One Respiration Consists of One Inspiration and One Expiration.

Control of Human Respiration Your respiratory system allows you to obtain oxygen, eliminate carbon dioxide, and regulate the blood’s pH level. The process of taking in air is known as inspiration, while the process of blowing out air is called expiration. A respiratory cycle consists of one inspiration and one expiration. The rate at which your body performs a respiratory cycle is dependent on the levels of oxygen and carbon dioxide in your blood. You will learn how to use the Respiration Monitor Belt to monitor the respiratory patterns of one member of your group. A Respiration Monitor Belt will be strapped around the test subject and connected to a Gas Pressure Sensor. When the test subject inspires, the air pressure in the bladder of the Respiration Monitor Belt will decrease. When that same air is expired, the air pressure in the bladder will increase. This pressure is measured by the Gas Pressure Sensor and converted into a respiratory rate by the data-collection program. OBJECTIVES In this experiment, you will • Use a Respiration Monitor Belt and Gas Pressure Sensor to monitor the respiratory rate of an individual. • Evaluate the effect of holding of breath on the respiratory cycle. • Evaluate the effect of rebreathing of air on the respiratory cycle. MATERIALS LabQuest LabQuest App Vernier Gas Pressure Sensor Vernier Respiration Monitor Belt Styrofoam cup plastic 40 L (10 gallon) garbage bag PROCEDURE 1. Set up LabQuest for the Respiration Monitor Belt. a. Connect the Gas Pressure Sensor to CH 1 of LabQuest and choose New from the File menu. b. Choose Sensor Setup from the Sensors menu. c. Select Respiration Monitor Belt from the Channel 1 sensor list. d. Select OK. 2. On the Meter screen, tap Rate. Change the data-collection rate to 0.1 samples/second and the data-collection length to 180 seconds. Select OK. 3. Select a member of your lab group as the test subject. Wrap the Respiration Monitor Belt snugly around the subject’s chest. Press the Velcro strips together at the back. Position the belt so the air bladder is resting over the diaphragm as shown in Figure 1. position belt over diaphragm bulb pump Luer-lock connector Figure 1 4. Attach the Respiration Monitor Belt to the Gas Pressure Sensor. There are two rubber tubes connected to the bladder. One tube has a white Luer-lock connector at the end and the other tube has a bulb pump attached. Connect the Luer-lock connector to the stem on the Gas Pressure Sensor with a gentle half turn. 5. Have the test subject sit upright in a chair. Close the shut-off screw of the bulb pump by turning it clockwise as far as it will go. Pump air into the bladder by squeezing on the bulb pump. Fill the bladder as full as possible without being uncomfortable for the test subject. Part l Holding of Breath 6. Collect respiration data. a. Instruct the test subject to breathe normally. b. Start data collection. Data will be collected for 3 minutes. c. After data has been collected for 30 seconds, have the test subject take a deep breath and hold it as long as possible. d. After the subject releases his or her breath, instruct him or her to breathe normally for the remainder of data collection. 7. When data collection has finished, a graph of respiration rate vs. time will be displayed. To examine the data pairs on the displayed graph, tap any data point. As you tap each data point, the respiration rate and time values of each data point are displayed to the right of the graph. 8. Determine the mean respiration rate before and after the subject’s breath was held. a. Identify the three data points just before the subject’s breath was held. b. Tap the first point and drag your stylus across the next two points. c. Select Statistics from the Analyze menu and record the mean (average) value in Table 1 as the respiration rate before holding breath. d. Identify the three data points just after the subject’s breath was held. e. Tap the first point and drag across the next two points. f. Statistics will be updated for the new region. Record the mean (average) value in Table 1. Control of Human Respiration Part ll Breathing Exhaled Air 9. Set up LabQuest for Part II. a. Tap Table. b. Choose Clear All Data from the Table menu. 10. On the Meter screen, tap Rate. Change the data-collection rate to 2 samples/second and the data-collection length to 60 seconds. Select OK. 11. Obtain a respiration bag from your teacher. The bag will consist of a plastic liner with a cup taped to one corner of the bag as shown in Figure 2. The subject will be required to breathe in and out of the bag through the cup during this portion of the experiment. Figure 2 12. The subject will breathe in and out of the respiration bag for a period of 6 minutes. During the 6 minute period, three runs of data will be collected. Use a watch or clock to make sure that data collection is performed at the proper times. • The first run will be done between 0 and 1 minute, followed by a statistical analysis. • The second run will be done between 2.5 and 3.5 minutes, followed by a statistical analysis. • The third run will be done between 5 and 6 minutes, followed by a statistical analysis. Run 1 0 Run 3 Run 2 1 2 3 4 5 6 Time (min) 13. Fill the respiration bag with air and have the subject hold the bag closed so that the air does not escape. 14. Have the subject begin breathing into the bag. Check to make sure that he or she is able to easily breathe both in and out of the respiration bag. The subject must breathe from the bag for the entire 6 minutes. Start data collection. Data will be collected for 1 minute. 15. When 1 minute has elapsed, data collection will stop. a. One member should perform Step 16 immediately. b. Another member of your lab group must continue to keep track of the running total of time. c. The subject must continue breathing into the bag for the entire 6 minute period. LabQuest 26 16. Calculate the relative amplitude of the respiration waves for the data collection. You must proceed quickly, this step must be done in 1 minute. a. Choose Statistics from the Analyze menu. Statistics will be calculated for all the data on the graph. b. Subtract the minimum pressure from the maximum pressure to calculate the amplitude. c. Record the calculated amplitude for the time interval in Table 2. 17. After a total of 2.5 minutes have elapsed, with the subject still breathing into the bag, start data collection. Repeat Steps 15–16, and record the amplitude value in Table 2 for 2.5 to 3.5 minutes. 18. After a total of 5 minutes have elapsed, with the subject still breathing into the bag, start data collection. Repeat Steps 15–16, and record the amplitude value in Table 2 for 5 to 6 minutes. DATA Table 1 Holding of breath Before holding breath After holding breath breaths / minute breaths / minute Table 2 Breathing exhaled air: Amplitudes of respiration waves 0 to 1 minute 2.5 to 3.5 minutes kPa kPa 5 to 6 minutes kPa QUESTIONS 1. Did the respiratory rate of the test subject change after holding his or her breath? If so, describe how it changed. 2. What is different about the size (amplitude) or shape (frequency) of the respiratory waveforms following the release of the test subject’s breath? Explain. 3. What would be the significance of an increase in the amplitude and frequency of the waveform while the test subject was breathing into the bag? 4. How did the respiratory waveforms change while the test subject was breathing exhaled air from the bag? How would you interpret this result? 5. Explain how you think carbon dioxide affects your breathing.