Development of the Heart Flashcards
What forms the horsehoe-shaped endothelial cord?
Splanchnic mesoderm
What forms the primitive heart tube?
Lateral body folding causes angioblastic cords to fuse together and forms the primitive heart tube
How and when does the heart and pericardial cavity reposition?
Week 4 - Neural tube overgrowth pushes the heart area underneath the foregut
What happens to the dorsal mesocardium?
Becomes the transverse pericardial sinus
Sinus venosus (R horn) adult derivative
Sinus venarium (smooth walled portion of the right atrium
Sinus venosus (L horn) adult derivative
Coronary sinus
Primordial atrium adult derivative
L and R auricles
Trabeculated portions of the atria
Primordial ventricle adult derivative
Left ventricle
Primordial bulbus cordis adult derivative
Right ventricle
Conus cordis adult derivative
outflow tract of the ventricles
Truncus arteriosus adult derivative
Roots and proximal portions of the aorta and pulmonary trunk
Blood flow through the primordial heart
- Sinus venosus
- SA canal
- Primordial atrium
- AV canal
- Primordial ventricle
- IV foramen
- Right ventricle
- Conus cordis
- Truncus arteriosis
- Aortic sac
- Pharyngeal arteris
- Dorsal aortae
What causes blood flow to shift to enter the R atrium?
Remodeling of the Vitelline, Umbilical, and Anterior cardinal veins
What is another effect of the Vitelline, Umbilical, and Anterior cardinal veins being remodeled?
The right horn of the sinus venosus becomes larger than the left horn
Ventricular Septal Defect
Failure of the Interventricular septum to close
-this mixes the R and L ventricle blood, combining oxygenated and deoxygenated blood (bad)
Transposition of the great vessels
The aorta and the pulmonary trunks switch places
- Nonspiraling aorticopulmonary septum
- Sends deoxygenated blood back to the body
Tetralogy of Fallot
Aorticopulmonary septum doesn’t spiral evenly
- Interventricular septal defect
- Hypertrophy of R ventricle
- Overriding aorta
- Pulmonary stenosis
What are the steps of the development of the interatrial septum?
1) Septum priming grows inferiorly to fuse with the endocardial cushions
2) Septum secundum forms once foramen secundum opens up
3) Both septa develop and for the interatrial septum
How does the atrioventricular septum form?
The dorsal and ventral endocardial cushions join
Why isn’t there any ventricular flow in fetal heart?
Because the mother provides oxygen
Hoe does blood flow from the R atrium to the L atrium in the fetus?
Foramen ovale and Foramen secundum
What happens to septum primum and septum secundum after birth?
Pressure in the L atrium becomes greater than the R, causing the septum secundum and primum valve system to shut, pushing blood to the lungs
Fossa ovalis
Remnant of foramen ovale in mature hearts
Muscular portion of the IV septum
Projection of cardiac muscles along the midline that stops short of the cushion
Membranous portion of the IV septum
Made of the mesenchyme of the endocardial cushion tissue
Grows superiorly to meet the muscular portion to the create the septum
The aorticopulmonary septum divides to creates what?
The aorta and pulmonary tract
From what does the aorticopulmonary trunk derive from?
Endocardial cushions of the distal bulbus cordis
