Embryology Flashcards
Bulbus cordis gives rise to…
Smooth parts (outflow tracts) of left and right ventricles
Primitive atrium gives rise to…
The trabeculated parts of the left and right atria.
Primitive ventricle gives rise to…
The trabeculated part of the left and right ventricles.
The primitive pulmonary vein gives rise to…
The smooth part of the left atrium.
The left horn of the sinus venosus gives rise to…
The coronary sinus.
The right horn of the sinus venosus gives rise to…
The smooth part of the right atrium (sinus venarum).
The right common cardinal vein and right anterior cardinal vein give rise to…
The superior vena cava (SVC).
Heart beats spontaneously by the…week of fetal development.
Fourth
Cardiac looping to establish left-right polarity begins in…
Week 4 of gestation.
Defect in left-right dynein (involved in L/R asymmetry) can lead to…, as seen in…
Dextrocardia; Kartagener syndrome (primary ciliary dyskinesia)
Describe the process by which the atria become septated.
- Septum primum grows toward endocardial cushions, narrowing the foramen primum.
- Foramen secundum forms in septum primum (foramen primum disappears).
- Septum secundum develops as foramen secundum maintains right-to-left shunt.
- Septum secundum expands and covers most of the foramen secundum. The residual foramen is the foramen ovale.
- Remaining portion of septum primum forms valve of foramen ovale.
- Septum secundum and septum primum fuse to form the atrial septum.
- Foramen ovale usually closes soon after birth because of increased left atrium pressure.
Patent foramen ovale is caused by…
Failure of septum primum and septum secundum to fuse after birth. Most are left untreated.
A patent foramen ovale can lead to…
Paradoxical emboli (venous thromboemboli that enter systemic arterial circulation).
Ventricular septal defects most commonly occur in the…
Membranous portion of the septum.
Describe the process by which the ventricles become septated.
- Muscular ventricular septum forms. Opening is called the interventricular foramen.
- Aorticopulmonary septum rotates and fuses with muscular ventricular septum to form the membranous interventricular septum, closing the interventricular foramen.
- Growth of endocardial cushions separates atria from ventricles and contributes to both atrial septation and formation of the membranous portion of the interventricular septum.
Describe the process by which the outflow tracts form.
Truncus arteriosus rotates; neural crest and endocardial cell migrations –> truncal and bulbar ridges that spiral and fuse to form aorticopulmonary septum –> ascending aorta and pulmonary trunk