Placenta Flashcards
When is the uterus receptive to implantation?
Days 16-20 of the menstrual cycle
What two hormones control the ovarian cycle?
FSH and LH
When is progesterone level high?
During ovulation
What do stromal cells differentiate into?
Decidual cells
What is the function of the decidual cells?
Control degree of implantation
What does the hypoblast form?
Yolk sac
What does the trophoblast form?
Placenta
What is the function of the yolk sac in mammals?
Primordial germ cells arise from the extraembryonic mesoderm near the base of the allantois.
Extraembryonic haematopoiesis
What is the function of allantois in humans?
Vestigial
May be involved in respiration- blood cells differentiate from the mesoderm
What are the two parts of the trophoblast?
Syncytiotrophoblast and cytotrophoblast.
What is the syncytiotrophoblast
- Lines the villous
- Multinucleated
- Bathed in maternal blood
Formed from the fusion of cytotrophoblast cells
What is the cytotrophoblast?
- Proliferative cell column
- Beneath the syncyitotrophoblast
- Differentiate into the syncytiotrophoblast or the invasive trophoblast
What is the invasive trophoblast?
- Extravillous trophoblast from the cytotrophoblast
What are the two types of invasive extravillous trophoblast?
Interstitial (iEVT) or endovascular (eEVT).
