Download Instructor Preparation Guide: Blood Vessel Activity

Multidisciplinary Senior Design I
TEAK – Bioengineering
Biomedical Engineering: The Circulatory and Respiratory Kit
Instructor Preparation Guide:
Blood Vessel Activity
Bioengineering Overview
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.
Circulatory System Overview
The main components of the human circulatory system are the heart, blood, and
the blood vessels which 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 in which provides the oxygen rich blood to the rest
of the body.
Figure 1.0 - The Human Circulatory System
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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 build of waste 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
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Blood Vessel Flow Characterization Overview
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 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:
ρ VD
Re =
µ
Where:
ρ = fluid density
V = fluid velocity
D = 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.
Figure 2.0 – Turbulent vs. Laminar Flow
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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
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