Embryology Flashcards
Truncus Arteriosus
Gives rise to ascending aorta and pulmonary trunk
Bulbus cordis
Gives smooth parts (outflow tract) of LT and RT ventricle
Primitive ventricle
Gives rise to trabeculated LT and RT ventricles
Primative atria
Gives rise to trabeculated LT and RT atrium
LT horn of the sinus venosus
Gives rise to the coronary sinus
RT horn of sinus venosus
Gives rise to the smooth part of the RT atrium
RT common cardinal vein and RT anterior cardinal vein
Gives rise to the SVC
Truncus Arteriosus Formation
Neural crest migration leads to truncal and bulbar ridges that spiral and fuse to form the aorticopulmonary septum
- leads to formation of aorta and pulmonary trunk - Can have transposition of great vessels if fails to spiral - Tetrology of fallot w/ skewed AP septum development - Persistent TA w/ partial septum development
Interventricular septum Development
- Muscular ventricular septum forms: opening is IV foramen
- AP septum meets and fuses w/ muscular ventricular septum to form membranous IV septum: closes IV foramen
- Growth of endocardial cushions separates atria from ventricles
- contributes to both atrial separation and membranous portion of the IV septum
- Pathology: Improper neural crest migration into TA can cause transposition or persistent TA - Membranous septal defects cause initial LT to RT shunt that then becomes RT to LT
- contributes to both atrial separation and membranous portion of the IV septum
Interatrial septum Development
- Forament primum narrows as septum primum grows toward endocardial cushions
- Perforations in septum primum forms foramen secundum
- Foramen secundum maintains RT to LT shunt as septum secundum begins to grow
- Septum secundum contains foramen ovale
- Septum secundum enlarges and upper part of septum primum degenerates
- Remaining portion of septum primum forms valve over foramen ovale
- Septum secundum and septum primum fuse to form atrial septum
- Foramen ovale usually closes shortly after brith due to increased LA pressure
- Pathology: patent foramen ovale caused by excessive absorption of septum primum or secundum
Right to Left Shunts
- Cause early cyanosis: blue babies
- 5Ts
- Tetrology of Fallot: most common cause of early cyanosis
- Transposition of great vessels
- Truncus arteriosus: persistent b/c failed to divide aorta/pulm
- Tricuspid atresia: no tricuspid-hypoplastic RV
- Total anomalous pulmonary venous sys: pulmonary veins drain into RT heart
Left to Right Shunts
- Late cyanosis: blue kids
- VSD: most common congenital cardiac anomaly
- ASD: loud S1; wide fixed split S2
- PDA:
Tetrology of Fallot
- Pulmonary stenosis: most important determining prognosis
- RT ventricular hypertrophy
- Overriding aorta: overrides (sits on top of) the VSD
- VSD
- Early cyanosis due to RT to LT shunt thru VSD
- Shunt due to increased pressure from pulmonary stenosis
- XRay shows boot shaped heart due t RVH
- Caused by anterosuperior displacement of the infundibular septum
D-Transposition of the Great Vessels
- Aorta leaves RT ventricle and pulmonary leaves LT ventricle
- Caused by failure of aorticopulmonary septum to spiral
- Leads to separation of systemic and pulmonary circulations
- Req VSD, PDA, or patent foramen ovale to live
Coarctation of the Aorta
- Infantile: aortic stenosis proximal to insertion of ductus arteriosus
- Associated w/ Turner Syndrome
- Adult: stenosis distal to ligamentum arteriosum
- Associated w/ notching of the ribs due to collateral circulation
- HTN in upper extremities and weak pulses in lower
- Can result in aortic regurge
