Embryology I Flashcards
(25 cards)
What is the pre-embryonic stage?
weeks 1-2
What is the embryonic stage?
weeks 3-8
What is the fetal stage?
weeks 9-38
What does the initial cleavage form?
morula
What is formed after compaction?
blastocyst
Where is oocyte fertilised?
ampulla
Where is the fertilised egg implanted?
posterior uterine wall (high up)
What coats the morula?
zona pellucida- glycoprotein coat
exclude other sperm
What the first fluid filled cavity called?
blastocoele
What the outer cell mass called? what cells does it provide?
trophoblast
cells for placenta
What the inner cell mass called? what cells does it provide?
epiblast
all cells of the body
What kind of cells doe the morula contain?
totipotent
What kind of cells does the blastocyst contain?
pluripotent
What happens on day 5?
blastocyst hatches from zona pellucida allowing enlargement and interaction with uterine surface
In week two what layers form in outer cell mass?
synctiotrophoblast- multinucleated sheet invades endometrium
cytotrophoblast- forms skin cell layer
What cavity is above the embryo at the end of week 2?
amniotic cavity
What cavity is below the embryo at the end of week 2?
yolk sac
What is the structure of maternal-fetal exchange called?
chorionic villus
What happens if implantation occurs in the fallopian tube?
ectopic pregnancy
What happens if implantation occurs in the lower uterine segment?
placenta praevia
haemorrage risk
c-section delivery required
What is established when maternal sinusoids are invaded by synctiotrophoblast?
utero-placental circulation
What forms between the yolk sac and the cytotrophoblast?
acellular extra-embryonic reticulum
What does the extraembryonic reticulum convert to?
extra embryonic mesoderm
What forms when spaces in extraembryonic mesoderm merge?
chorionic cavity
