Tissue arrangements [12

On the fetal side of the placenta, the avascular amnion covers the chorionic plate. Underneath the amnion, chori-onic vessels continue with those of the umbilical cord and are arranged in a star-like pattern. At the other end, these vessels continue with those of the villous

Placental shape -»- discoidal placenta

Uterine cavity

Uterine wall

Uterine cavity

Uterine wall

Umbilical cord

Placenta

Placental bed

Placenta

Umbilical cord

Placental bed

Umbilical cord

Materno-fetal interdigitations -»- villous trees

Villous trees

Chorionic plate

Umbilical cord

Villous trees

Chorionic plate

Basal plate

Maternal blood in Artery Vein the intervillous space

Maternal blood in Artery Vein the intervillous space

Basal plate

Endometrium/ decidua

Materno-fetal barrier -»- villous trophoblast

Vascular arrangement multivillous flow

FEr FC

Villous stroma

FEr FC

Villous stroma

ST CT FEn

Fetal blood flow

Maternal blood

m

11

r

Spiral

Uterine

artery

Fetal blood flow

Maternal blood

Fig. 3.1 Schematic representation of the structural characteristics of the human placenta. (a) The human placenta displays a discoidal shape. (b) The materno-fetal interdigitations are arranged in villous trees bathing in maternal blood that floats through the intervillous space. (c) The hemochorial type of placentation results in a materno-fetal barrier composed of villous trophoblast in direct contact with maternal blood. (d) Fetal and maternal blood flows are arranged in a multivillous flow. Abbreviations: CT, cytotrophoblast; FC, fetal capillary; FEn, fetal endothelium; FEr, fetal eryrocyte; MC, mesenchymal cells; MEr, maternal erythrocyte; ST, syncytiotrophoblast.

trees where the capillary system between arteries and veins is located. The villous trees originate from the chorionic plate and float in a lake of maternal blood. On the maternal side of the placenta, the basal plate is located (see Fig. 3.1b). It is an artificial surface generated by the separation of the placenta from the uterine wall during delivery. The basal plate is a colourful mixture of fetal trophoblast and maternal decidua cells, which are embedded in trophoblast-secreted matrix-type fibrinoid, decidual extracellular matrices, and fibrin-type fibrinoid. At the placental margin, chorionic plate and basal plate fuse with each other, thereby closing the intervillous space and generating the fetal membranes or chorion laeve.

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Pregnancy Diet Plan

Pregnancy Diet Plan

The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.

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