Implantation Flashcards
When does implantation occur?
21st day menstrual cycle
7 days after fertilisation
What cells provide fuel for early growth?
Endometrial cells
Function of placenta (4)?
1) Nutrition
2) Gas exchange
3) Waste removal
4) Endocrine and immune support
What are 6 phases of implantation?
1) Apposition- orientation blastocyst
2) Attachment integrins between endometrium and trophoblast
3) Differentiation- trophoblast split- cytotrophoblast
- synctiotrophoblast
4) Invasion- synctiotrophoblast erode blood vessels
- use enzymes to digest basal lamina
5) Decidual reaction- differentiation stromal cells
6) Maternal recognition- prevent rejection
What are 3 germ layers?
Endoderm (inner)
Mesoderm (middle)
Ectoderm (outer)
During differentiation what does trophoblast split into?
Cytotrophoblast
Synctriotrophoblast
Function of synctiotrophoblast?
During invasion erode blood vessels
Digest basal lamina
What is outermost layer of trophoblast cells called?
Chorion
Function of chorion?
Supply embryonic portion of placenta
Extend villi into endometrium
Help exchange gas, waste, nutrients
Where does placental blood enter?
Where does placental blood leave?
Via uterine vein
Via decidual (maternal chorion)
What is amniotic cavity?
Form between inner cell mass and chorion
Eventually fuses with chorion
What function of amniotic cavity?
Buffer mechanical disturbances
Buffer temp
What is fluid inside amniotic cavity?
Resemble ECF
What are barriers to transport?
1) Foetal endothelial cells
2) Foetal connective tissue
3) Chorionic epithelial cells
4) Endometrial epithelial cells
5) Maternal connective tissue
6) Maternal epithelial cells
