Both men and women have kidneys, and everyone has two kidneys, which are located on the back of the waist and where the spine intersects with the 12 rib. Although it is sometimes called "kidney", the word is actually used to refer to the kidney. Kidney is an important organ of human body, which is responsible for filtering impurities in blood, maintaining the balance between body fluids and electrolytes, and finally producing urine to be excreted through urethra.