Cardiovascular - Embryology Flashcards
Which layer is most of the CV system derived from?
Mesoderm
What does the primary heart field develop into?
Future left ventricle
What does the secondary heart field develop into?
Outflow tracts, future left and right atria, future right ventricle
Name the 3 stages of cardiac formation
1 - Primitive heart tube formation
2 - Cardiac looping
3 - Cardiac septation
Describe the formation of the primitive heart tube
- Day 19, 2 endocardial tubes fuse
List the parts of the primitive heart tube
- Truncus arteriosus
- Bulbos cordis
- Primitive ventricle
- Primitive atrium
- Left and right horn of sinus venosus
Describe cardiac looping
- On day 23 - 28.
- Cranial end folds ventrally and caudally (forwards and down) and shifts right.
- At same time, caudal end fold dorso-cranially and shifts to left.
What is cardiac looping caused by?
Differential growth rates of the heart.
Where are atria in relation to ventricles after cardiac looping?
Atria end up behind ventricles
What structure does the truncus arteriosus give rise to?
- Ascending aorta
- Pulmonary trunk
What structure does the bulbus cordis give rise to?
- Smooth part (outflow tract) of L+R ventricles
What structure do the endocardial cushions give rise to?
- Atrial spetum
- Interventricular septum
- AV and semilunar valves
What structure does the primitive atrium give rise to?
- Trabeculated parts of the atria
What structure does the primitive ventricle give rise to?
- Trabeculated parts of the ventricles
What does the right horn of the sinus venosus give rise to?
- Smooth part of right atrium
What structure does the left horn of the sinus venosus give rise to?
- Coronary sinus
What structure does the primitive pulmonary vein give rise to?
- Smooth part of left atrium
What structure do the primitive right common carotid and right anterior cardinal veins give rise to?
- Superior vena cava
Describe atrial cardiac septation
- 2 endocardial cushions form on dorsal and ventral walls of atria.
- They grow towards each other and fuse = AV canal.
- Septum primum then grows from superior aspect of atrium. Gap between it and cushions = foramen primum.
- Another space opens up in septum primum = foramen secundum, and the foramen primum closes.
- Septum secundum then begins to grow from top and bottom, next to septum primum.
- Top part of septum primum begins to disappear.
- Gap between septum secundum from top and septum primum from bottom = foramen ovale.
Describe ventricular septation
- Ventricle had a membranous and muscular septum growing from apex.
- Walls grow and fuse together = interventricular septum
What does the 1st aortic arch give rise to?
Regresses and forms part of maxillary artery (in face)
What does the 2nd aortic arch give rise to?
Regresses and forms part of stapedial artery (in ear)
What does the 3rd aortic arch give rise to?
Internal and common carotid arteries
What does the 4th aortic arch give rise to?
Right: Part of right subclavian artery
Left: Part of aortic arch
