The kidneys are a pair of bean shaped organ located at the back of the abdomen. Healthy kidneys are reddish brown in colour and each measures 10-15 cm in length and weighs approximately 160 grams. The kidneys are made up of millions of filters called Nephrons. The Nephrons work continuously filtering blood and removing waste products from the body. The kidneys filter about 250 ml of blood every minute and this way they maintain blood volume and remove excess fluids from the body. The fluid filtered out is called urine. The urine is collected in the central part of the kidney and passes through the urinary ducts or ureters down to the bladder. Each day the two kidneys excrete about 1-2 liters of urine depending on fluid intake.
The kidneys perform the vital jobs of cleaning the blood of waste products and removing excess fluid.
The other functions of the kidney are to maintain the body's balance of various salts such as Sodium, Potassium, Calcium and phosphate as well as acid. They release hormones, which influence the bone structure (Vit D), the generation of red blood cells (erythropoietin) and the regulation of blood pressure (angiotensin).