Vascular Embryology

Question 0

How do vessels enlarge?

Answer 0

Fusion with smaller vessels

Enlargement of individual capillary beds

Question 1

2 mechanisms of vascular development

Answer 1

1. Vasculogenesis: coalescence of angioblasts (Major vessels such as dorsal aorta and cardinal veins)
2. Angiogenesis: vessels sprout from existing vessels (remainder of vascular system)

Question 2

Major arterial conduits in the early embryo

Answer 2

Dorsal aortas (continuation of endocardial tubes, arose from aortic sac)

Question 3

Formation of the first pair of aortic arches

Answer 3

Cranial portions of the dorsal aortas create an arc on both sides of the foregut due to movement of the developing heart tube and pericardium

Question 4

3mm embryo

Answer 4

1st pair of aortic arches large
2nd pair just forming
All other arches form from aortic sac

Question 5

Aortic arch one becomes

Answer 5

Maxillary artery

Question 6

Aortic arch two becomes

Answer 6

Stapedial artery

Question 7

Primitive pulmonary artery comes from which arch?

Answer 7

Aortic arch 6

Question 8

What happens when the turn aortic sac divides?

Answer 8

Aortic arch 6 is now continuous with the pulmonary trunk

Starting to lose symmetry

Question 9

Inter segmental arteries are important in the formation of?

Answer 9

Subclavian arteries

Question 10

Aortic arch 3 forms:

Answer 10

Common carotid artery and first part of internal carotid

Question 11

Aortic arch 4 forms:

Answer 11

Left side: aortic arch between L common carotid and L subclavian
Right side: proximal right subclavian

Question 12

Another name for arch 6

Answer 12

Pulmonary arch

Question 13

Aortic arch 6 becomes:

Answer 13

Dorsal portion of right arch 6 disappears
Proximal part of right arch becomes right pulmonary artery
Distal Left arch becomes ductus arteriosus
Proximal left arch becomes proximal left pulmonary artery

Question 14

Ductus arteriosus at birth

Answer 14

Normally obliterates, forming ligamentum arteriosum

Question 15

Aortic sac becomes

Answer 15

Ascending aorta
Aortic arch
Brachiocephalic artery

Question 16

Right dorsal aorta becomes

Answer 16

Right subclavian

Question 17

Left dorsal aorta becomes

Answer 17

Distal aortic arch and descending aorta

Question 18

Right intersegmental artery becomes:

Answer 18

Right subclavian

Question 19

Left intersegmental artery becomes:

Answer 19

Left subclavian

Question 20

Major point of entry into common atria

Answer 20

Sinus venosus

Question 21

In 4mm embryo, 3 distinguishable parts of sinus venosus

Answer 21

Central (unpaired) portion
Transverse portion
Right and left sinus horns

Question 22

Blood supply to the sinus venosus, week 4:

Answer 22

Sinus venosus receives blood via right and left horns

Each horn receives blood from vitelline, umbilical, and common cardinal veins

Question 23

Communication between the sinus and atrium is initially wide open, what causes a shift from this?

Answer 23

Shifts to the right due to shift in blood in venous system

Occurs at about 4-5 weeks

Question 24

Fate of right umbilical vein, left vitelline vein, and left common cardinal vein

Answer 24

Obliterated week 5: right umbilical and left vitelline veins
-Left horn no longer important
Obliterated week 10: left common cardinal vein
-all that remains of left sinus horn is oblique vein of the LA and the coronary sinus

Question 25

Only communication between the original sinus venosus and the atrium?

Answer 25

Right sinus horn

• shunts blood left to right, so right sinus horn enlarges
• forms the smooth wall part of the right atrium

Question 26

Left sinus horn and right sinus horn become?

Answer 26

Left sinus horn: oblique vein of LA and coronary sinus

Right sinus horn: smooth wall of RA

Question 27

Valvular fold on either side of the sinuatrial orifice:

Answer 27

Left venous valve: fuses with atrial septum
Superior right venous valve: disappears
Inferior right venous valve: becomes valve of IVC and valve of right coronary sinus

Question 28

Function of vitelline veins:

Answer 28

Carry blood from yolk sac to sinus venosus

Question 29

Function of umbilical vein:

Answer 29

Originate in chorionic villi and carry OXYGENATED blood to the embryo

Question 30

Function of common cardinal veins:

Answer 30

Drain the body of the embryo

Question 31

In primitive heart tube, left and right sinus horns drain into?

Answer 31

Central sinoatrial orifice

Question 32

Where does the vitelline venous system enter and what does it give rise to?

Answer 32

Enters sinus venosus

Gives rise to hepatic veins

Question 33

Were does the umbilical venous system enter and what does it give rise to?

Answer 33

Enters sinus venosus lateral to vitelline veins

Persists as umbilical vein in the fetus

Question 34

Where does the cardinal venous system enter and what does it give rise to?

Answer 34

Enters sinus venosus lateral/superior to the umbilical veins

Forms a large complex network of veins throughout body

Question 35

Fate of left vitelline vein

Answer 35

Disappears

Question 36

Fate of right vitelline vein

Answer 36

Becomes hepatic veins and all other veins of hepatic portal system

Question 37

Fate of left umbilical vein

Answer 37

Joins hepatic system, bit still persists in fetus as umbilical vein

Question 38

Fate of right umbilical vein

Answer 38

Subcardinohepatic anastomosis

Question 39

What does the left sinus horn become?

Answer 39

Coronary sinus

Question 40

Right side of the subcardinal venous system develops into?

Answer 40

Principle venous channels to the heart from lower body

Question 41

Anterior and posterior cardinal veins:

Answer 41

Anterior drain the upper limbs

Posterior mostly disappear (so even greater demand on right subclavian vein)

Question 42

Chamber between the anterior cardinal veins:

Answer 42

Brachiocephalic vein

Drains entire head and upper extremities

Question 43

Sub cardinal veins completely fuse to become:

Answer 43

IVC