COMPARATIVE MICRORHEOLOGY OF AVIAN AND MAMMALIAN BLOOD

Abstract

This chapter presents the results of comparative microrheology of avian and mammalian blood. In considering the design of the capillary system with respect to exchange conditions, the pressure energy required to maintain flow of blood through this system must be taken into account. Because the available driving pressures are limited, there is also a limitation for the geometric design represented by the hydraulic flow resistance provided by a capillary network. From the standpoint of hydrodynamics, very narrow capillaries are obviously less favorable. In the study described in the chapter, experiments in vitro were performed in which suspensions of avian and mammalian red blood cells were perfused at constant pressures through glass capillary tubes with internal diameters ranging from 3 to 12 μm. Microscopic observation of the flowing cells and quantitative analysis of cell shape clearly indicated that the deformation of the nucleated erythrocytes was significantly less pronounced compared to that of the non-nucleated cells. The rheological measurements show that the difference in cell morphology between avian and human erythrocytes leads to significantly different microrheological properties, which predict higher viscous resistance of these cell suspensions in capillary flow.