A myogenic muscular circulatory organ found in the vertebrate cardiovascular system composed of chambers of cardiac muscle. It is the primary circulatory organ.
Comment:
Taxon notes:" the ascidian tube-like heart lacks chambers....The ascidian heart is formed after metamorphosis as a simple tube-like structure with a single-layered myoepithelium that is continuous with a single-layered pericar- dial wall. It lacks chambers and endocardium.... The innovation of the chambered heart was a key event in vertebrate evolution, because the chambered heart generates one-way blood flow with high pressure, a critical requirement for the efficient blood supply of large-body vertebrates... all extant vertebrates have hearts with two or more chambers (Moorman and Christoffels 2003)" DOI:10.1101/gad.1485706; [homology-note] "As noted, the hearts of birds and mammals have four chambers that arises from the two chambers (atrium and ventricle) of the fish heart.[well established][VHOG]" xsd:string {date_retrieved="2012-09-17", external_class="VHOG:0000276", ontology="VHOG", source="ISBN:978-0072528305 Kardong KV, Vertebrates: Comparative Anatomy, Function, Evolution (2006) p.481", source="http://bgee.unil.ch/"}