Great Vessels Embryo

Question 1

When does vasculogenesis begin and what are the steps?

Answer 1

End of third week, hemangioblasts aggregate and form blood islands (endothelial precursor cells lining hematopoietic progenitor cells), channels forms within plexuses, then the channels enlarge and unite to form arteries and veins

Question 2

When is the 1st aortic arch formed?

Answer 2

4th week, supplies the 1st pharyngeal arch

Question 3

What are the branches of the fused dorsal aorta?

Answer 3

• ventral segmental arteries (supply splanchnic LP and endoderm)
• lateral segmental arteries (supply intermediate mesoderm)
• dorsal segmental arteries (supply somites)

Question 4

When do the rudiments of the remaining arches form?

Answer 4

Days 26-32

Question 5

When do the aortic arches complete formation?

Answer 5

Days 32-37, they give of branches to the developing head

Question 6

What does the 1st aortic arch give rise to?

Answer 6

External carotid, maxillary (jaw area)

Question 7

What does the 2nd aortic arch give rise to?

Answer 7

Stems of stapedial arteries (ear)

Question 8

What does the aortic sac give rise to?

Answer 8

Brachiocephalic artery and base of the arch of the aorta

Question 9

What does the 3rd aortic arch give rise to?

Answer 9

Common carotid and internal carotid arteries

Question 10

What does the 4th aortic arch give rise to?

Answer 10

Left: medial portion of the arch of the aorta
Right: proximal right subclavian

Question 11

What does the 6th aortic arch give rise to?

Answer 11

Pulmonary arteries!

• left distal ductus arteriosus
• right distal will degenerate

Question 12

What do the 7th intersegmental arteries give rise to?

Answer 12

Left: entire subclavian artery
Right: distal part of right subclavian

Question 13

What does the dorsal aorta give rise to?

Answer 13

Left: descending aorta
Right: proximal portion of the right subclavian artery

Question 14

What happens when the distal part of the 6th arch degenerates?

Answer 14

On the left: distal 6th arch persists as the ductus arteriosus and the left recurrent laryngeal wraps around it.

The right right: the distal 6th arch degenerates and the right recurrent laryngeal travels farther up and hooks around the right subclavian artery (because there isn’t anything on the left side keeping it in place

Question 15

When does remodeling of the inflow heart take place?

Answer 15

Weeks 4-8

Question 16

What does the right horn of sinus venosum give rise to?

Answer 16

Orifice of IVC, orifice of coronary sinus, becomes smooth wall of the atria and crista terminalis

Question 17

What is the fate of the vitelline veins proximal to heart?

Answer 17

Left vein degenerates, right vein persists as right hepatocardiac channel (IVC from liver to heart)

Question 18

What is the fate of the vitelline veins within the liver?

Answer 18

Right forms hepatic vein (part of IVC), both right and left form portal vein (from gut)

Question 19

What is the fate of the umbilical vein?

Answer 19

Right degenerates entirely, left proximal degenerates, distal left persists in embryo forming anastomosis with the ductus venosus providing placental return

Question 20

What is the fate of the anterior cardinal vein?

Answer 20

Right forms internal jugular and SVC, left forms left brachiocephalic trunk

They provide drainage from cranial territory.

Question 21

What is the fate of the right posterior cardinal vein?

Answer 21

It becomes the proximal part of the azygous vein

Question 22

What is the fate of the left umbilical vein?

Answer 22

It becomes the round ligament of the liver

Question 23

What is the fate of the left posterior cardinal vein?

Answer 23

It becomes the left superior intercostal vein