A Tentative Study On Properties Of Blood Transportation Of Vascular Tree Network

Whether within the nature, or in the social territory of human beings, always are there some forms of tree-like network to be existent. Above all, the network forms, which exist in vascular systems of all kinds of animals and plants, are the most typical ones. Such as respiratory systems and circulatory systems of mammals, roots of plants and the vascular systems within botanical stems and leaves, and so on. Diverse as the biologic forms are, transport networks supply tissues with water, air and nutrients, etc. , are allied structurally. So we just need to select a fractal-like tree branching network model to study the basic transport properties of these systems.The thesis focuses on selecting a certain branching network model, which bears several specific characteristics, to simulate vascular systems for studying blood transport properties. In the thesis, the progresses on study of theory and applications about the fractal-like tree networks were briefly reviewed at first. Then, the theoretical basis of hemodynamics were introduced specifically, including constitution and mechanical properties of blood vessels, stress in vessels, and vascular remodeling. Thirdly, the thesis studied the blood transport properties again through a vascular network which was simulated by the WBE fractal-like tree network model. But, here, I took wall shear stress and vascular remodeling into account, and made Murray's optimization as the core idea throughout the thesis. Above all, the optimal model was applied in the evolvement of biologic individual, namely, in the processes of growth or decline. I found that blood pressure and velocity in capillaries experienced abnormal changes which deviated the facts. The results from the deduction showed that an optimal vascular tree may be unfit for growth. Finally, I questioned the simplicity and direct application of the Murray's and the WBE's model, and I presented some of my opinions subsequently.