Embryology 3 Flashcards
the maternal-fetus circulation depends on ?
- a fetal cardiovascular system
- structures within the endometrium that allow exchange with the fetal cardiovascular system
what are the types of chorionic villi?
- primary
- secondary
- tertiary
when do you see primary chorionic villi?
present in week 2
when do you see secondary chorionic villi?
present in week 3
when do you see tertiary chorionic villi?
present by the end of week 3
what are primary chorionic villi made out of?
only composed of cytotrophoblasts surrounded by a syncytiotrophoblastic shell
what are secondary chorionic villi?
extraembryonic mesenchymal core surrounded cytotrophoblastic and synctiotrophoblastic shell
what are tertiary chorionic villi?
- blood vessels (capillaries) within the mesenchymal core
fetal blood can now exchange substances between the maternal lacuna through the membrane formed by the tertiary villus
as the villi develop, the cytotrophoblast proliferates and extends through the synctiotrophoblast layer which forms?
cytotrophoblastic shell
what does the cytotrophoblastic shell do?
it anchors the chorionic sac and attaches it to the endometrium
what are anchoring villus?
a villus that attaches to the endometrium via cytotrophoblastic extensions
what is the decidua?
the endometrium in a pregnant woman
what are the 3 separate areas of the decidua?
- decidua basalis
- decidua capsularis
- decidua parietalis
which decidua forms the placenta?
decidua basalis
how is the decidua basalis connected to the embryo
by the umbilical cord
which decidua does not include the basalis, but is still associated with/covers the embryo?
decidua capsularis
which decidua is formed by the endometrium that is not part of the embryo?
decidua parietalis
what is the smooth chorion?
the chorionic membrane that is associated with the decidua capsularis, the villi degenerate (don’t contact maternal blood)
where is maternal blood found?
intervillous spaces
what is vasculogenesis?
development of brand new blood vessels from mesoderm
what is the angiogensis?
“sprouting” of blood vessels formed by vasculogenesis, connects blood vessels to each other
angioblasts derived from mesoderm develop in specialized regions known as ?
blood islands
what give rise to RBC?
angioblasts
what is the dorsal aorta?
blood to the embryo and then connects to umbilical artery and cardinal veins
what makes blood flow through the umbilical vesicle?
vitelline artery and vein
what returns blood from tertiary villi back to the embryonic heart?
umbilical vein
by the 4th week, the paired heart tubes have fused, resulting in?
a single ventricle and atrium
