The kidney is an organ located near the middle of the back on both sides of the spine, just below the back ribs. Kidney function is very important in maintaining survival. Kidney consists of a pair of organs, namely the left kidney and right kidney. Each kidney is about 10-12 cm or the size of a fist, and contains about one million nephrons, which are tiny blood filters. There are various kidney functions that have an important role for health. Know the Kidney Function Kidney functions vary, including: Filter blood All blood in the body passes through the kidneys several times a day. When the kidneys filter blood, urine will be formed from residual substances and excess fluid in the body. The urine is then flowed through the ureter, to then be brought to the bladder and discharged as urine. Filter and dispose of waste Another function of the kidneys is to filter and dispose of waste, such as poisons, excess salt, and urea (nitrogen-containing waste results from protein