Fetal Cardio Flashcards
When does formation of the embryonic vessels and heart begin?
day 18
What are sites of hematopoiesis?
Yolk sac>Intraembryonic organs>liver>spleen>thymus>bone marrow
How does blood formation occur?
Mesenchymal cells differentiate into angioblasts, which aggregate to form blood islands which contain pluripotent hematopoietic stem cells. During vasculogenesis, cavities appear and angioblasts form an endothelial cell lining. Cavities fuse to form a network of endothelial channels during angiogenesis.
How do endocardial tubes form?
bilateral, parallel endocardial tubes form by vasculogenesis in the rostral splanchnic mesoderm, This embryonic folding occurs cranial to caudal during 3rd-4th weeks
What does sinus venarum become?
becomes sinus venarum, coronary sinus, oblique vein left atrium
What does primitive atrium become?
trabeculated parts of atria
What does primitive ventricle become?
trabeculated parts of left ventricles
What does bulbus cordis become?
conus arteriosus (smooth part of right ventricle), aortic vestibule (smooth part of left ventricle
What does truncus arteriosus become?
ascending aorta
pulmonary trunk
How does heart loop during the 4th week?
The cardiac loop forms when the cranial aspect of the heart tube bends ventrocaudally and to the right while the caudal aspect of the heart tube bends toward the dorsocranial aspect and towards the left. The formation of the cardiac loop takes approximately five days and usually complete by day 28
What happens in dextrocardia?
If a D-bulboventricular loop fails to migrate into the left hemithorax, it can result in dextrocardia with the heart in the right hemithorax.
What do cells of secondary heart field form?
derivatives at arterial pole, parts of right ventricle and OFT
What do do extracardiac progenitor cells give rise to?
cardiac neural crest cells and proepicardium
When and how does cardiac septa form?
during 4th-6th weeks the formation of AV cushions allow septation of AV canal and OFT, the myocardium deposits inducing epithelial mesenchymal transformation of endocardium at AV border
What forms membranous portion of atrial/ventricular septa, AV canal, and valves?
when neural crest cells invade conotruncal region to form aortic/pulmonary OFT branches
When does atrial septation form?
the 5th week and finishes after birth when foramen ovale
grows as a crescent-shaped wedge from dorsal wall toward cushions forming in AV canal
septum primum
allows oxygenated blood to be shunted from right to left atria like foramen secundum, Dorsal and ventral AV cushions form to divide canal and becomes obliterated
foramen primum
grows from dorsal wall of right atrium to the right of septum primum
septum secundum
continues to grow cranial-caudally and ventral-dorsally; stops before AV septum to form foramen ovale
septum secundum