The maternofetal barrier

Compounds that move from maternal into fetal circulation encounter a layer of syn-cyttotrophoblast (syntrophoblast). a layer of cytotrophoblasts. and the endothelial cell layer of the fetal capillaries. During the later months of pregnancy the cyiotrophoblast layer becomes incomplete and eventually disappears. The endothelium of the fetal capillaries constitutes no significant barrier. Pores in the intcrendothelial clefts provide for the relatively unrestricted diffusion of small and large molecules (Michel and Curry, 1999), The syntrophoblast, on the other hand, is fused into a contiguous celi layer without gaps and blocks the transit of any compound that is not transported either through a carrier or channel or by endocytosis. The discussion of matemo-fetal nutrient transfer in this section will focus primarily on the syntrophoblast. since this cell layer constitutes the main materno-fetal barrier and is the main site of placental nutrient metabolism later in pregnancy.

The maternally facing side (microvillous membrane. MVM) of the syntrophoblast has numerous cell protrusions (microvilli) while the fetal side < basal membrane. BM t is relatively smooth. Due to this structural difference the ratio of microvillous membrane to basal membrane surface areas is typically about 6:1 (Tcasdalc and Jean-Jacques. 1988).

Maternal intervillous space


Microvillous membrane

Basal membrane

Capillary epithelium

Fetal capillary lumen figure 4.S Structural organization of the human placenta

Understanding And Treating Autism

Understanding And Treating Autism

Whenever a doctor informs the parents that their child is suffering with Autism, the first & foremost question that is thrown over him is - How did it happen? How did my child get this disease? Well, there is no definite answer to what are the exact causes of Autism.

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