In quiet breathing muscular effort is mainly in inspiration

In quiet breathing, muscular effort is mainly in inspiration, and expiration it largely passive, due to elastic recoiling of the lung. Can you relate this fact to the pattern of expiratory and inspiratory flow? Explain why RV cannot be determined by ordinary spirometry. What factors do you think could contribute to differences in pulmonary parameters between the members of your group?

Solution

2. The time between expiration peaks is shorter in comparision to the time between the inspiration peaks,which proves that exhalation is a passive process due to which the air flows out faster.Inspiration is mainly dependent on the contraction of the diaphragm .No muscles are needed during expiration.

3. Residual volume is the volume of the lungs that is required to keep the airways of lungs opened.Since spirometry measures the air flowing in and out of this volume ,it cannot be used to measure residual volume.

4. Age is one of the main factors that brings abot a change in pulmonary function test results,which are normally interpreted as a percentage of age prdicted values.Other factors that could contribute to differnces in pulmonary parameters between the members of the group are obesity,COPD,asthma,pulmonary fibrosis,neuromuscular disease,pulmonary surgery.Some other factors are smoking,lung volume,medications,temperature.