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					                         Observing Atherosclerosis
RET Program: Summer 2005
RET Teacher: Pamela Maurer

Course(s):    Biology Honors, AP Biology, Anatomy & Physiology Honors
Grade levels: 9-12

Sunshine State Standards:
SC.F.1.4.1 Knows that the body processes involve specific biochemical reactions governed by
biochemical principles.

SC.H.1.4.1 Knows that investigations are conducted to explore new phenomena, to check on
previous results, to test how well a theory predicts, and to compare different theories.

SC.C.2.4.6 Explains that all forces come in pairs commonly called action and reaction.

SC.F.1.4.1 Knows that the body processes involve specific biochemical reactions governed by
biochemical principles.

SC.F.1.4.4 Understands that biological systems obey the same laws of conservation as physical
systems.

SC.F.1.4.7 Knows that organisms respond to internal and external stimuli.

SC.E.2.4.7 Understands the importance of a sense of responsibility, a commitment to peer
review, truthful reporting of the methods and outcomes of investigations, and making the public
aware of the findings.

Purpose: Students will physically observe plaque accumulation in an artery and its effect
        on the rate of blood flow.

Objectives:
   Students will develop a model to visually observe the change in blood flow rates
      between healthy and unhealthy arteries.
   Students will learn about cardiovascular disease and how it affects the
      homeostasis of the human body.
   Students will calculate data they have collected and graph results.
   Students will use problem solving skills to design a system that will demonstrate
      the flow of blood
   Students will determine the relationship between resistance and pressure of a
      biological system.




                                                                                              1
Background

   According to the American Heart Association, 38% of all deaths in the year 2002
were due to cardiovascular disease (CVD). This disease affects males slightly more than
females and it even affects people under the age of 65. Although deaths due to CVD
have been declining it is still one of the leading causes of death in the United States today
    Over time plaque may form within an artery exposed to stress. The stress could be
caused by hypertension, chemicals in the blood, bacterial infections, viral infections, or
physical damage to the vessel. Damage to the vessel causes a continued response by the
immune system and accumulation of fibrin, calcium, cholesterol, proteins, and other
particles within the blood to the site. This accumulation of particle eventually will
restrict blood flow through that vessel which minimizes the amount of oxygen to the
surrounding tissues and causes restriction and stress on the other parts of the
cardiovascular system. If atherosclerosis is not treated the vessel eventually looses its
elasticity and hardens as it forms scar tissue. This is not only damaging to the vessel but
to the surrounding tissues as well.
        Preventative measures should be a part of ones daily routine to lower their risk of
heart disease. Since this disease is a result of many years of damage, one should prevent
their risk by following a healthy diet, exercise plan, not smoking, and eliminating as
much stress as possible. There are many treatments for CVD including surgical measures
and by prescription medications.

Materials
Two (2ft.) Clear vinyl tubing                                     Permanent marker
           (1 in. diameter)                                       Funnel
Two 2-Liter plastic bottles                                       Paper towels
Hot glue gun                                                      1-Liter graduated cylinder
Hot glue                                                          Masking tape
Water                                                             1 metal hose clamp
Glycerine (600 mL)                                                Flathead screwdriver
Red food dye (~1mL) (optional)                                    Scissors or scalpel
Stop watch

Tubing=artery
Hot glue=fibrin, calcium, proteins, minerals, cholesterol, & tissues
Water & glycerol=blood


Procedure

Day 1** – Making a clogged artery.
   1. Obtain one of the 1 inch diameter clear tubes to use as your “clogged artery”.
   2. Using a glue gun add glue to one end of the tube.
             a. Be sure to leave enough room for it to fit over the mouth of the bottle.
             b. Add glue in increments allowing some time to dry in between.
             c. Pinch the tube to help glue accumulate into a confined area or it will
                 continue to spread thin.
**This step can be done on the same day as the lab if you do this first and let other members work on the
rest of the preparations


                                                                                                            2
Day 2
Part A – Making simulated blood (1 liter)
    1. Mix 400 ml of glycerine with 600ml of water.
    2. Label one 2-liter “A” and the other “B”
    3. Remove caps from the bottles including the ring.
    4. Using scissors or scalpel, cut small opening (~1cm) in bottle A and cover with
       tape to prevent leakage.
    5. Pour simulated blood into one of the 2-Liter bottles.
    6. Add approximately 1-mL red food dye replace cap and mix thoroughly.


Part B – Making the system
    1. Place the metal hose clamp over the opening of bottle A.
    2. Place one end of the “healthy artery” (hose without the glue) over the opening of
       bottle A and tighten the clamp over the end of the hose to create a tighter seal.
    3. Attach opposite end of healthy artery over bottle B.




Part C – Observing the system
    1. Slant bottle A so that the cut out opening is above the fluid and remove the tape
       over the opening.
    2. Have one lab partner flip the full bottle upside down, begin timing the flow until
       the second bottle is full. Record data in table 1.1 for the healthy artery. (Be sure
       to take note of when timing begins so that you start it at the same motion with the
       next trial)
    3. Remove healthy artery from bottle A and attach the unhealthy artery using the
       same steps as before (in part B)
    4. Repeat steps 1-2 from above (Part C)




                                                                                           3
Data & Observations

Table 1.1 Flow time and rate of arteries.
  Artery       Blood vol.     Flow time                         Flow rate     Observations
 condition        (ml)        (seconds)                         (ml/sec.)
                  1000
Healthy

                                       1000
Unhealthy



Table 1.2 Differences in flow rate.
                           Artery condition              Flow rate            Difference ∆ in
                                                     (ml/sec) table 1.1     Flow rate (ml/sec)

Healthy (H)

Unhealthy (U)

Table 1.3 Calculate amount of blockage

 A) Blood flow (U) x 1                        = ______
     Blood flow (H)


 B) 1 - __________(answer from A) = __________ X 100 = ___________% blocked


Graph 1.1 – The relationship between plaque build up and flow rate
  Blood flow rate (ml/s)




                                 Artery Condition


                                                                                                 4
Analysis
  1. Using data from table 1.2 create a bar graph. Be sure to label appropriately and
      create a legend.
  2. Determine the relationship between the amount of plaque build up and flow.
  3. Did you observe any difference in flow when running the blood through arteries
      with plaque? Explain how this would affect a person physiologically.
  4. Predict what would happen to a person who has plaque completely filling an
      artery.
  5. Determine the relationship between the amount of artery blockage versus the rate
      of blood flow.
  6. List and describe any complications you lab group encountered with this lab.


Questions
  1. Consider the change in flow between all the arteries simulated here, if this artery
      was the descending aorta how might the heart be affected?
  2. What was the purpose of mixing glycerine with water rather than just sending
      water through the system?
  3. What are side effects of having a clogged artery?
  4. Consider a patient with serious artherosclerosis, their bodily tissues and organs
      still need enough blood supply to maintain homeostasis.
           a. Describe how the heart will try physiologically to accommodate for this
               obstacle.
           b. Describe how the heart will anatomically change during this time.
  5. What are some methods of treating atherosclerosis?
  6. Differentiate between atherosclerosis and arteriosclerosis.
  7. Considering the excretory system, how might it be affected by atherosclerosis?
  8. How would you expand on this lab?




                                                                                           5
Teacher notes:

Preparation time: 15 minutes
Lab time: 1 – 1.5 hours

Preparation and lab considerations:
   1. You may want to clog the “unhealthy tubing” yourself prior to the lab or you may
       want to save the unhealthy tubing made in one class to use for all classes.
   2. You do not have to use red dye and may just want to leave the liquid clear to
       avoid staining.
   3. This lab could be done in one day if the unhealthy artery is made beforehand.


Materials:
    Alternatives may be used for the glue gun such as caulking or any other drying
       agent.
    Tubes can be cut and reused or saved and reused.

      Clear tubes: Cut tubes into 2ft sections & set out materials.



Additional resources:
   1. Choose lab area with a sink for easier clean up.
   2. Quicktime video demonstrating artherosclerosis,
       http://www.atenmedicalart.com/anim/athero.htm#


Accommodation for students with special needs:
   1. Assign lab tasks according to each student’s ability level considering tasks such as
      constructing, designing, calculations, and reading procedures.
   2. You may want to demonstrate how this works with your own model during your
      prelab discussion.




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