13. Week 2 - Formation of the Bilaminar Embryo Flashcards
What does the embryoblast transform to?
The Epiblast and hypoblast, forming a bilaminar embryonic disk.
What structure marks the future site of the mouth?
The prochordal plate.
Who produces the hCG and what does it do?
It is produced by the syncytiotrophoblast, which stimulates the production of progesterone ny the corpus luteum (i.e., maintains the corpus luteum function).
Of the trophoblast that converts to syncytiotrophoblast and cytotrophoblast, which one of the 2 is mitotically active?
The cytotrophoblast is mitotically active.
Where does the extraembryonice mesoderm derive from?
From the epiblast.
What does the extraembryonic VISCERAL mesoderm cover?
It covers the yolk sac.
What does the extraembryonic SOMATIC mesoderm cover?
Lines the cytotrophoblast, forms the connecting stalk, and covers the amnion.
What is a hydatidiform mole?
It is a blighted blastocyst (embryo dies) followed by hyperplastic proliferation of the trophoblast within the uterine wall. Clinical signs are preeclampsia during the first trimester, high hCG levels (>100k mlU/mL) and an enlarged uterus with bleeding.
What is the chorion?
It is the wall of the chorionic cavity, which consists of extraembryonic somatic mesoderm, cytotrophoblast, and syncytiotrophoblast.
What is gestational trophoblastic neoplasia?
AKA GTN, or choriocarcinoma, it is a malignant tumor of the trophoblast that may occur after a normal pregnancy, abortion or hydatidiform mole. Hish hCG levels are diagnostic, with a high degree of suspicion. Nonmetaplatic GTN is the most common form, and the treatment is higly succesfull.
Where does metatastic GTN likes to target?
Liver or brain.
