Gas Exchange in the Lungs — Flashcards

Flashcard 1: _____ dead space can be measured by the single-breath N2 curve (Fowler's method).

Answer: Anatomical

Flashcard 2: The _____ of a respiratory system pressure-volume curve represents lung compliance

Answer: slope

Flashcard 3: The lung diffusing capacity, DL, _____ during exercise due to increased surface area (A)

Answer: increases

Flashcard 4: In _____ lung disease, the flow volume loop shifts to the right

Answer: restrictive

Flashcard 5: Due to the presence of dead space in pulmonary embolism (V/Q = _____), the PO2 of the alveolus will be _____ that in the inspired air.

Answer: ∞; equal to

Extra: In alveolar dead space (e.g., pulmonary embolism), ventilation occurs but perfusion is absent (Q = 0). Therefore, the V/Q ratio is infinite (∞). Because no gas exchange takes place, the alveolar gas composition remains identical to inspired air (PO2 ≈ 150 mmHg, PCO2 ≈ 0 mmHg).

Flashcard 6: If there is a(n) _____ obstruction, the V/Q ratio = $\infty$ (infinity) (physiological dead space)

Answer: blood flow

Flashcard 7: Due to the presence of dead space in pulmonary embolism (V/Q = _____), the PO2 of the alveolus will be _____ that in the inspired air.

Answer: Infinity; equal to

Flashcard 8: The lung diffusing capacity, DL, _____ in emphysema due to decreased surface area (A)

Answer: decreases

Flashcard 9: The upper limit for the linear relationship between the increase in % of CO2 in inspired air and respiratory minute volume is _____% CO2.

Answer: 6

Flashcard 10: The graph given below shows _____ _____thoracic obstruction

Answer: variable