The lung may be visualized bag

pressThe lung may be visualized bag situated a closed pleura! cavity it the inraalvenlar pressure is say 761 mmure The pressure volume curve Compliance in an ntact man can be measured clinically The principle, in short, of this measurement, is as foflows Irtrapleural pressure is recorded and simultaneousty the lung volume is also recorded The person, now, partially inspires (or expires) and stops in the midway making no further inspiration or expiration His intrapieurai pressure and the lung volume are again recorded at this point A series of such observanons are made and the graph plotted (figure A 22) ( HYPERUl*: http //Fig 4 2 2 Compliance ) of lung, the hysteresis loop (descnption in the text) The intrapleural pressure is recorded by placing a balloon m the esophagus as mentioned above The subject breathes from a spirometer The volume of ar that has entered from a spircrneter [thus which can be measured due to the expansion of the lung must be the volume of expansron of the lung In this way the values of v and P are obtained This curve therefore denotes the Interrelationship between the intrapleural pressure (PpL)and the volume of lung Such a pressure volume curve is also called a compliance curve