Distensible musculomembranous organ situated in the anterior part of the pelvic cavity in which urine collects before excretion[MP].
Comment:
[homology-note] "In tetrapods, the urinary bladder arises as an outpocketing of the cloaca. (...) The tetrapod urinary bladder appears first among amphibians and is present in Sphenodon, turtles, most lizards, ostriches among birds, and all mammals.[well established][VHOG]" xsd:string {date_retrieved="2012-09-17", external_class="VHOG:0000740", ontology="VHOG", source="ISBN:978-0072528305 Kardong KV, Vertebrates: Comparative Anatomy, Function, Evolution (2006) p.577-78", source="http://bgee.unil.ch/"}; [taxon-note] "The urinary bladder evolved in tetrapods. Birds to not possess a true urinary bladder, although Palaeognathae have an undifferentiated cloacal outpocketing that serves a similar function[https://github.com/obophenotype/uberon/issues/454]"