Embryonic Structures Flashcards
Name the embryonic structures that make up the right atrium in adults.
- Sinus venarum
- from right sinus horn of sinus venosus - Atrial auricle
- from original embryonic atrium
What embryonic structure is the precursor for the coronary sinus?
Left sinus horn of sinus venosus
What was the precursor for the trabeculated portion of the left ventricle?
Primitive ventricle
What forms the trabeculated region of the right ventricle?
caudal portion of bulbus cordis
What forms the outflow region for both ventricles?
Conus cordis for both
Conus arteriosus for right ventricle
Aortic vestibule for left ventricle
What embryonic structure forms the pulmonary trunk and (ascending) aorta?
Truncus arteriosus
What forms the bulk of the interatrial septum?
Septum secundum
PFO is a result when what doesn’t fuse completely?
Valve of foramen ovale (septum primum) doesn’t completely fuse to septum secundum
What forms AV valves?
Neural crest of endocardial cushions
What forms semilunar valves?
Neural crest of conotruncal ridges
Which aortic arch arteries regress?
1*, 2, 5
1* forms maxillary aa, which we don’t care about right now
What aortic arch arteries go on to form important structures that we care about?
aortic sac, 3, 4, 6, and 7th intersegmental
What does the aortic sac form?
proximal portion of aortic arch and brachiocephalic artery
What does the third aortic arch form?
Common carotid artery
What does the fourth aortic arch form?
Know right from left!
R: R subclavian artery
L: portion of aortic arch
What does the sixth aortic arch form?
Know right from left!
R: pulmonary artery
L: pulmonary artery, and ductus arteriosus
What does the seventh intersegmental artery form?
Know right from left!
R: distal part of R subclavian
L: L subclavian artery
What structure created the ligamentum arteriosum?
Ductus arteriosus
What is the relationship of the right recurrent laryngeal nerve to other structures?
Nerve loops around 4th aortic arch
- (aortic arches 5 and distal 6 regress)
4th aortic arch becomes R subclavian
What is the relationship of the left recurrent laryngeal nerve to other structures?
Nerve loops around distal part of 6th aortic arch
Arch goes on to become ductus arteriosus
Nerve ends up wrapped around ligamentum arteriosum in adults
What structures create the left and right brachiocephalic veins?
Anterior cardinal veins
What structure creates the superior vena cava?
Right common cardinal
What structure creates the azygos system of veins?
Supracardinal veins
What forms the renal portion of the inferior vena cava?
Right subcardinal vein
What forms the distal portion of the IVC?
Right Sacrocardinal veins
What embryological structures form the left atrium?
- Smooth-walled portion of atrial chamber
- from proximal portion of pulmonary vein - original embryonic atrium forms the Auricle
