Fetal and placental physiology

Question 1

What is cortisol essential for in fetal dev?

Answer 1

1. lung compliance and surfactant production
2. B R and glycogen deposition in the liver
3. villus prolif and digestive enxymes

Question 2

Where does oxygenation occur in the fetus?

Answer 2

The placenta

Question 3

What structures allow the fetal lungs to be bypassed?

Answer 3

1. ductus venosus - shunts blood away from liver
2. ductus arteriosus - shunts blood from pulm trunk to aorta
3. foramen ovale -blood from right to left atrium
   DRAW FETAL CIRULATION OUT

Question 4

What keeps to DA open and what closes it prem?

Answer 4

PGE2 and prostacyclin

COX

Question 5

After birth what happens to fetal circ?

Answer 5

Drop in P - FO closes

Vent of lungs = decrease vasc resist

Question 6

What does surfactant do?

Answer 6

fills fetal lungs with fluid - allows them to expand (find video)

Question 7

What is oligohydramnios?

Answer 7

Not enough amniotic fluid - if there is not enough fluid in the lungs then they will not grow properly

Question 8

Where is fetal blood produced?

Answer 8

Yolk sac - liver (5w) - bone (dom from 26w)

Question 9

What is different about fetal blood?

Answer 9

Hb has 2a and 2b chains - higher affinity for oxygen

Question 10

When does the switch from HbF to HbA occur?

Answer 10

28-34 wk

Question 11

What happens if there is abnorm Hb?

Answer 11

Thalassaemia

Question 12

When are lymphoctyes prod?

Answer 12

From 8w

Question 13

What cells appear mid 2T?

Answer 13

Phago, T and B cells

Question 14

Which Ig can cross placenta?

Answer 14

IgG

Question 15

What general immunological defenses are in place?

Answer 15

Amniotic fluid (IgG)
Placenta (phgo)
Granuloctyes from liver and BM
Interferon from lymphocytes

Question 16

When is the fetal skin similar to the adult?

Answer 16

23wk

Question 17

What is the vernix?

Answer 17

Desequemated skin, cholesterol, glycogen

Prem babies don’t have it - H20 loss

Question 18

What happens during gut form?

Answer 18

It herniates into umbilical cord as it grows faster than the abdomen

Question 19

When does the gut reenter? What happens if it doesn’t?

Answer 19

12wk
In sac - omphalocele
Gastroschisis - not in sac

Question 20

Swallowing reflex

Answer 20

Develops naturally

Failure = polyhydroamnios

Question 21

When is nephrogenesis complete?

Answer 21

By 36wk - maturation is gradual

Question 22

What forms most of the amniotic fluid?

Answer 22

Fetal urine - kindey failure = oligohydra

Question 23

What is the increase in amniotic fluid?

Answer 23

30ml - 1000ml at term

Question 24

What is the function of amniotic fluid?

Answer 24

Protect
Allow movement
Stop adhesions
Lung development

Question 25

What are the fetal and maternal comp of the placenta?

Answer 25

F - chorion

M - modified endo

Question 26

What is the main source of energy for fetus?

Answer 26

1/2 carbs and 1/2 aa and lactate

Question 27

What happens to the maternal insulin sensititivey?

Answer 27

Decreases to allow the fetus to uptake more glucise

Question 28

How is glucose Tp?

Answer 28

By diffusions

Question 29

What happens to placental/fetal pH?

Answer 29

Placental pH - falls - release o2

Fetal - increases - better o2 uptake

Question 30

What hormones does the placenta secrete?

Answer 30

P - stops contraction
E - OTR synth
Lactogen - fetal growth and mammary glands
Relaxin - relaxes smt muscle

Question 31

Physiology of parturition

Answer 31

DRAW