This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System Pa 1, Subject name: Physiology
[{'content': 'Physiologic shunt refers to: \nSelect and explain. \nA. shunt between bronchial and pulmonary circulation, B. airflow from small to large alveoli, C. Wasted ventilation, D. Perfusion more than ventilation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: If some pa of the lung does not have ventilation but has blood perfusion, blood leaving this pa will remain mixed venous blood. That is, this blood will not be oxygenated. And, it will mix with aerial blood in left ventricle. This is called physiologic shunt or venous admixture. Atelectasis is the most common cause of a physiologic shunt; ventilation: perfusion ratio (VA/Q) is zero.', 'role': 'assistant'}]