Renal cortex

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Renal cortex and related structures.

The renal cortex is the outer layer of the kidney, just deep to the fibrous capsule and surrounding the the inner medullary layer. Extensions of the renal cortex, known as renal columns, project into the renal medulla dividing it into triangular shaped segments called renal pyramids. Together, the renal cortex and the medulla constitute the renal parenchyma.

Contained within the cortex are glomeruli of all renal nephrons, along with the proximal and distal convoluted tubules. Collecting ducts also extend from the cortex into the medulla towards the renal papillae, the tapered ends of the renal pyramids in the medulla.

The renal cortex is highly vascularized. Arcuate arteries travel along the bases of the renal pyramids at the corticomedullary boundary and give rise to cortical radiate (interlobular) arteries that traverse through the cortex. These give rise to afferent arterioles which bring blood to the glomeruli for filtration. Filtered blood leaves via the efferent arterioles that give rise to peritubular capillaries in the cortex and the vasa recta in the medulla. The cortical peritubular capillaries then reunite to form peritubular venules and then cortical radiate veins, before draining into the arcuate veins at the corticomedullary junction.