Effect of Surfactant and Intrapleural Pressure on Respiration

10/29/2019 PhysioEx Exercise 7 Activity 3 PhysioEx Lab Report Exercise 7: Respiratory System Mechanics Activity 3: Effect of Surfactant and Intrapleural Pressure on Respiration Name: Date: 29 October 2019 Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. false ? 1 Which of the following statements about surface tension is You correctly answered: Surface tension acts to increase the size of the alveoli within the lungs. 2 Which of the following statements about surfactant is false ? You correctly answered: Surfactant works by increasing the attraction of water molecules to each other. 3 Just before an inspiration begins, the pressure within the intrapleural cavity You correctly answered: is less than the pressure within the alveoli. 4 The respiratory condition of pneumothorax refers to You correctly answered: any opening that equalizes the intrapleural pressure with the atmospheric pressure. 5 A pneumothorax can lead to You correctly answered: atelectasis. Experiment Results Predict Questions 1 Predict Question 1: What effect will adding more surfactant have on these lungs? Your answer: Airflows will further increase. 2 Predict Question 2: What will happen to the collapsed lung in the left side of the glass bell jar if you close the valve? Your answer: The lung will reinflate over several breaths. 1/6 10/29/2019 PhysioEx Exercise 7 Activity 3 Stop & Think Questions 1 Why did the sequential additions of surfactant change this lung system? You correctly answered: Surface tension was sequentially decreased. 2 Premature infants often have difficulty breathing because the amount of surfactant in their lungs is You correctly answered: too low. 3 What happened to the left side of the bell jar when the valve was opened? You correctly answered: The intrapleural pressure equalized with the atmospheric pressure. 4 Did the collapsed left lung reinflate? You correctly answered: No, it did not. Experiment Data Airway Radius (mm) Breath Rate (breath/min) Surfactant Pressure Left (atms) Pressure Right (atms) Flow Left (ml/min) Flow Right (ml/min) Total Flow (ml/min) 5 15 0 -4.00 -4.00 49.69 49.69 99.38 5 15 2 -4.00 -4.00 69.56 69.56 139.13 5 15 4 -4.00 -4.00 89.44 89.44 178.88 5 15 0 -4.00 -4.00 49.69 49.69 99.38 5 15 0 0.00 -4.00 0.00 49.69 49.69 5 15 0 0.00 -4.00 0.00 49.69 49.69 5 15 0 -4.00 -4.00 49.69 49.69 99.38 2/6 10/29/2019 PhysioEx Exercise 7 Activity 3 3/6 10/29/2019 PhysioEx Exercise 7 Activity 3 Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 The addition of surfactant to the lung interior You correctly answered: increased airflow. 4/6 10/29/2019 PhysioEx Exercise 7 Activity 3 2 Opening the valve in the side of the glass bell jar You correctly answered: simulated pneumothorax. 3 In this activity a pneumothorax is automatically followed by You correctly answered: atelectasis. 4 The best way to rapidly reinflate a person's collapsed lung is to You correctly answered: pump air out of the intrapleural space to recreate negative pressure. Review Sheet Results 1 What effect does the addition of surfactant have on the airflow? How well did the results compare with your prediction? Your answer: The airflow increased. 2 Why does surfactant affect airflow in this manner? Your answer: Surfactant affects airflow by decreasing the resistance, but increases the gas exchange surface. 3 What effect did opening the valve have on the left lung? Why does this happen? Your answer: When opening the valve on the left lung, the lung shrunk in size and was unable to function. This occurred because the pressure of the intrapleural space and intrapulmonary are equal, thus making the pressure of the atmosphere of the intrapulmonary are the same so the air could not get to the left lung. 4 What effect on the collapsed lung in the left side of the glass bell jar did you observe when you closed the valve? How well did the results compare with your prediction? Your answer: I previously thought the lung would reinflate over several breaths, however after observing the stimulation the lung remained collapsed. This occurred because the pressure difference with intrapleural space and lung did not re-established. What emergency medical condition does opening the left valve simulate? 5/6 10/29/2019 PhysioEx Exercise 7 Activity 3 Your answer: The medical emergency condition opening the left valve stimulates pneumothorax. 6 In the last part of this activity, you selected the Reset button to draw the air out of the intrapleural space and return the lung to its normal resting condition. What emergency procedure would be used to achieve this result if these were the lungs in a living person? Your answer: The emergency procedure used on a living person would be inserting a chest tube. The chest tube would create a partial vacuum from the intrapleural space and creating a valve below the atmospheric pressure. 7 What do you think would happen when the valve is opened if the two lungs were in a single large cavity rather than separate cavities? Your answer: If both the lungs were in one single large cavity, the lungs would collapse if the valve was open. 6/6