Kidney
Ren
UrinaryOrgansAbdomenLeft and right
View left in 3D View right in 3D
- What it is
- Bean-shaped retroperitoneal organ lying on the posterior abdominal wall between T12 and L3, wrapped in a tough fibrous capsule and perirenal fat. Its hilum, facing anteromedially, transmits the renal artery, vein and pelvis.
- Function
- Filters about 180 L of plasma a day into 1–2 L of urine, regulating water, salt, potassium, acid–base balance and blood pressure, and secretes renin, erythropoietin and active vitamin D.
- Size
- About 11 × 6 × 3 cm, 120–170 g each; ~1 million nephrons per kidney.
- Clinical note
- The right kidney usually sits 1–2 cm lower than the left because the liver lies above it. Both move 2–3 cm with breathing.