23. Great Vessel Development

Question 1

how many aortic arches are there & how do they form

Answer 1

6 (but the 5th doesnt form)

form via vasculogenesis & angiogenesis

Question 2

where do the dorsal aortae fuse & what do they become

Answer 2

at T4

become descending thoracic & abdominal aorta

Question 3

what branch from the dorsal aortae

Answer 3

intersegmental As

Question 4

how many intersegmental As are there

Answer 4

cervical = 7

thoracic = 12

lumbar = 5

Question 5

what forms the vertebral As

Answer 5

anastomisis btn cervical intersegmental As 1-6

& roots drop out

Question 6

what happens to the 7th intersegmental A

Answer 6

L = left subclavian A

R = part of R subclavian A

Question 7

what forms the R subclavian A

Answer 7

R 7th intersegmental A = distal

dorsal aorta = middle

R IV AA = proximal

Question 8

what do the thoracic intersegmental As become

Answer 8

anastamosis w/ each other –> internal thoracic As

intersegmentals become intercostal As

Question 9

what do the lumbar intersegmental As form

Answer 9

superior epigastic A

Question 10

what do the 5th lumbar intersegmental As become

Answer 10

common illiac A

Question 11

what happens to the umbilical As from the embryo to birth

Answer 11

branch off dorsal aorta

• connect to umbilicus
• have a branch going to bladder –> become superior vascicular A
• form new connection from distal end to 5th lumbar intersegmental A –> become umbilical As after birth
• initial connection from dorsal aorta disappear & connection to umbilicus becomes medial umbilical ligament

Question 12

what does the III AA become

Answer 12

R & L common carotid A & part of internal carotid A

-external carotid will branch from common carotid

Question 13

what forms internal carrotic A

Answer 13

III AA & dorsal aorta

Question 14

what does the L IV AA become

Answer 14

part of aortic arch

(rest of aortic arch from aortic sac, L dorsal aorta before & after 7th intersegmental A)

Question 15

what does the R IV AA make

Answer 15

proximal R subclavian A

Question 16

what do the VI AAs become

Answer 16

both - pul A

L - ductus arteriosus

R - goes away

Question 17

why do the L & R recurrent laryngeal As loop around different areas

Answer 17

L recurrent - around aortic arch bc L VI AA becomes ductus arterosis

R recurrent - around R subclavian bc R VI goes away

Question 18

what is the flow of fetal circulation

Answer 18

liver –> IVC & RA –> foramen ovale –> LA –> aorta

some to RV –> 90% thru ductus arteriosus –> aorta

Question 19

what occurs with a patent ductus arteriosus

Answer 19

blood from aorta to pul A

–> blood circulate lungs multiple times so LV hypertrophy to get same amount of blood around

-increase pul resistance –> pul congestion –> CHF

*increased risk w/ maternal rubella*

Question 20

what is coarctation of aorta

Answer 20

high risk = Turners syndrome pt

aortic lumen distal L subclavian narowed

can be before or after ductus arteriosus

Question 21

what is the differnce btn postductal & preductal coarctation

Answer 21

postductal - still have collateral circulation thru intercostal & internal thoracic As

preductal - little blood to LE bc no collateral circulation

Question 22

what happens w/ aberrant origin of R subclavian A

Answer 22

R IV AA & proximal R dorsal aorta obliterate

dysphagia & dyspnea bc cross esophagus

Question 23

what occurs when there is a vascular ring around trachea & esophagus

Answer 23

double aortic arch

-strangle trachea & esophageal dysfxn

Question 24

how do you get a R aortic arch

Answer 24

left IV AA & L dorsal aorta obliterate so R side takes over

-dyspena & dysphagia bc L subclavian before esophagus & ligamentum arterosum infront of trachea

Question 25

which congenital defect has increased risk with DiGeorge syndrome

Answer 25

interrupted arotic arch

• L IV AA gone - aortic arch doesnt form & R IV AA gone -part of R subclavian doesnt form
• ductus arteriosus stays open - descending aorta * subclavian A wupplied w/ deoxy blood

Question 26

what happens in ther vitelline system

Answer 26

form hepatic sinusoid w/i liver primordia

–> blood flow chagned toward R side of liver

–> R side –> R hepatocardiac channel –> form IVC

-L goes away

Question 27

what occurs with the umbilical system

Answer 27

connect hepatic sinusoids

-every part except L distal umbilical V remains –> form ductus venosus

becomes ligamentum teres hepatus & ligamentum venosum after birth

Question 28

what does the R & L ant cardinal V form

Answer 28

L brachiocephalic V

Question 29

what does the right common carotid V become

Answer 29

SVC

Question 30

what happens to L ant cardinal V & L CCV

Answer 30

disappear as L brachiocephalic V forms

remaining forms coronary sinus

Question 31

what do the post cardinal Vs form

Answer 31

subcardial part make Vs associated w/ kidneys, gonads & abd IVC

supracardial part makes part of IVC & azygous V