In the process of tubular secretion, this is where the renal tubule extracts chemicals from the capillary’s blood chemicals and secretes these to the tubular fluid. The two main purposes are waste removal and the maintenance of acid-base balance. This is the process in the urine formation where urea, uric acid, bile acids, ammonia and creatinine exits to the renal tubule. This clears the pollutants in the blood as well. It is also in this process where tubular secretion of hydrogen and bicarbonate irons functions to regulate the pH of the fluids of the body.