Fetal Circulation and Physiology- Topic 8 Flashcards

1
Q

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

A

Lungs
Kidneys
GI Tract

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2
Q

How does the fetus obtain oxygen and nutrients?

A

Via diffusion form the maternal blood

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3
Q

How are wastes and CO2 eliminated in fetal circulation?

A

Via diffusion into the maternal blood

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4
Q

How does exchange occur in fetal circulation?

A

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

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5
Q

Placenta

A

way of communication between mother nad baby

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6
Q

Umbilical Artery

A

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

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7
Q

Umbilical Vein

A

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

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8
Q

Fetal capillaries

A

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

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9
Q

Intervillous spaces

A

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

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10
Q

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

A

Uterine blood vessles

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11
Q

Wastes diffuse out of the capillaries into what spaces?

A

Intervillous spaces, containing maternal blood in the placenta

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12
Q

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

A

uterine arteries; diffuse from intevillous spaces into the fetal capillaries

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13
Q

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

A

50%

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14
Q

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

A

Greater

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15
Q

Fetal hemoglobin can carry what percent more oxygen?

A

30-35%

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16
Q

Is there direct mixing of maternal and fetal blood?

A

NO

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17
Q

Rogam Shot

A

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

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18
Q

How many mls o2/min extracted?

A

20-30 mL

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19
Q

Placental circulation has low or high resistance?

A

Very low resistance

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20
Q

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

A

Late first trimester

21
Q

Fetal Immunoglobin Type

A

IgG

22
Q

When are immunoglobulins transported from mother to fetus?

A

At about 14 weeks; provides passive immunity

23
Q

When do newborns reach adult levels of IgG produced?

A

Age 3

24
Q

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

A

4th month

25
Q

Placenta continues to produce what estrogenic hormone?

A

Estriol, which rises until the end of pregnancy

26
Q

Blood passes from the fetus to the placenta via what?

A

2 umbilical arteries; branch of the internal iliac arteries

27
Q

Whats the saturation of the umbilical arteries?

A

~58%

28
Q

Oxygenated blood is what saturation?

A

~80%

29
Q

Oxygenated blood returns from the placenta via what?

A

1 umbilical vein

30
Q

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

A

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

31
Q

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

A

67%

32
Q

What are the fetal lungs filled with?

A

Fetal lung fluid

33
Q

Are the fetal lungs used to oxygenate blood?

A

No

34
Q

What does the liquid in the fetal lungs do?

A

Increases pulmonary vascular restitance to blood flow

35
Q

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

A

Foramen ovale

36
Q

Foramen Ovale

A

Hole between the right and left atria

37
Q

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

A

The LA

38
Q

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

A

95%

39
Q

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

A

Ductus Arteriosus
Formane Ovale
Ductus Venosus

40
Q

When does complete closure of the umbilical arteries?

A

2-3 months

41
Q

Autopsy shows what percent prevalence of PFO?

A

27%

42
Q

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

A

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

43
Q

How long does complete obliteration of the lumen take?

A

1-3 months

44
Q

Umbilical Arteries become what?

A

Medial Umbilical Ligaments

45
Q

Vein becomes?

A

Ligamentum Teres (Round ligament)

46
Q

Ductus Venosus becomes what?

A

Ligamentum Venosum

47
Q

Foramen Ovale becomes what?

A

Fossa Ovalis

48
Q

Ductus Arteriosus becomes what?

A

Ligamentum Arteriosum