- Gross anatomy
1.Chorionic frondosum- fetal part the major component
2.Decidua basalis- maternal part the minor component
Begins at 6th weeks of gestation
Ends at 12th weeks of gestation
- Normally situated at or near fundus of uterus
- Shape- discoid
- Size- 15*20 cms, 2.5cm in thickness in centre
- 500gms in weight
- Two surfaces
1.Fetal- smooth, amniotic membrane, cord insertion and branching vessels.
2.Maternal- irregular,15-20 cotyledons,
- Hormonal- CRH, GnRH, TRH, GHRH, ACTH, hCG, hPL, hCT
- Immunological- placental hormones, proteins(SP1), early pregnancy factor(EPF), steroids and hCG
One or more smaller lobes of placenta placed at varying distances from placental margin.
Smaller chorionic plate than basal plate.
The cord is attached to the membranes.
The cord is attached to the margin of the placenta.
- CONSISTS OF 2 LAYERS
FUNCTIONS OF MEMBRANES
1.PRODUCES AMNIOTIC FLUID
2.PREVENTS FETUS FROM INFECTIONS
3.HELPS IN CERVICAL DILATION IN LABOR
4.PRODUCES PGE2, PGF2alpha