[Vascular flow-regulating devices in the human kidney].

Small arterious and venous vessels of the juxtamedullary cortex of normal human kidney present wall formations regulating the blood flow. The arterious devices appear either as sphincterial rings at the origins of collateral branches of interlobular arteries, or as groups of myoepithelioid cells in the wall of small arteries immediately preceding the afferent arterioles. The venular devices consist of circular muscular thickenings repeated along the course of the vessel.