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
Urinary bladder a series of ridges, thick mucosal folds known as rugae that allow for the expansion of the bladder. The Latin phrase for "urinary bladder" is "vesica urinaria", and the term "vesical" or prefix "vesico -" appear in connection with associated structures such as vesical veins. The modern Latin word for "bladder" - "cystis" - appears in associated terms such as cystitis (inflammation of the bladder). The outside of the bladder is protected by a serous membrane. The bladder wall itself is smooth muscle. The inner side of the bladder is lined with a mucosal membrane consisting of a surface glycocalyx