Cardiovascular Embryology

Question 1

what is the advantage of developing the cardiovascular system early?

Answer 1

diffusion can only transfer nutrients and oxygen so far, the CV system allows it to grow beyond those short distances

Question 2

what is the cardiogenic plate?

Answer 2

splanchnic mesoderm situated anterior to the embryo, moves ventrally as head process grows
site of first heart development with bilateral vessel formation

Question 3

what fuses to form the future tubular heart?

Answer 3

endocardial tubes

Question 4

What are the 5 primitive heart regions?

Answer 4

truncus arteriosus
bulbus cordis
ventricle
atrium
sinus venosus

Question 5

truncus arteriosus

Answer 5

output region of heart

becomes ascending aorta and pulmonary trunk

Question 6

bulbus cordis

Answer 6

becomes right ventricle

Question 7

ventricle

Answer 7

becomes left ventricle

Question 8

atrium

Answer 8

expands to become left and right auricles

Question 9

sinus venosus

Answer 9

paired region where veins drain
left becomes coronary sinus
right becomes part of right atrium wall

Question 10

what partitions the common AV opening?

Answer 10

endocardial cushions

Question 11

foramen ovale

Answer 11

open septum in embryo that allows blood to flow from right atrium (higher pressure) to left

Question 12

what happens if the truncus arteriosus isn’t partitioned in a spiral pattern?

Answer 12

the pulmonary trunk would be attached to the left ventricle and the aorta to the right which would be fatal

Question 13

ventral and dorsal aortae

Answer 13

paired in embryo, connected by up to 6 aortic arches, each situated in a pharyngeal arch
dorsal aortae form the descending aorta
ventral aortae form the brachiocephalic trunk

Question 14

what does the third aortic arch become?

Answer 14

the carotid arteries

Question 15

what do the left and right fourth aortic arches become?

Answer 15

left becomes the arch of the aorta

right becomes right subclavian artery

Question 16

what do the sixth aortic arches become?

Answer 16

pulmonary arteries

left distal arch becomes ductus arteriosus

Question 17

ductus arteriosus

Answer 17

shuts blood from pulmonary trunk to aorta
abruptly constricts at birth, shifts flow to lungs
then becomes ligamentum arteriosum

Question 18

vitelline veins

Answer 18

drain yolk sac into embryonic sinus venosus

form liver sinusoids and portal vein as liver develops and surrounds veins

Question 19

umbilical veins

Answer 19

drain allantois into embryonic sinus venosus
contribute to liver sinusoids
create ductus venosus to shunt blood from liver until born

Question 20

cardinal veins

Answer 20

drain the embryo into sinus venosus

Question 21

which way does venous return shift in embryonic development?

Answer 21

to the right and the right sinus venosus become part of the right atrium

Question 22

lymph node and vessel formation

Answer 22

begin as lymph sacs and vessels outgrow from sacs

nodes made by mesodermal invaginations

Question 23

what happens to the shunts at birth?

Answer 23

ductus venosus slowly closes and allows flow to liver
ductus arteriosus constricts rapidly
foramen ovale closes rapidly as pressure equalizes between atria