Kidney Structure

The kidney has a bean-shaped, multi-layered structure with functional tissues in the internal section, surrounded by several protective layers. The main filtration structure, the nephron is located both in the medulla and the cortex in the inner tissues.

From the outermost layer, moving inwards:

In the external layers

-Renal fascia: a strong connective tissue surrounding the kidney and the adrenal gland

-Perirenal fat capsule: a layer of fat tissue providing some protection to the kidney from damage and trauma

-Renal capsule: a tough fibrous layer encapsulating the functional tissues of the kidney

In the internal and functional tissues

-Outer Cortex: includes most of the blood vessels and the collecting ducts, as well as some of the structure from the nephron such as the renal corpuscle and parts of the convoluted proximal and distal tubules. This is where most of the blood is filtered and larger molecules such as sugar and amino acids are recycled in the bloodstream.

-Medulla: the innermost tissue of the kidney, split up in identifiable structures called pyramids. Poorer in blood vessels, in these pyramids are located the other structures of the renal nephron, particularly the loop of Henle. This is where most of the ions and water are reabsorbed into the body.

Finally in the concave section of the kidney can be found the hilum, which is not a layer but where arteries, veins and the ureter connect to the renal tissues.