The heart is a pump with valves that control the direction and pace of blood flow throughout the body. It is a key part of the body, so Biomedical Engineers must develop solutions to potential non- functioning parts that may be fatal in humans. The heart valve is an example of this, which our group created a model of. This could be used to understand how the heart valve functions, or as a prototype for a possible heart valve replacement in humans.
Our model took several different forms before we came upon one that was truly accurate. We began with a glass jar that featured straws, balloons, and water, until we realized that our model focused more on the function of the heart as a whole rather than just a heart valve. After a bit more research into the true functionality of a heart valve, we came upon our final model. It includes two rubber pipes, one slightly smaller, than the other, so that one fits inside the other without water leaking out. We also put a rubber ball inside of the smaller tube, which blocks the flow of water one way, but allows it to flow the other way.
Our Heart Valve Model (Sketch)
Picture of a Real Heart Valve
Elasticity of a Balloon
We do not have a material in our model that is able to be tested for elasticity, so instead we tested the Young's Modulus of a balloon:
This graph demonstrates Strain vs. Stress, of the balloon:
SYSTOLE
when the heart is pumping, blood is forced through the heart and other blood flow vessels
blood exits the left ventricle and passes through the aortic semilunar valve. The flow of blood and the mechanical structure of the heart valve cause the valve to open
it cause the elastin in the ventricularis layer to relax so the valve can reset to the open position
Open valves cause laminar flow across the ventricular layer of the heart valve
DIASTOLE
the ventricles relax, allowing the flow of blood to change
backflow of blood into the heart applies a force on the aortic semilunar valve and causes it to close.
The force that is now exerted on the aortic side of the heart valve (the fibrosa layer of the valve) causes the collagen in the layer to move slightly to reinforce the valve
This rearrangement of the collagen causes the elastic in the ventricular is layer to stretch, allowing the three leaflets of the valve to seal the valve and prevent blood regurgitation.This means that the valve is no longer experiencing laminar flow, causing different currents