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Bilaminar Stage
WVSOM Class of 2012 Bilaminar Stage
Question | Answer |
---|---|
the trophoblast above the epiblast produces what new layer? why? | syncytiotrophoblast, produces progesterone |
all cells not becoming a part of the syncytiotrophoblast become what? | cytotrophoblast |
how do syncytiotrophoblast nuclei proliferate if they are amitotic? | as the cytotrophoblast cells divide, they fuse with the syncytiotrophoblast to donate nuclei |
the embryoblast laminates into what 3 cell layers? which two are the bilaminar layer? | the amnion, epiblast, and hypoblast; bilaminary layer is the hypoblast and epiblast |
what is the amnion? | the thin membrane that forms along the interior of the cytotrophoblast |
what cells comprise the epiblast? why is this important? | high columnar cells; this is the entire fetus with the exception of the primordial germ cells |
the hypoblast produces what structure? what cells is it comprised of? | the yolk sac; it is comprised of small cuboidal cells |
after the blastocyst embeds, what cells close the hole on the endometrial surface? | fibrin coagulum |
the hypoblast spreads along the inner surface of the endometrium to form what? | extraembryonic endoderm |
where is the primary yolk sac? | bound by the extraembryonic endoderm and the hypoblast |
spaces formed in the syncytiotrophoblast are called what? what is this period called? | trophoblastic lacunae; lacunar stage |
what is the new layer that forms between the cytotrophoblast and the extraembryonic endoderm? | extraembryonic mesoderm |
extraembryonic lacunae expand to form what? | chorionic cavity |
the extraembryonic mesoderm layer lining the yolk sac is what? | splanchnic extraembryonic mesoderm |
the extraembryonic mesoderm layer lining the cytotrophoblast is what? | somatic extraembryonic mesoderm |
what are the 3 layers of the chorion? | somatic mesoderm, cytotrophoblast, and syncytiotrophoblast |
what primordial structure becomes the umbilical cord? | the connecting stalk |
placental circulation begins to develop where? | at the embryonic pole |
syncytiotrophoblast erodes the endometrium endothelial lining of the maternal capillaries to produce what? | sinusoids |
what process has glandular secretions causing endometrium surrounding the embryo to become edematous with glycogen and lipids? | the decidua reaction |
what does the decidua region of the endometrium develop into? | maternal component of the placenta |
what is the portion of the primary yolk sac that is pinched off from the embryo? | the exocoelomic cyst |
increased blood flow to the lacunar spaces can produce bleeding when? | 28th day of menstrual cycle |
what term means to have multiple nuclei within an extended, continuous cytoplasm? | synctytium |
A fluid filled cavity develops between the amnion and epiblast known as what? | amniotic cavity |
during amniocentesis, what marker is being checked for? what might this indicate if found? | alpha-fetoprotein; developmental defect |
where do extraembryonic lacunae develop? | extraembryonic mesoderm |
after the primary yolk sac pinches off the exocoelomic cyst, what is it then called? | secondary yolk sac |