Respiratory Air Flow and Volume

1. Comment on the differences between the experimental and predicted values for VC, FRC and TLC in the table above. What could cause these differences, if any?

The experimental values for Vital Capacity, Functional residual capacity, and Total Lung Capacity appear to be lower than the predicted values. We recognized that these differences could be explained by differences in the physical fitness or chest cavity capacity. Similarly, the long tube connection with the equipment could contribute to the dead space, increasing the level of carbon dioxide and altering the results.

2. In quiet breathing, muscular effort is used mainly in inspiration, and expiration is largely passive, due to elastic recoil of the lung. Can you relate this fact to the pattern of expiratory and inspiratory flow? Hint: the normal pattern of breathing is efficient in that it requires muscular effort for only a short time.

The time elapsed between expiration peaks in flow patters when compared to that of inspiration peaks is definitely shorter-exhibiting that exhalation is a passive action as it does not require much effort, leading to a shorter time period as air flows out quicker. However, during inspiration, muscular effort is required and the pattern of the flow shows this as the period of inspirations is longer when compared to that of expiration.

3. Explain why RV cannot be determined by ordinary spirometry?

RV or Residual Volume cannot be determined by ordinary spirometry, as it is not possible to physically exhale it. The purpose for the Residual Volume is because of the low pressure in our lungs during inspiration. If it were not, the lungs would collapse.

4. Comment on the differences between the experimental and predicted values for FVC, FEV1 and the FEV1/FVC ratio in the table above. What could cause these differences, if any?

Though not shown, based on what was discussed in class, the experimental values were thought to be lower than...