Blood supply to the Kidneys

BLOOD SUPPLY TO THE KIDNEYS

Fig.1

 

Each kidney receives blood supply from the Renal Artery.  The Renal Artery (See Fig.1) arises directly from the aorta (the main trunk that carries blood from the heart).  After the blood has flown through the kidney tissue, the venules unite to form the renal vein that directly drains into the Inferior Vena Cava (the main trunk that carries blood towards the heart).  Each Kidney has normally one renal artery and one renal vein.  Sometimes there can be an additional smaller renal artery supplying the upper pole or the lower pole of the kidney.  Rarely, there can be more than one renal vein.

The main renal artery soon divides into the segmental artery that continues as an interlobar artery.  Interlobar artery branches to form interlobular artery which finally forms the arcuate artery.  The arcuate gives rise to afferent arteriole that forms the capillary tuft called the glomerulus (Fig.2)

 

Fig.2 Glomerulus

From glomerulus blood gets filtered and comes out through an efferent arteriole which then passes through a network of small capillaries called peritubular capillaries.  This is the point where these capillaries come in contact with the loop of Henle which is a part of the tubule wherein reabsorption & secretion the process takes place whereby ions such as sodium, potassium, chloride & water that is necessary for the body is reabsorbed and metabolic waste such as Blood Urea Nitrogen, Creatinine, etc is secreted into the tubule from the blood.  Now the purified blood from the peritubular capillaries flows into the interlobular vein to the Arcuate vein to the interlobar vein getting into the segmental veins then into the Renal vein finally into the inferior vena cava.