Topic 12: Cardiovascular System - Fetal Circulation

Question 1

What is the function of the mother’s blood?

Answer 1

• gets O2 and nutrients
• fetus expels wastes here

Question 2

Where is the exchange site of nutrients, oxygen, etc?

Answer 2

• placenta

Question 3

Is the placenta blood of fetus and mother mixed?

Answer 3

• blood supply is close together, but not mixed

Question 4

What are 3 differences of fetal circulation to adult circulation?

Answer 4

• umbilical vein
• lungs and liver are basically non-functional
• umbilical arteries

Question 5

What are umbilical veins?

Answer 5

• carries oxy blood from placenta to vena cava (towards fetal heart)

Question 6

What type of blood do umbilical veins only have?

Answer 6

• has fully oxygenated blood
• others are either mixed or fully deoxygenated

Question 7

Why are the lungs and liver basically non-functional? (2)

Answer 7

• 3 shunts to bypass
• but some blood flow to these organs for nourishment/growth

Question 8

What are the 3 shunts called?

Answer 8

• ductus renosus
• foramen ovale
• ductus arteriosus

Question 9

What is the ductus renosus? (3)

Answer 9

• connects umbilical vein (oxy blood) to inferior vena cava (deoxy) to bypass liver
• oxygenated and deoxy blood mix
• mixed blood enters fetal heart via inferior vena cava

Question 10

What does the ductus renosus allow for?

Answer 10

• permits most of the oxygenated blood coming from the placenta to bypass the liver

Question 11

What is the foramen ovale? (2)

Answer 11

• hole in interatrial septum
• blood to move from right to left atrium (bypass lungs)

Question 12

What is the ductus arteriosus?

Answer 12

• connects pulmonary trunk and aorta to bypass lungs

Question 13

What are umbilical arteries?

Answer 13

• returns mixed blood to placenta (away from fetal heart)

Question 14

Please see boxed diagram

Answer 14

thx