INFLUENCE OF FLOW PROPERTIES OF BLOOD UPON VISCOSITY-HEMATOCRIT RELATIONSHIPS*

Abstract

The fluid mechanical forces determining blood viscosity, described in terms of shear stress and shear rate, were quantitated by means of a cone plate viscometer. The viscosity of blood is shown to be shear rate dependent, i. e. viscosity decreases as shear rate rises. Since shear rate is a function of velocity of flow and vessel diameter, it is emphasized that within the vascular system the vicosity of blood may be any one of an infinite number of values at any instant.. These matters are considered in relation to the viscosity changes ascribed to axial streaming of cells in the smaller vessels.