teach about the circulatory system this valentine's dayIts fun to celebrate holidays with students, but you want to keep it academic, as well. Model building is an effective way for students to learn about how systems work. In fact, I remember building a model heart in school from a kit that was provided by one of my teachers. My friend and I pumped water through a bunch of interconnected plastic cylinders (that were part of the kit), as we explained what was happening in each of the "chambers". Here, I have created my own DYI model using some commonly found materials. Save money instead of ordering a kit! AND CELEBRATE VALENTINES DAY. students construct 4-Chambers & make them workThe heart is located under the rib cage, slightly to the left of the breastbone (sternum), between the lungs. It is an efficient pump that is made of four separate areas called chambers. Oxygen-rich blood is pumped by the right chambers to the body (systemic circuit), where it picks up wastes from the body’s cells. Oxygen-poor / waste-rich blood is pumped by the left chambers to the lungs (pulmonary circuit) to become re-oxygenated. To teach the circulatory system with this model, you will need to gather these materials. Then students can have a great hands-on learning activity! Materials:
Procedure:Make a small hole in the bottom of 4 of the bottles using a needle or skewer to fit plastic tubing through. Position two of the bottles so that their caps are facing each other and thread the four-inch tubing through the holes in their caps so that the bottles are connected. Seal holes around the tubing with clay &/or tape, as needed. (Clay/tape is less necessary if you are using silicone bottles). Repeat this process with the other 2 bottles that also have holes in the bottom. Tape the pairs of bottles next to each other. These bottles represent the four-chambered heart. It is a good idea to have some paper clamps on hand to attach to the tubing. They can help prevent backflow in the “heart valves” between the atria and ventricles. Tape the remaining bottles together in pairs of two. One set will represent the lungs and the other set will represent the body. Label them as such. Fill one of the “body bottles” with water and add blue food coloring to it to create “deoxygenated blood”. Screw the caps onto both “body bottles”. Thread one piece of twelve-inch tubing through the cap of the bottle with “deoxygenated blood” and thread the other end of the tube through the cap of the right atrium of your model heart. Seal the holes around the tubing with clay &/or tape, as needed. Take a second piece of twelve-inch tubing and thread it through the cap of the empty “body bottle”. Thread the other end of the tube through the bottom hole of the bottle that represents the left ventricle. Seal the holes around the tubing with clay &/or tape, as needed. If necessary, place a paper clamp on the tube just below the “left ventricle” to prevent backflow into that chamber. Fill one of the “lung bottles” with water and add red food coloring to it to create “oxygenated blood”. Screw the caps onto both “lung bottles”. Thread a third piece of twelve-inch tubing through the cap of the bottle with “oxygenated blood” and thread the other end of the tube through the cap of the left atrium of your model heart. Seal the holes around the tubing with clay &/or tape, as needed. Take the fourth/last piece of twelve-inch tubing and thread it through the cap of the empty “lung bottle”. Thread the other end of the tube through the bottom hole of the bottle that represents the right ventricle. Seal the holes around the tubing with clay &/or tape, as needed. If necessary, place the fourth/last binder clip on the tube just below the “right ventricle” to prevent backflow into the chamber. Add additional labels to the model: Pulmonary valve, tricuspid valve, mitral valve, aortic valve, systemic circuit, and pulmonary circuit. Have students add any additional labels that will help their understanding of the circulatory system. Students should use a diagram of the heart to help with labeling and understanding of the model. How the Heart Works includes a diagram of the heart, as well as a more elaborate discription, an article, and a vocabulary based activity. Make the Heart PumpSend deoxygenated blood into the right atrium by squeezing the “body bottle” with blue water. If you are using clamps, open the "tricuspid valve" allowing the deoxygenated blood to move into the right ventricle, then close the valve again. Open the pulmonary valve allowing the deoxygenated blood to move into the lungs, then close the valve again. (In a classroom, this is more easily achieved with two students working together.) Send oxygenated blood into the left atrium by squeezing the “lung bottle” with red water. Again, if you are using clamps, two students can work together to, first, open the mitral valve allowing the oxygenated blood to move into the left ventricle, then close the valve again. Then, open the aortic valve allowing the oxygenated blood to move to the body, then close the valve again. Students should demonstrate the pumping action as they describe what is happening aloud. Blood Flow through the HeartAs blood leaves each chamber of the heart, it passes through a valve. Heart valves prevent blood from flowing in the wrong direction. The tricuspid and mitral valves lie between the atria and ventricles. The aortic and pulmonary (semilunar) valves lie between the ventricles and the major blood vessels leaving the heart. Coronary arteries on the surface of the heart supply oxygen-rich blood to the organ, itself, since the blood that is within its chambers does not provide it with nourishment. Blood flows in a continuous patternThe Right Side of the Heart- Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from the right atrium into the right ventricle through the open tricuspid valve. When the ventricle is full, the tricuspid valve shuts, preventing the backward flow of blood into the atrium while the ventricle contracts. As the right ventricle contracts, blood leaves the heart through the pulmonary valve, into the pulmonary artery and to the lungs to complete the pulmonary circuit. In the lungs the blood becomes oxygenated and then returns to the left atrium through the pulmonary veins. Left Side of the Heart- The pulmonary veins empty oxygen-rich blood from the lungs into the left atrium of the heart. As the atrium contracts, blood flows from the left atrium into the left ventricle through the open mitral valve. When the ventricle is full, the mitral valve shuts preventing the backward flow of blood into the atrium while the ventricle contracts. As the left ventricle contracts, blood leaves the heart through the aortic valve, into the aorta and to the body to complete the systemic circuit. The blood travels to the all of the body’s cells and exchanges oxygen and nutrients for wastes, which it returns to the right atrium. The Heart BeatThe atria and ventricles work together, alternately contracting and relaxing to pump the blood through the circuit. Heart contractions are triggered by electrical impulses from specialized bundles of cells within the organ. The heart’s natural electrical pacemaker coordinates the beat to deliver blood to the body, depending its state of activity, health, emotion, or rest. the Model heartAfter students demonstrate one cycle of deoxygenated blood pumping from the right atrium to the right ventricle to the lungs to get oxygenated, and then back from the lungs to the left atrium, left ventricle, and out to the systemic circuit, they will need to replace the blue and red water into the body and lungs, respectively, in order to repeat the correct circulatory demonstration a second time. Have students explain why the circulatory process can’t be repeated without resetting the model. Here is a video of the model construction:
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AuthorGertrude Katz has spent over 30 years teaching K-12 public school students all major subjects. She has taught biology and education at the college level. The majority of her career has been spent instructing biology at the secondary level. Categories
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