Renal blood vessels


The kidneys are highly vascular and thus are equipped with vast and intricate networks of circulation in order to effectively cleanse and modify vast amounts of blood. The hilum permits the entry of the arterial blood flow via the renal artery. The renal artery then branches off creating the interlobular arteries. These then pass between the renal pyramids via the renal columns.


Along the boundary created by the renal cortex and the renal medulla the interlobular arteries branch out to create the arcuate arteries. From there, protruding into the renal cortex, the smaller interlobular arteries branch off from the arcuate arteries. The interlobular arteries yield the microscopic afferent glomerular arterioles. These arterioles are responsible for the transportation of blood into the capillary networks of which resemble little balls, and are referred to as the glomeruli. The glomeruli are responsible for the filtration of the blood entering the urinary tubules. Any blood which has been left behind in the glomeruli is the drained via the efferent glomerular arterioles. Throughout the rest of the body, blood normally exits a capillary bed via venules rather than additional arterioles.

When the blood exits the efferent glomerular arterioles it then flows into either the vasa recta which encompasses the ascending and descending tubules or it flows into the peritubular capillaries which encompasses the convoluted tubules. The blood exits this capillary network via an identical pathway of venous networks that run along the kidney’s arterial network. The network is constructed by the various interlobular veins, arcuate veins, and the interlobular veins that run parallel with the arteries of the same names. The interlobular veins run down in between the renal pyramids where they unite and then exit the kidney via a single renal vein. Once it has left the kidney, the venous drainage then empties into the inferior vena cava.


Renal blood vessels
Image: Renal Blood Vessels

The capillary system of the kidney creates a natural filtration system. Each individual glomerulus of the kidney houses a capillary level in between the arterioles. The water and dissolves liquid wastes in the bloodstream are then forced through the urinary tubular section of the nephron from the significant blood pressure within the glomerulus.

The tubular section of the nephron is encompassed by peritubular capillary networks and vasa recta, which creates a secondary capillary network. The purpose of the second capillary bed is designed for absorption instead of filtration. There are certain amounts of water and other substances which should avoid being excreted in the urine and thus are reabsorbed into the body.

Kidneys are a higher than average vascular organ which can be damaged via excessive force to the lumbar region. Injury to the kidneys can cause bloody urine. Because the kidneys are so susceptible to serious hemorrhagic injury, it is protected. Located retroperitoneally, the kidneys are protected from frontal injuries.
  Member Comments