Urinary bladder an organ that regularly stores a hyperosmotic concentration of urine. It therefore is relatively impermeable and has multiple epithelial layers. The urinary bladder of the cetaceans (whales and dolphins) is proportionally smaller than that of land-dwelling mammals. In the whole class of Aves there is no urinary bladder per se. Although all birds have kidneys, the ureters open directly into a cloaca which serves as a reservoir for urine, fecal matter, and eggs. In crustaceans, the urinary bladder consists of two sets of lateral and central lobes. Urinary bladder The urinary bladder is a hollow muscular organ in humans and
Bladder cancer cancer might partly be caused by the bladder directly contacting carcinogens that are excreted in urine, although this has not yet been confirmed in other studies. The treatment of bladder cancer depends on how deeply the tumor invades into the bladder wall. Superficial tumors (those not entering the muscle layer) can be "shaved off" using an electrocautery device attached to a cystoscope, which in that case is called a resectoscope. The procedure is called transurethral resection of bladder tumor—TURBT—and serves primarily for pathological staging. In case of non-muscle invasive bladder cancer the TURBT is in itself the treatment, but in