Cardiac Embryology

Question 0

Smooth parts of left and right ventricles (outflow) derived drom

Answer 0

bulbis cordis

Question 1

ascending aorta and pulmonary trunk derived from

Answer 1

Truncus arteriosus

Question 2

Trabeculated left and right ventricles derived from

Answer 2

primitive ventricle

Question 3

Coronary sinus derived from

Answer 3

left horn of sinus venosus

Question 4

Smooth part of right atrium derived from

Answer 4

Right horn of sinus venosus

Question 5

superior vena cava derived from

Answer 5

Right common cardinal vein and right anterior cardinal vein

Question 6

What structure divides the truncus arteriosus into the aortic and pulmonary trunks? What is the cellular origin of this structure?

Answer 6

Aorticopulmonary (spiral) septum–> derived from neural crest cells

Question 7

What 3 defects can occur due to pathologic aorticopulmonary septum formation?

Answer 7

1. Transposition of great vessels (failure to spiral)

2. Tetralogy of Fallot (skewed septum development; blocs off some of pulmonary artery outflow)

Question 8

Which fetal blood vessel has the highest oxygenation? What is the path through fetal circulation

Answer 8

Umbilical vein (highest oxygen; 80%)--> ductus venous (bypasses portal circulation in liver)--> IVC--> Right atrium to left atrium via Foramen ovale--> Ductus arteriosus to circulation
Umbilical arteries branch off illiacs to go back to placenta

Question 9

What causes the ductus arteriosus to close?

Answer 9

Increased oxygen due to first breaths–> increased O2 in aorta–> decreased prostaglandin (PGE2) synthesis = closure of ductus arteriosus

Question 10

What causes the foramen ovale to close?

Answer 10

First breaths–> increased O2 in pulmonary vasculature–> dilation and decreased resistance–> increased left atrial pressure–> snaps foramen ovale shut

Question 11

What structure first forms between the top of the heart and the dorsal endocardial cushion when the interatrial septum is developing?

Answer 11

Septum primum

Question 12

What two opening derive from the septum primum? Which one doesnt persist for long?

Answer 12

1. Foramen primum (the one formed before septum primum fuses with endocardial cushion fully; goes away once they fuse)
2. Foramen secundum –> this one remains

Question 13

Which atrium does the Septum secundum form from? What structure does it create?

Answer 13

Right atrium–> creates the foramen ovale

*fetal blood bypasses pulmonary circulation by going through foramen ovale and foramen secundum

Question 14

What structure composes the valve that prevents backflow of blood from the left to right atria through the foramen ovale in fetal circulation?

Answer 14

portion of the septum primum that fused with the endocardial cushion

Question 15

What herat development issues are seen with Trisomy 21?

Answer 15

Endocardial cushion defects–> growths from these separate atria from ventricles and contributes to both atrial separation and membranous portion of the interventricular septum

Question 17

What four structures does fetal erythropoiesis occur in?

Answer 17

1. Yolk sac (3-10 weeks)
2. Liver (6wks - birth)
3. Spleen (15-30 weeks)
4. Bone Marrow (22wk-adult)
   * Young Liver Synthesizes Blood

Question 18

maxillary artery comes from which aortic arch

Answer 18

1st arch

• “1st arch is maximal”; is branch of external carotid

Question 19

common carotid artery and proximal internal carotid artery come from which aortic arch

Answer 19

3rd arch

Question 20

aortic arch (on left) and proximal subclavian on the right come from which aortic arch

Answer 20

4th arch

Question 21

2nd aortic arch derivatives (2)

Answer 21

1. Stapedial arch

2. hyoid artery

Question 22

6th aortic arch derivatives (2)

Answer 22

1. proximal part of pulmonary arteries

2. ductus arteriosus (on left only)