HE 22 Vascular Development

Question 1

What blood vessels flow into the fetal heart and which have oxygen and which do not?

Answer 1

Umbilical vein: Ox
Cardinal veins: de ox
Vitelline veins: de ox

Question 2

What two main blood bypasses exist in the fetus that are changed after birth?

Answer 2

Liver and pulmonary bypass

Question 3

What structure is used by blood to bypass the liver?

Answer 3

Ductus venosus
It is blood from the umbilical vein that is oxygenated and headed for the heart. After passing the liver, it dumps into the inferior vena cava.

Question 4

In the fetus, once the inferior vena cava dumps into the right atrium, what bypass structure is the blood flow directed at?

Answer 4

Foramen Ovale which is the hole between the atria.

Question 5

What is the difference between the blood in the superior vs inferior vena cava?

Answer 5

Superior has deoxygenated blood and the inferior has oxygenated blood. The blood mixes in the right atrium.

Question 6

For blood that makes it into the right atrium, what secondary structure allows some of the blood from here to skip pulmonary circulation?

Answer 6

Ductus arteriosus which is a small duct connecting the pulmonary trunk to the aortic arch.

Question 7

What do the bypass structures become after they close?

Answer 7

Ductus venosus: ligamentum venosum (posterior side of liver)
Umbilical vein: round ligament of liver (anterior side of liver)
Foramen ovale: fossa ovalis
Ductus arteriosus: ligamentum arteriosum

Question 8

What main veins develop from the anterior cardinal veins?

Answer 8

Internal jugular
Subclavian
Brachiocephalic
Superior vena cava
Inferior vena cava
Azygos system

Question 9

What fetal vessels give rise to the veins below the diaphragm?

Answer 9

Posterior cardinal veins

Question 10

What fetal vessels give rise to the veins above the diaphragm?

Answer 10

Anterior cardinal veins

Question 11

What are the inflow and outflow parts of the heart called?

Answer 11

Inflow: sinus horns into the sinus venosus
Outflow: truncus arteriosus

Question 12

Early on, each sinus horn of the heart tube receives blood from three vessels, what are they?

Answer 12

Common cardinal veins
Umbilical veins
Vitelline veins

Question 13

What happens to the right and left sinus horns as they become adult structures?

Answer 13

Left horn preserves only cardinal flow and it becomes the coronary sinus.
Right horn preserves flow from vitelline and cardinal veins and it becomes the S & I vena cava as well as part of the right atrium.

Question 14

As blood is pumped out of the heart, what are the next three structures that it passes through?

Answer 14

Truncus arteriosus
Aortic sac
Aortic arches

Question 15

What is coarctation of the aorta?

Answer 15

Constriction of the aorta after the origin of the left subclavian.
Can be preductal and postductal in relation to the ductus arteriosus.

Question 16

How can the blood compensate for preductal coarctation?

Answer 16

Blood can still reach the lower extremities through the ductus arteriosus which connects to the descending aorta below the constriction. Prostaglandin E2 can be given to keep the ductus arteriosus open after birth until a repair can be done. A baby could have cyanosis of lower extremity if this is happening.

Question 17

How does the body compensate for postductal coarctation of the aorta?

Answer 17

Blood flows through the subclavian, down the internal thoracic arteries, through the anterior and posterior intercostal arteries into the thoracic aorta and on to the lower extremities.
Would see enlargement of collateral arteries, notching of posterior portion of ribs, and blood pressure difference between upper and lower extremities.

Question 18

What happens to the dorsal aortae in the fetus?

Answer 18

The two fuse together to form the thoracic aorta.

Question 19

What do left and right aortic arch 3 become?

Answer 19

Left and right common corotid arteries.

Question 20

What does the aortic sac become?

Answer 20

Aortic arch before the brachiocephalic trunk, brachiocephalic trunk

Question 21

What does the truncus arteriosus become?

Answer 21

Ascending aorta, pulmonary trunk

Question 22

What do both sides of aortic arch 4 become?

Answer 22

Very beginning of the right subclavian, the part of the aortic arch between the left common corotid and the left subclavian.

Question 23

What do both sides of aortic arch 6 become?

Answer 23

Ductus arteriosus and the right branch of the pulmonry arteries.

Question 24

Where do the right subclavian and the descending and thoracic aorta come from?

Answer 24

Right subclavian comes from the right dorsal aorta.
Descending aorta comes from the left dorsal aorta.
Thoracic aorta comes from the fusion of both dorsal aortae.