Fetal Circulation and Physiology- Topic 8

Question 1

In the fetus, what organs do not function until birth?

Answer 1

Lungs
Kidneys
GI Tract

Question 2

How does the fetus obtain oxygen and nutrients?

Answer 2

Via diffusion form the maternal blood

Question 3

How are wastes and CO2 eliminated in fetal circulation?

Answer 3

Via diffusion into the maternal blood

Question 4

How does exchange occur in fetal circulation?

Answer 4

Via the placenta, inside the uterus, attached to baby via the umbilical cord

Question 5

Placenta

Answer 5

way of communication between mother nad baby

Question 6

Umbilical Artery

Answer 6

carries blood away from the fetus to the placenta; carries wastes and CO2/ low O2 content

Question 7

Umbilical Vein

Answer 7

carries blood from the placenta to the fetus; carries nutrients and O2; high O2 cotent

Question 8

Fetal capillaries

Answer 8

umbilical arteries and veins branch into these capillaries located inside the intervillous spaces in the placenta

Question 9

Intervillous spaces

Answer 9

spaces filled with maternal blood from uterine arterioles; drained by uterine veins

Question 10

The placenta communicates with the mother’s cardiovascular system via what structure?

Answer 10

Uterine blood vessles

Question 11

Wastes diffuse out of the capillaries into what spaces?

Answer 11

Intervillous spaces, containing maternal blood in the placenta

Question 12

Nutrients travel from mother’s blood vessels to hte intervillous space via what structure?

Answer 12

uterine arteries; diffuse from intevillous spaces into the fetal capillaries

Question 13

The concentration of hemoglobin in fetal blood is what percent higher than maternal blood

Answer 13

50%

Question 14

Fetal hemoglobin has a _________(greater/lower) affinity for oxygen than maternal blood?

Answer 14

Greater

Question 15

Fetal hemoglobin can carry what percent more oxygen?

Answer 15

30-35%

Question 16

Is there direct mixing of maternal and fetal blood?

Answer 16

NO

Question 17

Rogam Shot

Answer 17

attenuates the response of the Rh - mother against the Rh + baby

Question 18

How many mls o2/min extracted?

Answer 18

20-30 mL

Question 19

Placental circulation has low or high resistance?

Answer 19

Very low resistance

Question 20

When does the fetus make components of complement? (the start of immunological competence)

Answer 20

Late first trimester

Question 21

Fetal Immunoglobin Type

Answer 21

IgG

Question 22

When are immunoglobulins transported from mother to fetus?

Answer 22

At about 14 weeks; provides passive immunity

Question 23

When do newborns reach adult levels of IgG produced?

Answer 23

Age 3

Question 24

When does the placenta produce enough progesterone to support pregnancy, should corpus leuteum fail?

Answer 24

4th month

Question 25

Placenta continues to produce what estrogenic hormone?

Answer 25

Estriol, which rises until the end of pregnancy

Question 26

Blood passes from the fetus to the placenta via what?

Answer 26

2 umbilical arteries; branch of the internal iliac arteries

Question 27

Whats the saturation of the umbilical arteries?

Answer 27

~58%

Question 28

Oxygenated blood is what saturation?

Answer 28

~80%

Question 29

Oxygenated blood returns from the placenta via what?

Answer 29

1 umbilical vein

Question 30

Oxygenated blood returning from the placenta goes to the liver of the fetus where it divides into what 2 branches?

Answer 30

Joins hepatic portal vein --> Liver (1/3) Ductus venosus --> IVC (2/3) *Sphincter mechanism in ductus tat controls blood flow through the liver

Question 31

In the IVC, oxygenated blood via the ductus venosus meets deoxygenated blood form the lower body. Sat falls to what percent?

Answer 31

67%

Question 32

What are the fetal lungs filled with?

Answer 32

Fetal lung fluid

Question 33

Are the fetal lungs used to oxygenate blood?

Answer 33

No

Question 34

What does the liquid in the fetal lungs do?

Answer 34

Increases pulmonary vascular restitance to blood flow

Question 35

Most fetal blood does not go from the RV to lungs. Instead, it passes through what?

Answer 35

Foramen ovale

Question 36

Foramen Ovale

Answer 36

Hole between the right and left atria

Question 37

Blood entering from the IVC is guided toward the foramen ovale to where?

Answer 37

The LA

Question 38

Pulmonary vascular resistance is so high that what percent of this blood bypasses hte pulmonary arteries?

Answer 38

95%

Question 39

What are the 3 shunts present in the fetal circulation that normal close after birth?

Answer 39

Ductus Arteriosus Formane Ovale Ductus Venosus

Question 40

When does complete closure of the umbilical arteries?

Answer 40

2-3 months

Question 41

Autopsy shows what percent prevalence of PFO?

Answer 41

27%

Question 42

When does the ductus arteriosus start to close? How long does it take?

Answer 42

Via vasoconstriction immediately after birth; takes about 1-2 days to close in a full term infant

Question 43

How long does complete obliteration of the lumen take?

Answer 43

1-3 months

Question 44

Umbilical Arteries become what?

Answer 44

Medial Umbilical Ligaments

Question 45

Vein becomes?

Answer 45

Ligamentum Teres (Round ligament)

Question 46

Ductus Venosus becomes what?

Answer 46

Ligamentum Venosum

Question 47

Foramen Ovale becomes what?

Answer 47

Fossa Ovalis

Question 48

Ductus Arteriosus becomes what?

Answer 48

Ligamentum Arteriosum