Heart Embryology Flashcards
Types of folding in early development
- Lateral folding
- Cranio-caudal folding
Cranio caudal folding of heart development
-Repositioning of the cardiogenic region from the cranial rim to the thorax
Lateral folding
leads to merging of the endocardial tubes which leads to development of the primitive heart tube
Embryo: Aortic arches
Adult: Cranial/Thoracic arteries
Embryo: Truncus arteriosus
Adult: Distal OFT
Embryo: Bulbus cordis
Adult: Proximal OFT
Embryo: Primitive ventrical
Right ventricle
Left ventrical
Primitive atrium
R Atrium
L Atrium
Sinus venosus
Coronary sinus
Cardinal, umbilical, vitelline veins
Vena cava veins
Formation of cardiac loop
The heart tube elongates and loops ventrally
Heart looping
Cranial aspect bends to the right (ventro-caudally)
Caudal aspect bends to the left (dorso-cranially)
Ventricle- caudally and right
Atrium- cranially and left
Major transition: cranial caudal to transverse right to left
Septation of the heart chambers and OFT
- Atrial septation
- Ventricular
- A-V canal
- OFT septation (pulmonary from aorta)
Endocardial cushions
Epithelial to mesenchymal transition
All layers of heart tube come from:
Splanchnic mesoderm
Atrial septation
- 2 walls –> foramen ovale
- Ostrium secundum: second hole
- first wall –> first hole –> second hole –> second wall
- second hole is located in the first wall
patent foramen ovale
the two septae fail to close allowing continued shunting of blood from the right atrium to the left atrium after birth, eventually left to right atrium
Name of the second hole in the developing atrial septum and where is it located
Ostium secundum within the septum primum
Ventricular septation
Inter ventricular septum : muscular, from apex of the ventricular myocardium
Inter-ventricular foramen: while we wait for AV canal and OFT to septate
Inter-ventricular septum: membranous, from endocardial cushions of AV canal and OFT
AV Canal Septation
Shared AV canal–> Left and Right AV canals (looping) –> Involves AV looping
OFT septation (out flow tract)
Involves endocardial cushions
Spiral Septum in order to get P.V. from RV and A. V. from the LV
(Linear septum = parallel septum and RV goes to aorta and LV to pulmonary trunk)
Closing the IV foramen
sdf
3rd aortic arches
Give rise to L and R common carotid arteries
4th aortic arch
Gives rise to R subclavian artery and the aorta
6th aortic arch
Gives rise to pulmonary trunk and the ductus arteriosus
Left subclavian
contributed by 7th segmental artery
NOT AORTIC ARCH
Asymmetric remodeling of aortic arches
3rd aortic arch detaches to become common carotid artery
- degeneration of the LR dorsal aortae
- segregates blood going to the head from blood going to the trunk
