Which of the following is seen in pneumothorax

Ans. b. Reduced concentration of surfactant Pneumothorax decreases the quantity of surfactant in the collapsed lung. Over expanded chest wall is characteristically seen in conditions where the lung loses its elasticity, such as in emphysema, and the natural tendency of the chest wall to recoil towards the outside, causes an over expanded chest. In pneumothorax, intra-pleural pressure equilibrates with the ambient barometric pressure and the lung's natural recoil tendency causes it to collapse. Pneumothorax tends to cause collapse of the lungs and a decreased compliance Surfactant Produced by Type 11 alveolar epithelial cells (pneumocytes)Q Synthesis of surfactant begins at 16-18 weeks of gestation and peaks at 35 weeks of gestationQ. It is stored in alveolar cells until 26 weeks when release on the alveolar surface occurs. Secreted by exocytosis in the form of lamellar bodieswhich is conveed to tubular myelin Composed of Dipalmitophosphatidyl choline (62%)Q, phosphatidyl glycerol (5%)Q, and other phospholipids, neutra lipids, protein and carbohydrate. Function Reduces alveolar surface tensionQ Prevent alveolar collapseQ Prevent pulmonary edemaQ Deficiency occur with Occlusion of main bronchusQ Occlusion of pulmonary aeryQ Cigarette smokersQ Long term inhalation of 100% 02.Q