Residual Capacity Lab Report

The first table and figure shows the result for the first experiment involving the measurement of lung volumes and capacities. Results from this particular experiment may deviate from the predicted values obtained using the Goldman and Becklake equations for Pulmonary function if the individual tested has a habit of smoking which could lead to a drop in functional residual capacity. The natural recoil of the lung is also evident in figure 1. During natural inspiration, the volume of air increases in an exponential manner until it reaches the inspiratory reserve volume. The shape of the plot proves that muscular action is needed. On the other hand, expiration is largely passive, made possible by the elastic recoil of the lungs. This is evident on the shape of the plot which is just a straight line with a declining slope with a shorter period. Residual volume cannot be measured by a spirometer because this tool can only measure the amount of the difference of the volume outside, not inside the lungs. It is also physically impossible to exhale the residual volume of air into the spirometer.
Differences between the experimental and predicted values for forced vital capacity, forced vital capacity in one second, and the FEV1/FVC ratio may be accounted to the psychological effects the individuals have during the test such as self-consciousness on breathing. The ratio can also be used to indicate alterations on the lung capacity due to some obstructive lung diseases. The FEV1/FVC ratio represents the percentage of vital capacity which is expelled in the period of the first second of the expiration. The trials also showed consistent results for this test, meaning that there is minimal variation of results for an