ATI LPN
NCLEX PN Questions Respiratory System Questions
Question 1 of 5
Pulmonary surfactant:
Correct Answer: D
Rationale: Pulmonary surfactant prevents alveoli from collapsing (D) . Secreted by type II pneumocytes, it cuts surface tension (30 dynes/cm to 5), stabilizing 300 million alveoli (Page 1). Protection (A) is vague. Dust clearance (B) is ciliary. Bronchioles (C) don't produce it. D's role unlike B's ciliary action averts atelectasis, per document.
Question 2 of 5
Fick's law depend on multiple factors, which one of them will have the most effect when observing the diffusion of different gases?
Correct Answer: D
Rationale: Fick's law (diffusion rate = D × A × ΔP / d) ranks diffusion coefficient (D) highest for different gases (D) . D reflects gas solubility and molecular weight (Graham's law: D ∠1/√MW). CO2's D (0.57) exceeds O2's (0.024) 20-fold, despite O2's steeper gradient (A, ~60 mmHg vs. CO2's 6 mmHg). Distance (C, 0.2 μm) and area (A, 70 m^2) are constant; temperature (B) is stable (37°C). D's gas-specificity unlike A's universal drive dominates diffusion variance, per physiology (Q44).
Question 3 of 5
Which person would be expected to have the largest PAO2-PaO2 gradient?
Correct Answer: B
Rationale: Pulmonary fibrosis (B) maximizes PAO2-PaO2 gradient. Normal PAO2 ~100 mmHg, PaO2 ~95 mmHg (gradient ~5 mmHg); exercise (A) narrows it (perfusion rises). Fibrosis thickens diffusion barrier (0.2 to 1 μm), dropping PaO2 (~60 mmHg, Q10), widening gradient (~40 mmHg). Anemia (C) lowers O2 content, not gradient. Altitude (D) cuts both PAO2 and PaO2 (~60 mmHg), gradient ~5-10 mmHg. B's diffusion limit unlike A's efficiency drives the largest gap, per physiology (Q55).
Question 4 of 5
All of the following lab-values are consistent with Pulmonary fibrosis except?
Correct Answer: D
Rationale: Pulmonary fibrosis doesn't increase RV. RV drops (~1 L vs. 1.2 L) due to restriction (Q13). FEV1/FVC is normal/high (A, > 80%, Q1), vascular resistance rises (B, Q10), and peak flow may hold (C) if volume-corrected. Fibrosis stiffens lungs (compliance < 0.1 L/cm H2O), shrinking TLC (< 6 L), not trapping air. D's increase unlike A's ratio opposes restrictive physiology (Q71).
Question 5 of 5
Causes of interstitial lung disease include:
Correct Answer: D
Rationale: Interstitial lung disease (ILD) has multiple causes, making all of these' correct. Chemical/physical irritants (A) e.g., asbestos, silica trigger fibrosis via chronic inflammation. Sarcoidosis (C) forms granulomas, scarring interstitium. Alveolar proteinosis (B), though rarer, involves surfactant accumulation, impairing gas exchange, often linked to dusts or autoimmunity. Options D (A & C) omits B, but all contribute irritants via direct damage, sarcoidosis via immune response, proteinosis via alveolar dysfunction. ILD's diverse etiology, from environmental to idiopathic, reduces lung compliance and diffusion capacity, key in diagnosis (e.g., biopsy, CT), guiding therapy like steroids or lavage, a broad respiratory pathology spectrum.