Block III: Venous circulation (conf 1)

Question 1

What is the main purpose of the venosus circulation?

Answer 1

Return to the primitive heart tube through the Sinus Venosus

Question 2

What side is the venous circulation dominant?

Answer 2

Venous circulation is right side dominant, so left side will shift mostly to the right side

Question 3

how many horns does the sinus venosus has?

Answer 3

2 horns (left and right)

Question 4

Name the components of the sinus venosus

Answer 4

From “lateral to medial”:
- Right Common Cardinal Vein
- Left Common Cardinal Vein
- Right/Left Umbilical Veins
- Right/Left Vitelline Veins

Question 5

THe right and left vitelline veins form a plexus around what structure? Where do they move into and their function/placement into which they drain?

Answer 5

form plexus around GI tract (duodenum), and move into the liver, where they form small, highly permeable capillaries that drain into the right/left hepatic veins, which cross through the septum transversum, and drain into the sinus venosus

Question 6

Where does the vitelline veins connect?

Answer 6

follow yolk stalk into the embryo (connection between yolk sac and midgut)

Question 7

What important vessel does vitelline veins form?

Answer 7

portal vein; eventually turns into hepatic segment of inferior vena cava (right one)

Question 8

What happens with the left vitelline system?

Answer 8

digresses

Question 9

Who drains in the vitelline veins plexus?

Answer 9

Splenic, superior and inferior mesenteric drain here

Question 10

Where do hepatic veins form from?

Answer 10

form from the remains of the right vitelline vein in the region of the developing liver.

Question 11

The hepatic portal veins develops from?

Answer 11

develops from an anastomotic network formed by the vitelline veins around the duodenum

Question 12

What venus end do vitelline veins enter into?

Answer 12

They enter the venous end of the heart known as the sinus venosus.

Question 13

What is the exception in umbilical veins?

Answer 13

left vein persists only in its caudal part, rostral part loses connection to heart. (even tho it is a right side dominant system)

The right umbilical vein disappears during the 7th week; left umbilical vein is
then the only vessel carrying O2-rich blood from the placenta to the embryo (via the ductus venosus to the heart = shunt).

Question 14

Where do the umbilical veins run through?

Answer 14

Run on each side of the liver and carry O2-rich blood from the placenta to the sinus
venosus (partially going through the liver = shunt).

As the liver develops, they lose their connection with the heart and empty into the liver.

Question 15

What becomes the ligamentum venosus?

Answer 15

Ductus venosus

Question 16

what does the left umbilical vein become and its function?

Answer 16

ligamentum teres hepatis = round ligament of liver (connects liver to umbilicus).

Question 17

What does ductus venosus connect?

Answer 17

left umbilical vein and inferior vena cava (shunt/bypass)

Question 18

Why does ductus venosus turn into a ligament?

Answer 18

you dont need more oxygen from placenta, youre on your own

Question 19

Vitelline arteries become what?

Answer 19

from descending aorta branches :
1) Celiac trunk to the foregut.
2) Superior mesenteric artery to the midgut.
3) Inferior mesenteric artery to the hindgut.

Question 20

Umbilical arteries remain as:

Answer 20

Partsof descending aorta:
1) Proximal part: Internal iliac arteries and superior vesical arteries
2) Distal part: Medial umbilical ligaments

Question 21

Which structures are the main drainage of the embryo?

Answer 21

Cardinal Veins (CV); recogen sangre del embryo que tiene q regresar al corazon

Question 22

Where do anterior and posterior parts of the cardinal veins drain into?

Answer 22

drain cranial and caudal parts of the embryo, respectively.

Question 23

How many common cardinal veins are there?

Answer 23

2

Question 24

How many cardinal veins are there?

Answer 24

4 (anterior/posterior right = 2) (anterior/posterior left = 2); could be 6 if you count the common cardinals

Question 25

When the anterior cardinal veins connect by anastomosis, what happens?

Answer 25

shunting blood from the left to the right anterior CV. This shunt becomes the left brachiocephalic vein when the caudal part of the left anterior CV degenerates

Question 26

Where does the superior vena cava form from?

Answer 26

from the right anterior Cardinal Vein and the right common Cardinal Vein.

Question 27

What are the adult remnants of the posterior cardinal veins?

Answer 27

1) Root of the azygos vein (parte rostral)
2) Common iliac veins

Question 28

The posterior cardinal veins develop primarily as vessels of?

Answer 28

as the vessels of the mesonephro (interim kidneys) and disappear with these transitory kidneys.

Question 29

What replaces gradually and supplements the posterior cardinal veins?

Answer 29

The subcardinal and supracardinal veins gradually replace and supplement the posterior CVs)

Question 30

explain the subcardinal veins origin and function

Answer 30

The subcardinal veins, which appear first, are connected with each other (subcardinal anastomosis) and with the posterior CV; they form the stem of the left renal vein (not the right one), the suprarenal veins, the gonadal veins (testicular and ovarian), and a segment of the IVC.

Question 31

Explain the supracardinal veins origin and function

Answer 31

The supracardinal veins are the last pair to develop; they become disrupted in the region of the kidneys.

Cranial to the kidney, they unite by an anastomosis that is represented in the adult by the azygos (right side anterior piece) and hemiazygos veins (left side anterior piece).

Caudal to the kidneys – the left supracardinal vein degenerates; the right supracardinal vein becomes the inferior part of the IVC.

Question 32

where does azygos vein drain?

Answer 32

directly into superior vena cava

Question 33

where does hemiazygos vein drain?

Answer 33

into azygos vein

Question 34

The right renal vein comes from?

Answer 34

anastomosis between subcardinal veins and supracardinal veins; turns into inferior vena cava (renal segment of inferior vena cava)

Question 35

What are the main segments of the inferior vena cava?

Answer 35

1) hepatic segment = hepatic vein (proximal part of right vitelline vein).
2) pre-renal segment = right subcardinal vein.
3) renal segment = subcardinalsupracardinal anastomosis.
4) postrenal segment = right supracardinal vein.