Issue title: Proceedings of the Fourth International Congress of Biorheology. Jikei University School of Medicine, Tokyo, Japan, 27 July – 1 August 1981. Dedicated to Alex Silberberg
Affiliations: Division of Circulatory Physiology and Biophysics, Department of Physiology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
Abstract: The apparent viscosity (η) of blood is determined by plasma viscosity, hematocrit (Hct), cell deformation and cell aggregation. The optimum Hct for oxygen transport varies with shear conditions and shows regional differences. In circulation in vivo, the complex geometry causes inertial, in addition to viscous, losses. Microvessels have low Hct and correspondingly low η. Hydrodynamic interactions between red blood cells (RBCs) and white blood cells (WBCs) may contribute to WBC adhesion to the endothelium. Entry of WBC into diverging branches may cause redistribution of RBCs. There is some understanding of the relation between in vitro and in vivo blood rheology, but further investigations are needed.
