Kidneys

Kidneys

Reddish brown, bean-shaped organs that are about 12 cm long, 6 cm wide, and 3 cm thick in adults.

Location of the kidneys

Lie on both sides of the vertebral column, in a depression on the posterior abdominal wall.

Right kidney position

The right kidney is positioned 1.5 to 2 cm lower than the left due to the position of the liver.

Retroperitoneal

Refers to the kidneys being located behind or outside of the parietal peritoneum.

Surrounding structures of the kidneys

The kidneys are surrounded by a fibrous renal capsule, adipose tissue (renal fat), and connective tissue (renal fascia).

Function of the kidneys

Regulate the volume and composition of body fluids.

Excretion function of the kidneys

Remove excess water/electrolytes and metabolic wastes from the blood and excrete wastes in the urine.

Dialysis

When kidneys are not functioning properly, hemodialysis and continuous peritoneal dialysis can be used to filter wastes out of the blood.

Erythropoietin

A hormone secreted by the kidneys that stimulates red blood cell production.

Renin

An enzyme secreted by the kidneys that helps to increase blood pressure.

Calcitriol

The active form of Vitamin D produced by the kidneys, which increases calcium absorption from the small intestine when blood calcium level is low.