased RV). Normal or above TLC fits obstruction, not restriction (decreased TLC). Vascular resistance isn't a PFT metric; it rises in fibrosis, not decreases. Decreased FEV1's shared reduction reflects impaired exhalation, a unifying feature despite differing mechanisms, distinguishing it as the overlapping value.