Embryology and Anatomy Flashcards
Gestational week when primitive embryonic heart tube forms
3rd week
Gestational week and day when heart starts beating and looping occurs
4th week - Day 22
Gestational week when AV canal divides into tricuspid and mitral valves
4-6 weeks
Gestational week when outflow tract septates into PA and aorta
6-8 weeks
What does the primary heart field become
Embryonic ventricle (precursor to LV) and embryonic atria (becomes atrial appendages)
What does the secondary heart field become
Proximal bulbus cordis (precursor to RV), distal bulbus cordis (infundibulum), truncoaortic sac (outflow tracts)
Neural crest cell abnormalities can lead to what type of defects
Conotruncal defects (ToF, truncus, IAA) - affect the great arteries
What highlights a right atrium
- Septum secundum covers over septum primum on RA side
- Broad based appendage
- Pectinate muscles extend onto lateral RA wall
Borders of triangle of Koch and what does it contain
- Septal leaflet of TV
- Coronary sinus os
- Tendon of Todaro
- Contains the AV node
What highlights a left atrium
- Two attachments of septum primum onto back/left of septum secundum on LA side
- Narrow, finger like appendage
- Pectinate muscles only in LA appendage
Where is the hole in a secundum ASD
Septum primum
Where is the hole in a primum ASD
Canal septum
Defining a right ventricle
- Coarse trabeculations
- Tricuspid valve - chordal attachments to the free wall and septum (SEPTOPHILIC) and tricuspid valve is more apically displaced
- Moderator band
Defining a left ventricle
- Fine trabeculations
- Mitral valve - chordal attachments to the free wall only (SEPTOPHOBIC)
- Smooth septal surface at the base
What does the 3rd embryonic arch become
Common carotid artery
What does the 4th embryonic arch become
The aortic arch on one side and the innominate artery on the other side
What does the 6th embryonic arch become
Ductus arteriosus
Embryonic arch process to form normal left aortic arch
- Regression of the right dorsal aorta and right 6th arch
- 4th arch persists and forms the arch, left 6th arch is the ductus
Embryonic arch process to form left aortic arch with aberrant right subclavian artery
Regression of the right 4th arch and right 6th arch
Embryonic arch process to form right aortic arch with mirror image branching
Regression of the left dorsal aorta but both 6th arches remain
Embryonic arch process to form right aortic arch with aberrant left subclavian artery
- Regression of left 4th arch (but both 6th arches remain)
- If right ductus persists then not a vascular ring
- If left ductus persists then it IS a vascular ring
Most common symptomatic vascular ring
Double aortic arch
IAA Type A embryologic development
- Regression of both dorsal aortas
- A = AFTER all arch vessels arise (distal to L subclavian)
IAA Type B embryologic development
- Regression of left 4th arch and right dorsal aorta
- B = BETWEEN (interruption between L carotid and L subclavian)
- Commonly associated with 22q11 deletion