Shape of a dilution curve as the consequence of stochasticity within microcirculation

Introduction. There is a problem with commonly accepted parameters for microcirculation. This problem is due to many used mathematical models. The aim of notes to reveal that hypothesis about stochasticity of microflow leads to the uniqueness of mathematical equations for passage throughout microcirculation. Thus stochasticity could be a motivation for the choice of parameters of microcirculation. Method. The passage throughout microcirculation is formed by next five events: (1) be in intravascular space, (2) be in extravascular space, (3) a microvessel is closed, (4) a microvessel is open, and also (5) a particle, being in open microvessel, experiences a variation of velocity. Result: Markovian property leads to a uniqueness of distributions of named events and (a) the first four events are exponentially distributed; (b) the distribution of time to pass through open microvessels is infinitely divisible and is a gamma distribution.