Image Analysis and Cytometry in Three-Dimensional Digital Reconstruction of Porcine Native Aortic Valve Leaflets

Native Aortic Valve Leaflets Chi Zheng, M1 University of Pittsburgh; BSE University of Michigan In association with: John A. Stella and Michael S. Sacks, Ph. D. Department of Bioengineering, University of Pittsburgh June.16.2006 Introduction The mammalian heart is a four-chambered pulsating pump that circulates the blood within two parallel loops: the systemic and the pulmonary circulation. Blood flow is regulated by four pressuresensitive valves that are located at the outlet of the four chambers. In the duration of a complete cardiac cycle, oxygenated blood first enters the left atrium from the pulmonary circulation. It flows past the mitral valve into the left ventricle. The left ventricle contracts, causing the mitral valve to close and the aortic valve to open, resulting in the ejection of oxygenated blood from the ventricle, through the aortic artery, and into the systemic circulation. After delivering oxygen to the tissues, deoxygenated blood returns to the right atrium of the heart. It, then, flows into the right ventricle passing the tricuspid valve in the process. When the right ventricle contracts, the tricuspid valve closes and blood is ejected through the pulmonary valve into the pulmonary vein, which carries the deoxygenated blood to the lungs to be oxygenated. The synchrony of heart muscle contraction and relaxation along with the opening and closing of each valve maintains the quasi-steady state blood flow necessary for mammalian life.