Anatomy and Function of the Urinary System

It may be helpful to begin a discussion of urinary stone disease with an overview of the anatomy of the urinary tract. The urinary system consists of two bean-shaped kidneys, a triangle shaped, balloon-like organ in the lower abdomen called the bladder, two tubes called ureters which connect each kidney to the bladder, and the urethra, a channel which allows urine to flow from the bladder to the outside of the body. Each kidney is located toward the back and lateral to the spine. The lowest rib signals the midportion of the kidney.

After the body extracts energy from the food we eat, waste is sent into the blood. The kidneys process about fifty gallons of blood each day. Urine is produced as waste containing excess water and dissolved solids after the kidneys filter and clean blood. The kidneys also maintain a stable balance of salts and other substances in the blood. The ureters carry urine from the kidneys to the bladder, which can hold over a pint of urine. The bladder holds the urine until urination, where the urethra carries urine from the bladder out of the body.