Comparative anatomy of the heart of mammals

Abstract

Hearts from 20 mammalian orders were examined according to a fixed protocol to determine if the gross differences of shape and internal anatomy could be explained. Three generalizations can be made: firstly differences are most closely related to taxonomic position, secondly some features, such as the prominence of the conus of the right ventricle in animals that leap, dig or sprint regularly as part of their defence mechanism and a long, narrow left ventricle in endurance performers may be more closely related to activity than ancestry, and lastly some characteristics may be pleiotropic effects of thoracic morphogenesis.

DESCRIÇÕES ANATÔMICAS DO CORAÇÃO E VASOS DA BASE DE Procyon cancrivorus (CUVIER, 1798)

“…O cone arterioso, situado junto à base do tronco pulmonar, se mostra bem delimitado nos canídeos enquanto que nos felídeos não é proeminente (ROWLATT, 1990;GUIMARÃES, 2009 (ÀVILA et al, 2010).…”

Little variation in the morphology of the atria across 13 orders of birds

“…barn swallow and lesser redpoll, to have particularly few pectinate muscles. Generally, the position of atrioventricular junctions and arterial bases were fixed, but the aorta did exhibit some rotation in the transverse plane (but much less so than in mammals (Rowlatt, 1990)). …”

“…Birds always have 3 sinus horns, whereas mammals may have 2, if the left sinus horn is regressed, or 3. In mammals, the sinuatrial valve can be well-developed and reptile-like as in monotremes, well-developed only around the inferior caval vein and coronary sinus, or almost completely regressed (Rowlatt, 1990;Jensen et al, 2014a). In contrast, in birds both leaflets are always present although their state of development varies as we show here and has been noted before (Benninghoff, 1933).…”

“…When the hearts of mammals and reptiles are compared, it is evident that mammalian hearts are remodeled by incorporation of systemic and pulmonary vein myocardium to the atria (Jensen, Boukens, Wang, Moorman, Christoffels, 2014a; Carmona, Ariza, Cañete, Muñoz-Chápuli, 2018). The number of venous orifices to the left atrium can vary between 1 (dugongs) and 7 (armadillos), and the myocardial sleeve of the veins may be extensive (mouse) or all but gone (harbour porpoise) (Rowlatt, 1990; Mommersteeg et al.,2007). The number of orifices and the extent of myocardium even varies within the species (Nathan, Eliakim, 1966;Calkins et al, 2007, Rowlatt, 1990.…”

“…The number of venous orifices to the left atrium can vary between 1 (dugongs) and 7 (armadillos), and the myocardial sleeve of the veins may be extensive (mouse) or all but gone (harbour porpoise) (Rowlatt, 1990; Mommersteeg et al.,2007). The number of orifices and the extent of myocardium even varies within the species (Nathan, Eliakim, 1966;Calkins et al, 2007, Rowlatt, 1990. In human, for example, the left atrium typically receives four pulmonary veins, but three and five veins are also frequently observed, two and six can occur but are rare (Mansour et al, 2004).…”