Search results
Results from the WOW.Com Content Network
The aortic sac or aortic bulb [1] is a dilated structure in mammalian embryos, lined by endothelial cells and is the most distal part of the truncus arteriosus. [2] It is the primordial vascular channel from which the aortic arches arise (and eventually the dorsal aortae ) and is homologous to the ventral aorta of gill-bearing vertebrates.
The aortic arches or pharyngeal arch arteries (previously referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral to the dorsal aorta and arise from the aortic sac.
The paired dorsal aortae arise from aortic arches that in turn arise from the aortic sac. The primary dorsal aorta is located deep to the lateral plate of mesoderm and move from lateral to medial position with development and eventually will fuse with the other dorsal aorta to form the descending aorta. [2]
The truncus arteriosus and bulbus cordis are divided by the aorticopulmonary septum.The truncus arteriosus gives rise to the ascending aorta and the pulmonary trunk.The caudal end of the bulbus cordis gives rise to the smooth parts (outflow tract) of the left and right ventricles (aortic vestibule & conus arteriosus respectively). [2]
The tube starts receiving venous drainage in its caudal pole and will pump blood out of the first aortic arch and into the dorsal aorta through its polar head. Initially the tube remains attached to the dorsal part of the pericardial cavity by a mesodermal tissue fold called the dorsal mesoderm.
Upon sectioning of the heart the atrioventricular endocardial cushions can be observed in the lumen of the atrial canal as two thickenings, one on its dorsal and another on its ventral wall. These thickenings will go on to fuse and remodel to eventually form the valves and septa of the mature adult heart.
Most are located above the aortic arch, [2] while some are located on the posterior side of the aortic arch between it and the pulmonary artery below. [3] They consist of glomus cells and sustentacular cells. [1] Some sources equate the "aortic bodies" and "paraaortic bodies", while other sources explicitly distinguish between the two.
Ductus arteriosus evolved with the lung in the ancestors of the lungfish as a connection between the pulmonary arteries and dorsal aorta. During embryonic development, reptiles, birds, and mammals all have either one or two paired ductus arteriosi that provide a fetal shunt of blood away from the lungs.