Placental function and pregnancy

Question 1

what makes up the placenta

Answer 1

3 blood vessels

2 foetal membranes

Question 2

what are the 3 blood vessels of placenta

Answer 2

2 veins to carry oxygenated blood from mother’s heart to baby
one artery to carry deoxygenated blood away from the baby

Question 3

what carries deoxygenated blood away from baby

Answer 3

artery of placenta

Question 4

what carries oxygenated blood to baby from mother

Answer 4

veins of placenta

Question 5

what are the two foetal membranes

Answer 5

amnion closest to amniotic fluid

chorion on the outside

Question 6

which foetal membrane is closest to amniotic fluid

Answer 6

amnion

Question 7

which membrane is on the outside of placenta

Answer 7

chorion

Question 8

what increases SA of placenta’s blood vessels

Answer 8

tree-like structure

Question 9

how many layers of cells are there between maternal blood and placenta

Answer 9

2

Question 10

why dont maternal and foetal blood directly connect

Answer 10

• at birth mother would bleed out

- foetus cannot withstand mothers BP

Question 11

how does placenta recieve mother’s blood supply

Answer 11

spiral arteries of the placenta attach to the vessels of the endometrium

Question 12

how do spiral arteries pevent bleeding out at birth

Answer 12

spiral artiers are clamped

Question 13

when does the placenta begin to develop

Answer 13

implantation

Question 14

before the placenta, what is major source of prgesterone

Answer 14

corpus luteum

Question 15

how does implantation occur

Answer 15

blastocys attatches then trophoblast forms migrating columns to invade endometrium to reach maternal vessels

Question 16

what do trophoblast differentiate to at day 7

Answer 16

cytotrophoblasts and outer syncytiotrophoblast

Question 17

what do syncytiotrophoblast do

Answer 17

form basis primary vili stems

Question 18

what do cytotrophoblasts do

Answer 18

form finger like projections that extend through syncytiotrophoblast

Question 19

when are spiral arteries plugged

Answer 19

• until oxygen is needed at end of first trimester

- at birth to prevent bleeding out

Question 20

what would happen if spiral artieres werent plugged during first trimester

Answer 20

there would be too much oxidative stress for foetus

Question 21

how does foetus get oxygen and nutrtients in first trimester

Answer 21

diffusion

Question 22

what is the ideal conditon of placenta in frist trimester

Answer 22

hypoxic environment

Question 23

what does hypoxic environment do

Answer 23

ensure angiogenesis and protects foetus

Question 24

when is hypoxic environment needed

Answer 24

first trimester

Question 25

angiogenesis

Answer 25

formation of new blood vessels

Question 26

what is the transition between week 6 and 10 for

Answer 26

where both placenta and corpus luteum are producng progesterone

Question 27

pros and cons of maternal arteries being plugged in first trimester

Answer 27

pro - no oxygen | cons - no nutrition

Question 28

what provides embryo with nutrition in first trimester

Answer 28

endometrial glands

Question 29

what do endometrial glands do

Answer 29

provide growth factors and nutrtion for embryo | they are essential for foetal and placental growth

Question 30

where is hCG produced and what is its purpose

Answer 30

endometrial glands and essential to maintain corpus luteum for 6-10 weeks

Question 31

where is glycodelin A produced and what is its purpose

Answer 31

endometrial glands and supresses the activity of natural killer cells and it nutrient source

Question 32

what do endometrial glands prduce

Answer 32

hCG and glycodelin A

Question 33

when and why does foetus need maternal blood supply

Answer 33

end of first trimester becuase foetus is bigger and needs oxygen and increased nutrtional support

Question 34

how does foetus get oxygen and increased nutrtional support at end of frist trimester

Answer 34

from maternal blood by unplugging of arteries

Question 35

when does unplugging of spiral artiers occur

Answer 35

10 weeks end of first trimester

Question 36

what happens when spiral arteries are unplugged

Answer 36

placental environment changes from hypoxic to hyperoxic by maternal blood

Question 37

functions of established placenta

Answer 37

- respiratory organ - nutrient transfer - excretion of foetal waste - hormone synthesis

Question 38

how does gas exchange occur between mother and foetus

Answer 38

two umbilical arteries remove waste and co2 from baby | one umbilical vein deliverys o2 , nutrients and hormones to baby

Question 39

beneficial feature of foetal Hb

Answer 39

very good at getting oxygen, which is good becuase pO2 decreases from maternal to foetal blood

Question 40

what happens to pO2 from maternal to foetal blood

Answer 40

decreases, lower in foetus

Question 41

what is the site of placental nutrient transport

Answer 41

syncytiotrophoblasts

Question 42

why are syncytiotrophoblasts good for nutrient transport

Answer 42

- short transfer barrier for efficency

Question 43

how are nutrients transported at syncytiotrophoblasts

Answer 43

passivley and actively | several mechanisms for AA tranpsort

Question 44

what different methods of AA transport occur at syncytiotrophoblasts

Answer 44

- ATP dependent - AA specific - concentration gradient dependent

Question 45

how does foetus get glucose

Answer 45

placental transfer from mother

Question 46

why is foetus dependent on mother for glucose

Answer 46

- foetus has little capacity for gluconeogenesis becuase enzymes do not function at the ambient low pO2

Question 47

why does foetus have little capacity for gluconeogenesis

Answer 47

necessary enzymes dont function at ambient low pO2

Question 48

where does foetus get insulin from

Answer 48

synthesises it it self from week 9-11; not from mother

Question 49

what determines glucose metabolism in foetus

Answer 49

foetal insulin

Question 50

what does excess glucose do to foetus

Answer 50

excess growt & fat depostion

Question 51

what does inadequate glucose cause to foetus

Answer 51

emanciation

Question 52

how does glucose travel across placenta

Answer 52

actively; predominantly through GLUT1 in second half of pregnancy

Question 53

method of fatty acid transport in placenta

Answer 53

diffusion via syncytiotrophoblasts

Question 54

process of fatty acid transport from mother to foetus

Answer 54

- preferantial transfer of long PUFA - passive diffusion or membrane carrier proteins - binds to intracellular FABP - basal membrane FA trasport proteins FAT/CD36 FATP - enter foetal circulation and bind to alpha foetal protein - go to liver for resestierfication - re enter circualtion with lipoproteins mainly as TAG

Question 55

bilirubin

Answer 55

orangey-yellow pigment formed in liver by breakdown of Hb

Question 56

what is the role of placenta for bilirubin

Answer 56

placenta is an important channel for removing bilirubin

Question 57

why does bilirubin need removing from foetus

Answer 57

it is toxic and cannot be brokenn down by foetus becuase have low levels of BUDGT foetus produces lots of bilirubin becuase of its acive heame conversion

Question 58

why does foetus produce lots of bilirubin

Answer 58

active haem conversion

Question 59

how is bilirubin removed

Answer 59

moves through channel of placenta down concetration into maternal compartment which has high BUDGT so can breakdown toxic bilirubin

Question 60

what breaks down bilirubin

Answer 60

BUDGT

Question 61

BUDGT

Answer 61

breaksdown bilirubin

Question 62

where does steroidogenesis occur in pregnancy

Answer 62

``` 3 compartments: - foetus - placenta - maternal circulation all make hormones and work in synergy ```

Question 63

where does the basis of steroid hormones come from in pregnancy

Answer 63

cholesterol comes from maternal circuation and enters placenta

Question 64

where does progesterone come from and what are its effects

Answer 64

placenta and causes chages in mother's physiology to prepare for pregnancy

Question 65

what does progesterone block the production of in placenta

Answer 65

DHEA-S

Question 66

where does DHEA-S come from

Answer 66

foetus

Question 67

why does the placenta need the foetus and maternal circulation

Answer 67

it is an incomplete steroid producng organ

Question 68

3 types of pro labour oestrogens

Answer 68

oestradiol, ostriol and oestrone

Question 69

effects of oestrogen in pregnancy

Answer 69

- CV adaptation - growth of uterus - priming of uterus for labour - weak anti insulin activity - cervical ripening - onset of labour

Question 70

effects of progesterones in pregnancy

Answer 70

- prepares and maintains endometrium - suppress immune response - role in partuition - growth of mammary glands - ihibtion of uterine contractilty - prevention of cervical ripening

Question 71

what causes cervical ripening and onset of labour

Answer 71

oestrogens

Question 72

what inhibits uterine contractility and prevents cervical ripeing

Answer 72

progesterone

Question 73

effect of hCG in pregnancy

Answer 73

maintains corpus luteum

Question 74

hCG

Answer 74

human chorionic gonadotropin

Question 75

metablic actions of placental lactogen

Answer 75

- induces maternal lipolysis for more NEFA - increases maternal insulin to promote protein synthesis and AA mobilisation - increases insulin resistance but reduces glucose utilsation to spare for foetus

Question 76

- induces maternal lipolysis for more NEFA - increases maternal insulin to promote protein synthesis and AA mobilisation - increases insulin resistance but reduces glucose utilsation to spare for foetus

Answer 76

placental lactogen

Question 77

- prepares and maintains endometrium - suppress immune response - role in partuition - growth of mammary glands - ihibtion of uterine contractilty - prevention of cervical ripening

Answer 77

progesterone in pregnancy

Question 78

- CV adaptation - growth of uterus - priming of uterus for labour - weak anti insulin activity - cervical ripening - onset of labour

Answer 78

oestrogens in pregnancy

Question 79

corticotrophin releasing hormone in pregnancy

Answer 79

- immunosupression (?) - rise near end of gestation - used as treatment to increase prostaglandin formation

Question 80

- immunosupression (?) - rise near end of gestation - used as treatment to increase prostaglandin formation

Answer 80

corticotrophin releasing hormone in pregnancy

Question 81

leptin in pregnancy

Answer 81

stimulates placental AA and FA transport | probably important for foetal development and growth

Question 82

stimulates placental AA and FA transport | probably important for foetal development and growth

Answer 82

leptin in pregnancy

Question 83

where is leptin secreted from in placenta

Answer 83

cytotrophoblast and syncytiotrophoblast

Question 84

what doe foetal [leptin] correlate positively with

Answer 84

birth weight

Question 85

how are maternal leptin levels different in pregnancy

Answer 85

higher than normal