ABSTRACT
The term hematocytes refers to the circulating cells of the blood. These are divided into two main classes: erythrocytes, or red cells, and leukocytes, or white cells. In addition to these there are specialized cell-like structures called platelets. The mechanical properties of these cells are of special interest because of their physiological role as circulating corpuscles in the flowing blood. The importance of the mechanical properties of these cells and their influence on blood flow is evident in a number of hematological pathologies. The properties of the two main types of hematocytes are distinctly different. The essential character of a red cell is that of an elastic bag enclosing a Newtonian fluid of comparatively low viscosity. The essential behavior of white cells is that of a highly viscous fluid drop with a more or less constant cortical (surface) tension. Under the action of a given force, red cells deform much more readily than white cells. In this chapter we focus on descriptions of the behavior of the two cell types separately, concentrating on the viscoelastic characteristics of the red cell membrane, and the fluid characteristics of the white cell cytosol.
