The kidneys are two bean-shaped excretory organs, about the size of a closed fist, located at the back of the abdomen, one on each side of the spine.
The right kidney is located below the liver and the left below the diaphragm, next to the spleen. The asymmetry of the abdominal cavity produced by the liver makes the right kidney slightly lower than the left.
Above each kidney is an adrenal gland, with endocrine functions.
In the kidney three parts can be distinguished:
- The cortex, the outermost part, and contains the glomeruli .
- The medulla, the innermost part. It has six triangular areas, the renal pyramids , with their vertices directed towards the renal pelvis .
- The renal pelvis, a cavity that collects urine formed in the cortex and medulla.