Kidneys are a pair of bean-shaped structures that are located just below and posterior to the liver in the peritoneal cavity. Externally, the kidneys are surrounded by three layers, the renal fascia, perirenal fat capsule and renal capsule. While internally, it comprises of 3 different regions – the cortex, medulla and renal pelvis. The renal cortex contains the nephrons making it granular in nature, while the medulla has multiple pyramidal tissue masses, called the renal pyramids. In between the pyramids are spaces called renal columns through which the blood vessels pass. The renal pelvis leads to the ureter on the outside of the kidney while inside of the kidney, the renal pelvis branches out into two or three extensions called the major calyces, which further branch into the minor calyces.
Discuss the structure and the functions of the kidneys.