Implantation Flashcards
How much time does the embryo spend in the fallopian tube?
3 days
What is the blastocoele?
The vacuolized space adjacent to the inner cell mass
What is decidualization?
The morphological and biochemical differentiation of uterine stroma
It is characterized by the accumulation of glycogen and lipds, activation of COX-2, recruitment of dNK cells, and production of prolactin and IGFBP-1
COX-2 stimulates increased synthesis of _________.
PGE2
It’s thought that decidualization results from __________ signalling.
progesterone and estrogen
Trophoblasts secrete __________.
bHCG
True or false: the zona pellucida merges with the endometrium.
False. The blastocyst “hatches” on day 5 from the zona pellucida and implants in the endometrium. It is believed that there is a lytic agent in the uterine cavity that causes this. This depends on a morula/blastocyst - unfertilized eggs dont hatch
When (in the cycle) is the uterus receptive for implantation?
Day 20-24
What are pinopods?
Microvilli on the endometrial surface that aid in implantation
The first step in implantation is _______________.
apposition
The uterine stroma just deep to the embryo is called the ___________ and the uterine stroma just superficial to the embryo is called the __________ and the uterine stroma next to the myometrium is called the _________.
decidua basalis; decidua capsularis, decidua parietalis
Where is the most common site of implantation?
The posterior wall of the uterus, just superior to the fundus
______________ is when the placenta obscures the cervix.
Placenta previa
What is placenta accreta?
When the placenta grows deep into the walls of the uterus
The leading cause of maternal death in the first trimester is _____________.
ectopic pregnancy
When do serum hCG tests become positive?
About three weeks after her last period (urine tests are four weeks)
At what beta-hCG value should you be able to see an intrauterine pregnancy on ultrasound?
1,500
When, in the gestational age of the embryo, does implantation occur?
Day 6-7
_____________ also has immunosuppressive qualities.
Beta hCG
After the interdigitation involved in apposition, the trophectoderm interacts with ___________ receptors on the endometrium in a process called adhesion.
integrin
The syncytiotrophoblasts secrete TNF-alpha from their protrusions which ______________.
causes the down-regulation of cadherins that allows for placental invasion
What often causes placenta accreta?
Implantation on the site of a uterine scar
What stage follows adhesion?
Invasion
what are the 3 stages of implantation
1) apposition
2) adhesion
3) invasion
what prevents immune rejection of the fetus?
- syncytiotrophoblasts lack MHC antigens
- extravillous trophoblast contain special HLA antigens (HLA-G may down-regulate t cell and NK cell activation in the local placental environment)
risk factors for ectopic pregnancy
tubal disease, prior eptopic, infertility and ART, smoking, vaginal douching
