Placenta Part 1

Front 1

trophoblasts in human blastocyst

Back 1

develop into placenta

Front 2

inner cell mass in human blastocyst

Back 2

give rise to fetus

Front 3

monozygotic twins

Back 3

20% dichorionic diamnionic
80% monochorionic diamnioic
1% monochorionic monoamnionic

Front 4

lateralization of blastocyst

Back 4

continues to day 5
at time of hatching inner cell mass is split with each group of cells expressing different genes
individuals produced have same DNA, but differential gene expression

Front 5

Implantation

Back 5

5-7 days post ovulation - the blastocyst begins to interact with the endometirial surface epithelium
- once the trophectodermal trophoblasts have firmly become attached to the endometrial surface, trophoblasts begin to invade through the epithelial layer an dinto the enometrial stroma

Front 6

day 21

Back 6

organs formed

Front 7

How does the fetus get oxygen?

Back 7

from the mother's blood that circulates in the placenta
30-35% partial pressure of PO2
cord accidents abruption (seperation of the placenta)

Front 8

How much blood does a uterus have?

Back 8

.5% no pregnancy
20-25% during pregnancy

Front 9

Role of fetal fibronectin

Back 9

glue
also surrounds fetus

Front 10

Normal spiral arteries

Back 10

in the non pregnant state, the uterine spiral arteries are very small
only .5% of a non-pregnant women's cardia output enters the uterus

Front 11

Increased blood flow happens how?

Back 11

invasive trophoblasts enlarge the mother's vessels to increase blood flow to the uterus
4-5 weeks after trophoblasts invade leave placenta causing expansion of uterus that brings mor o2 --- if not, pregnancy fails

Front 12

Invasive trophoblasts

Back 12

vessel wall destroyed increasing blood flow

Front 13

how do we assess pathology in a placenta?

Back 13

look at placenta
abnormalities
umbilical cord goes to edge rather than middle
vessels in membrane

Front 14

what can go wrong in pregnancy?

Back 14

immunologic attack
maternal lymphocytes can attack the placenta
t-cells can attack chorionic villus
CD3 immunohistochemistry - mother rejecting placenta
dichrorionic diamniotic fused

Front 15

decreased maternal blood flow to placenta

Back 15

spinal arteries and invasice trophoblasts
failure to convert maternal spiral arteries

Front 16

Pregnancy will fail if

Back 16

trophoblasts fail to expand vessels - also leads to gestational HTN

Front 17

gestational HTN

Back 17

placenta does not get enough blood b/c the vessels are not big enough
uterus need to be removed

Front 18

small blood flow leads to

Back 18

a small fetus

Front 19

decreased flow causes

Back 19

fibrin to collect around the villi - fibrin clots can lead to calcification and possibily death of placental tissue
the trapped villi eventually die

Front 20

what can go wrong with pregnancy?

Back 20

immunologic attach
decreased maternal blood flow to placenta
infection

Front 21

ascending infection

Back 21

most common route for an intrauterine infection - bacteria from vagina

Front 22

fighting an infection

Back 22

WBCs
neutrophils first attach the bacteria fromt he external membrane
the mother's neutrophils also attach the bacteria throught he chorionic plate
eventually even the fetus will begin to attack the bacteria with its neutrophils

Front 23

How do infections harm the fetus?

Back 23

damage caused by inflammatory cytokines
bacteria within the amnitic fluid induces an inflammatory response which causes cytokine release
the cytokines can damage the placenta the baby
there is biolgical variability in the cytokine network

Front 24

when the fetus is stressed

Back 24

the villi form syncytial knots

Front 25

syncytial knots are the source of..

Back 25

corticotropin releasing hormone

Front 26

CRH is criticial for

Back 26

fetal cortisol
production and organ maturation

Front 27

CRH made by

Back 27

syncytial knots entering the fetal circulation

Front 28

CRH causes the fetus to produce

Back 28

cortisol (steriods)

Front 29

Cortisol presares the fetus for

Back 29

delivery, including promoting lung maturation

Front 30

Cortisol also increases

Back 30

placental CRH production (positive feedback)

Front 31

Stressed fetus in uterus

Back 31

will deficate
the bowel contents will eventually dissolve in amniotic fluid
the meconium material slowly dissolves into the membranes that surround the fetus
after several days, little meconium is visible in the amniotic fluid, but the pigmented meconium can be seen in the membrances using a microscope

Front 32

when the fetus is stressed it will make

Back 32

nucleated RBCs

Front 33

when o@ levels drop

Back 33

the marrow increases RBC production and nucleated RBCs are released

Front 34

Nucleated RBCs can be best seen in

Back 34

the umbilical cord vessels