Embryology Flashcards
What is angiogenesis/ vasculogenesis?
Formation of new blood vessels from spaces lined by angioplasty
What is an angioblast?
Primordia of vascular endothelial cells that form within the mesoderm and spontaneously form blood vessels
What is an atrial septal defect?
A hole in the septum that divides the 2 atria
Why does an atrial septal defect commonly occur?
The septum secundum fails to completely cover the foramen secundum
Bulbus cordis dorms what with the truncus arteriosus?
The outflow tract of the primitive heart tube
What are cardinal veins?
System of veins draining the head and body of the developing embryo, joining the sinus venosus
What is the cardiogenic region?
The region of mesoderm at the anterior end of the trilaminar disk that will give risk to endocadial tubes
What is the conus cordis/ conus arteriosus?
Segment of bulbus cordis that forms the route of the truncus arteriosus
What is the Crista terminalis?
Dividing line between smooth walled atrium(sinus venosis) and rough walled atrium (primitive)
What is the ductus arteriosis?
The fetal shunt connecting the pulmonary trunk to the aorta to bypass the lungs in utero
What’s the ductus venosus?
Fetal shunt directing oxygenated blood carried by umbilical vein from the placenta to inferior vena cava passing the liver
What are the endocardial cushions?
4 structures responsible for septation within the heart, loose connective tissue covered by endothelium
What forms the primitive heart tube when they fuse during embryonic folding?
Endocardial tube
What’s the foramen ovale?
Hole in septum secundum allowing right to left shunt
What is a patent ductus arteriosus?
Failure of closure of the ductus arteriosus
What is persistent truncus arteriosis?
Failure of the aortic pulmonary septum to form properly. Defect with single arterial trunk
Where is the primitive atrium?
Rough walled chamber at the caudal end of primitive heart tube
What does the primitive heart tube consist of from inflow to outflow?
Sinus venosus, primitive atrium, primitive ventricle, bulbus cordis, truncus arteriosis
What does the primitive ventricle form?
Left ventrcle
What is the septum primum?
First membrane to divide primitive atrium.
What is the septum secundum?
A muscular infolding of the atrial wall that forms the second membrane dividing the atrium
The sinus venosis is the collecting chamber for the primitive heart tube recieving cardinal drainage from the left and right horns. What do the left and right horns become?
Right horn becomes right atrium
Left horn becomes coronary sinus
What is tetralogy of fallot? What does it result from?
Result of defective septation of outflow tract
4 defects- Ventricular septal defect, pulmonary stenosis, overriding aorta and RV hypertrophy
What is it called when the aorta lies anterior and to the right of the pulmonary trunk?
Transposition of great arteries
What is a ventricular septal defect?
Hole between right and left ventricles caused by defect in septation
What is the heart tube consisting of at the bottom and top?
Sinus venosus-> aortic roots
What is the direction of blood flow at day 28 in vitro
Common atrium-> narrow atrioventricular foramen-> primitive left ventricle-> interventricular foramen-> primitive right ventricle->bulbus cordis (conus cordis to truncus arteriosus)
How does the septum of the atrium develop?
Septum primum grows down. Gap at bottom ostium primum, second gap at top Ostium secundum (primum closes)
Septum secundum grows down leaving the fossa ovales
Failure leads to atrial septal defect
How does the interventricular septum form?
Muscular septum grows bottom up
Endocardial cushion grows from the side
Membranous interventicular septum grows down
What will failure of the membranous portion of the interventricular septum result in?
Ventricular septal defect
What does the spiral septum divide in development
Pulm tract and aorta
Failure leads to transposition of great vessels
What is the inter-uterine blood flow once development of heart has taken place?
RA->Foramen ovale-> LA->LV->system circ
LV->ductus arteriosus-> System circ
What happens to the ductus arteriosus after birth
Closes to leave the ligamentum arteriosum
