ABSTRACT
The hepatic microcirculatory system consists of four microvascular components: the terminal portal venule and the terminal hepatic arteriole as two afferent vessels, the sinusoids corresponding to the capillary bed, and the terminal hepatic venule as an efferent vessel. The regulatory mechanism of hepatic sinusoidal blood flow has not been fully understood. There is general agreement, however, that the adrenergic and cholinergic nerves directly innervate the portal venules and arterioles in the portal tract, regulating the sinusoidal blood flow. The most prominent structural and functional alterations of hepatic microvasculature are noted in liver cirrhosis, among a variety of human liver diseases. Autoregulation works to some extent in the hepatic microcirculatory system to maintain a constant blood flow through the liver in response to hemorrhagic shock. Based on the current concept of ischemia/reperfusion injury, reoxygenation of tissue after prolonged ischemia enhances ischemia-induced cell damage concomitant with microvascular injury.
