What is Difference in trajectory between inspiratory loop and the expiratory loop in the curve is due to and explain in detail?
Ans. (b) Difference in conc, of surfactant during inspiration and expiration(Ref - Boron, Medical physiology, 2nd ed p.634)Important points to be noted in compliance curve are:The curve has inspiratory and expiratory componentsNote that the inspiratory and expiratory compliance curves do not coincide. This difference is called hysteresisThe difference between the inflation and the deflation paths--hysteresis--exists because a greater transpulmonary pressure is required to open a previously closed airway, owing to a deficit of surfactant at the air-water interface, than to keep an open airway from closing, reflecting abundant surfactantCompliance is the slope DV/DPThe lung volume at any given pressure is greater during expiration than during inspirationCompliance is greatest at mid pressure range