Embryology 1 and 2 Flashcards
Briefly define “cardiovascular field” and “vasculogenic”.
cardiovascular field is when blood vessels first appear in the yolk sac, allantois, connecting stalk and chorion
Describe the formation of heart tube and name its constituent parts.
Describe the formation of heart tube and name its constituent parts.
Describe the formation of the bulboventricular loop
Primitive heart tube invaginate pericardium and as the growing tube becomes too large for the pericardium it needs to fold/ loop forming bulboventricular loo
bulbus cordis and ventricle enlarge and loop to the right and ventricles pushed left and inferiorly. atria pushed superior and posteriorly
Describe the development of the cardiac valves and the special conducting system of
the heart.
Ductus venous
ductus venous- shunts blood in left umbilical vein into inferior vena cava allows oxygenated blood from the placenta to bypass the liver
when does the cardiovascular system start to form
4th week as the rapidly growing embryo can’t function by diffusion alone
what do heart tubes do
fuse and join blood vessels in other areas of cariogenic field to form primitive cardiovascular system
and explain “dextrocardia”.
Heart tube loops to the left (not right) and ventricles come to lie facing right (not left)
formation of left and right atrioventricular canals
endocardial cushion growth. superior and inferior endocardial cushion push down and fuse to from canals
partitioning left and right atria
Formation of septum primum. Ostium secundum forms by apoptosis to form septum primum. Ostium primum meets septum primum and formation of foramen ovale. one way shunt flowing blood between right and left atrium
differences between foramen ovale before and after birth
Before it allows blood to pass from right to left atrium and after birth it closes
non-closure results in patent foramen ovale which is a hole in the heart
describe partitioning of primitive ventricles
Muscular ventricular septum forms. Opening is called the intraventricular foramen. aorticopulmonary septum divides bulbs cordis and trucus arteriosus into aorta and pulmonary trunk
what forms from trunks arteriosus
aortic arches, ascending aorta, pulmonary trunk
what forms from bulbus cordis
outflow tracts (smooth) of L+R ventricle
what forms from primitive ventricle
rough part of L+R ventricles
what forms from primitive atrium
Rough part of L+R atria
what forms from sinus venosus
right horn of smooth part of right atrium. left horn forms the coronary sinus
describe formation of aortic sac
First arteries to appear in the embryo. Aortic sac is formed by the fusion of the 2 ventral aortae which then becomes an extension of the trances arteriosus
aortic arch branches from the aortic sac.
Formation of aortic arches
6 pairs of aortic arches are formed from the aortic sac. Give rise to the great arteries of the neck and head.
vasculogenesis
defined as the new formation of a primitive vascular network
angiogenesis
defined as the growth of new vessels from the pre existing blood vessels
development of lymphatic system
Develops at end of sixth week. thoracic duct develops from two vessels anterior to aorta and become the left and right thoracic ducts
foraman ovale
shunts blood to right atrium to left atrium allows blood to bypass the lungs
