ATI LPN
Respiratory System Practice Questions Questions
Question 1 of 5
The largest cross-sectional area and therefore lower resistance of airways?
Correct Answer: B
Rationale: Alveoli (B) have the largest cross-sectional area (~70 m^2), minimizing resistance . Trachea (A) is wide (~2.5 cm) but singular. Bronchi (D) branch, increasing area (~0.1 m^2), yet less than alveoli. Bronchioles (C) narrow (1 mm), but 300 million alveoli dwarf them (Poiseuille's law: R ∠1/r^4). Resistance dominates in medium airways (bronchi), not alveoli, where flow slows for exchange. B's vast area unlike A's single tube cuts velocity (1-2 cm/s vs. 100 cm/s in trachea), per physiology's airflow distribution.
Question 2 of 5
A person breathes into and from a spirometer (volume 12 liters) containing 10% helium gas mixture. After equilibration, helium concentration of expired gas was found to be 6.67%. His ERV is 4.2 liters. What is his residual volume?
Correct Answer: C
Rationale: Residual volume (RV) is 1800 mL. Helium dilution: V1C1 = V2C2. V1 = 12 L, C1 = 10%, C2 = 6.67%. Total lung volume (V2) = V1 × C1 / C2 = 12 × 10 / 6.67 ≈ 18 L. At FRC (ERV + RV), he exhales ERV (4.2 L), so FRC = 18 - 12 = 6 L. RV = FRC - ERV = 6 - 4.2 = 1.8 L. C's 1800 mL unlike A's 1000 fits dilution math, per physiology.
Question 3 of 5
When the inspiratory muscles are relaxed, the lungs are said to be at?
Correct Answer: D
Rationale: Inspiratory muscle relaxation sets lungs at FRC (D) (~2.5 L). VC (A) is max exhale (~4.8 L). RV (B) is post-forced (~1.2 L). Minimal volume' (C) isn't standard likely RV. FRC RV + ERV occurs post-expiration, with intrapleural -5 cm H2O, alveolar 0 mmHg (Q17). D's resting state unlike A's effort or B's extreme defines quiet breathing's end, per physiology (Q28).
Question 4 of 5
The primary step in the diagnosis of pulmonary carcinoma is:
Correct Answer: A
Rationale: Sputum cytology (A) is the primary diagnostic step for pulmonary carcinoma non-invasive, it detects malignant cells (e.g., squamous or adenocarcinoma) shed into airways, with 60-80% sensitivity if repeated. Chest x-ray (D) spots masses but isn't diagnostic alone lacks cellular detail. Bronchoscopy (C) visualizes and biopsies but follows suspicion. Gastric aspiration (B) is irrelevant lung cells don't migrate there. Scalene biopsy assesses metastasis, not initial diagnosis. Sputum's simplicity and specificity make it first-line, key in early detection, guiding imaging or invasive steps in oncology nursing protocols.
Question 5 of 5
Which of the following are necessary in the work up and diagnosis of a lung abscess:
Correct Answer: D
Rationale: Bronchoscopy (D) is necessary for lung abscess diagnosis visualizes cavities, obtains cultures (e.g., anaerobes), rules out malignancy. Bronchography (A contrast imaging) is obsolete, replaced by CT. Pulmonary angiography (B) targets vessels, not abscesses. Photoscans (C likely perfusion scans) assess embolism, not infection. Pulmonary function gauges impact, not diagnosis. Bronchoscopy's direct sampling and imaging (CT adjunct) are gold standards, key in chest nursing for guiding therapy and excluding obstruction.