Implantation to Gastrulation Flashcards
(26 cards)
What does the syncytiotrophoblast do?
digests the uterine lining to allow implantation, can cause implantation bleeding/spotting.
The epiblast is the precursor to_____
other body cells
In week 2 what 2 layers form in the embryo, and what 2 layers form in the trophoblast?
Embryo- epiblast and hypoblast
Trophoblast - syncytiotrophoblast and cytotrophoblast
What are the two cavities formed in week 2?
Amniotic sac cavity and yolk sac cavity
What is the purpose of the amniotic membrane/fluid?
prevents dessication of embryo AKA drying out
What does hCG signal tell the ovary to do?
Continue to secrete the necessary hormones to maintain the pregnancy and prevent menses.
The critical period of development occurs in which weeks?
3-8
Where is the XE found (extraembryonic Mesoderm)?
between the inner lining of cytotrophoblast and yolk sac
Is the mesoderm intraembryonic or extramembryonic?
extraembryonic
What do the trophoblastic lacunae do?
allows maternal vessels a place to supply blood to the embryo.
What does the connecting stalk become?
the umbilical cord
By week 3 there are 3 layers of trophoblast and 3 cavities, what are they?
syncytiotrophoblast, cytotrophoblast, XE mesoderm
Amnion, yolk sac, chorion
Somatic =
wall of the body cavity
Splanchnic =
visceral “internal organs”
What is significant about the chorionic villus?
a sample of it can be used to test for genetic diseases/birth defects
Prior to gastrulation there embryo exists as a bilaminar disk, gastrulation changes this to trilaminar, what are the 3 germ layers?
Endoderm, Mesoderm, Ectoderm
What happens to cells at the primitive streak?
differentiation
The primitive streak is the future ____ of the embryo
axis
Elongation of the primitive streak occurs through the addition of ____ cells to the _____ end
epiblast cells to the caudal end
Mesenchyme can be thought of a primitive form of _____
connective tissue
Sacrococcygeal Teratoma is thought to occur as a result of
multipotent cells from the anterior portion of the primitive streak
Germ layer defects result in VATERL
Vertebral abnormalities, Anal atresia, Tracheoesophageal fistula, Renal defects & Limb defects
What is a cause of germ layer defects?
abnormal gastrulation AKA the migration of the mesoderm is disturbed
Major week 3 events include
Appearance of the primitive streak
Differentiation of the 3 primary germ layers
Development of the notochord
