Microcirculation velocity changes under hypoxia in brain, muscles, liver, and their physiological significance

Linear blood flow velocity in brain, muscle capillaries and hepatic sinusoids was measured by means of microfilming in normal and hypoxemic rats (breathing with 7% O2 in N2). The mean flow velocity was found to increase by 66% in brain capillaries and by 12% in hepatic sinusoids. In skeletal muscle the blood flow ceased in about 40% of the capillaries under investigation and in the others the flow velocity slowed down twofold. Different response to hypoxemia was explained by the physiological function peculiarities of the organs in question as well as the type of the energetic exchange and that of the microvascular net structure.