Truncus arteriosus (embryology) 4928614 141797971 2007-07-01T13:30:01Z CSWarren 567897 Fixing [[Wikipedia:Disambiguation pages with links|links to disambiguation pages]] using [[Project:AWB|AWB]] {{Infobox Embryology | Name = Truncus arteriosus| Latin = | GraySubject = 135 | GrayPage = 514 | Image = Gray462.png | Caption = Heart of human [[embryo]] of about fourteen days. (Truncus arteriosis visible at top.) | Image2 = Gray469.png | Caption2 = Diagrams to illustrate the transformation of the [[bulbus cordis]]. Ao. '''Truncus arteriosus'''. Au. [[Atrium (heart)|Atrium]]. B. Bulbus cordis. RV. [[Right ventricle]]. LV. [[Left ventricle]]. P. [[Pulmonary artery]]. | System = | CarnegieStage = | Precursor = | GivesRiseTo = [[aorta]], [[pulmonary artery]] | MeshName = Truncus+Arteriosus | MeshNumber = A07.541.278.930 | DorlandsPre = | DorlandsSuf = | }} The '''truncus arteriosus''' and [[bulbus cordis]] are divided by the [[aorticopulmonary septum]]. This makes its appearance in three portions. (1) Two distal ridge-like thickenings project into the lumen of the tube; these increase in size, and ultimately meet and fuse to form a septum ([[aorticopulmonary septum]]), which takes a spiral course toward the proximal end of the truncus arteriosus. It divides the distal part of the truncus into two vessels, the [[aorta]] and [[pulmonary artery]], which lie side by side above, but near the heart the pulmonary artery is in front of the aorta. (2) Four [[endocardial cushions]] appear in the proximal part of the truncus arteriosus in the region of the future [[semilunar valves]]; the manner in which these are related to the aortic septum is described below. (3) Two endocardial thickenings—anterior and posterior—develop in the bulbus cordis and unite to form a short septum; this joins above with the aortic septum and below with the ventricular septum. The septum grows down into the ventricle as an oblique partition, which ultimately blends with the ventricular septum in such a way as to bring the bulbus cordis into communication with the pulmonary artery, and through the latter with the sixth pair of [[aortic arches]]; while the left ventricle is brought into continuity with the aorta, which communicates with the remaining aortic arches. ==Developmental anomalies== Failure of the truncus arteriosus to close results in the condition known a [[Persistent Truncus Arteriosus]]. One of [[cyanotic heart defect]]s or [[congenital heart defects]]. ==Additional images== <gallery> Image:Gray1088.png|Liver with the septum transversum. Human embryo 3 mm. long. </gallery> ==External links== * {{EmbryologyUNSW|Notes/heart3b}} * [http://sprojects.mmi.mcgill.ca/embryology/cvs/early_chambers.html Overview at mcgill.ca] * [http://www.med.umich.edu/lrc/coursepages/M1/embryology/embryo/13cardiovascular_system.htm Description and diagram at umich.edu] {{Gray's}} {{Development of circulatory system}} [[Category:Embryology]] {{developmental-biology-stub}}