Cardio: Embryology Flashcards
Truncus arteriosus (TA), gives rise to
Ascending aorta Pulmonary trunk
and Aorticopulmonary Septum
Bulbus cordis, gives rise to
Smooth parts (outflow tract) of Left (Aortic Vestibule) and Right Ventricles (Conus Cordis)
Primitive atria, gives rise to
Trabeculated part of Left and Right Atria
Primitive ventricle, gives rise to
Trabeculated part of Left and Right Ventricles
Primitive pulmonary vein, gives rise to
Smooth part of Left Atrium
Left horn of Sinus venous (SV), gives rise to
Sinus Venarum (smooth part of the Right Atrium), Coronary sinus, and the Oblicque Vein of the Left Atrium
Right horn of Sinus venous (SV), gives rise to
Smooth part of Right Atrium
Right common cardinal vein and right anterior cardinal vein, gives rise to
Superior Vena Cava (SVC)
Kartagener syndrome
- Autosomal dominant
- Primary ciliary dyskinesia (cilia moving incorrectly)
- Situs inversus
Patent foramen ovale
- Failure of Septum Primum and Septum Secundum to fuse after birth
- Most are untreated
- Can lead to paradoxical emboli (venous thromboemboli that enter systemic arterial circulation
- Similar to those resulting from an ASD
(7) Steps of Septation of the Atria
- Septum Primum grows toward Endocardial Cushions, narrowing 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 Atrial pressure
(3) Steps of Septation of the Ventricles
- Muscular Ventricular Septum forms. Opening is called Interventricular Foramen
- Aorticopulmonary Septum rotates and fuses with Muscular Ventricular Septum, to form the Membranous Interventricular Septum, closing Interventricular Foramen
- Growth of Endocardial Cushions separates atria from ventricles and contributes to both atrial septation and the membranous portion of the interventricular septum
(3) Steps of Outflow tract formation
- 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
Dextro-Transposition of great vessels
- Cyanotic congential heart defect (CHD
- The Left and Right Ventricles pump in seperate circulatory cycles never oxygenating Systemic Circulatory blood with the Pulmonary system.
Tetralogy of Fallot
- The AP Septum fails to align properly with the AV Septum, resulting in pulmonary stenosis (right ventricular outflow reduction)
- Overriding Aorta (dextroposition of Aorta)
- VSD and Right Ventricular Hypertrophy
- Most common cyanotic heart defect (blue baby) (R->L)
- Mixing of oxygenated and deoxygenated blood in the Left Ventricle via the Ventricular Septal Defect (VSD) and preferential flow of the mixed blood from both ventricles through the Aorta because of the obstruction to flow through the pulmonary valve
Persistent truncus arteriosus
- The embryological structure known as the Truncus Arteriosus fails to properly divide into the Pulmonary Trunk and Aorta
- Results in one Arterial Trunk arising from the heart and providing mixed blood to the Coronary Arteries, Pulmonary Arteries, and Systemic Circulation
Valve derived from endocardinal cushions of outflow tract
- Aortic valve
- Pulmonary valve
Valve derived from fused endocardinal cushions
of the AV canal
- Mitral valve
- Tricuspid valve
Stenotic valvular anomaly
Aortic stenosis occurs when abnormalities of the aortic valve lead to narrowing and obstruction between the left ventricle and the aorta.
Regurgitant valvular anomaly
Atretic valvular anomaly (tricuspid atresia)
Ebstein anomaly
- Congenital malformation of the heart that is characterized by apical displacement of the septal and posterior tricuspid valve leaflets.
- Leading to atrialization of the right ventricle with a variable degree of malformation and displacement of the anterior leaflet.
Fetal erythropoitesis
- Yolk sac (3 - 8 weeks)
- Liver (6 weeks - birth)
- Spleen (10 - 28 weeks)
- Bone marrow (18 weeks to adult)
“Young Liver Synthesizes Blood”
Fetal Hemoglobin (HbF)
α2γ2
Alpha Always, Gamma Goes, Becomes Beta
Adult hemoglobin (HbA)
α2β2
Alpha Always; Gamma Goes, Becomes Beta
HbF higher affinity for oxygen
- Less avid binding of 2,3-BPG
- This allows HbF to extract oxygen from (HbA) maternal hemoglobin across the placenta
Blood entering the fetus through the umbilical vein is conducted via the ____________ into the the IVC to bypass the hepatic circulation.
Ductus venosus
Most highly oxygenated blood reaching the heart via the IVC is diverted through the __________ and pumped out the aorta to the head and body.
And is also an oval opening in the Septum Secundum that provides a communication between the Atria.
Foramen ovale
Deoxygenated blood entering the RA from the SVC goes:
RA –> RV –> main PA –> __________ –> descending aorta
Ductus arteriosus due partly to low O2 tension
At birth, infant takes a breath:
- Low resistance in pulmonary vasculature causes increase left atrial pressure vs. right atrial pressure
- Foramen ovale closes (now called the fossa ovalis) Increase in O2 (from respiration) and decrease in prostaglandins (from placental separation)
- Closure of Ductus arteriosus
Umbilical vein, gives rise to
Ligamentum teres hepatis (round ligament of the liver)
Umbilical arteries, gives rise to
Medial umbilical ligaments
Ductus arteriosus, gives rise to
Ligamentum arteriosum
Ductus venosus, gives rise to
Ligamentum venosum
Foramen ovale, gives rise to
Fossa ovalis
Allantois, gives rise to
- Urachus-median umbilical ligament
- The urachus is the part of the allantoic duct between the bladder and the umbilicus.
- Urachal cyst or sinus is a remnant
Notochord, gives rise to
Nucleus pulpous of intervertebral disc
Levo-Transposition of the great vessels
- acyanotic heart defect
- The primary arteries are transposed, with the aorta anterior and to the left of the pulmonary artery, and the morphological left and right ventricles are also transposed
Divides the Truncus Arteriosus into the Aorta and Pulmonary trunk
AP Septum
Aortic Arch #1
Has no derivative because it disappears soon after development.
Aortic Arch #2
Has no derivative because it persists only during the early development.
Aortic Arch #3
Forms the Common Carotid Arteries and the proximal part of the Internal Carotid Arteries
Aortic Arch #4
Forms the Aortic Arch on the Left and the
- *Brachiocephalic Artery** and the
- *Proximal Subclavian Artery** on the Right.
Aortic Arch #5
Has no derivative.
Aortic Arch #6
Forms the Proximal Pulmonary Arteries
and Ductus Arteriosus.
