Excretory system properly dissolved, they have the ability to build up, and form these kidney stones. These stones are most commonly made up of substances such as calcium, cystine, oxalate, and uric acid, as these are the substances that normally would dissolve within the urine. When they do not dissolve correctly and further build up, they will commonly lodge themselves in the urinary tract and in this case, are usually small enough to pass through urine. In extreme situations, however, these stones may lodge themselves within the tube that connects the kidney and the bladder, called the ureter. In this case, they
Urinary bladder urinary bladder is poorly developed. It is largest in those fish which lack an air bladder, and is situated in front of the oviducts and behind the rectum. All mammals have a urinary bladder. This structure begins as an embryonic cloaca. In the vast majority, this eventually becomes differentiated into a dorsal part connected to the intestine and a ventral part which becomes associated with the urinogenital passage and urinary bladder. The only mammals in which this does not take place are the platypus and the spiny anteater both of which retain the cloaca into adulthood. The mammalian bladder is