Fetal Membranes & Placenta Flashcards
________ is the fetal contribution to the placenta and consists of _________, __________, and ________.
Chorion - consists of
- Somatic extraembryonic mesoderm
- Cytotrophoblast
- Cynctiotrophoblast
Primary Villi
Synctiotrophoblast covering + cytotrophoblast core
Secondary Villi
Primary villi + extraembryonic mesoderm at the core
Tertiary villi
Secondary villi + vessel formation in extraembryonic mesoderm core
Extension of villi from __________ to the ___________ on the maternal side anchors the placenta to the uterus
Chorionic plate (residual extraembryonic mesoderm) Cytotrophoblastic shell (adjacent to the endometrium, which is referred to as the decidua basalis)
Chorionic Frondosum + Decidua Basalis =
Placenta
Note that chorionic frondosum simply refers to the growth of villi on the embryonic side opposite the decidua capsularis
This functions as a transfer agent for nutrients from the trophoblast to the embryo (2-3 weeks)
Yolk Sac
Source of primordial germ cells
Yolk Sac
The Yolk Sac is connected to the midgut via the _________ duct
Vitteline
Provides vessels for the establishment of the definitive placenta and forms umbilical blood vessels
Allantois
From an out-pouching of the yolk sac, this forms the hindgut and also becomes incorporated into the umbilical cord and persists from the urinary bladder to the umbilicus as the urachus
Allantois
After birth, the urachus becomes ___________
MediaN umbilical ligament (AllaNtois)
The amnion cells are derived from the __________
Epiblast
The fluid of the amnion is initially derived from _______, but it is later derived from _________.
Mother’s blood
Fetal urine
Chorionic sampling can give results at _____ weeks, but amniocentesis is usually performed after ____ weeks
8 weeks
15 weeks
