|MadSci Network: Immunology|
The suspended particles in blood are of the right dimensions for it to be considered a sol, a type of colloid. A colloid can be defined as any 'stable' heterogeneous mixture composed of a continuous phase and a disperse phase of dimensions of the order (approximately) 10 nanometres - 1 micron.
Under normal conditions, blood is stable, and hence is properly referred to as a colloidal suspension. When subjected to extremely high forces as in a centrifuge, it is no longer stable and separates into its components. Sols can be destabilised in many ways (by shearing, heating, addition of a salt, etc.) so that they separate into their components, but this does not mean they were not colloidal to begin with!
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