Flashcards in Lect. 8 - Implantation Deck (22):
How soon after ovulation does fertilization typically occur?
12 hours. (in upper ampulla)
Uterine tube transport - End of day 1
2-cell stage in isthmus
uterine tube transport - day 3
morula in isthmus/corona radiata lost by this time
uterine tube transport - day 4
blastocyst in uterus
uterine tube transport - day 5
loss of ZP
uterine tube transport - day 6
beginning of implantation
A small region of the ZP, usually directly over the ICM in the primate, dissolves and the blastocyst emerges from the hole.
major functions of the ZP
promotes maturation of the oocyte and follicle;
barrier; initiates the acrosomal reaction; prevents any additional sperm from reaching the zygote; porous filter through which certain substances secreted by the uterine tube can reach the embryo; immunological barrier b/w the mother and the antigenically embryo; prevents the blastsulas of the early cleaving embryo from dissociating; differentiation of trophoblastic cells; prevents premature implantation of the cleaving embryo into the wall of the uterine tube.
Stages of implantation
1. attachment of expanded blastocyst to the endometrial epithelium
2. penetration of the uterine epithelium
3. invasion into the tissues underlying the epithelium
4. erosion of the maternal vascular supply
what facilitates attachment of the blastocyst to the endometrium?
adhesion molecules expressed by the endometrium and also by the trophoblast cells
closest to ICM
closest to endometrium; its projections penetrate the endometrial basal lamina and invade the stroma
response of the endometrial stroma cells to the invading blastocyst
what would happen w/o the decidual reaction?
possible the trophoblast would erode through the endometrial wall
what are decidual cells derived from?
endometrial stroma cells that accumulate glycogen and lipid droplets
result of the decidual reaction
massive cellular matrix that completely surrounds the embryo and fills most of the endometrium
IL-2 in the decidual reaction
prevents the mother's immune system from recognizing the embryo as a foreign body
most common place for ectopic pregnancies to occur
w/i the uterine tube, where is the most common place for ectopic pregnancies
if ectopic pregnancy happen outside of the reproductive system where's most common?
where is low pH most important?