Cardiac Embryology

Question 1

What genetic abnormality is associated with endocardial cushion defects?

Answer 1

Down syndrome (Trisomy 21)

Question 2

Which fetal vessel has the highest oxygenation?

Answer 2

Umbilical vein

Question 3

What causes the foramen ovale to close?

Answer 3

Increased LV pressure, Decreased pulmonary resistance

Question 4

What causes the ductus arteriosus to close?

Answer 4

High pressure in aorta
Increased oxygen content in aorta
NSAIDs

Question 5

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

Answer 5

Aorticopulmonary septum. Neural crest cells.

Question 6

What embryologic structure of the heart gives rise to each of the following adult structures?
Ascending aorta and pulmonary trunk

Answer 6

Truncus arteriosus

Question 7

What embryologic structure of the heart gives rise to each of the following adult structures?
Coronary sinus

Answer 7

Left horn of sinus venosus

Question 8

What embryologic structure of the heart gives rise to each of the following adult structures?
SVC

Answer 8

Right common cardinal vein and Right anterior cardinal vein

Question 9

What embryologic structure of the heart gives rise to each of the following adult structures?
Smooth parts of the left and right ventricles

Answer 9

Bulbus cordis

Question 10

What embryologic structure of the heart gives rise to each of the following adult structures?
Smooth part of the right atrium

Answer 10

Right horn of the sinus venosus

Question 11

What embryologic structure of the heart gives rise to each of the following adult structures?
Trabeculated left and right atria

Answer 11

Primitive atrium

Question 12

What embryologic structure of the heart gives rise to each of the following adult structures?
Trabeculated parts of the left and right ventricles

Answer 12

Primitive ventricle

Question 13

Briefly outline atrial septal development

Answer 13

Septum primum grows towards endocardial cushions
Forms ostium primum between itself and cushions
Ostium secundum forms within septum primum
Septum secundum forms next to septum primum (on right side)
Forms foramen ovale in gap between two septa

Question 14

Name the three places of blood shunting in fetal circulation.

Answer 14

Ductus venosus (at liver)
Foramen ovale (between atria)
Ductus arteriosus (pulmonary artery to aorta)

Question 15

What are the derivatives of the 3rd aortic arch?

Answer 15

Common carotid
Proximal part of internal carotid

Question 16

What are the derivatives of the 4th aortic arch?

Answer 16

Left: Arch of adult aorta
Right: Proximal part of right subclavian artery

Question 17

What are the derivatives of the 1st and 2nd aortic arches?

Answer 17

1st: Part of maxillary artery
2nd: Stapedial artery, Hyoid artery

Question 18

What are the derivatives of the 6th aortic arch?

Answer 18

Proximal part of pulmonary arteries
Ductus arteriosus

Question 19

What structure grows to close the opening/canal between the atrial chamber and ventricular chamber into two smaller openings?

Answer 19

Superior and inferior endocardial cushions

Question 20

What are three possible causes of ASD?

Answer 20

Ostium secundum too big and overlaps foramen ovale
Absence of septum secundum
Neither septum secundum or primum develop

Question 21

Name four of the six truncoconical (spiral) defects.

Answer 21

Fenestrae
Ventricular septal defect
Tetralogy of Fallot
Persistent truncus arteriosus
Transposition of the great vessels
Dextrocardia (MF)