When blood flows through small blood vessels (vessels of diameter less than 300 um), it behaves somewhat strangely due to the red blood cells (RBCs). Because of their size, they cannot be immediately...

When blood flows through small blood vessels (vessels of diameter less than 300 um), it behaves somewhat strangely due to the red blood cells (RBCs). Because of their size, they cannot be immediately adjacent to the vessel wall; furthermore, lift forces also move them away from the wall. Owing to these phenomena, the fluid behaves as if it had two phases: the thin layer next to the wall,