Heart Development Flashcards
What is the first functional organ to develop in the embryo?
The heart
At what day does the heart start beating?
Day 22
From which embryonic layer does the heart develop?
Mesoderm (splanchnic mesoderm)
What is the cardiogenic area, and where is it located?
A region in the splanchnic mesoderm between the septum transversum and prochordal plate where the heart forms.
What is the primary heart tube derived from?
Endocardial tubes that fuse in the midline.
Which structure suspends the developing heart tube?
Dorsal mesocardium
What happens when the dorsal mesocardium disappears?
It forms the transverse pericardial sinus.
What are the five dilations of the primitive heart tube?
Truncus arteriosus, Bulbus cordis, Primitive ventricle, Primitive atrium, Sinus venosus.
What is the significance of cardiac looping?
It establishes the correct positioning of atria and ventricles.
What is the role of neural crest cells in heart development?
They contribute to the truncoconal (aorticopulmonary) septum formation.
What does the truncus arteriosus give rise to?
Ascending aorta and pulmonary trunk.
What does the bulbus cordis form?
Smooth parts of the right and left ventricles (conus arteriosus and aortic vestibule).
What does the primitive ventricle develop into?
Trabeculated part of the left and right ventricles.
What does the primitive atrium form?
Trabeculated parts of the left and right atria.
What does the sinus venosus become?
Right horn forms the smooth part of the right atrium (sinus venarum), left horn forms the coronary sinus.
What is dextrocardia, and what causes it?
Abnormal rightward positioning of the heart due to defective cardiac looping.
Which septum divides the truncus arteriosus into the aorta and pulmonary trunk?
Aorticopulmonary septum.
Which structure contributes to membranous ventricular septum formation?
Neural crest-derived endocardial cushions.
Which congenital defect is caused by failure of neural crest migration in the truncus arteriosus?
Persistent truncus arteriosus.
Which congenital defect results from incomplete spiraling of the aorticopulmonary septum?
Transposition of the great vessels.
What is Tetralogy of Fallot, and what are its four components?
- Pulmonary stenosis 2. Right ventricular hypertrophy 3. Overriding aorta 4. VSD (ventricular septal defect).
What causes atrial septal defect (ASD)?
Failure of septum primum and septum secundum to properly fuse.
What is Eisenmenger syndrome?
A late cyanotic shunt reversal due to an untreated left-to-right shunt causing pulmonary hypertension.
Why does the foramen ovale remain open in patent foramen ovale (PFO)?
Failure of septum primum and septum secundum to fully fuse after birth.
