BIOC34; Third Assignment (2013)
PhysioEx Lab 7 (Respiratory System Mechanics)
Due Date: Friday March 8, 2013
Perform the experiments in PhysioEx lab 7 (Respiratory System Mechanics). Provide the results
requested, and answer the questions, for each of the following activities. There are a total of 20
Note: The activity names and numbers listed below correspond to those in PhysioEx version 9.0.
If you are using an older version of PhysioEx the exact activity names and numbers may not
match. In this case, identify which activities in the older versions correspond to the ones listed
below and place the appropriate data in the corresponding section.
Activity 1: Measuring Respiratory Volumes and Calculating Capacities
Provide the data recorded from the experiments in this section (i.e., chart 1). (3 marks)
Activity 2: Comparative Spirometry
Provide the data recorded from the experiments in this section (i.e., chart 2). (3 marks)
Activity 3: Effect of Surfactant and Intrapleural Pressure on Respiration
Provide the data recorded from the experiments in this section (i.e., chart 2). (3 marks) 2
1. In activity 1 (in which the airway radius is reduced and lung volumes and capacities are
measured) do the results suggest that there is an obstructive or a restrictive, lung disorder?
Explain your answer. (3 marks)
One way of determining the difference between obstructive and restrictive diseases is to
determine the forced expiratory volume (FEV1), which is the forced volume expired in one
second. Obstructive lung disorder affects airflow by reducing airway radius and hindering
expiration. The reduction of the airway radius should cause the FEV1 to decrease
proportionately. This can be seen in the results, as the radius decreases from 5.00 mm to 3.00
mm, the FEV1 decreases from 3541 ml to 436 ml. As well, FEV1 can be expressed as a
percentage of the forced vital capacity (FVC). An obstructive lung disorder should indicate a
decrease in the FEV1/FVC percentage. From the results, the FEV1 (%) at a radius of 5.00 mm is
73.9% and at a radius of 3.00 mm the percentage has decreased to 70.2%. Thus, the decrease in
FEV1 and FEV1(%) indicate that there is an obstructive lung disorder.
2. How and why would vigorous exercise change: tidal volume, total lung volume, residual
volume, IRV, ERV and vital capacity? (3 marks)
During vigorous exercise, the human body has an increased metabolic demand ( increased
need of oxygen and increased need to