Cardiac embryo Flashcards
Cardiac muscle origin
Splachnic mesoderm
Begining of heart formation?
End of week 3
Primordial heart starts beating
beginning of week 4
Heart ends up in the thoracic cavity because of ___ folding
cranial
2 hearts fuse into one because of the _____ folding
lateral
the endothelial tube cells that fuse form the
endocardium
The embryonic heart begins to beat by day:
22-23
Primitive heart is surrounded by
the coleomic cavity, which will form the visceral and parietal layers of the pericardium
The primitive heart is surrounded by
coelomic cavity, will form the serous (visceral and parietal) and fibrous pericardium.
Fused tubes get thicker and form segments
bulbus cordis, ventricle, atrium and sinus venosus
Heart folds on itself, S shaped so,
ventricle move ventrally and right
atrium move dorsally and left
On the adult heart there is a portion that is trabeculated and the other smooth, why?
Depending on its “origin” primitive (trabeculated) or from the vessels ( smooth)
How is the heart attach to the body walls ( first weeks and later weeks)
First weeks by the dorsal mesocardium, later by blood vessels.
What is the transverse sinus and where does it originate from
space between pulmonary trunk/aorta and the SVC
Week 4 symmetrical veins that enter to the atrium
cardinal, umbilical and vitelline ( most disappear)
What is the crista terminalis?
Is the separation of smooth and trabecula on the right atrium.
Valves of the inferior vena cava and coronary sinus from on:
The caudal region of the right atrium
The left atrium smooth portion is formed by which vessels?
pulmonary veins
The atrioventricular septum is formed by:
the thickening of the endocardial cushions.
Endocardial cushion cells origin
neural crest cells
What is the septum primum
The septum primum grows toward the fusing endocardial cushions from the roof of the primordial atrium, partially dividing the common atrium into right and left halves.
What is the ostium/foramen primum?
As the septum primum grows the foramen primum forms as an opening that remains between its edge and the endocardial cushions
This foramen serves as a shunt, enabling oxygenated blood to pass from the right to the left atrium.
The foramen becomes progressively smaller and disappears
What is the ostium/foramen secundum
Before the foramen primum disappears, perforations produced by
apoptosis appear in the central part of the septum primum. These perforations form the foramen secundum.
The foramen secundum ensures continued shunting of oxygenated blood from the right to the left atrium.
What is the septum secundum?
The septum secundum, thicker, grows from the wall of the right atrium, adjacent to the septum primum.
As it grows it overlaps the foramen secundum.
The septum secundum forms an incomplete partition between the atria; conse-
quently, a foramen ovale(flap-like) forms
Why is the foramen ovale important
Before birth, the foramen ovale allows most of the oxygenated blood
entering the right atrium from the IVC to pass into the left atrium.
It also prevents the passage of blood in the opposite direction because the septum primum closes against the relatively rigid septum secundum
How does the foramen ovale allow blood flow to bypass from right to left before birth
Because the pressure on the left side is lower than on the right side, after birth it switches and no longer blood can flow
Embryonic circulation shunts
ductus venosus, foramen ovale and ductus arteriosus
What is the ductus venosus
Shunt for the umbilical vein
What is the ductus arteriosus?
Shunt between the pulmonary artery and the aorta.
Ductus arteriosus becomes the ligamentum arteriosum
Atrial septum defects (ASD)
Ostium primum defect and ostium secundum defect
What is the origin of the AV valves cells?
Neural crest cells, like the endocardial cushions.
Outflow of ventricles is formed by
the bulbus cordis and troncus arteriosus, they grow in a spiral way
How does the ventricular septum grows?
It grows from the floor of the ventricles, leaving an opening (interventricular foramen), which closes by week 7.
Cardiac anomalies
tetralogy of fallot (pulmonary stenosis), aortic stenosis, etc.
