Cardiovascular - Fetal Circulation

Question 1

How does fetus receive gases, nutrients and wastes?

Answer 1

Through placenta

Their lungs are non functional

Question 2

What are the three vessels the umbilical contain?

Answer 2

1. Umbilical vein
   2-3. Umbilical arteries (2)

Question 3

What does umbilical vein do?

Answer 3

Carry oxygenated blood (still takes blood to heart)

Question 4

What do the umbilical arteries do?

Answer 4

Carry deoxygenated blood (still takes blood away from heart)

Question 5

Three extra parts to circulation for fetuses

Answer 5

1. Ductus venosus
2. Foramen Ovale
3. Duchus artenosus

Question 6

Step one of fetal circulation

Answer 6

1. Umbilical vein carries oxygenated blood through the ductus venosus (which allows blood to bypass liver) and enter the inferior vena cava (where it mixes with deoxygenated blood and becomes slightly less oxygenated)

Question 7

Step two of fetal circulation

Answer 7

2. Inferior vena cava takes oxygenated blood to right atrium

Question 8

Step three of fetal circulation

Answer 8

3. Most of the mixed blood will then jump to the left atrium via the foramen ovale

Question 9

Step four of fetal circulation

Answer 9

4. It will then go to the left ventricle and then the aorta

Question 10

Step five of fetal circulation

Answer 10

5. Not all the blood went through the foramen ovale and som of it will instead go to the right ventricle

Question 11

Step six of the fetal circulation

Answer 11

6. Goes from right ventricle to pulmonary trunk however the lungs are high resistance so instead it will be pushed through the ductus arteriosis, into the aorta

Question 12

Why does the artery umbilical cord carry deoxygenated blood and the and the vein umbilical cord carry oxygenated blood?

Answer 12

The deoxygenated blood from fetus picks up oxygenated blood from placenta, becoming oxygenated, and then returns to the fetus via the umbilical vein

The deoxygenated blood from fetus enters the placenta via umbilical arteries

Question 13

What happens to ductus arteriosis after birth? What happens to the foramen ovale after birth?

Answer 13

Collapses and becomes ligamentum arteriosum (helps anchor the aorta beside the pulmonary trunk)

Turns into fossa ovalis so blood now can only travel from right atrium to right ventricle

Question 14

When does the heart pump in a embryo?

Answer 14

By week 4

Question 15

When do the four chambers develop?

Answer 15

Week 7

Question 16

What happens to the heart as u age?

Answer 16

• Decreases in size
• heart valves become stiff
• left ventricle wall thickens
• decreased contractile strength (ouput lessons to about 35% by age 70)