Regarding surfactants, one is true?

Correct Answer: B

Rationale: Surfactant reduces alveolar surface tension (B). From type II cells, it drops tension (30 dynes/cm to 5), preventing collapse (Q9). Pleural pressure (A) stays negative (-5 cm H2O). Alveolar pressure (C) is 0 at rest, unaffected directly. Inspiration eases (D, false), compliance rises (0.2 to 0.5 L/cm H2O). B's role unlike A's irrelevance stabilizes 300 million alveoli, per physiology (Q64).

Correct Answer: A

Rationale: In hypoxia with hypercapnia (e.g., COPD), cautious oxygen via a Venturi device (A) is optimal. Hypercapnia reflects COâ‚‚ retention; high Oâ‚‚ (B) risks suppressing the hypoxic drive, worsening COâ‚‚ buildup and acidosis a danger in chronic respiratory failure. Intubation (C) is invasive, reserved for acute failure, not initial management. None' (D) ignores hypoxia's urgency. The Venturi mask delivers precise, low-flow Oâ‚‚ (e.g., 24-35%), correcting hypoxemia without over-oxygenation, balancing Oâ‚‚ saturation (e.g., 88-92%) and COâ‚‚ levels. This approach, rooted in respiratory physiology, prevents ventilatory depression, a key nursing consideration in titrating oxygen therapy for obstructive lung diseases.

Correct Answer: D

Rationale: Silicosis stems from silica dust (D) crystalline silicon dioxide from quartz or sand in mining, quarrying. Inhaled particles trigger macrophage activation, fibrosis, forming silicotic nodules. Coal (A) causes pneumoconiosis, not silicosis carbon-based. Silicates (B) are related but less fibrogenic. Iron (C) links to siderosis, benign. Beryllium causes berylliosis, distinct granulomas. Silica's unique pathogenicity scars lungs, reducing compliance, key in occupational lung disease diagnosis (e.g., CT showing nodules), guiding prevention like ventilation controls in at-risk workers.

Correct Answer: C

Rationale: Most pulmonary metastases arise from glandular tissues (C e.g., breast, prostate, thyroid) adenocarcinomas favor hematogenous lung spread, forming cannonball lesions. GI (A) and GU (B) metastasize, but glandular primaries dominate (e.g., 40% breast). Pericardium (D) and brain rarely seed lungs reverse is commoner. This reflects vascular drainage, key in imaging (e.g., CT) and nursing for systemic therapy planning.

Correct Answer: C

Rationale: Aspiration pneumonia ties to debilitation in elderly (C) impaired swallow (e.g., stroke) aspirates oropharyngeal bacteria (e.g., anaerobes), causing right lower lobe infection. Collaterals (A) are SVCS. Tracheal perforation (B) is mechanical. Elderly risk altered consciousness, dysphagia is key, guiding antibiotics and swallow therapy in nursing care.