Anatomy and Physiology Of the Urinary System Kidneys

Kidneys Anatomy Bean Shaped – approximately the size of a fist Location: Dorsal wall behind the peritoneum in the abdominal cavity – Retroperitoneal Surrounded by a fibrous connective tissue – the Renal capsule Around the renal capsule is the renal fat pad which protects the kidney from shock due to jarring. The renal fascia anchors the kidneys to the abdominal wall On the medial portion of each kidney is an area called the hilum. This is where the renal artery and nerves enter and the renal vein and ureter exit. The hilum opens into the renal sinus which is lined with fat and connective tissue.

Kidney Cross Section

The kidney is composed of the outer cortex and the inner medulla, both are surrounding the renal sinus. The medulla contains the renal pyramids which extend into medullary rays Extensions of the cortex, the renal columns, project between the pyramids. The base of each pyramid is on the border of the cortex and medulla. The points, renal papillae, are in the center of the pyramid. There are two major “funnel” types: major and minor calyces which come together to create the largest “funnel” the renal pelvis.

The renal pelvis is within the renal sinus. The renal pelvis narrows to the ureter. Urine is formed within the pyramids – goes to the renal papillae – the minor calyx – the major calyx – the renal pelvis – the ureter.