You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is The foetal blood is separated from syncytiotrophoblast with all except: and explain in detail?
The maternal blood in the lacuna is never in direct contact with fetal blood. They are separated by:

Syncytiotrophoblast
Cytotrophoblast
Basement membrane
Mesoderm
Endothelium of fetal capillaries

Together called as placental barrier or membrane (0.025 mm)