This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'The collapse of the lung is called \nSelect and explain. \nA. Emphysema, B. Bronchiectasis, C. Atelectasis, D. Bronchitis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Atelectasis (collapse)\n\nAtelectasis refers to:-\n\n\nIncomplete expansion of lungs →\xa0Neonatal atelectasis.\n\tor\nThe collapse of previously inflated lung → Acquired atelectasis.\n\n\nThis results in areas of relatively airless pulmonary parenchyma.\nAcquired atelectasis may be divided into\n\n1.\xa0\xa0 Resorption (obstruction) atelectasis\n\nIt is a consequence of complete obstruction of an airway.\nWith time trapped oxygen in the affected alveoli is resorbed and collapse occurs.\nResorption atelectasis is caused principally by obstruction due to excessive secretions (mucus plug) or exudates within small bronchioles as seen in Bronchial asthma, chronic bronchitis, Bronchiectasis and foreign body aspiration.\n\n2.\xa0\xa0 Compression atelectasis\n\nThe collapse of lung occurs due to external pressure on the lung.\nIt is seen most commonly in patients with cardiac failure who develop pleural effusion and in patients with neoplastic pleural effusion.\n\n3.\xa0\xa0 Contraction atelectasis\n\nThe collapse is due to contracture in the lung because of fibrotic changes.\nExcept for contraction atelectasis, atelectasis is a reversible disorder, i.e. collapsed lung parenchyma can be re-expanded.', 'role': 'assistant'}]