The kidney filters body fluids within the nephron units and expels wastes via the ureter.
Kidney is one of a pair of organs located at the back of the abdomen, against the strong muscles next to the spine, and behind the intestines and other organs.
The adrenal glands lie on top of the kidneys.
Each kidney weighs about 5 ounces (140g) and is about 4 inches (10cm) long in the average adult.
Its inner structure, which is called the renal pelvis, collects urine as it is formed and passes it out of the kidney to the bladder via the ureter.
The renal pelvis also is connected to the artery and vein that carry blood to and from the kidney.
What is the function of the Kidneys?The kidneys filter out water and also unwanted substances in the blood.
These substances are produced by the normal working of the body.
They are excreted by the kidneys in the form of urine.
The kidneys also keep the salts and water of the body in correct balance.
How do kidneys work?The blood passes through each kidney under high pressure.
The blood is filtered by the glomeruli, special structures in the kidney containing clusters of capillaries that collect water, salts, and unwanted substances.
The filtrate passes along a fine tube, the nephron (of which there are approximately one million in each kidney), which reabsorbs any of the water, glucose, and salts that the body still re-quires and allows the rest to pass into the pelvis of the kidney as urine.