[Phasic processes in the kinetics of the formed elements of the blood]

When quantitating blood shifts in response to environmental effects, it is important to take into account the phasic pattern of certain processes. Theoretical considerations and experimental data on the fluctuations of the counts of formed elements have been published. Since the fluctuations cannot be easily detected by experimental methods, they can be investigated using mathematical modeling. A model describing the counts of red blood cells and their precursors in relation to the age structure of the population has been developed. Depending on the oxygen requirements and physiological parameters, humoral regulation controls cell proliferation and release into the functioning pool. The model allows for incidental hemolysis as well as for life-time of red blood cells. Simulation of various processes in the blood system when exposed to unusual environmental effects has shown that some of the processes can be phasic in character.