Editing Bladder (section)

=== Amphibians ===
Most aquatic and semi-aquatic amphibians can absorb water directly through their skin. Some semi-aquatic animals also have similarly permeable bladder membranes.<ref>{{Cite journal|last1=Urakabe|first1=Shigeharu|last2=Shirai|first2=Dairoku|last3=Yuasa|first3=Shigekazu|last4=Kimura|first4=Genjiro|last5=Orita|first5=Yoshimasa|last6=Abe|first6=Hiroshi|title=Comparative study of the effects of different diuretics on the permeability properties of the toad bladder|journal=Comparative Biochemistry and Physiology Part C: Comparative Pharmacology|language=en|volume=53|issue=2|pages=115–119|doi=10.1016/0306-4492(76)90063-0|pmid=5237|year=1976}}</ref> They tend to have high rates of urine production, to offset this high water intake; and the dissolved salts in their urine are highly dilute. The urinary bladder helps these animals to retain salts. Some aquatic amphibians, such as ''[[Xenopus]]'', do not reabsorb water from their urine, to prevent excessive water influx.<ref>{{Cite journal|last1=Shibata|first1=Yuki|last2=Katayama|first2=Izumi|last3=Nakakura|first3=Takashi|last4=Ogushi|first4=Yuji|last5=Okada|first5=Reiko|last6=Tanaka|first6=Shigeyasu|last7=Suzuki|first7=Masakazu|title=Molecular and cellular characterization of urinary bladder-type aquaporin in Xenopus laevis|journal=General and Comparative Endocrinology|volume=222|pages=11–19|doi=10.1016/j.ygcen.2014.09.001|pmid=25220852|year=2015}}</ref> For land-dwelling amphibians, dehydration results in reduced urine output.<ref name="VittCaldwell2013">{{cite book|url=https://books.google.com/books?id=Gay9N_ry79kC&pg=PA184|title=Herpetology: An Introductory Biology of Amphibians and Reptiles|date=25 March 2013|publisher=Academic|isbn=978-0-12-386920-3|author1=Laurie J. Vitt|author2=Janalee P. Caldwell|page=184}}</ref>

The amphibian bladder is usually highly distensible; among some land-dwelling species of frogs and salamanders, it may account for 20%–50% of total body weight.<ref name="VittCaldwell2013" /> Urine flows from the kidneys through the ureters into the bladder and is periodically released from the bladder to the cloaca.<ref>{{Cite book |last1=Feder |first1=Martin E. |url=https://books.google.com/books?id=oaS-OpEjPtUC&pg=PA108 |title=Environmental Physiology of the Amphibians |last2=Burggren |first2=Warren W. |date=1992-10-15 |publisher=University of Chicago Press |isbn=978-0-226-23944-6 |language=en}}</ref>