B4.046 - Cardiovascular Embryology Prework 2 Flashcards
when does atrial septation happen
weeks 4-7
when does ventricular septation happen
weeks 4-7
identify what each of these structures turns into
orange - pulm. artery and aorta
dark orange - valves of aorta and pulm a.
red - right ventricle
pink - left ventricle
purple - both atria
how does the endocardial cushion form
The myocardium deposits a unique extracellular matrix between the endocardium and itself
Endocardial cells in a certain region undergo an epithelial-to-mesenchymal transformation
Mesenchymal cells (migrating endocardial cushion cells) aid in formation of the atrioventricular canal
what regio does endocardium derived cushion tissue form in
atrioventricular region and the outflow tract region
the outflow tract region is also populated by what
invading neural crest cells
fusion of opposing cushion tissues forms what
2 atrioventricular canals, and the outlets of both ventricles, the aorta and pulmonary trunk
the conotruncal cushions contribute to what structure
membranous portion of the interventricular septum
describe the heart at day 30
- atrial pertitioning just beginning to happen
- primary interventricular foramen undivided
- outflow tract (bulbus cordis/truncus arteriosus) undivided
- proximal portion of bulbus cordis becomes trabeculated and forms the right ventricle
- atrioventricular canal undivided
describe the septum primum
grows down from common atrium roof towards the endocardial cushions in the atrioventricular canal
what is the formaen (ostium) primum
connects the right and left atrium
identify the 2 structures pointed out here
top - foramen secundum
bottom - foramen premum
what happens in the 5th week to the septum primum
programmed cell death creates new openings in the septum primum near the superior edge, called the foramen secundum
what happens to the endocardial cushions in the 5th week
grow along septum primum and close foramen primum
what happesn to the septum secundum in the 5th week of life
it forms to the right of teh septum primum
it grows down and fuses with an intermediate septum by the end of teh 6th week, but a foramen ovale persists throughout embryonic development
what happens to the septum secundum in the 6th week of development
it grows down and fuses with an intermediate septum but a foramen ovale persists throughout embryonic development
what is the function of the foramen ovale, in the septum secundum and foramen secundum in teh septum primum
it allows the blood to flow from right atrum to left atrium, but not left to right
what happens in the 6th week of development
the septum primum meets and fuses with the septum intermedium
the foramen secundum is obliterated and the right and left atria are now separated.
Blood flows through the foramen ovale when its valve is open, but not when its closed
during the 5th week of development what happens when the medial walls of the expanding ventricles become apposed
it formes the muscular interventricular septum
what is the interventricular foramen
its the foramen between the muscular IV septum and the endocardial cushions, it remains open until about day 37
what closes the IV foramen
the formation of the membranous portion of the IV septum, outgrowth of endocardial cushions towards muscular IV septum
what cell type contributes to the membranous part of IV septum
neural crest cell derivatives
outflow tract septation contribute to what on day 37
membranous IV septum
when does formation of the atrioventricular valves happen
5th to 8th weeks
what are conotrucal swellings or cushions
they form a spiral within the outflow of the beating heart while growing towards the aortic sac. On opposite walls they form the aorticopulmonary septum to divide the outflow of the heart into 2 spiraling channels, one for the aorta and one for the pulmonary trunk
the lower portion of the AP septum contributes to what
upper (membranous) portion of the IV septum
what do neural crest cells contribute to
the conotruncal ridges in truncus arteriosus (aslo membranous IV septum)
what contributes to the formation of semilunar (aortic and pulmonart artery) valves
Outflow cushion with contribution from neural crest
where are SA node cells originated from
caudal end of left heart tube, later sinus venosus, then right atrium
where are AV node and bundle of His cells derived from
- cells in teh left wall of the sinus venosus
- cells from the atrioventricular canal
when is circulation established
week 4
what does arch 1 form in adults
part of maxillary arteirs (head)
what does arch 2 form in adults
parts of hyoid and stapadial arteries (in neck and head)
what does arch 3 form in adults **
common and part of internal carotid artery (in neck)
External carotid forms from sprout off 3rd arch
what does arch 4 form in adults
right subclavian artery (R) and arch of the aorta (L)
what does arch 5 form
Trick question!!! IT REGRESSES!!
what does arch 6 form in adults
pulmonary arteries, ductus arteriosus
what doe vitelline arties do
supply yolk sac; eventually fuse and form vessels to gut
what do paired umbilical arteries form
(ventral branches of dorsal aortae) course to placenta
describe coronary artery formation
Partially arise from epicardium following EMT (epithelial to mesenchymal transformation); mesenchymal cells contribute to endothelial and smooth muscle cells
how do neural crest cells contribute to coronart arteries
contribute to smooth muscle cells along proximal segments of coronary arteries
coronary arties grow into what structure
the aorta to establish blood flow to the heart muscle
what do vitelline veins become
portal veinous system
what does the umbillical vein do
carries blood from the placenta to the embryo
what do the cardinal veins do
drain the body of the embryo; will form superior vena cava
what to all veins drain to
sinus venosus
while cardinal veins are initially bilateral, as they return blood to eh right and left horn of the sinus venosus portion of the heart what happens
venous system shifts to the right
what happens to the right horn of the sinus venosus
becomes incorporated into the wall of the right atrium
what happens to the left horn of the sinus venosus
becomes the coronary sinus (major venous drainage for blood that has perfused myocardium)
