Great Vessels Embryo

Question 1

Where do the aortic arches arise?

Answer 1

from aortic sac at the distal truncus arteriosus

Question 2

What divides the trunks arteriosus? What is the outcome?

Answer 2

aorticopulmonary septum

- outflow divided into ventral aorta and pulmonary a.

Question 3

What does the R horn of the aortic sac become? L?

Answer 3

R = brachiocephalic a
L = proximal aortic arch

Question 4

What is left of the 1st arch after resorption? 2nd?

Answer 4

1st = maxillary a
2nd = hyoid and stapedial a

Question 5

What happens when the heart is repositioned?

Answer 5

• lengthens carotid and brachiocephalic aa
• reposition L subclavian close to origin of L CCA
• Recurrent laryngeal nn hook around aortic arch (R around subclavian; L aorta)

Question 6

What do the vitelline aa form upon fusion?

Answer 6

dorsal mesentery of gut

- celiac, superior mesenteric and inf mesenteric

Question 7

What does the umbilical a form upon connection to the dorsal aorta?

Answer 7

common iliac a

Question 8

Where do the vitelline vv pass through to form a plexus around the duodenum?

Answer 8

septum transversum

Question 9

What develops as the liver cords expand into the septum?

Answer 9

hepatic sinusoids develop

Question 10

What happens when the L sinus horn is reduced?

Answer 10

blood from L side of liver channels to R enlarging R vetelline v; now termed R hepatocardiac channel goes on to form hepatocardiac portion of IVC

Question 11

What does the anastomotic network around duodenum develop?

Answer 11

single portal v

Question 12

What does the sup mesenteric v arise from?

Answer 12

R vitelline v

Question 13

What does the ductus venous connect?

Answer 13

L umbilical v and R hepatocardiac channel

- ductus venous bypasses liver sinusoids

Question 14

What does L umbilical v become? ductus venous?

Answer 14

ligamentum teres heptis and ligamentum venosus

Question 15

What do the cardinal vv drain ?

Answer 15

anterior = cephalic
post = reminder of embryo

Question 16

What does the anastomoses between the ant cardinal vv develop?

Answer 16

L brachiocephalic v

Question 17

What forms the SVC?

Answer 17

R common cardinal v and proximal R ant cardinal v

Question 18

what doe the sub cardinal vv anastomoses form?

Answer 18

L renal vv

• L sub cardinal v resorbs leaving L gonadal v
• R develops into renal segment of IVC

Question 19

What do anatomies between sacrocardinal vv form?

Answer 19

L common iliac V

- R becomes sacrocardinal segment of IVC

Question 20

What contributes to IVC formation?

Answer 20

hepatic, renal and sacrocardinal vv

Question 21

What do 4-11th R intercostals drain to? 4th -7th L intercostal v becomes?

Answer 21

• drain to R supra cardinal v which becomes azygous

- become hemiazygous v

Question 22

How does blood return to the fetus from the placenta?

Answer 22

umbilical v

- flows through ductus venous into IVC short cutting the liver

Question 23

How does blood flow to the liver sinusoids?

Answer 23

via sphincter present within ductus venous protecting developing heart

Question 24

What are the first structures fed by blood circulation?

Answer 24

heart musculature (coronary aa) then brain (ascending aorta)

Question 25

What is the initial change in post-natal circulation due to self respiration?

Answer 25

changes pressure and increases flow and size of vessels rapidly

Question 26

Why does the foramen oval close?

Answer 26

due to increased pressure in L atrium and decreased in R

- septum primum pressed against septum secundum

Question 27

What two channels arise to connect sacs to one another and drain lymph?

Answer 27

thoracic ducts (L and R) between jugular sacs and cisterna chyli to form an anastomosis

Question 28

What does the definitive thoracic duct form?

Answer 28

distal R thoracic duct, the anastomosis and cranial portion of L thoracic duct

Question 29

What does the R thoracic duct form?

Answer 29

R lymphatic duct

Question 30

Where do the thoracic ducts drain to?

Answer 30

areas of IJV and subclavian vv junction