Modeling vasomotion

The phenomenon of vasomotion, consisting in periodic oscillations of blood vessels walls is particularly important at the scale of small vessels and exhibits different features in arterioles (in which flow is mainly driven by the hydraulic pressure gradient) and in venules provided with valves preventing back flow and helping centripetal hematic propulsion. Here we formulate a model for both situations, based on approximations of the flow equations implied by the smallness of the radius-to-length ratio. For venules we postulate the presence of an inlet and an outlet valve and we show that the model reproduces the periodic pressure pulses that have been detected in the experimental literature devoted to venules of the batwing. We have developed a model for describing the vasomotion, i.e. the flow in oscillating arterioles and oscillating venules. In arterioles vasomotion has little effect while in venules equipped with valves contractionexpansion cycles exert a propulsive action on the blood. The model reproduces reasonably well the data reported in the experimental literature.