1. Placenta Fetal Surface

2. Placenta Maternal Surface

3. Development Placenta is developed from two sources
Fetal Chorion Frondosum
Maternal Decidua basalis
Stem villi 13th day
Arterio-Capillary-venous system completed in each villus on 21st day

8. Fetal haemodynamics Foetal blood flow throuhg the placenta
400 ml per minute
Pressure in the umbillical artery
60 mm Hg
Pressure in the umbilical vein
10 mm Hg
Foetal capillary pressure in villi
20 – 40 mmHg
O2 Saturation
Umb artery
50 –60 %
Umb vein
70 – 80%
PO2
20 – 25 mm Hg
30 – 40 mmHg

9. Intervillous haemodynamics
Blood in the placenta _____________ 500 mls
Blood in the intervillous space ______ 150 mls
Blood flow in the inter villous space _ mls
Pressure in the inter villous space
During UT contraction ________ mm Hg
During UT relaxation _________ mm Hg
Pressure in the UT artery _________ mm Hg
Pressure in the UT vein________ mm Hg

10. Spiral Arterioles at the
Placental Site

12. Placental Function Urea, uric acid creatinine By simple diffusion
Respiratory
Oxygen supply to the fetus is at the rate of 5ml/Kg/min (cord blood flow of 165 – 330 ml/min
Excretory
Urea, uric acid creatinine By simple diffusion
Nutritive function
Glucose. Lipids. Amino acids, Water and electrolides, Vitamens

13. Facilitated diffusion
Simple diffusion
Water
Sodium
Potassium
Chloride
Oxygen,CO2,
Facilitated diffusion
Glucose
Active transport
Fatty acids
Amino acids
Vitamins
Calcium, Phosphorus, Iron

14. Hormonal Barrier function Human Chorionic Somatomammotropin (HSG)
Human Chorionic Gonadotrophin (HCG)
Human Chorionic Thyrotropin (HCT)
Corticotrophin Releasing Hormone (CRH)
Oestrogen
Progestogens
Adrenocorticoids
Barrier function
Placental membrane in early pregnancy _____ 0.02 mm
at term ____ 0.002mm
Substances more than 500 Daltons can not cross

15. Immunological Enzymatic function Fibrinoid coating of trophoblast
Specific mucoprotein mucopolysaccharides by
Decidua
Placental hormones ( HCG,steriods) have
weak immunosuppressive property.
Nitabuch’ layer between decidua & trophoblast
inactivate antigen
Enzymatic function
Oxytocinase
Phpsphplipase A2