Cardiovascular Mechanics: Investigation of Two Components,Tissue Heart Valves and Blood Cells

A fundamental anatomical composition of the heart valves is presented along with its relationship to the tissue mechanical behavior. During the loading and unloading phases of the tissue different stress strain pathways are followed with the curves composing the characteristic hysteresis loop, exhibiting the viscoelastic mechanical behavior of valvular tissue. The storage modulus and the phase shift (tan ) as well as the collagen modulus of human heart valves were measured in orthotropic directions using uniaxial dynamic tensile tests at 10 Hz. Viscoelastic properties of human erythrocytes are presented as calculated from micropipette aspiration experiments. Employing the hemorheometre, from filtration experiments an index of rigidity (IR) of erythrocytes is estimated. A relationship between the global parameter IR and the shear elastic modulus of erythrocyte membrane, , is established. The same two techniques adapted for leukocytes and their subpopulations have been used and a relationship between the rigidity index of leukocytes (ILR) and their apparent bulk viscosity (_app), has been found.