Cardiac Embryology: Key Milestones
The heart is the first functional organ to develop, beginning to beat at approximately day 22. Development relies on complex septation and looping.
| Structure | Adult Derivative |
|---|---|
| Truncus Arteriosus | Ascending aorta and pulmonary trunk |
| Bulbus Cordis | Smooth parts (outflow tract) of the left and right ventricles |
| Endocardial Cushions | Atrial and ventricular septa; AV valves |
| Primitive Atrium | Trabeculated parts of the left and right atria |
| Sinus Venosus | Smooth part of the right atrium (sinus venarum); the coronary sinus |
High-Yield Developmental Notes:
- Septation: The atrial septum (septum primum and secundum) and ventricular septum (muscular and membranous) must close properly. Failure causes ASDs/VSDs.
- Neural Crest Cells: Critical for the aorticopulmonary septum. Failure here leads to Conotruncal abnormalities (e.g., Tetralogy of Fallot, Transposition of the Great Arteries, Persistent Truncus Arteriosus).