It is an organ present at the back of the body, along the spinal column.They are bean shaped organs that are connected to the body and each other through a series of blood vessels. Every human has two kidneys and they play a very important role in regulating the urinary system, electrolyte balance, acid-base regulation and blood pressure in the body. It serves as the body’s natural filter, and helps remove toxins. These are then sent to the urinary bladder where it is thrown out of the body as urine. The kidney also regualtes the salt concentration in the body, and bloating or oedema is a common symptom of kidney disease patients. According to research humans have two kidneys because they filter all the blood in the human body under very high pressure, wich is evenly distributed between the two kidneys, although experts say that a human can survive on one kidney as well.