Fetal Circulation

Question 1

What are the three shunts in the fetus?

Answer 1

• Foramen ovale
• Ductus arteriosus
• Ductus venosus

Question 2

What vessels does the ductus arteriosus connect?

Answer 2

The pulmonary artery to the aorta

Question 3

Where is the placenta located?

Answer 3

At the fundus of the uterus

Question 4

What is the placenta connect to the fetus via?

Answer 4

The umbilical cord

Question 5

What is the umbilical cord surrounded by?

Answer 5

The amnion which contains Wharton’s jelly

Question 6

What is embedded in Wharton’s jelly?

Answer 6

Two umbilical arteries and the umbilical vein

Question 7

What does the umbilical vein carry?

Answer 7

Oxygen and nutrient rich blood from the placenta

Question 8

What does the ductus venosus drain into

Answer 8

The IVC

Question 9

What is the purpose of the valve of the inferior vena cava?

Answer 9

It directs blood to pass through the foramen ovale

Question 10

When does the foramen ovale close?

Answer 10

4 months

Question 11

When id the functional closure of the ductus arteriosus?

Answer 11

First hour caused by increased oxygen and fall in prostaglandins

Question 12

When is the structural closure of the ductus arteriosus?

Answer 12

Between 1 and 4 months. Caused by thickening of tunica intima

Question 13

What does the umbilical vein become?

Answer 13

Ligamentum teres hepatis

Question 14

When does the ductus venosus functionally close?

Answer 14

Within 1 to 3 hours

Question 15

What do the umbilical arteries become?

Answer 15

Medial umbilical ligaments (within medial umbilical folds)

Question 16

When do the umbilical arteries atrophy?

Answer 16

Around 2-3 months

Question 17

What percentage of blood in the descending aorta is distributed in the abdomen, pelvis and lower limbs?

Answer 17

• 33%

- Other third goes to placenta via internal iliac artery to the umbilical artery and then placenta