Topic 5 - Embryology 2-3 Development Flashcards
What two types of cells does the trophoblast split into?
Cytotrophoblast
Syncytiotrophoblast
What does the Embryoblast split into?
Hypoblast
Epiblast
What type of cell hides the bilaminar disc from the mothers immune system?
Syncytiotrophoblast secretes factors
What blast forms the dorsal and ventral surfaces of the embryo?
Epiblast - Dorsal
Hypoblast - Ventral
Where does the amniotic cavity sac start from?
Centre of Epiblast
What day post implantation does the hypoblast cells encase the blastocyte cavity?
9 days post implantation
What forms to seal the blastocyte within the site of implantation
Coagulation Plug
What two areas does the blastocyte receive nutrients
Mammillary Gland via diffusion
Syncytiotrophoblst breaks down capillaries
At what day does the syncytiotrophoblast break down the mammillary capillaries?
What does this establish?
10-11 days
Uteroplacental Circulation
As syncytiotrophoblast expand outwards, what do they lose?
membranes
When the hypoblast starts to encapsulate the blastocyte cavity, what membrane is formed?
Heuser’s membrane
When does the Extraembryonic Mesoderm form?
What does it do?
10-11 days
Encompasses bilaminar disc
Extraembryonic Mesoderm is derived from what?
Yolk Sac
After day 11-12, what happens to the Extraembryonic Mesoderm
Encompasses amniotic cavity
What day does the chorionic cavity form? Where does it form?
12-13 days
Extraembryonic Mesoderm
Pregnancy test involves detection of what hormone?
How is it measured
human chorionic gonadotrophin (hCG)
Urine
Role of hCG
Maintains endometrium
Maintains maternal immunotolerance
Placenta Pervia involves what?
Covering of cervix with placenta
When the foetus is too large to reabsorbed when it has failed, what is the condition called?
Lithopedion
Hydatidiform Mole forms how?
Structure:
Empty egg fertilised by sperm
trophoblast with no embryonic tissue
