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Flashcards in Severson heart Dev Deck (42):

Where germ layer do the neural crest cells derive from?



What is the purpose of neural crest cells in heart dev?

Migrate the outflow tract where they participate in separation of the outflow tract and from the aortic arches


Why are the neural crest cells significant?

They migrate from regions of cervical and thoracic areas to cardiac structures
- Supply visceral sensory and motor
- explains why heart pain is referred to the neck, chest and jaw (also has a cervical nerve


What are the 3 venous systems of the developing fetus?

Vitelline veins
Umbilical veins
Caval system


What is the vitelline veins?

Drain GI tract


What is the umbilical vein?

Drains the placenta


What are the cardinal veins?

Forms Superior and inferior vena cava


What are the 5 components of the developing heart tube

Sinus venosus
Primitive atrium
Primitive ventricle
Bulbus cordis
Truncus arteriosus


What does the truncus arteriosus give rise to?

Aortic arch
pulmonary trunk


What does the sinus venosus do?

Drains the 3 venous systems
Vitelline, umbilical and caval


What does the bulbus cordis give rise to?

Smooth parts of left and right ventricle (outflow)


What does the primitive atrium and ventricle give rise to?

Trabeculated part of left and right atrium and ventricle


What does the left and right horn of sinus venosus give rise to

L- Coronary sinus
R- Smooth part of right atrium


Which way does the heart tube bend to get the general appearance of the adult heart?

To the right
- brings the superior and inferior vena cava to the right


What is Dextrocardia?

Condition of which the heart tube bends to the left and thus is displaced to the right rather than the left
- Transposition
- Heart vessels are reversed (mirror image of what it should be)


What dextrocardia or dextrocardia with situs inversus is compatible with life? Which is less serve?

Situs inversus


What is the purpose of the endocardial cushion?

Extracellular matrix that enlarges and grows towards one another to separate the single atrioventricular canal
- creates left and right atrioventricular canal as well


What other purpose does the endocardial cushion function?

1. Formation of tricuspid and mitral valve
2. Membranous portion of interventricular septum
3. Participates in closure in primary atrial septum


What are the dev anomalies of abnormal endocardial cushion dev?

1. Mitral atresia (narrow or absence of passage
2. Tricuspid atresia
3. Atrial septal defect
4. Ventricular septal defect
5. Persistent atrioventricular canal


What is the foramen ovale?

Hole in the atrium in utero and a product of the secondary septum


How does the atrial septum form?

Primary septum forms first. Grows down towards the endocardial cushion. Between the endocardial cushion and primary cushion there is a primary foramen. As you continue to grow toward the EC leads to a smaller primary foramen and thus to compensate the fetus creates a secondary foramen superior to the primary. Then the primary septum coms into contact with the EC and the secondary foramen gets bigger! Primary septum becomes valve of foramen ovale! Thus there is no backflow into right atrium in the fetus

The secondary septum is also forming at the same time. It is the right of the primary. It never really reaches the EC and thus creates the Foramen ovale


Bulbar and truncal ridges are derived from what?

Neural crest mesenchyme


What separates the the bulbar and truncal ridge tissues?

Spiraling of the aorticopulmonary septum
- to create the bulbus cordis and truncus arteriosus


What gives rise to the aorticopulmoary septum?

Bulbar and truncal ridges


What is the muscular portion of the ventricle derived from?



What creates the membranous portion of the ventricle?

Endocardial cushion when they fuse with the aorticopulmonary septum (Bulbar ridges)


What consists of the aortic sac?

Aortic arch
Brachiocephalic trunk


What does the left 4th Aortic arch contribute to?

Aortic arch


What does the right 4th aortic arch contribute too?

Subclavian artery


What does the left 6th aortic arch form (proximal portion)

Proximal part of left pulmonary artery


What does the left 6th aortic arch form distal portion?

Ductus arteriosus
- after birth forms the ligamentum arteriosum


What does the right 6th aortic arch form Proximal portion?

Right pulmonary artery


What does the right 6th aortic arch form distal portion?



What is the purpose of the ductus venosus?

Shunts blood from the left umbilical vein directly through the liver and into the IVC
- to prevent the liver from receiving all the well oxygenated blood.


About how much blood enters the lung in utero?



Fetal blood circulation?

-Enters umbilical vein
-Shunted around the liver via ductus venosus
-Into the IVC mixes with blood from lower extrems and vicera
-In right atrium meets blood of SVC goes to right ventricle and pumped out into pulmonary truck
-however only 10% goes to lungs the other 90 travels through the ductus arteriosum to the aorta


What cause the foramen ovale to close postnatal?

Increased pressure in the lungs increaes left atrial pressure

- decreased blood from placenta decreases the pressure in the right atrium


What does the ductus arteriosus give rise to and when does it close after birth?

about 24hrs after
- Gives rise to the ligamentum arteriosum


What does the umbilical vein become after birth?

Hepatic ligamentaum teres
- aka rough ligament of the liver
- remains open for a long period of time and can be used for blood sampling


What does the ductus venosus form after birth?

Ligamentum venosum


What do the superior vesical arteries give rise to? (proximal part)

Supply the urinary bladder


What doe the other umbilical arteries give rise to? (Distal Part)

Medical umbilical ligaments