الفهرس | Only 14 pages are availabe for public view |
Abstract This work was carried out on the placenta of native (Baladi) rabbit at different stages of gestation period. The placenta of rabbit is formed on the mesometrial side of the pregnant uterus, it attains its known discoidal shape at the 14th day of pregnancy. It consists of two cotyledons separated by a deep intercotyledonary groove, each cotyledon consists of a large number of different shaped and sized lobes, which may be elongated, oval or heart shaped. In the first third of gestation period the diameter of the maternal placenta (decidua) is greater than the diameter of the fetal cotyledons. In the middle third the diameter of both becomes nearly equal, while, in the last third the relation is reversed where the diameter of the fetal piacenta becomes more greater than that of the decidua. There is a strong positive correlation between the placental weight and fetal weight in the first two thirds of gestation period, while in the last third of gestation the fetal weight exceeds in more apid rate than the placental weight. The histological feature of the chorioallantoic placenta of the rabbit is completely organized by the 14th day of pregnancy where becomes differentiated into three main zones, the fetal placenta or cot- yledons, the intermediate zone and the maternal placenta or decidua. The fetal placenta comprises the tortuous trophoblastic lamellae, which border the narrow trophoblastic lacunae, that carry the maternal blood from the surface sinuses towards the venous sinuses of the intermediate zone. |