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 tract infection such as cystitis. Frequent urination can be due to excessive urine production, small bladder capacity, irritability or incomplete emptying. Males with an enlarged prostate urinate more frequently. One definition of an overactive bladder is when a person urinates more than eight times per day. An overactive bladder can often cause urinary incontinence. Though both urinary frequency and volumes have been shown to have a circadian rhythm, meaning day and night cycles, it is not entirely clear how these are disturbed in the overactive bladder. Urodynamic testing can help to explain the symptoms. An underactive bladder is the condition