Implantation Flashcards
(20 cards)
When does implantation occur in humans?
Around day 7 post-fertilisation
Where does implantation occur?
In the uterine endometrium
What structure is required for implantation?
Hatched blastocyst
What is the role of progesterone?
Maintains the uterine lining and decidualisation
What hormone indicates uterine receptivity?
Leukaemia Inhibitory Factor (LIF)
What is MUC1 and why is it important?
An anti-adhesive glycoprotein; must be downregulated for implantation
What are the stages of implantation?
Apposition - Adhesion - Invasion
What are syncytiotrophoblasts?
A multi-nucleated, invasive outer layer derived from trophoblast
What does the syncytiotrophoblast secrete?
hCG
What is the function of hCG?
Maintains the corpus luteum to sustain progesterone production
What is the cytotrophoblast?
The inner, mitotically active layer of trophoblast cells
What is decidualisation?
Transformation of uterine stromal cells into supportive decidua
What are decidual cells?
Maternal cells that support embryo growth and immune tolerance
What immunological changes support implantation?
Suppression of maternal T cells and NK cells by syncytiotrophoblatss
What forms the maternal part of the placenta?
Decidua basalis
What forms the foetal part of the placenta?
Chorion
How does the embryo invade the endometrium?
Via matrix metalloproteinases (MMPs)
What replaces the role of the corpus luteum later in pregnancy?
The placenta (luteoplacental shift)
What type of immune molecules are expressed by the trophoblast?
Non-classical HLA (HLA-G, -E, -F)
Why is implantation tightly regulated?
To prevent ectopic pregnancy or immune rejection
