Editing Bladder (section)

==Other animals==
=== Mammals ===
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All species of mammal have a urinary bladder.<ref>{{Cite book |last1=Flower |first1=William Henry |url=https://books.google.com/books?id=YclRAAAAMAAJ&dq=bladder&pg=PA69 |title=An Introduction to the Study of Mammals Living and Extinct |last2=Lydekker |first2=Richard |date=1891 |publisher=A. and C. Black |language=en}}</ref> This structure begins as an [[embryonic cloaca]]. In the vast majority of species, it eventually becomes differentiated into a dorsal part, connected to the intestine, and a ventral part, associated with the urinogenital passage and urinary bladder. The only mammals in which this does not take place are the [[platypus]] and the [[Echidna|spiny anteater]], both of which retain the cloaca into adulthood.<ref name="ABC">{{cite book|url=https://archive.org/stream/chordates00rand/#page/276/mode/1up/search/bladder|title=The Chordates|date=1950|publisher=Balkiston|author=Herbert W. Rand}}</ref>

The mammalian bladder is an organ that regularly stores a hyperosmotic concentration of urine. It therefore is relatively impermeable and has a multi-layer epithelium. The urinary bladders of [[cetacean]]s (whales and dolphins) are proportionally smaller than those of land-dwelling mammals.<ref name="Hunter2015">{{cite book|url=https://books.google.com/books?id=TNAIBwAAQBAJ&pg=PR35|title=The Works of John Hunter, F.R.S.|date=26 March 2015|publisher=Cambridge University|isbn=978-1-108-07960-0|page=35|author=John Hunter}}</ref>

=== Reptiles ===
In all reptiles, the urinogenital ducts and the [[rectum]] both empty into the organ called the [[cloaca]]. In some reptiles, a midventral wall in the cloaca opens into a urinary bladder. The urinary bladder exists in all species of turtle and tortoise and most species of lizard. [[Monitor lizard]]s, the [[legless lizard]]s, snakes, alligators, and crocodiles do not have urinary bladders.<ref name="ABC" />{{rp|p. 474}}

Many turtles, tortoises, and lizards have proportionally very large bladders. [[Charles Darwin]] noted that the bladder of the [[Galapagos tortoise]] could store urine weighing up to 20% of the tortoise's body weight.<ref name="Bentley2013" /> Such adaptations are the result of environments, such as remote islands and deserts, where fresh water is very scarce.<ref>{{Cite journal|last=Paré|first=Jean|date=January 11, 2006|title=Reptile Basics: Clinical Anatomy 101|url=http://www.ivis.org/proceedings/navc/2006/SAE/600.pdf?LA=1|journal=Proceedings of the North American Veterinary Conference|volume=20|pages=1657–1660}}</ref> Other desert-dwelling reptiles have large bladders, which can hold long-term reserves of water for several months and aid in [[osmoregulation]].<ref>{{Cite journal|last1=Davis|first1=Jon R.|last2=DeNardo|first2=Dale F.|date=2007-04-15|title=The urinary bladder as a physiological reservoir that moderates dehydration in a large desert lizard, the Gila monster Heloderma suspectum|journal=Journal of Experimental Biology|language=en|volume=210|issue=8|pages=1472–1480|doi=10.1242/jeb.003061|issn=0022-0949|pmid=17401130|doi-access=free|bibcode=2007JExpB.210.1472D }}</ref>

Turtles have two or more accessory urinary bladders, beside the neck of the urinary bladder and above the pubis, occupying much of the body cavity.<ref>{{Cite journal|last1=Wyneken|first1=Jeanette|last2=Witherington|first2=Dawn|date=February 2015|title=Urogenital System|url=http://www.ivis.org/advances/wyneken/16.pdf?LA|journal=Anatomy of Sea Turtles|volume=1|pages=153–165}}</ref> Turtles' bladder is also usually divided into two lobes: the right lobe is under the liver, which prevents large stones from remaining in the lobe; the left lobe is likelier than the right to have [[Bladder stone (animal)|calculi]].<ref>{{Cite book|title=Reptile Medicine and Surgery|last1=Divers|first1=Stephen J.|last2=Mader|first2=Douglas R.|publisher=Elsevier Health Sciences|year=2005|isbn=9781416064770|location=Amsterdam|pages=481, 597}}</ref>

=== 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>

=== Fish ===
The gills of most [[teleost]] fish help to eliminate ammonia from the body, and fish live surrounded by water, but most still have a distinct bladder for storing waste fluid. The urinary bladder of [[teleost]]s is permeable to water, though this is less true for freshwater dwelling species than saltwater species.<ref name="Bentley2013">{{cite book|url=https://books.google.com/books?id=U0D3BwAAQBAJ&pg=PA143|title=Endocrines and Osmoregulation: A Comparative Account in Vertebrates|date=14 March 2013|publisher=Springer Science & Business Media|isbn=978-3-662-05014-9|author=P.J. Bentley}}</ref>{{rp|p. 219}} In freshwater fish the bladder is a key site of absorption for many major ions<ref name=":2">{{Cite journal |last1=Takvam |first1=Marius |last2=Wood |first2=Chris M. |last3=Kryvi |first3=H. |last4=Nilsen |first4=Tom O. |date=2023-06-29 |title=Role of the kidneys in acid-base regulation and ammonia excretion in freshwater and seawater fish: implications for nephrocalcinosis |journal=Frontiers in Physiology |volume=14 |doi=10.3389/fphys.2023.1226068 |doi-access=free |issn=1664-042X |pmc=10339814 |pmid=37457024}}</ref> in marine fish urine is held in the bladder for extended periods to maximise water absorption.<ref name=":2" /> The urinary bladders of fish and [[tetrapod]]s are thought to be analogous while the former's swim-bladders and latter's [[lung]]s are considered homologous.

Most fish also have an organ called a [[swim-bladder]] which is unrelated to the urinary bladder except in its membranous nature. The [[loach]]es, [[pilchard]]s, and [[herring]]s are among the few types of fish in which a urinary bladder is poorly developed. It is largest in those fish which lack an air bladder, and is situated in front of the [[oviduct]]s and behind the [[rectum]].<ref>{{Cite book|title=Lectures on the comparative anatomy and physiology of the invertebrate animals|last=Owen|first=Richard|publisher=Longman, Brown, Green, and Longmans|year=1843|location=London|pages=283–284|url=https://books.google.com/books?id=pNpPpKj4_tgC}}</ref> 

=== Birds ===
{{further|Urogenital systems of birds}}
In nearly all bird species, there is no urinary bladder per se.<ref name="Ornithology2016">{{cite book|author=Cornell University. Laboratory of Ornithology|title=Handbook of Bird Biology|url=https://books.google.com/books?id=OGyQDAAAQBAJ&q=bird+urinary+bladder|date=19 September 2016|publisher=John Wiley & Sons|isbn=978-1-118-29105-4}}</ref> Although all birds have kidneys, the [[ureters]] open directly into a [[cloaca]] which serves as a reservoir for urine, fecal matter, and eggs.<ref name="Knight1854">{{cite book|url=https://archive.org/details/in.ernet.dli.2015.45180|title=The English Cyclopaedia: A New Dictionary of Universal Knowledge|publisher=Bradbury and Evans|year=1854|page=[https://archive.org/details/in.ernet.dli.2015.45180/page/n71 136]|author=Charles Knight}}</ref>

=== Crustaceans ===
Unlike the urinary bladder of vertebrates, the urinary bladder of [[crustacean]]s both stores and modifies urine.<ref name=":1">{{Cite book|url=https://books.google.com/books?id=trazj_5gCSQC&pg=PA47|title=Nonmammalian animal models for biomedical research|date=1989|publisher=CRC Press|others=Woodhead, Avril D.|isbn=0-8493-4763-7|location=Boca Raton, Fla.|pages=51–52|oclc=18816053}}</ref> The bladder consists of two sets of lateral and central lobes. The central lobes sit near the digestive organs and the lateral lobes extend along the front and sides of the crustacean's body cavity.<ref name=":1" /> The tissue of the bladder is thin [[epithelium]].<ref name=":1" />