Abstract
The fluidity of blood is reviewed from the standpoint of colloid science. Since the blood can be simplified as disperse systems consisting of erythrocytes and plasma, the suspension rheology would serve to understand the complex flow behavior in vessels. The fundamental properties of ordinary suspensions and emulsions are summarized to clarify the issues. The hydrodynamics of a single particle and droplet in shear fields is analyzed as a function of internal circulation. To predict the viscosity behavior of concentrated suspensions and emulsions, the analysis is expanded by incorporating the hydrodynamic interactions between nonflocculating particles and the deformation of network of thin liquid. The flow behavior and dynamic viscoelasticity of highly flocculated suspensions are explained in connection with particle-particle interactions and geometry of flocculated structures. Finally, the fluidity of blood in narrow vessels is discussed on the basis of the erythrocyte deformability, with a perspective of quantitative understanding of hemorheology.
