Development of extra embryonic membranes III Flashcards
What specific molecules does the amniotic fluid contain?
lipids, phospholipids, urea, electrolytes, AAs, minerals, hormones, growth factors
What happens to the amniotic fluid volume during early gestation?
It increases bc it gets water from the mothers plasma and transports it to the fetus
Why is there a bidirectional fluid diffusion between the fetus and amniotic fluid at around 8-10 wk gestation?
The skin it not keratinized yet
When does keratinization of fetal skin start?
20 wk
When is the amniotic fluid at its max volume?
28wk, 800mL
What is amniotic fluid important for?
Development and maturation of the gut
Which growth factors are in the amniotic fluid?
GF-1, insulin like, epidermal, transforming, hepatocyte etc
What does the amniotic fluid have a similar composition to?
Human milk
How can the amniotic fluid be used for prenatal diagnosis?
Can do chromosome counts of the cells, find neural tube defects
Amniotic fluid stem cell characteristics?
Some features of pluripotency, and can differentiate into cells from all 3 germ layers in vitro
What will the chorion eventually form?
The chorionic villi–> bit that connects to and implants in the mother
What lines the chorionic cavity?
Extraembryonic mesiderm
What covers the chorionic cavity, and what do they do?
Trophoblast cells which form villi
Where is the chorionic cavity in mammals?
Outside the yolk sac and surrounds the amniotic sac
Difference between amnion and chorion?
Amnion is the sac that covers the embryo, chorion is the sac that covers everything
Where are the amnion/chorion present/absent?
Both present in reptiles, birds and mammals
Amnion is absent in amphibians and fish
What forms the amnion?
Ectoderm and extraembryonic mesiderm
What forms the chorion?
Trophoblast and mesoderm
How does the amnion protect the fetus?
The water in the sac absorbs shock and prevents desiccation of the embryo
How does the chorion act as an extraembryonic lung?
Helps in gas exchange
What does the chorionic villi initially act as?
A barrier between maternal blood and fetal blood
What tissue makes up the placenta and chorionic tissue?
foetal tissue
Difficulty of doing prenatal diagnosis with placenta and chorionic tissue?
They are embedded in the maternal tissue so its difficult to tell if you have maternal ot foetal tissue
Which end of the sac do the chorionic villi end up at?
The foetal end
