TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 1
TEAK
Traveling Engineering Activity Kits
Biomedical Engineering Kit:
The Circulatory and Respiratory Systems
Clogged Blood Vessel Activity
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Instructor Preparation Guide:
Page 2
Blood Vessel Activity
Bioengineering Overview
Bioengineering is the application of engineering principles to address challenges
in the fields of biology and medicine. Bioengineering is the application of the principles
of engineering design to the full spectrum of living systems.
Circulatory System Overview
The main components of the human circulatory system are the heart, blood, and
the blood vessels that carry blood through the rest of the body. These three components,
the heart, blood, and blood vessels form what is known as the cardiovascular system.
The circulatory system includes two loops throughout the body know as the pulmonary
circulation loop and the systemic circulation loop. The pulmonary circulation loop is the
loop in which the blood becomes oxygenated while the systemic circulation loop is the
loop that provides the oxygen rich blood to the rest of the body.
Figure 1.0 - The Human Circulatory System
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 3
Figure 1.1 – Clogged Blood Vessel
Blood vessels are the part of the circulatory system that transports blood
throughout the body. Blood vessels become clogged when a material known as plaque
builds up on the interior walls of the blood vessels. Composed of fats, cholesterol,
calcium, and other blood cell waste, the build up of plaque causes the heart to work
harder due to the increase in resistance to flow through the blood vessel. Typical results
of clogged blood vessels are heart attack, stroke, and arrhythmia (irregular heart beat). In
order to reduce the risk of heart attack and stroke due to clogged blood vessels,
biomedical engineers and doctors have designed devices such as stents, balloon catheters,
and catheters to open clogged blood vessels and allow for normal flow conditions to
resume.
Figure 1.2 Balloon Catheter Applications
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 4
Blood Vessel Flow Characterization Overview
The flow of fluid particles can be described as either turbulent or laminar.
Laminar flow is flow in which the fluid particles move in smooth layers, or laminas.
Turbulent flow is flow in which the particles rapidly mix as they move along due to
random three dimensional velocity fluctuations. Flow within a blood vessel is
characterized as turbulent flow. Though turbulent flow is not ideal for most practical
applications, it is desirable for blood flow because the random mixing allows for all of
the blood cells to contact the walls of the blood vessels to exchange oxygen and other
nutrients. Flow can be characterized as either laminar or turbulent through the evaluation
of the Reynolds Number for the given flow conditions. Reynolds Number is calculated
by the equation:
VD
Re 

Where:
ρ = fluid density
V = fluid velocity
D = Tube Diameter
μ = kinematic viscosity
For most applications, if the Reynolds Number is greater than 2300, flow is
characterized as turbulent. If the Reynolds Number is less than 2300, flow is
characterized as laminar. For example, blood flow in the aorta has a Reynolds Number
of around 3400. This is an example of turbulent flow.
Figure 2.0 – Turbulent vs. Laminar Flow
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 5
Resources


Introduction to Fluid Mechanics. 6th Edition. Fox, McDonald, Pritchard.
www.wikipedia.com
Image Resources

Figure 1.0: http://gonatural.com.ph/herbalblog/wpcontent/uploads/2007/07/Circulatory%20system.jpg
Date: January 29, 2009
Time: 9:48 pm

Figure 1.1: http://images.google.com/imgres?imgurl=http://www.biotechweblog.com/50226711/images/atherosclerosis.jpg&imgrefurl=http://www.agorav
ox.com/article.php3%3Fid_article%3D4888&usg=__fHScGPEoARdANkr2qIXN
PyLb5Wk=&h=200&w=250&sz=10&hl=en&start=1&tbnid=dStyit3sgN5bkM:&
tbnh=89&tbnw=111&prev=/images%3Fq%3Dclogged%2Bblood%2Bvessel%26
gbv%3D2%26hl%3Den%26sa%3DG
Date: January 29, 2009
Time: 9:48 pm

Figure 1.2: http://www.heart-stint.com/images/angio1a.gif
Date: January 31, 2009
Time: 2:38 pm

Figure 2.0:
http://www.cheng.cam.ac.uk/research/groups/electrochem/JAVA/electrochemistr
y/ELEC/l2fig/laminar.gif
Date: January 29, 2009
Time: 9:48 pm
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 6
Activity Preparation Guide – Clogged Blood Vessel Activity
Overview
This kit contains activities for students to gain a better understanding of how the
heart functions and operates for a typical individual and how engineers study heart
behavior in order to design and fabricate medical instrumentation and prosthetics to
improve the quality of human life. It further explains how the heart pumps and circulates
blood to and from the body as the centerpiece of the circulatory system. The main focus
of this kit is the circulatory system, conditions that lead to heart attacks and strokes, and
biomedical engineering solutions.
Learning Objectives
By the end of this lesson, students should be able to…




Explain what laminar and turbulent flow is.
Explain what it means for a blood vessel to become blocked.
Identify bioengineering tools and instruments that can open a blocked blood
vessel and increase blood flow.
Explain how engineering contributes to problem solving in the body.
Engineering Connection
Engineers work with Doctors and Surgeons to create biomedical instrumentation
to measure and record human biological functions such as heart rates and blood pressure
in order to identify and eliminate possible design parameters when developing such
biomedical prosthetics and instruments as catheters, balloon catheters, and stents. Just as
an engineer must acquire data from a biological system in order to model, design, and
fabricate a new design, the students participating in this activity will analyze and asses
the flow characteristics of blood flow through blocked and unblocked blood vessels, and
then design and develop devices and approaches to unclog a blood vessel.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 7
Activity Descriptions
A.) Introductory Discussion: Bioengineering and the Heart: 15 Minutes
This discussion will be an introductory discussion to the topic of
bioengineering and the broad scope that this discipline of engineering
encompasses. This discussion will further examine the function of blood
vessels and the conditions that arise within them that lead to strokes and heart
attacks. Additional to this, students will be introduced to the concepts of
laminar and turbulent flow and how such flow conditions may impact the
vessels that they are encompassed in. After this part of the discussion,
students will be introduced to biomedical solutions to prevent heart attacks
and improve blood flow such as catheters, balloon catheters, and stents.
B.) Circulatory System Blood Flow Activity: 15 Minutes
This activity will allow students to observe the flow of blood through a
miniature circulatory system for both blocked and unblocked flow conditions.
During this activity, students will pump “blood” through the miniature setup
for unblocked conditions and observe how easy the heart is able to pump
blood through the blood vessels when the vessels are not blocked. After doing
this, the students will repeat the exercise for the blocked flow conditions and
observe how the heart must work much harder in order to pump blood
throughout the circulatory system now that the blood vessels are blocked.
After completing both of these exercises, the students will begin to
hypothesize various ways in which they will be able to unblock the blocked
blood vessels and increase the flow rate through the circulatory system.
C.) Blood Vessel Flow Analysis and Testing: 15 Minutes
This activity will allow the students to test their hypothesized solution to the
blocked blood vessel as developed from part B of this activity. The students
will be given an unblocked blood vessel and a blocked blood vessel. The
students participating in this activity will first analyze the blood flow through
the unblocked blood vessel and determine the flow rate through this blood
vessel. The students will then do the same for the blocked blood vessel and
determine if the flow rate is greater or less than that of the unblocked blood
vessel. In order for the students to calculate the flow rate through the blocked
and unblocked blood vessel, they will need to apply this simple equation:
FlowRate  FluidVolum e  Time
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 8
From this equation for flow rate, the students will be able to calculate and
compare the values for both the blocked and unblocked blood vessels.
After completing their calculations, the student will then design and
determine the best engineering solution to increase the flow rate of the
blocked blood vessel. To complete this “design challenge” activity, the
student will be given materials to construct a stent, catheters, etc. Due to
the number of students participating in each group, the members of each
group will be given engineering titles as part of an engineering team.
Such engineering titles will be that of mechanical engineer, fluids analyst,
engineering data analyst, and a test engineer.
D.) Closing Discussion: Biomedical Applications: 5 Minutes
This closing discussion will tie together the concepts presented throughout the
activity by giving examples of how engineers are currently working on such
technological advances in the field of biomedical engineering as stents,
artificial heart valves, and artificial hearts. During this discussion, students
will be presented with numerous visuals to aid in their ability to understand
the topics and devices being presented to them.
E.) Engineering Team Roles:
Mechanical Engineer – Develops a solution to increase the flow velocity
based the materials given along with the assistance of the other team
members.
Fluids Engineer – Calculates and determines the Reynolds Number for
the unblocked and blocked blood vessel.
Engineering Data Analyst - Collects data throughout the experiment.
Test Engineer - Supervises and assists in the setup of the blood vessel test
configuration.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 9
New York State Learning Standards
MST
1
E
Engineering
Design
Discuss how best to test the solution; perform the test under teacher supervision;
record and portray results through numerical and graphic means; discuss orally
why things worked or did not work; and summarize results in writing, suggesting
ways to
make the solution better
MST
1
E
Engineering
Design
Plan and build, under supervision, a model of the solution using familiar materials,
processes, and hand tools
New York State Health Learning Standards
a.) Standard 3: Resource Management
1. Students: Distinguish between invalid and valid health information,
products, and services.
2. Students: Analyze how the media and technology influence the selection
of health information, products, and services.
New York State Technology Learning Standards
a.) Standard 1: Engineering Design
3. Engineering design is a repetitive process involving modeling,
optimization, and finding the best solution within the given constraints
that is used to develop technological and innovative solutions to technical
problems.
4. Students:
• Activate devices.
• Recognize why an object or choice is not working properly.
• Recognize how a defective simple object or device might be fixed.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 10
• Under supervision, manipulate components of a simple,
malfunctioning device to improve its performance.
• Design a structure or environment.
b.) Standard 5: Management of Technology
- Students: Must work cooperatively with others on a joint task.
New York State Math Learning Standards
a.) 6th Grade Standards
5. Students will apply and adopt a variety of appropriate strategies to solve
problems.
6. Students will organize and consolidate their mathematical thinking
through communication.
7. Students will determine what can be measure and how, using appropriate
methods and formulas.
8. Students will collect, organize, display, and analyze data.
New York State Science Learning Standards
a.) Intermediate Standard 1: Analysis, Inquiry, and Design.
9. T1.1a: Identify a scientific or human need that is subject to a
technological solution which applies scientific principles.
10. T1.3a: Identify alternative solutions base on the constraints of the design.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 11
Resources
A.) Wikipedia: www.wikipedia.com
B.) Introduction to Fluid Mechanics. Fox, McDonald, and Pritchard. 6th Edition.
C.) National Heart and Lung Institute:
http://www.nhlbi.nih.gov/health/dci/Diseases/HeartAttack/HeartAttack_WhatIs.h
tml
D.) http://www.emsc.nysed.gov/ciai/mst/techmap/map.html
E.) http://www.albanyinstitute.org/Education/standards.pdf
F.) http://www.nylearns.org/standards/browsestandards.asp
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
The Circulatory System
DURATION
45-50 Minutes
CONCEPTS
Bioengineering
Circulatory System
Blood Flow Characteristics
Biomedical Applications
Page 12
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 13
Bioengineering Discussion: (5.0 Minutes)
Background Information:
Bioengineering is the application of engineering principles to address challenges
in the fields of biology and medicine. Bioengineering applies the principles of
engineering design to the full spectrum of living systems.
Group Discussion:
Bioengineering Background
(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)
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.
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 any other living system.
 Examples of products that have been bioengineered are:
o Artificial Hearts
o Artificial Heart Valves
o Stents
o Catheters
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Circulatory System Discussion:
Page 14
(5.0 Minutes)
Background Information:
Your heart is the centerpiece of the circulatory system that pumps blood
throughout your entire body. In order to move blood throughout the body, the heart must
act as a pump. As with all other pumps, it can become clogged, break down, and need
repair. This is why it is critical that engineers know how the heart works and functions in
conjunction with the rest of the body in order to design solutions to help keep the heart
working properly.
Simplified Definitions:
A.) Atheroma (ath·er·o·ma) Plaque – A build up of fat and cholesterol from cell
debris on the interior walls of blood vessels.
B.) Arrhythmia – An abnormal heart beat.
C.) Heart Attack - A heart attack occurs when blood flow to a section of heart
muscle becomes blocked.
D.) Stroke – A stoke is a loss in brain function due to the rapid disturbance in the
supply of blood to the brain.
Group Discussion:
Clogged Arteries and Biomedical Solutions
(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)
What does it mean when a blood vessel is clogged?


Atheroma Plaque builds up on the interior walls of the artery.
Prevention of normal blood flow due to a buildup of waste.
What is atheroma plaque made of?




Calcium
Fat
Cholesterol
Blood Cell Waste
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 15
Once a blood vessel becomes blocked, is it easier or harder for the blood to flow?

It becomes harder for the blood to flow once the blood vessel becomes blocked.
What do you think is an effect of a blocked blood vessel?



Impedes blood flow or stops it all together.
Result in a heart attack.
Results in stroke or heart arrhythmia.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 16
Blood Flow Activity – 15 Minutes
Learning Objectives
By the end of this exercise, students should be able to…
1. Describe that, if the circulatory system has no clogs, the heart does not have to work very
hard to pump blood throughout the body.
2. Describe that, if the circulatory system is clogged, the heart has to work harder,
generating a greater force to pump the blood throughout the body. A clogged system
may lead to stroke, heart attacks, or abnormal heart beats.
Materials
1. 1 clogged system per group.
2. 1 unclogged system per group.
3. 1 activity worksheet per student.
Procedure
1. Get the students into 5 groups.
2. Have the students pump water through the miniature circulatory system for the unclogged
configuration.
3. Once each student has had an opportunity to pump water through the system, have the
students record their observations on the given worksheet.
4. Next, have the students pump water through the miniature circulatory system for the
clogged configuration.
5. Once each student has had an opportunity to pump water through the system, have the
students record their observations on the given worksheet.
6. Now that the students have evaluated both the clogged and unclogged circulatory
systems, discuss with the class their findings and observations in terms of the force
required to pump the fluid for the clogged and unclogged setup and how the pumping
force the had to apply compares to the force required by the heart to pump blood.
Expected Results
1. The force required to pump the fluid through the unclogged system should be less than
the force required to pump the fluid through the clogged system.
2. The amount of force required to pump the fluid through these configurations is
representative of the force output required by the heart to pump blood through the
circulatory system.
End Blood Flow Activity
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 17
Miniature Circulatory System Worksheet
The Unclogged Circulatory System:
How hard was it to pump the fluid through the system?
Did the fluid flow freely through the “blood vessels”?
Are there any other observations?
The Clogged Circulatory System:
How hard was it to pump the fluid through the clogged system?
Did the fluid flow freely through the “blood vessels”?
Are there any other observations?
The Engineering Evaluation:
Was it harder to pump the fluid through the clogged or unclogged circulatory system?
What do you think will be a result of the clogged circulatory system?
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Flow Characterization Discussion:
Page 18
(5.0 Minutes)
Background Information:
The flow of fluid particles can be described as either turbulent or laminar flow.
Laminar flow is flow in which the fluid particles move in smooth layers, or laminas.
Turbulent flow is flow in which the particles rapidly mix as they move along due to
random three dimensional velocity fluctuations. Flow within a blood vessel is
characterized as turbulent flow. Though turbulent flow is not ideal for most practical
applications, it is desirable for blood flow because the random mixing allows all the
blood cells to contact the walls of the blood vessels to exchange oxygen and other
nutrients.
Simplified Definitions:
A.) Laminar Flow – The smooth flow of fluid particles along a straight line.
B.) Turbulent Flow – The rapid and chaotic flow of fluid particles along a straight
line.
Group Discussion:
Laminar and Turbulent Flow
(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)
How would you describe the flow of water out of a drinking fountain?



Smooth
Gentle
Slow
How would you describe the flow of water out of a fire hose?




-
Very Fast
Chaotic
Rough
Hard
Explain to the students that the drinking fountain is an example of
laminar flow. Laminar flow is when the flow of a fluid is very smooth.
-
Explain to the students that the fire hose is an example of turbulent flow.
Turbulent flow is when the flow of a fluid is very chaotic, fast, and wants
to go in many directions.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 19
What do you think the flow of blood through a blood vessel is? Is it Laminar or
Turbulent?

Flow within a blood vessel is characterized as turbulent flow.

Explain to the students that blood travels at about 23 mph through their
blood vessels and that the heart pumps 5L of blood every minute
throughout the body.
Do you think this is good or bad for your blood vessels? And why?


This good for your blood vessels.
It is desirable for blood flow because the random mixing allows all the blood
cells to contact the walls of the blood vessels to exchange oxygen and other
nutrients.
Why do you think an Engineer might need to know about how blood flows within a
blood vessel?



To determine if the flow is laminar or turbulent.
To model blood flow accurately.
To design and develop medical instruments to improve blocked flow.
Explain to the students these three biomedical applications utilized to increase the flow
of blood through clogged and blocked blood vessels:
A.) Catheter – A tube inserted into a blood vessel so as to increase the flow of
blood.
B.) Balloon Catheter – A type of soft catheter with an inflatable balloon at its tip that
is used to enlarge a narrow opening within the body.
C.) Stent – A tube inserted into the body to prevent or counteract a localized flow
constriction.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 20
Blood Vessel Flow Analysis Activity
Learning Objectives
By the end of this exercise, students should be able to …
1. Describe what laminar and turbulent flow is.
2. Identify biomedical solutions and applications to unclog a clogged blood vessel.
3. Explain how engineering contributes to problem solving in the body.
Materials
1. 1 Water collection bin.
2. 1 Plastic measuring cup.
3. 1 Tripod stand.
4. 1 Clogged blood vessel.
5. 1 Unclogged blood vessel.
6. 1 Stopwatch.
7. 1 Activity worksheet per engineering team.
8. 1 Can of playdoh.
9. 1 Package of catheter supplies.
Procedure
1. Have the students get into 5 groups, with each student assuming one of the
engineering roles.
2. Set up the unclogged blood vessel on top of the tripod stand. Next, place the
water collection bin in front of the unclogged blood vessel.
3. Take the measuring cup, and fill it with 2 cups of water. Next, in a steady
manner, have a student poor the water through the blood vessel and into the water
collection bin. While one student pours the water, another student should be
timing the amount of time it takes for the water to flow through the vessel and
into the bin. This value should be recorded on the activity worksheet. During this
step, another student should take the can of playdoh and clog the other blood
vessel in preparation for the next exercise.
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 21
4. Set up the clogged blood vessel on top of the tripod stand. Next, place the water
collection bin in front of the clogged blood vessel.
5. Take the measuring cup, and fill it with 2 cups of water. Next, in a slow and
steady manner have a student poor the water through the clogged blood vessel and
into the water collection bin. While one student pours the water, another student
should be timing the amount of time it takes for the water to flow through the
vessel and into the bin. This value should be recorded on the activity worksheet.
6. After conducting the blood vessel flow analysis for both the clogged and
unclogged blood vessel, the students should calculate the flow rate for the clogged
and unclogged blood vessel from the equation given on the activity worksheet.
7. Next, the students should take the materials out of the package of catheter
supplies. From the materials given, the students should construct a balloon
catheter. Once constructed, have the students insert the catheter into the clogged
blood vessel. Once setup, have the students repeat step 5 of this procedure and
record the amount of time it takes for the water to flow through the vessel now
that the catheter has been inserted.
8. After conducting the blood vessel flow analysis for the application of the balloon
catheter, have the students recalculate the flow rate from the given equation on the
activity worksheet.
9. The students have now completed all the exercises and should finish filling out
the activity worksheet. Once completed, discuss with the class the findings of
their experiments.
Expected Results: These results are based on average values taken from three trails of
testing.
Unclogged Blood Vessel Results
Volume
500 mL
Time
12.27 s
Flow Rate
40.75 mL/s
Clogged Blood Vessel Results
Volume
500 mL
Time
16.43 s
Flow Rate
30.43 mL/s
Clogged Blood Vessel with Balloon Catheter
Volume
Time
500 mL
14.26 s
Flow Rate
35.06 mL/s
End Blood Vessel Flow Analysis Activity
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 22
Blood Vessel Flow Analysis Worksheet
Governing Equation: Flow Rate = Volume ÷ Time
Analysis:
Unclogged Blood Vessel Analysis:
Volume
Time
Flow Rate
Time
Flow Rate
Clogged Blood Vessel Analysis:
Volume
Clogged Blood Vessel with Balloon Catheter:
Volume
Time
Flow Rate
Post Analysis Questions:
Is the flow rate greater for the clogged or unclogged blood vessel?
Which blood vessel do you think is turbulent flow and which do you think is laminar?
What part of your design to unclog the blood vessel did you like? What part of the
design would you change or improve if you were to do this experiment again?
TEAK – Bioengineering
Clogged Blood Vessel Lesson Plan
Page 23
Concluding Discussion
(Pick and choose depending on student questions/responses to the activity worksheet)
Was the flow rate greater for the clogged blood vessel or the unclogged blood vessel?

The flow rate should be greater for the unclogged blood vessel.
Which is an example of turbulent flow? The clogged or unclogged blood vessel?

The clogged blood vessel is a better representation of turbulent flow conditions.
However, in reality, flow through an actual blood vessel is always turbulent.
Was the balloon catheter a good method for increasing the flow rate through the blood
vessel?


In actual practice, yes, catheters will significantly increase blood flow and
decrease the risk for stroke and heart attack. For this exercise, the difference in
values will be minimal.
Balloon catheters are a good application when unclogging blood vessels around
the heart, or within larger branches of the body such as the arms and legs.
What do you think are some other possible solutions to blocked flow in blood vessels?


Stents
Medication