All of the following are components of placental barrier, EXCEPT:
The fetal and maternal blood is never in contact. They are separated by the placental barrier or placental membrane, which consists of: Syncytiotrophoblast Cytotrophoblast Basement membrane Mesoderm Endothelium of the fetal capillaries This thins out as term approaches due to attenuation of the syncytiotrophoblast. These thinned out areas, offer better exchange between the mother and fetus. Ref: Textbook of Obstetrics Sheila Balakrishnan, 1st Ed, page 75
Trophoblast
Fetal capillary endothelium
Mesoderm
Amnion