ATI LPN
Respiratory System Practice Questions Questions
Question 1 of 5
Which of the following is NOT true concerning respiratory distress syndrome in premature infants?
Correct Answer: D
Rationale: In infant respiratory distress syndrome (IRDS), surfactant deficiency (A) reduces compliance (C), needing higher pressures. Alveoli collapse (atelectasis), not overexpand (D, false), due to high surface tension (T) without surfactant (Q7). Premature lungs (28 weeks viable, Q15) lack type II pneumocytes' lamellar bodies, raising T (normal 30 dynes/cm to 50+), dropping C (< 0.1 L/cm H2O). D's burst claim contradicts collapse B's pressure (e.g., 20-30 cm H2O) fights this, and positive pressure aids, per physiology.
Question 2 of 5
Which of the following will the have the highest percentage of CO2?
Correct Answer: B
Rationale: Pulmonary arteries (B) carry highest CO2 (~46 mmHg, 8%). Alveolar air (A) is ~40 mmHg (5.6%). Pulmonary veins (C) and systemic arteries (D) match arterial blood (~40 mmHg, 5.6%) post-exchange. B's deoxygenated blood venous return from tissues exceeds A's exhaled mix or C's oxygenated flow, reflecting metabolism's CO2 output (5 L/min), per gas transport physiology (Q6).
Question 3 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 4 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 5 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.