Thus, the Fahraeus effect can largely explain the Fahraeus-Lindqvist effect. Some other factors may also play a role. For example, the smaller the vessel the larger the relative volume of the slippage layer since the width of the slippage layer remains constant (~4 um). The high shear rate in the arterioles, and the increased erythrocyte deformation in small vessels, may also be important.
As a consequence of these mechanisms, the relative erythrocyte to plasma distribution varies according to vessel caliber. In a 1.1 mm diameter vessel the hematocrit may be 40.5% and the red cells and plasma move at the same velocity. In contrast, in a vessel with a 50 um diameter, the hematocrit may be 28% and the velocity of the red cells may be 175% that of the plasma. This strikingly illustrates the Fahraeus effect.
Back to Index