Page 73 - كتاب تمريض نسا الاكتروني

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-Divided by grooves into 15-20 lobes

2. Fetal surface

-Covered by amnion (thin smooth membrane)

-Under amnion there is a (chorionic plate) (few mm in thickness- from which villi rise-

composed of connective tissue- contain branches of umbilical blood vessels which

divide to enter the villi)

-Umbilical cord is inserted in fetal surface (centric- e-centric)

-Vessels branch out over the surface of the placenta and further divide to form a

network covered by a thin layer of cells. (This results in the formation of villous tree

structures).

-On the maternal side, these villous tree structures are grouped into lobules called

cotyledons.

Umbilical cord

-50-70cm

-2cm diameter

-Consists of Warton jelly covered by amnion

-Contains 1 vein (carries oxygenated blood from placenta to fetus) and 2 arteries

(carries deoxygenated blood from fetus to placenta).

Placental barrier

Fetal blood in chorionic villi is separated from maternal blood in intervillious

spaces by placental barrier which is made of 4 layers:

1-Synthetiotrophoblast

2-Cytotrophoblast

3-Mesoderm

4-Wall of blood vessels

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