Cell‐free layer formation at an arteriolar bifurcation

The phase separation of blood at the bifurcation in the arteriolar network could alter the characteristics of the cell‐free layer formation observed in an unbranched arteriolar segment. To study this effect, we investigated the layer width around an arteriolar branch point in the rat cremaster muscle under physiological flow conditions before and after dextran infusion to simulate aggregation levels seen in humans. Normalized mean layer widths were attenuated in the parent and larger daughter vessels at their walls adjacent to the side branch but not at their opposite walls. Asymmetries of normalized mean layer widths, larger than those seen in the parent vessel, were found on opposite sides of the larger daughter vessel irrespective of the aggregation induction. A positive correlation was observed between normalized mean layer widths in the downstream vessel and on the side of the parent vessel from which flow entered. The fractional volume flow in the side branch required to maintain equal normalized mean layer widths between the downstream vessels increased with the aggregation level. These findings demonstrate the dependence of the layer formation on flow separation at an arteriolar bifurcation which can be influenced by the extent of aggregation. This work was supported by NUS URC grant R‐397‐000‐091‐112.