Fåhræus–Lindqvist effect

As Fahraeus - Lindqvist effect is called with decreasing diameter of a vessel, the decrease in the apparent viscosity of the blood.

In vessels of 7-10 microns in diameter, the apparent viscosity of the blood is only slightly higher than that of the plasma. The decrease in apparent viscosity arises from the fact that the erythrocytes in the middle of the blood flow to move faster through lower shear forces, which causes an increased shift there ( axial migration ). This leads to the formation of a cell- poor lubricating layer ( marginal zone ), which accelerates the movement of the central liquid. In addition, erythrocytes are very malleable ( fluidity ) and can be customized to an altered shear stress and thereby reduce hemodynamic disturbance effects.

Due to the Fahraeus - Lindqvist effect, the hematocrit only a small influence on the size of the peripheral resistance in small vessels.