Kidney Blood Supply
Blood travels toward the kidney from the descending aorta via the renal artery. Before entering the renal hilum, the renal artery divides into segmental arteries, followed by further branching to form the interlobar arteries, which pass through the renal columns. At the bases of the renal pyramids, the arcuate arteries branch from the interlobar arteries and enter the renal lobes, where they run alongside the arched intersections between the renal pyramids and cortex.
Small Arteries, Arterioles, and Capillaries
Cortical radiate arteries (interlobular arteries) branch at right angles and extend into the renal cortex from the arcuate arteries.
The cortical radiate arteries give off afferent arterioles that deliver blood to the Bowman’s capsules of nephrons. Within a Bowman’s capsule, an afferent arteriole forms a tuft of high-pressure capillaries called the glomerulus. The glomerulus and the Bowman’s capsule together form the renal corpuscle. Blood is filtered across the capillary walls of this tuft through the glomerular filtration barrier, which yields its filtrate of water and soluble substances to the interior space of the Bowman’s capsule. The glomerular capillaries eventually merge to form an efferent arteriole, which exits the Bowman’s capsule.
The efferent arterioles branch extensively, forming a network of capillaries that wind around the distal portions of the renal tubule. The capillaries that travel alongside the proximal and distal convoluted tubules are called the peritubular capillaries. Those that travel alongside the loops of Henle are called the vasa recta capillaries. The proximity of the capillaries and renal tubules allows substances to be exchanged between the neighboring structures.
After the blood is cleansed and rebalanced by the nephrons, it drains into the cortical radiate veins (interlobular veins). The cortical radiate veins merge at right angles with the arcuate veins, which carry the blood away from the renal lobes.
The arcuate veins drain into the interlobar veins, which transport blood through the renal columns and renal pelvis to the renal vein. Blood is then carried out of the kidney by the renal vein and delivered to the inferior vena cava.
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Reference: “Gross Anatomy of the Kidney“