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Cardio Kickers & Heart Bodies
Activity 2B
Activity Objectives:
Using a model of the heart, students will be able to:
u examine the structure and function of the human heart
u compare and contrast the capacity of cardiac muscle and
skeletal muscle
u kinesthetically explore the concept of blood pressure
u analyze the similarities between a human heart and the
heart model
u discuss limitations of the heart model compared to the
human heart
Activity Description:
Your students will marvel at the heart model made from plastic bottles and tubes! In doing this activity, students will understand how the heart keeps blood circulating through our bodies. While listening to heart sounds, students will use the heart model to pump “blood” at the proper rate and rhythm. As they work the model, your students will begin to better grasp the abstract concept of blood pressure. While squeezing the “ventricles” students will feel the pressure they are work-ing against. As the activity progresses and a clamp is applied to simulate blood vessel blockage, students will feel how much harder it is for the heart to pump. This leads to discussion on how hard the heart must work when healthy, let alone when vascular disease is present.
Activity Background:
The heart, blood and blood vesselsmake up the circulatory system,
also called the cardiovascular system. The primary job of the circulatory
system is to deliver blood to body cells. This job is essential, because blood carries oxygen and nutrients required for our cells to stay alive. The blood is also involved in carrying carbon dioxide and other waste products away from the cells. The heart is a hardworking pump that sends blood through blood vessels to every organ, tissue and cell in our bodies.
The human body actually has two circulation pathways; they are
pulmonary circulationand systemic circulation. Pulmonary circulation
is the short pathway from the heart to the lungs and back to the heart again. Pulmonary circulation is handled by the right side of the heart.
Systemic circulationsends blood from the heart to all parts of the body and then back to the heart again; a much longer pathway. The left side of the heart pumps blood out into the systemic circulation. See Figure 1.
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The heart is a hollow, muscular organ made of cardiac muscle. It’s job is to pump blood throughout the body, usually beating 60 to 100 times every minute. The heart constantly receives messages from the body so the amount of oxygen can be regulated depending upon oxygen needs. We require much less oxygen
during rest than during exer-cise or high-stress events. The heart has four chambers; the two upper chambers are called the right and left atria(atrium; singular) and the two lower chambers are called the right and left ventricles. The atria receive blood coming into the heart and the ventricles pump blood out of the heart. See
Figure 2. If you have ever lis-tened to your heart with a stethoscope, you have heard distinct sounds that occur when the ventricles contract. These sounds are often described as “lub-dub”.
Figure 1 Pulmonary and Systemic Circulation
PULMONARY
CIRCULATION
S
YSTEMICC
IRCULATION Left Atrium Left Ventricle Right Atrium Right VentricleFigure 2 General Anatomy
of the Heart
Left Ventricle Left Atrium Right Ventricle Right Atrium AORTA Pulmonary Veins (from left lung) Large Vein(from upper body) Pulmonary Artery (to left lung) Pulmonary Artery (to right lung) Large Vein (from lower body)
KEY Blood Flow Tricuspid
Valve
Bicuspid Valve
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In order to keep blood moving in the correct direction and to prevent backflow, the heart contains valves. The tricuspid valveseparates the
right atrium and the right ventricle. The bicuspid valveseparates the left
atrium and the left ventricle. The pulmonary valve separates the right
ventricle from the pulmonary artery going to the lungs. The aortic
valveseparates the left ventricle from the aorta, going to the body. See Figure 2.
Blood vessels that carry blood to the heart are called veins; blood vessels that carry blood away from the heart are called arteries. In general, veins carry oxygen-poor blood and arteries carry oxygen-rich blood. Excep-tions are the pulmonary vein, which carries oxygen-rich blood and the
pulmonary artery, which carries oxygen-poor blood. Capillariesare tiny
blood vessels that join arteries to veins. The capillaries are so tiny that only one red blood cell at a time can pass and the capillary walls are only one cell thick. It is in the capillaries where the exchange of oxygen and carbon dioxide takes place, so they are very important to the job of circulation.
When the ventricles contract, blood is squeezed much like water in an eyedropper bulb. Blood pushes against the heart walls and valves with increased pressure. Eventually, blood moves through the path of least resistance, out the
arteries. In the case of pulmonary circulation, oxygen-poor blood moves
out of the right ventricle through the pulmonary artery to the lungs. In the lungs, blood picks up oxygen and releases carbon dioxide. The oxygen-rich blood returns to the left atrium through the pulmonary
vein. In systemic circulation, oxygen-rich blood moves from the left
ventricle out the aorta to all parts of the body. In the body, blood delivers oxygen to body cells and picks up carbon dioxide waste. The blood is now oxygen-poor and returns to the heart through the superior vena cava into the right atrium. See Figure 2. In this way, the heart acts as two separate pumps combined into one!
Activity Materials:
(per model)The heart model will need to be assembled prior to doing the activity with students.
20 ft—5/8 inch (outside diameter) x 1/2-inch (inside diameter) clear
vinyl tubing; WATTS 42143720; found in plumbing section at
hardware store
10 ft—7/8 inch (outside diameter) x 5/8-inch (inside diameter) clear
vinyl tubing; WATTS 42143912; found in plumbing section at
hardware store
15 ft—1 inch, 30 mm black SealWrap
™
Repair TapeEnergy-ActivatedTechnology 60 EL Tape; US Patent #5914371; found in hardware department of Wal-Mart
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1 cork/stopper hole bore tool set
1 bag—14 mm decorative marbles; found in florist section at craft store 1— 16 mm standard marble
1— needle nose pliers 1— metric ruler
1— straight edge with safety feature 1— cutting board
1— adult size pair of scissors 1— large serrated kitchen knife 1— marking pen
1— 1 L water bottle with sport top 3— 4 oz travel bottles
2— 2 oz travel bottles
4— 4-inch 18 lb. tensile strength cable ties 6— 7.5-inch 50 lb. tensile strength cable ties
1— Project display board or 4 ft. section of Pegboard 1— funnel
1— electric kettle
1— ceramic bowl or glass measuring cup
Activity Materials:
Instructions for assembling the Heart Model:
I. Making Openings in the Bottles
- Refer to Figure 3 Making Openings in Bottles1. You will need to build this at your kitchen table or in a room with a sink.
2. Remove the lids from the travel bottles.
3. Remove the pull sport top on the 1L water bottle.
4. Find the 1.5 cm cork/stopper bore and bore a hole in the bottom of the 1L water bottle. If the bottom is too stiff, try heating the bore with a match or lighter before using. 5. Use the 1.5 cm bore tool to put a
hole through the bottom of both 2oz travel bottles.
6. Use the 1.5 cm bore tool to put a hole as close to the bottle opening at the top of a 4 oz travel bottle.
7. Repeat step 6 with a second 4 oz travel bottle.
8. Use the 1.5 cm bore tool to make an opening 2.5-3.5 cm from bottom of the third 4 oz bottle. Make the hole on the side rather than the front or back.
Figure 3 Making
Openings in Bottles
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II. Making One-Way Valves
- Refer to Figure 4 Making One-way Valves9. Gather the scissors, ruler, the 16 mm marble, SealWrap
™
, markingpen, kettle with water, pliers, and 5/8-inch tubing 10. Turn the kettle on to boil water
11. Measure, mark and cut 8-5 cm length sections of tubing 12. Place the marble in the measuring cup/bowl
13. Once the water boils pour enough of the hot water in the measuring cup to cover the marble. Allow the marble to heat up a moment 14. Take one of the 5 cm sections and push it on the marble until the
marble is about half way in the opening of the tube. Insert only half
of the marble in so you can get it back out!
15. With the marble still in the opening of the tube, run the tube section under cold water. It is recommended that you use the pliers to remove the tube from the hot water if it is too hot to hold.
16. Keep running under cold water until the marble is cooled. Remove the marble by squeezing the tube behind the marble toward the opening in the tube.
17. Repeat steps 12-16 with 3 more of the 5 cm sections. This process is the first step in making a one-way valve. This procedure makes a seat for the smaller marble in order to prevent back flow
under pressure.
18. On the backside of the SealWrap
™
mark off 8-7 cm lengths. Cut the7cm lengths. Cut each length through the center length-wise.
19. Peal off the backing on one of the SealWrap
™
strips. Begin stretchingthe strip length-wise and then pulling from the sides. This warms and stretches the strip in order to cover the tubing.
20. Take one of the pieces of tubing that you stretched with a marble. Start near the opening that was stretched. Don’t cover the opening, start several mm below and start wrapping the outside of the tube. Pull tightly to make sure there is strong adher-ing effect with the
rubber. Use another pre-cut strip.
21. Repeat steps 19-20 for the other three pieces of tubing that you have already prepared.
Figure 4 Making One-Way Valves
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22. Take the four 4-inch cable ties and using the scissors cut off the locking end piece off of each. Next cut the non-grooved sections off the cable ties.
23. Take another SealWrap
™
strip and one of the remaining 4 sectionsof tubing. Stretch the strip until it is thin and 2-3 cm wide on the sides. Wrap one layer around the tube pulling tight enough to get the strip to adhere.
24. Get one of the 4 inch cable ties that you have prepped. Fold it and lay over one end of the tube you just prepped. Hold the cable tie on the sides of the tube and finish wrapping the rubber strip around. Use another strip to ensure the cable tie remains in place. It is fine if the part of the cable tie over the tube opening bulges a little. This will prevent the marble from blocking the tube. This is the second part of building a one-way valve!
25. Repeat steps 23-24 with the remaining tube sections and cable ties.
III. Connecting the Bottles
- Refer to Figure 5 Connecting the Bottles26. Get the two 4 oz bottles with the extra hole near the top.
27. Take one of the pieces of tubing with the cable tie on it and push it through the original opening in the bottle. You may have to fold the tube in to make it small enough to pass into the opening. Once the tube is in you may notice that part of the tube seems collapsed. Use the pliers and push the sides of the tube back in place. Make sure the tube is in tightly by giving it a tug. You should feel no slipping out of place.
28. Repeat step 27 for the second 4 oz bottle. You will use these two bottles in the following procedures.
29. Next take two of the tubes with one end stretched by the marble. Take the non-stretched end, fold it and insert into the hole you cut near the top. If the tube remains collapsed in the opening then use the pliers to stretch the walls of the tube back into place.
30. Repeat step 29 for the other 4 oz bottle.
31. You may want to add more strips of rubber. Just cut more strips, stretch and wrap. The tighter the better.
32. Get the 2-2 oz bottles.
33. Next take one of the two remaining tubes with one end stretched by the marble. Take the non-stretched end, fold it and insert into the bottles original opening at the top. If the tube remains
collapsed in the opening then use the pliers to stretch the walls of the tube back into place.
34. Repeat step 33 for the second 2 oz bottle.
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35. Measure and mark 4-5 cm on the 7/8-inch tubing. Because the wall on this tubing is so thick you will need to cut this on the cutting board. Use the large, serrated knife and saw across the tube. Use the knife to cut it all the way through or get your straight blade and finish cutting. Cut all 4 sections this way. Two of these sections you will use in the following steps. Two of the sections you won’t use until step 48 and on.
36. Boil the water again. While waiting you can drop one of the 5 cm sections of tubing that you just cut and place it sideways in the measuring cup/bowl. Once the water boils pour enough water to cover the tubing by at least a cm above the tubing. Allow the tube section a few moments to heat up. While you are waiting get one of the 2 oz and one of the 4 oz bottle that you previously prepped ready to make your one-way valve.
37. While the tube section is in the hot water, use the pliers to stretch the tube. Insert the pliers in one end at a time and open the pliers as far as you can to stretch the tube. Do this on both ends of the tube. 38. Take the 2 oz bottle fold the rubber strip covered tube and insert it
into the heated 7/8-inch tube. Make sure the smaller tube is approxi-mately 1.5 cm in the larger tube. If the
wall of the smaller tube collapses use the pliers to stretch the wall back out. 39. Add a 14 mm marble into the heated
tube section. Quickly push on the tube sticking out of the top, original opening of the 4 oz bottle until it is 1.5 cm into the larger tube. As you push it on you may notice some rolling of the rubber strip inside the larger, heated tube. Don’t worry this will actually make it more watertight. You have now made a
one way valve!
40. Repeat steps 36-39 with the other 2 oz and 4 oz bottles.
41. Make sure you wrap more rubber strips around the outside of these tubes. Tight wrapping is the best.
IV. Final Steps for Assembling Heart Model
- Refer to Figure 6 Final Steps for Assembling Heart Model42. Measure, mark and cut with the scissors two 55 cm sections of 5/8-inch tubing.
43. Find the two remaining prepped 4-inch cable ties.
Figure 5 Connecting
the Bottles
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45. Take one of the 55 cm section of 5/8-inch tubing and using a
SealWrap
™
strip that is stretched at least 2-3 cm wide wrap one end at least one layer. Fold one of the remaining 4-inch cable ties over theopening of the tube. Use the remaining part of the SealWrap
™
stripto hold the cable tie on the side of the tube. Add another strip of
SealWrap
™
to insure the cable tie is very secure.46. Repeat step 45 with the remaining 4-inch cable tie and 55 cm section of 5/8-inch tubing.
47. Boil the water again. While waiting you can drop one of the two remaining 5 cm-7/8-inch tube sections in the measuring cup/bowl, sideways in the measuring cup/bowl. Once the water boils pour enough water to cover the tubing by at least a cm above the tubing. Allow the tube section a few moments to heat up. While you wait for the water to boil get two more 14 mm marbles ready to make your remaining one-way valves.
48. While the tube section is in the hot water, use the pliers to stretch the tube. Insert the pliers in one end at a time and open the pliers as far as you can to stretch the tube. Do this on both ends of the tube. 49. Take one of the 4 oz/2 oz set of bottles. Fold the rubber strip covered
tube sticking out near the top and insert it into the heated 7/8-inch tube. Make sure the smaller tube is approximately 1.5 cm in the larger tube. If the wall of the smaller tube collapses use the pliers to stretch the wall back out.
50. Add a 14 mm marble into the heated tube section. Quickly push on the rubber strip/cable tie end of one of the 55 cm section of 5/8-inch tubing.
51. Repeat steps 47-50 with the remaining 55 cm section of tubing. 52. Measure, mark and cut the following lengths of 5/8-inch tubing:
22cm and 8cm.
53. Take the 8 cm section of tubing and using strips of SealWrap
™
rubber wrap the outside of the tube starting very close to the open-ing. Do not completely cover the tube and the students enjoy watch-ing the water flow throughout.
54. Take one of the sets of bottles, one-way valves and 55 cm tubing. You will notice that the 2 oz bottle has a hole remaining on one end. Insert the 8 cm tube into this hole. You may have to fold the tube to wedge it in. Of course you may need to use the pliers to expand the walls back into place.
55. Insert the other end of the 8 cm tube into the original opening on the remaining 4 oz bottle that hasn’t been used. If the tube collapses in this bottle you will have to work to get the walls back
in place. Use more rubber strips of SealWrap
™
to ensure thesedon’t leak.
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56. You now have one set with three bottles in a row and one set with only two bottles. Take the set with only two bottles and 55 cm tube.
Wrap a strip or two of the rubber SealWrap
™
near the end of thetube. Insert that tube into the hole in the 4 oz bottle at the top of the set of three bottles.
57. Boil the water again. While you wait get the 1 L water bottle.
58. Wrap a strip of the SealWrap
™
around the part of the sport top thatremains on the cap. Keep the cap on the bottle.
59. Once the water boils pour it into the measuring cup/bowl. Put one end of the 22 cm section of tubing in the water to heat. While the tube is heating use the pliers to stretch the tube. Place the heated tube over the end of the rubber wrapped end of the remaining part of the sport top on the 1 L bottle. Once the tube is on run cold water over the tube to help it set on the bottle.
60. Add more of the rubber stripping to insure against leaks.
61. Insert the far end of the tubing sticking out of the 1 L bottle into the top of the 2 oz bottle in the set of two bottles.
62. Take the remaining 55 cm tube and insert it into the hole you made in the 1 L bottle. You will notice that you now have somewhat of a closed system. Your heart is now finished.
It is recommended that you mount the heart on pegboard or on a project display board. You can use twist ties or the larger cable ties to keep the heart in place.
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Once the heart is mounted, label the parts as shown in
Figure 7 Labels.
Body=1 L bottle
Right Atrium=the 2 oz bottle connected to the “body”
Right Ventricle=the 4 oz bottle connected to the “right atrium”
Lung=the 4 oz bottle connected
to the “Right Ventricle”
Left Atrium=the 2 oz bottle connected to the “Lung”
Left Ventricle=the 4 oz bottle connected to the “left atrium” Once the heart is mounted and labeled set it up over a sink. Add water to the top of the 1 L bottle using a funnel and
pitch-er. Squeeze the ventricles to help move the water through the “heart”. The model is ready for student use!
Heart Model
photographs-Theo Risinger, Bush Middle School, NorthEast ISD
Activity Management Suggestions:
— work in groups of two to four
— monitor to ensure that groups are discussing the questions and
all members of the group are contributing
— make a transparency of the Human Circulation illustration that is
provided at the end of the Teacher InformationSection to use as
you Process Outblood flow during human circulation
Extensions:
• develop and calibrate a way to determine flow rate changes with
varying sizes of occlusions
• develop and calibrate a way to determine pressure in the vessels
Activity References Used:
National Health Institute Medline website:
http://www.nlm.nih.gov/medlineplus/aboutmedlineplus.html
Figure 7 Labels
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Background References Used:
National Heart Lung Blood Institute websites:
http://www.nhlbi.nih.gov/health/dci/Diseases/heartmurmur/hmurmur_h eartworks.html
http://www.nhlbi.nih.gov/health/dci/Diseases/heartmurmur/hmurmur_w hat.html
Other Wbsites:
Heart sounds can be found on many Internet sites, for your convenience, here are a few links:
Diagrams:
http://www.nhlbi.nih.gov/health/dci/Diseases/heartmurmur/hmurmur_ heartworks.html
