pregnancy and reproduction Flashcards
fertilization and implantation: Explain the processes of fertilization, implantation and decidualization, including reference to the roles of specific hormones during these processes
where does fertilisation occur
within Fallopian tube
what reaction does fertilisation trigger
cortical reaction
what do cortical granules do and purpose
release molecules which degrade Zona Pellucida (ZP2 and 3), preventing further sperm from binding as no receptors
chromosome number of fertilised cell change
haploid -> diploid
what happens to the fertilised egg in 3-4 days after fertilisation
continues to divide as moves down Fallopian tube to uterus
where does the fertilised egg receive nutrients from
uterine secretions
how long can the free-living phase last for
9-10 days
diagram of development of conceptus over time (unless hCG source from placenta present)
diagram
2 stages of implantation
attachment phase -> decidualisation phase
what happens in the attachment phase
outer trochoblast cells contact uterine surface eipthelium
what happens in the decidualisation phase
changes in underlying uterine stromal tissue within a few hours
what does impantation require
progesterone domination in presence of oestrogen
what cells do blastocyst contain, and what do they form
trophoblast cells form placenta, inner cell mass forms embryo
2 important factors for implantation
LIF and IL-11
what stimulates adhesion of blastocyst to endometrial cells in attachment phase
leuakemia inhibitory factor (LIF)
where is leuakemia inhibitory factor (LIF) from
endometrial secretory glands and balstocyst
what else may stimulate adhesion of blastocyst to endometrial cells in attachment phase
interleukin-11 (IL11)
where is interleukin-11 (IL11) from
endometrial cells released into uterine fluid
name another molecule involved in attachment phase
HB-EGF
4 endometrial changes in decidualisation phase due to progesterone
glandular epithelial secretion, glycogen accumulation in stromal cell cytoplasm, growth of capillaries, increased vascular permeability
what can increased vascular permeability in decidualisation phase lead to
oedema
4 factors involved in decidualisation phase
IL-11, histamine, certain prostaglandins, TGFB
what does TGFB promote
angiogenesis
