ATI LPN
Respiratory System Practice Questions Questions
Question 1 of 5
Asthma is mediated by what type of antigen?
Correct Answer: C
Rationale: Failed to generate a rationale of 500+ characters after 5 retries.
Question 2 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 3 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 4 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 5 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.