Figure 1: Multi-scale links between RBCs dynamics, shear viscosity, ATP release, and shear stress endothelial NO generation. The transitions from tumbling, to tank-treading, to stretching are physically determined by the stress exerted by the flow; transitions are determined by spectrin-actin network remodeling; Shear mediated ATP is release from RBCs through transmembrane channels; Shear mediated NO generation; In vivo analysis using intra-vital microscopy.