Alveolar Gas Exchange is part of the The Respiratory System section of Physiology. Practise 17 exam-style MCQs for NEET PG, FMGE, INI-CET and NEET SS, each with the correct answer and a detailed explanation.
Carbon monoxide diffusing capacity, the alveolar gas equation, the 4.2 L/min alveolar ventilation figure and the causes of hypoxaemia with a normal A–a gradient headline these Alveolar Gas Exchange MCQs, which test gas exchange as high-yield NEET PG revision.
In clinical practice, carbon monoxide is the gas of choice for measuring diffusion capacity because it is the diffusion limited gas The procedure is called diffusing capacity of the lung for carbon monoxide or DLCO Reference: Ganong, 25th edition page no.639
Alveolar ventilation is 4.2 L/min Alveolar ventilation = respiratory rate* (tidal volume - dead space) = 12 (500-150) = 4.2L/min Reference: Ganong, 25th edition page no.629
The alveolar oxygen tension is calculated using the modified alveolar gas equation: PAO2 = PIO2 - PaCO2/R. PAO2 = [0.5 x (747 - 47 mmHg)] - 40 mmHg/0.8 PAO2 = 350 mmHg - 50 mmHg = 300 mmHg Reference: Levitzky, pp 75, 262.
Ans. B. Capillary Site of gas exchange = Capillaries
Regional hypoventilation is the most common physiological factor for respiratory causes of hypoxemia(Reduced arterial PO2) and reflects a local ventilationperfusion imbalance resulting from a partially obstructed airway. Also hypoventilation leads to inadequate ventilation and fails to remove Alveolar CO2 from the pulmonary capillary blood leading to hypercapnia. So hypoventilation is the cause of both hypoxemia and hypercapnia.
Increase in alveolar ventilation washes out CO 2 - So, there is decreased partial pressure of CO 2 in alveoli Reference: Ganong, 25th edition page no.628
Kyphoscoliosis is a deformity of the spine involving both lateral displacement (scoliosis) and anteroposterior angulation (kyphosis). Muscle weakness can produce inadequate ventilation, which can lead to an accumulation of carbon dioxide and a decrease in arterial pH (respiratory acidosis). Chest wall compliance is decreased, which manifests as a restrictive lung impairment characterized by a decrease in all lung volumes and capacities. Reference: Kasper et al., pp 203, 1556. Levitzky, pp 23,171-173. Stead et al., pp 255-257.
Whether the air flow is laminar or turbulent is determined by Reynolds number Reynolds number = pDV/η Where, p-Density of the gas D-Diameter of the airways V-Velocity of gas η- Viscosity of gas Pressure of gas is not in the formula for Reynolds number Reference: Ganong, 25th edition page no.629
Carbon monoxide diffusing capacity, the alveolar gas equation, the 4.2 L/min alveolar ventilation figure and the causes of hypoxaemia with a normal A–a gradient headline these Alveolar Gas Exchange MCQs, which test gas exchange as high-yield NEET PG revision.
MedLadder includes 17 curated MCQs for Alveolar Gas Exchange under Physiology (The Respiratory System), covering NEET PG, FMGE, INI-CET and NEET SS preparation.
