Posted by e-Medical PPT Friday, July 20, 2012
The Placenta
The placenta develops from the chorion frondosum( foetal origin) and decidua basalis ( maternal origin).

Foetal surface
Smooth, glistening and is covered by the amnion which is reflected on the cord.
The umbilical cord is inserted near or at the center of this surface and its radiating branches can be seen beneath the amnion.

Maternal surface
Dull greyish red in colour and is divided into 15-20 cotyledons.
Each cotyledon is formed of the branches of one main villus stem covered by decidua basalis.

Functions Of The Placenta
Respiratory function
Nutritive function
Excretory function
Production of enzymes
Production of pregnancy associated plasma proteins (PAPP)
Barrier function
Endocrine function

Hormones Secreted by the Placenta
Human chorionic gonadotrophin(hCG)
It is a glycoprotein produced by the syncytiotrophoblast.
- It supports the corpus luteum in the first   10 weeks of pregnancy to produce oestrogen and progesterone until the syncytiotrophoblast can produce progesterone.
HCG rises sharply after implantation, reaches a peak of 100.000  mIU/ml about the 60 th day of pregnancy
then falls sharply by the day 100 to 30.000  mIU/ml and is maintained at this level until term.

Human placental lactogen (hPL)
It is a polypeptide hormone produced by the syncytiotrophoblast.
- The supposed actions of hPL include:
a. Lipolysis:
 increasing free fatty acids which provide a source of energy for mother and foetal nutrition.
b. Inhibition of gluconeogenesis:
thus spare both glucose and protein explaining the anti-insulin effect of hPL.
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