THE TEAK PROJECT: TRAVELING ENGINEERING ACTIVITY KITS Artificial Lung and Diaphragm Partial support for this project was provided by the National Science Foundation's Course, Curriculum, and Laboratory Improvement (CCLI) program under Award No. 0737462. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
Transcript
THE TEAK PROJECT: TRAVELING ENGINEERING ACTIVITY KITS
Artificial Lung and Diaphragm
Partial support for this project was provided by the National Science Foundation's Course, Curriculum, and Laboratory Improvement (CCLI) program under Award No. 0737462. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
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The TEAK Project
Rochester Institute of Technology
ACTIVITY OVERVIEW
Artificial Lung and Diaphragm Overview Students completing the artificial lung kit will build a lung/diaphragm system that can be used to simulate human breathing. After an initial discussion about design criteria, students will work on teams to make choices about how to best design their lung, and observe the performance changes that occur with different design choices. Just as an engineer must acquire data from a biological system to model, design, and fabricate a new design, the students participating in this activity will work to create an optimum model of the lung and diaphragm using various materials provided for them in the activity.
Activity Time Description
Lung Construction Activity 45 min This activity allows students to construct and manipulate an artificial lung to simulate human breathing, and see how the lung and diaphragm work together to achieve breathing.
Learning Objectives By the end of this lesson, students should be able to…
• Describe the relationship between the lungs and diaphragm used in breathing and where artificial lung technology is applied today
• Utilize engineering roles and work in teams to construct an artificial lung and diaphragm • Explain how engineers take a complex system and develop simple models • Identify similarities and differences between the functional respiratory system and the model in the kit • Identify the design considerations an engineer must consider when developing an artificial lung
NYS Learning Standards Standard 1: Engineering Design
• Under supervision, manipulate components of a simple, malfunctioning device to improve its performance
• Recognize why an object or choice is not working properly • Recognize how a defective simple object or device might be fixed • Design a structure or environment
Standard 5: Management of Technology
• Work cooperatively with others on a joint task
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The TEAK Project
Rochester Institute of Technology
INSTRUCTOR PREPARATION GUIDE
Bioengineering Overview Bioengineering is the application of engineering principles to address challenges in the fields of biology and medicine. Bioengineering also encompasses engineering design to the full spectrum of living systems.
Respiratory System Overview The two critical pieces of the human respiratory system are the lungs and diaphragm. They work together to perform breathing and oxygenate the bloodstream. Each person uses the muscles of the rib cage to breathe in; the diaphragm is the primary rib cage muscle utilized for breathing. To allow air into the lungs, the diaphragm flattens and tightens. Air then enters the lungs through the mouth and trachea and travels to the bronchial tubes. Air then enters gradually smaller airways until it reaches the small air sacs called alveoli.
Figure 1: The Human Respiratory System Figure 2: Lung Diaphragm Interaction There are around 300 million alveoli in each lung, and each alveolus is surrounded by blood vessels. Blood in these vessels pick up the surrounding oxygen and carry it to the body. Carbon dioxide then exits the body through the blood, eventually leaving through exhalation.
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The TEAK Project
Rochester Institute of Technology
Lung Disease Overview Lung disease is any disorder that occurs in the lungs or results in the improper function of the lungs. There are three main types of lung disease:
1. Airway diseases – Affect the airways that carry oxygen and carbon dioxide to and from the lungs 2. Lung tissue diseases – These diseases target the lung tissue 3. Pulmonary circulation diseases – These diseases are caused by clotting, scarring, or inflammation of the
blood vessels, and cause them to function improperly.
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The Respiratory System
DURATION 45-50 Minutes
CONCEPTS Bioengineering
Respiratory System Lung Disease
Artificial Lung Design
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BIOENGINEERING INTRODUCTION
Background Information Bioengineering is the application of engineering principles to address challenges in the fields of biology and medicine. Bioengineering also encompasses engineering design to the full spectrum of living systems.
Bioengineering Group Discussion (Pose the following questions to the group and let the discussion flow naturally…try to give positive feedback to each child that contributes to the conversation.)
Q: What do you think bio (biology) means?
• The study of life and a branch of the natural sciences that studies living organisms and how they interact with each other and their environment.
• The study of the environment. • The study of living organisms and living systems.
Q: What do you think engineering is? What do you think it means to be an engineer?
• A technical profession that applies skills in: o Math o Science o Technology o Materials o Structures
Discuss with the students what bioengineering is and the broad scope of areas that bioengineering includes. For this discussion, provide students with examples of bioengineered products and applications.
• Bioengineering is the application of engineering principles in the fields of medicine, biology, robotics, and other living systems.
• Examples of products that have been bioengineered are: o Ventilators o Stem cells for rebuilding lung tissue o Artificial lungs
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RESPIRATORY SYSTEM INTRODUCTION
Background Information The respiratory system is responsible for supplying the blood with oxygen and releasing unneeded carbon dioxide from the body. The lungs and diaphragm are two critical organs in the respiratory system used in breathing. The lungs contain tiny air sacs, called alveoli, where the oxygen and carbon dioxide exchange occurs. The diaphragm is the muscle which allows the lungs to take in and release air. To inhale, the diaphragm contracts and flattens, allowing air to enter into the lungs. The diaphragm relaxes in order to let air out of the lungs. There are many diseases associated with lungs, such as cancer and emphysema, which may leave humans unable to breathe without assistance. Engineers have created ventilators, which help premature babies breathe and recovering patients after surgery. They are also currently designing artificial lungs, which can be implanted surgically. It is critical that these engineers know how the respiratory system works and functions in conjunction with the rest of the body in order to design solutions to keep humans breathing properly.
Simplified Definitions Asthma – A chronic condition involving the respiratory system in which the airways occasionally constrict and become inflamed Chronic Bronchitis – An inflammation of the bronchi (medium-size airways) in the lungs Emphysema – A disease of the lungs resulting in decreased respiratory function; emphysema is commonly associated with smoking, chronic bronchitis, or old age Lung Cancer – A disease of uncontrolled cell growth in tissue of the lung; lung cancer is usually associated with smoking
Lung Disease and Biomediacal Solutions Group Discussion (Pose the following questions to the group and let the discussion flow naturally…try to give positive feedback to each child that contributes to the conversation.)
Q: What exactly is lung disease?
• Any disease or disorder that occurs in the lungs or that causes the lungs to not work properly. • In some cases, these diseases become so severe that it is impossible for a patient to breathe without the
assistance of a machine. Q: What are some problems you might have with your lungs?
• Asthma • Chronic bronchitis • Emphysema • Lung Cancer
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Q: Has anyone heard of a ventilator? • A device that facilitates breathing in cases of respiratory failure by mechanically introducing fresh air into
and out of the lungs and is used until a donor lung is found. • Ventilators can assist premature babies in breathing and help patients recovering from surgery. • Some patients use ventilators to perform long term breathing due to impairment from lung disease. • External rather than internal. A ventilator is 3-4’ tall in size.
Q: How is an artificial lung different from a ventilator?
• An artificial lung is implanted inside the body, while a ventilator is used outside the body. • Artificial lungs are made to mimic the movements and actions of real lungs (balloons that inflate and
deflate, diaphragms that move, the transfer of oxygen and carbon dioxide into and out of the bloodstream).
Q: Why implant an artificial lung rather than a ventilator?
• In some cases, a ventilator does not provide enough assistance to patients, and a lung donor must be found; however, this process may take a significant amount of time.
• An implantable artificial lung will extend the time to find a donor (anywhere from days to months). • The device can be left in place until the transplanted lungs are fully functioning.
Learning Objectives By the end of this exercise, students should be able to…
• Perform, understand and visualize the process of breathing • Identify the optimum design parameters for the artificial lung and diaphragm model based upon the
following customer needs: o Artificial lung model must work; that is the model must simulate breathing in the human lung. o Model must allow for the largest air intake possible to increase oxygen absorption o Model must be as sturdy as possible
Materials for Each Group • Nalgene Bottle with Top • Red Bag
o One-hole rubber stopper o Wye connector o 3” tube
• Blue Bag: o Two-hole rubber stopper o (2) 3” tubes o (2) 5” tubes
• White Bag: o (2) 12” balloons
o (2) 9” balloons o (2) 5” balloons o Balloon diaphragm o (2) rubber bands
• Green Bag: o (4) Activity role tags
• Activity Handout
Artificial Lung and Diaphragm Activity – 45 Minutes
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Procedure 1. Divide students into groups of 4-5.
2. Give each group a kit and the activity handout.
3. Before the students open their kits, discuss the design parameters with them. Make sure all students
understand the purpose of the activity and what they are supposed to be doing.
4. Walk the students through the building of their first lung configuration. Let each team member follow their given role, and walk around the room to make sure everyone understands what they are doing.
5. Instruct students to open their kits and begin the activity.
NOTE: There are a total of 12 different lung and diaphragm configurations that the students can construct. Since
it is unlikely that a group will complete all 12 setups, make sure that they are testing the ones they think will be the most successful.
Expected Results • Students should not see a noticeable difference in the air intake rate when using different tube lengths, as
the difference should be too small to detect. However, they should notice that the setup is much less sturdy.
• Students should notice that a much larger amount of air is taken in by the 12” balloons. • Students should notice the flimsy nature of the two-tube design, which can result in lung twisting and
collision.
Concluding Discussion There are many correct answers to these questions. Their purpose is to create an open-ended discussion. Q: How does this artificial model differ from the human respiratory system?
• Living Tissue • Diaphragm is a muscle • Trachea
Q: In today’s activity, we designed the tube configuration, tube length and balloon size for our artificial lungs. What else could bioengineers change or improve to design a more advanced artificial respiratory system?
• Size of the lung cavity (bottle size) • Thickness of the lungs/diaphragm • How to transfer oxygen once it is in the artificial lung
End Artificial Lung and Diaphragm Activity
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ARTIFICIAL LUNG ACTIVITY HANDOUT
Design Parameters (Customer Needs): • The Artificial Lung must “breathe” when it is assembled. • The Artificial Lung must have the largest air intake as possible. • The Artificial Lung must be sturdy and have minimal part movement during breathing.
DO NOT OPEN YOUR KIT UNTIL THE TEACHER HAS GONE OVER THE DESIGN
PARAMETERS! Procedure:
ALL
Take the water bottle and colored bags out of the box. You will need these to start making artificial lungs!
Take Activity Role tags out of the green bag and place them upside down on the table without reading them. Everyone should pick a tag and read the role description on the back.
Fluids It is time to start designing! Based on the design parameters, which tube configuration do you think will work the best? You can choose from red (one hole) or blue (two holes).
Material
Using the color chosen by the FLUIDS engineer, determine which tube length you think will work best.
Choose the balloon size you think will work best.
Test Record the tube configuration, tube length and balloon size.
Structural Build the lungs using the parts that were picked out by the FLUIDS and MATERIALS engineers. First, take the top off of the water bottle and put the rubber stopper into the hole.
Name(s) __________________________ Group #__________
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Structural
Next, insert the correct size tubes into the hole or holes of the stopper.
Using the rubber bands, attach the balloons onto the tubes.
Put the top back on the water bottle so that the balloons are hanging inside the bottle.
Stretch the blue balloon, or diaphragm, over the bottom of the water bottle very carefully!
Test
Hold the water bottle in one hand, and grab the blue balloon with the other. In order to simulate breathing: pull the blue balloon slowly away from the bottle. Watch as the inside balloons, or lungs, fill with air. Now, slowly push the blue balloon back towards the bottle. Notice that the lung balloons deflate.
All
As the TEST engineer is making the artificial lung “breathe,” talk about any observations you have. Some observations could be: - How full the lungs get - How easily air flows in and out of the lungs - How much the lungs move around or hit the bottle
Test Make note of all observations.
Structural Carefully take apart the lung.
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Repeat the procedure using different tube configurations, tube lengths, and balloon sizes. Record each lung that is tested in the chart. After you are done with all testing, answer the questions in the Engineering Evaluation. Design Chart
Tube Configuration
Tube Length
Balloon Size
Observations & Notes
1
2
3
4
5
Engineering Evaluation 1. Which balloon size seemed to allow the most air into it? ____________________________________________ 2. Did any of the tube lengths make it harder to fully inflate the lungs? __________________________________ 3. Did any of the tube lengths allow for lung movement? _____________________________________________ 4. Which tube configuration allowed air into the lungs easiest? ________________________________________ 5. Did any of the tube configurations allow for lung movement? _______________________________________ 6. What do you think the best configuration for the artificial lung is? Tube Configuration ________________________________________________ Tube Length ________________________________________________ Balloon Size ________________________________________________
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ENGINEERING EVALUATION (ANSWERS)
1. Which balloon size seemed to allow the most air into it? 12” Balloon 2. Did any of the tube lengths make it harder to fully inflate the lungs?
No, there was no noticeable difference in how hard it was to inflate the balloons. 3. Did any of the tube lengths allow for lung movement?
Yes, the longer tubes did because they are less sturdy than the shorter tubes. 4. Which tube configuration allowed air into the lungs easiest? The two tube configuration (blue) because air is allowed into the lungs easier. 5. Did any of the tube configurations allow for lung movement?
The two tube configuration because they do not have a sturdy mounting system, such as the wye connector used in the 1 tube configuration. Lung movement could cause the lungs to get tangled together or to hit the cavity wall, causing problems during breathing.
6. What do you think the best configuration for the artificial lung is? Tube Configuration One Tube (Red) Tube Length Shorter Tube
Balloon Size 12” Balloon
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IMAGE SOURCES
[1] SEER. Bronchi, Bronchial Tree and Lungs. 2013. JPEG file. http://training.seer.cancer.gov/anatomy/respiratory/passages/bronchi.html [2] The Lung Association. Respiratory System. 2012. JPEG file.
Changed respiratory system introduction, restructured the activity handout by adding the procedure and a design chart, updated engineering evaluation to match new handout, added to the respiratory system intro.
Heather Godlewski
01/11/2010 Spelling and grammar corrections made to lesson plan, changed on website/share folder, but didn’t re-print. Marked corrections with initials.
Konrad Ahlin
01/13/2010 Added pictures to activity handout Konrad Ahlin
4/25/2013 Edited for grammar and syntax issues. Reorganized the format.
