Editing Cetacea (section)

=== Abdominal organs ===
The stomach consists of three chambers. The first region is formed by a loose gland and a muscular forestomach (missing in beaked whales); this is followed by the main stomach and the [[pylorus]]. Both are equipped with glands to help digestion. A bowel adjoins the stomachs, whose individual sections can only be distinguished [[Histology|histologically]]. The [[liver]] is large and separate from the [[gall bladder]].<ref>{{cite book|author1=C. Edward Stevens|author2=Ian D. Hume|title=Comparative Physiology of the Vertebrate Digestive System|publisher=University of Cambridge|year=1995|access-date=5 September 2015|page=51|isbn=978-0-521-44418-7|url= https://books.google.com/books?id=DZuAsci2apAC&q=cetacean+digestive+system&pg=PR15}}</ref>

The kidneys are long and flattened. The salt concentration in cetacean blood is lower than that in seawater, requiring kidneys to excrete salt. This allows the animals to drink seawater.<ref>{{cite journal|author=Clifford A. Hui|title=Seawater Consumption and Water Flux in the Common Dolphin ''Delphinus delphis''|journal=Chicago Journals|volume=54|issue=4|pages=430–440|year=1981|jstor= 30155836}}</ref> The [[urinary bladder]] is proportionally smaller in cetaceans than in land 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> The [[testicles|testes]] are located internally, without an external [[scrotum]].<ref name="WürsigThewissen2017">{{cite book|author1=Bernd Würsig|author2=J.G.M. Thewissen|author3=Kit M. Kovacs|title=Encyclopedia of Marine Mammals|url=https://books.google.com/books?id=T3zGDgAAQBAJ&q=testes+OR+testis+OR+testicles|date=27 November 2017|publisher=Elsevier Science|isbn=978-0-12-804381-3|access-date=19 October 2020|archive-date=29 June 2023|archive-url=https://web.archive.org/web/20230629161516/https://books.google.com/books?id=T3zGDgAAQBAJ&q=testes+OR+testis+OR+testicles|url-status=live}}</ref><ref name="rommel2007">{{cite book | last1 = Rommel | first1 = S.A. | first2 = D.A. | last2 = Pabst | first3 = W.A. | last3 = McLellan | chapter = Functional anatomy of the cetacean reproductive system, with comparisons to the domestic dog | title = Reproductive Biology and Phylogeny of Cetacea: Whales, Porpoises and Dolphins | date = 2007 | pages = 127–145 | editor-last = Miller | editor-first = D.L. | chapter-url = https://www.researchgate.net/publication/286334625 | doi = 10.1201/b11001| isbn = 9780429063626 }}</ref><ref name="rommel1998">{{cite magazine | last1 = Rommel | first1 = S.A. | first2 = D.A. | last2 = Pabst | first3 = W.A. | last3 = McLellan | title = Reproductive Thermoregulation in Marine Mammals | journal = American Scientist | volume = 86 | number = 5 | date = 1998 | pages = 440–448 | jstor = 27857097 | url = https://uncw.edu/mmsp/documents/rommeletal1998reproductivethermoregulation.pdf | url-status = live | archive-date = 22 November 2021 | archive-url = https://web.archive.org/web/20211122202231/https://uncw.edu/mmsp/documents/rommeletal1998reproductivethermoregulation.pdf}}</ref><ref name="Pabst, D. Ann 1998">{{cite book | last1 = Pabst | first1 = D.A. | last2 = Sentiel | first2 = A.R | first3 = W.A. | last3 = McLellan | chapter = Evolution of thermoregulatory function in cetacean reproductive systems | title = The Emergence of Whales | publisher = Springer US | date = 1998 | pages = 379–397 | series = Advances in Vertebrate Paleobiology | doi = 10.1007/978-1-4899-0159-0_13 | isbn = 978-1-4899-0161-3 | editor-last = Thewissen | editor-first = J.G.M.}}</ref> The uterus is [[Uterus#Other animals|bicornuate]].<ref name="rommel2007"/>