second week Flashcards
(19 cards)
what is a syncytium
a mass of cytoplasm containing numerous dispersed nuclei
what is the syncytiotrophoblast
proliferation of trophoblast cells that lose their cell membranes to form a syncytium at the embryonic pole
what is the cytotrophoblast
the cells of the trophoblast that line the wall of the blastocyst and retain their cell membranes
what happes to the synctiotrophoblast during the second week
increases in volume.
when does the embryo become fully implanted in the endometrium
between day six and 9
what is secreted by the cytotrophoblast and function of that secretion
proteolytic enzymes, that break down the extracellualr matrix between the endometrial cells.
what is the coagulation plug
a plug of acellualr material that seals the small hole where the blastocyst implanted
By day 8th what to epithelial layers are formed by the embryoblast and what is internal and what external?
epiblast external/ columnar cells
2.intenal hypoblast or primitive endoderm. cuboidal
how is the two layered embryoblast by day 8 called? both names
bilaminar embryonic disc
or bilaminar blastoderm
is epiblast/ hypoblast dorsal or ventral
epiblast dorsal
hypoblast ventral
what is the first (new) cavity formed during the second week called and on what day is it formed
amniotic cavity
day 8
what is the amnion
layer of epiblast cells that differentiated into a thin membrane that separates the amniotic cavity from the cytotrophoblast.
when does the amniotic cavity enclose the entire embryo
week 8
when is the embryo fully implanted in the uterus?
week 9
what cells make Heusers membrane?
hypoblasts
When is the first/primitive ventral dorsal axis defined?
formation bilaminar disc
what is the primitve endoderm?
hypoblast
how is the amniotic cavity created?
when fluid starts to get between epiblast and trophoblast
what are the 4 extraembryonic membranes
amnion ,yolk sac, chorion and allantois
