What is Kidney ?
The kidneys are bean-shaped excretory organs in vertebrates. Part of the urinary system, the kidneys filter wastes (especially urea) from the blood and excrete them, along with water, as urine. The medical field that studies the kidneys and diseases affecting the kidney is called nephrology.

What is Dialysis ?
Is a method for removing waste such as urea from the blood when the kidneys are incapable of this, i.e. in renal failure

The two types of dialysis are hemodialysis and peritoneal dialysis.

Hemodialysis :
T he patient's blood is passed through a tube into a machine that filters out waste products. The cleaned blood is then returned to the body.

Peritoneal dialysis:
A special solution is run through a tube into the peritoneal cavity, the abdominal body cavity around the intestine. The fluid is left there for a while to absorb waste products, and then removed through the tube.