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 uterus by the vesico-uterine pouch. In infants and young children the urinary bladder is in the abdomen even when empty. Urine, excreted by the kidneys, collects in the bladder before disposal by urination (micturition). The urinary bladder usually holds 300-350 ml of urine. As urine accumulates, the rugae flatten and the wall of the bladder thins as it stretches, allowing the bladder to store larger amounts of urine without a significant rise in internal pressure. Urination is controlled by the pontine micturition center in the brainstem. Bacteriuria is the presence of bacteria in the urine which can indicate a urinary