Fetal Circulation

Question 1

What kind of circulation does the fetus practice?

Answer 1

Placental circulation

Which is designed to avoid the lungs.

Question 2

When does it convert to pulmonary circulation?

Answer 2

Once born, within 60 seconds of birth but full transformation takes upto 6 weeks.

Question 3

What is the ductus venosus ?

Answer 3

1) Ductus venosus- is formed when the umbilical vein divides to supply the liver via the hepatic portal vein and the ductus venosus then joins the inferior cena cava.

Question 4

What are the Hypogastric arteries?

Answer 4

• two arteries
• Carrie’s de-oxygenated blood from the fetus back to the heart
• branch from the internal iliac arteries and become a part of the umbilical cord

Question 5

What is the ductus arteriosus?

Answer 5

The ductus arteriosus leads from the bifurcation of the pulmonary arteries to the descending aorta. Just after the exit of the subclavian and carotid arteries.

Question 6

What is the foramen ovale?

Answer 6

This provides a right to left shunt between the right and left atrium.

It diverts blood away from the lungs .

Question 7

What do the temporary structures become?

Answer 7

Ligaments

Foramen ovale- Fossa ovale

Ductus venosus - ligamentum venosum

Ductus afteriosus - ligamentum arteriosum

Hypogastric arteries - obliterated hypogastric arteries.

Question 8

Briefly list the Cardiovascular changes at birth?

Answer 8

1) cord clamped
2) closure of foramen ovale
3) expansion of the lungs
4) closure of ductus arteriosus