Urology is the specialty that deals with problems in the urinary tract; the kidneys, ureters, bladder, and urethra. There are three main components to urology; stones, cancer, and problems with weeing:
Urinary tract stones can occur anywhere so rather than putting them on seperate pages, I've jammed them all on one. This is for kidneys, ureter and bladder. (If a stone's in the bladder, it'll probably pass through the urethra fairly easily).