This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Physiology
[{'content': 'Respiratory causes of hypoxemia are all except: \nSelect and explain. \nA. Hypoventilation, B. Physiological Shunt, C. VP mismatch, D. Dead space ventilation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref: Pai GK. Hypoxia and Oxygen therapy. In: Textbook of Medical Physiology. 2nd ed. Ahuja Publishing House. 2011: 94: 758-59.Explanation:Hypoxic hypoxia - PO2 of the arterial blood is reducedEg:High altitude flow PO2 in inspired air)Hypoventilation (airway obstruction, respiratory muscle paralysis depression of respiratory centers, scoliosis)Diffusion defect - pulmonary edema, fibrosis, lung collapseVentilation/ Perfusion mismatch - A-V shunt, atelectasis lung collapse, cyanotic heart diseaseDead spaceIt is the space within the airways that do not allow gas exchange with pulmonary capillary bloodAnatomical dead space -Conducting respiratory pathway from nose to terminal bronchiolesAbout 150 ml (25-30% of minute ventilation)', 'role': 'assistant'}]