Lecture 8: Implantation Flashcards Preview

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Flashcards in Lecture 8: Implantation Deck (11):

How long after fertilization does implantation begin?

Day 6


Blastocyst hatching

A small region of the zona pellucida overlaying the ICM dissolves and the blastocyst emerges, "shedding" the ZP in preparation for implantation


Functions of the zona pellucida

Promotes oocyte/follicle maturation, initiates acrosomal reaction, prevents polyspermy, acts as early immunological barrier between mother/embryo, facilitates trophoblast differentiation, prevents premature implantation


List the 4 stages of Implantation

1. Attachment of blastocyst to endometrium
2. Penetration of uterine epithelium
3. Invasion into tissues underlying epithelium
4. Erosion of maternal vascular supply


Which of the following is a function of the zona pellucida?

A. Nutritional supply for the egg
B. Initiates acrosomal reaction
C. Both of the above
D. Neither of the above

B. Initiates acrosomal reaction


What type of molecules facilitate attachment of blastocyst to endometrial epithelium?

Adhesion molecules such as integrins


What significant event occurs during the penetration of uterine epithelium?

Trophoblast separates into cytotrophoblast and synctiotrophoblast


Trophoblastic lacunae

Hollow cavities within syncytiotrophoblast which fill with maternal blood as endometrial blood vessels erode


Decidual reaction

Response of endometrial stroma cells to invading blastocyst; necessary because otherwise the trophoblast could potentially erode all the way through the endometrial wall


What is the result of the decidual reaction?

A massive cellular matrix that completely surrounds the embryo and fills most of the endometrium, IL-2 secreted to protect embryo from rejection


Ectopic pregnancy

Occurs when embryo is implanted somewhere other than the uterine wall