Pregnancy Flashcards
Where does fertilisation occur?
Ampulla of the uterine tube
The uterine isn’t just a passive tube
It has lots of secretory cells and growth factors that helps the sperm travel to the uterus
When does fertilisation occur?
Around day 4/5
What are two cell types of a fertilised embryo ( blastocysts)?
- Blastocoele fluid-filled
- Inner cell mass forms the fetus
When do endometrium changes reach maximum?
About 7 days after ovulation , if there is no fertilisation after this time progesterone levels drop , endometrium becomes thinner.
How many days after ovulation does decidual cells cover surface of uterus (pre decidualisation?
9-10 days
When does decuidalisation occur?
If pregnancy occurs , decidual cells are modified and become filled with lipids and glycogen. Decidual becomes maternal part of the placenta
What do the glandular secretions of endometrium contain?
Growth factors, adhesion factors, adhesion molecules, nutrients, vitamins, matrix proteins and hormones
Outline the process of uterine receptivity
- Endometrial changes reach their maximum about 7 days after ovulation. The implantation window 6-10 days after the LH spike
- pre decidualisation 9-10 days after ovulation decidual cells cover surface of uterus
- Decidualisation if pregnancy occurs, decidual cells are modified become fluid filled with lipids and glycogen. Decidual becomes maternal part of the placenta.
- Granular secretions of endometrium contains growth factors, adhesion molecules, nutrients, vitamins, matrix proteins and hormones
Decidual cells on surface of endometrium…..
-trophoblast cells project into the endometrial storma.
-syncytiotrophoblast results from cell fusion (forms a multi-nucleated cytoplasmic mass)and invades the endometrium
-chorionic gonadotropin = an autocrine growth factor for blastocyst
Implantation
Implanting day 7-8
1. syncytiotrophoblast erodes the endometrium. Cells of the embryonic discs form epiblast and hypoblast. -Epiblast develops fluid filled amniotic cavity
2. Implantation complete as extra embryonic mesoderm forms discrete layer beneath cytotrophoblast (day 12 blastocyst
-16 day embryo cytotrophoblast and associated mesoderm have become the chorion and chorionic villi are exts
stages of implantation
1.ovulation
2.fertilisation
3. cleavage
4.morula
5.early blastocysts
6.late blastocysts
maternal fetal interphase…
The placenta , where the fetus and mother are connected
Maternal recognition of pregnancy
Human chorionic gonadotrophin (hCG) secreted by syncytiotrophoblast increases rapidly and is the basis of pregnancy test.
hCG prevents the death of the corpus luteum so the endometrium is not shed.
The corupus luteum continues to produce steroids ; estrogen and progesterone which keep the endometrium healthy to hold pregnancy.
Rapid change in maternal systems in response to luteal and later placental steroids
hCG concentration
High in the early stages of pregnancy = pregnancy related complications occur in the first few weeks = bio marker to monitor ectopic pregnancy and other complications