Design a Heart Valve Model

In this project, our task was to construct a model that illustrated the purpose of our heart's aortic valve.

Initially, we completed extensive research to study how it functions and various anatomical components of the heart that contribute to the process of blood flow. The aortic valve is one of your four heart valves. It controls blood flow into your aorta and keeps blood moving in one direction. The aortic valve is located between and connects the left ventricle (the heart chamber that pumps blood from your heart to the rest of your body) and the aorta (the artery that carries blood away from your heart). This valve is one of two semilunar valves. Semilunar valves connect your heart ventricles (lower chambers) and arteries. The aortic valve opens to let blood flow from your left ventricle to your aorta. It closes to prevent blood from flowing in the wrong direction. The closed valve keeps blood from leaking from your aorta back into your heart. The aortic valve has three sections made of collagen. These sections are called leaflets, or cusps. In a healthy heart, the leaflets open wide to allow blood to flow through. Then, they come tightly together to prevent backflow.

Young's Modulus

Next, we setup our Young's Modulus, which is in essence the stiffness of a material. In other words, it is how easily it is bended or stretched. To be more exact, the physics and numerical values are worked out like this: Young's Modulus = Stress / Strain. We tested two different materials in hopes of seeing how similar they are in character to heart tissue. The first material was a cheesecloth. The goal was to measure how much the material moved when we put pressure on it. At first, we had difficulty connecting the weight to the cloth. We ended up using a backpack as the weight. It was about 8.25 pounds. To attach the backpack to the cloth, we had one person hold a hook and the other person measure how much it had stretched. For our second test. We used a plastic clear pipe. We utilized the same strategy here to measure the stretch. After we had our measurements. We calculated both stress and strain. To calculate stress, we took the force and divided it by their cross section of the area. To calculator strain, we took the change in size and divided it by the initial length. To find the Young’s modulus, we divided stress into strain. After seeing these results, we started to discuss the possibility of lining the rubber tube with the cheesecloth to demonstrate the layers of the heart.

Here is some of our testing data:

Weight Tested: 3.739 kg(8.25 pounds)

White cloth - .2565 m -> .2692 m (.0127m)

Force= 36.672 N

Stress- 36.672 / .0106 m = 3459.66

Strain- .0495 ɛ

Cross sectional area- .0106 m

Young’s Modulus- 8.6491 x 10 ^4 Pa

Clear plastic tube - .3162 m -> .3175 m (.0013m)

Force= 36.672 N

Stress- 36.672 / .0112 m = 3,274.28

Strain- .0041 ɛ

Cross sectional area- .0112 m

Young’s modulus- 8.16528 * 10 ^ 5 Pa

Aortic Valve Model

For our heart model, our plan initially was to use three water bottles to replicate a heart valve. However, we were advised to take a more creative approach. Because we are extremely short on time we had to make up a new idea very quickly. We ended up using a latex glove as a heart, the clear tube as the aorta, and a wooden piece connected with rubber-bands as the valve itself. As water was pumped through the tube, the pressure was supposed to push the rubber bands and thus allow water through. Once the water pressure weaned, the rubber bands would snap the wood piece back to the original position. As we had very little time to test the model, we couldn't make that many changes. We ended up having to slightly manually move the wooden piece to allow water through. However, the model still accurately represents the function of the aortic valve. As water flowed through, the water would not be allowed to flow back into the heart, which is the most important part of the valve. The sink represented the left ventricle, because we didn't have a cup on hand.

We achieved positive results with this model, and successfully modeled the function of the aortic valve.

Link to video showing results: https://youtube.com/shorts/LheX4D66-pg?feature=share

Through this project, we had to adapt and overcome many challenges. Given the shorter period of time to complete because we spent so much time working on our Capstone, we had to work very diligently to complete this project. We felt that if we had spent more time gathering and brainstorming about the correct materials, our model would have worked better. But we did successfully produce an effective model reflecting the function of the aortic valve.

We could have improved our conscientious learning skills, such as managing time effectively, goal-setting, and self regulation. But we did execute great collaboration skills as all of our group members divided the work to contribute to the success of our project and stayed motivated to accomplish our aortic valve model. We also utilized critical thinking throughout the project, using evidence and reasoning to guide our decision making and synthesizing knowledge we learned to generate creative solutions and ideas.