ATI LPN
Respiratory System Practice Questions Questions
Question 1 of 5
What is the anatomically correct name for the windpipe?
Correct Answer: D
Rationale: The trachea (D) is the windpipe . This 10-12 cm cartilaginous tube connects larynx to bronchi, conducting air. The pharynx (A) is a throat passage. Bronchioles (B) are smaller airways. The larynx (C) houses vocal cords. D's structural role 16-20 C-shaped rings warms and humidifies air (Page 5, Q11A), unlike A's dual role or B's distal position, per anatomy texts.
Question 2 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 3 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 4 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 5 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).