Surgical and Obstetrics Department By: Mohammad Rahawy
Fetal MembranesSurgery and Obstetrics Department By: Mohammad Rahawy
In the day (16) of pregnancy the embryo enter new stage of development known as differentiation period: 1-Formation of extra- embryonic membranes 2-Formation of all major organs and system occurs circulatory, muscular, CNS.Surgery and Obstetrics Department By: Mohammad Rahawy
At this time the differentiation will occur into the 3 layer from outside to inside: ectoderm, mesoderm, endoderm. Fetal Membranes start to develops, the 1st ectoderm start to folding around it self. For extra- embryonic membranes from during differentiation: 1-yolk sac 2-Amnion 3-Allatois 4- chorion.
Surgery and Obstetrics Department By: Mohammad Rahawy
The yolk sac contains a source of nutrient but disappears by the end of this stage development. The yolk sac origin is endoderm. The yolk sac disappears at 3 week in cow, sow but at 6 week in mare. The Amnion, folds around the embryo and contains fluids which suspend the embryo, protecting it and permitting its free growth. The amnion sac origin is ectoderm. The Allatois forms a pocket for waste products form the developing embryo. Allatoic membrane come from ectoderm & endoderm and is supplied by number of blood vessels.Surgery and Obstetrics Department By: Mohammad Rahawy
.The chorion from the outer membrane. Gradually, during differentiation the allantois and chorion fuse forming attaches to the endometrium, this processes in 16- 45 days of gestation.
Surgery and Obstetrics Department By: Mohammad Rahawy
Fetal Fluids The amniotic sac contains fluid supporting the fetus from injury and fetal infection so they contain proteins and Abs. The allantoic fluid also supporting Morula from trauma and this fluid coming from allantoic cells and from urination of fetus during the2nd stage of gestation, but in the1st stage of gestation embryo excrete its urine through the urethra to amniotic fluid. In the 2nd half of gestation the urine comes from urachusSurgery and Obstetrics Department By: Mohammad Rahawy
.The total volume of fetal fluids increases progressively throughout pregnancy with rapid rise at 70-80 days. During the first third of gestation the volume of amniotic is greater than allantoic whilst during the last third the volume of allantoic fluid is greater than the amniotic. There are considerable variations in the volume of fluid associated with individual fetus of the same gestation age
Surgery and Obstetrics Department By: Mohammad Rahawy
.Animal Amniotic fluid Allantoic fluid Cow 5-6L 9.5-10 L Mare 3-7 L 12-18L Doe 0.4-1.2L 1-1.5L Ewe 0.3- 0.7L 1- 1.5L Sow 0.04-0.1 L Bitch 0.01-0.3L 0.01-0.05L
Surgery and Obstetrics Department By: Mohammad Rahawy
.The Placenta: Placenta may be classified according to the way the villi are distributed on the fetal chorion or anatomically classification of the Placenta of animals which may be divided in to four general type:-
Surgery and Obstetrics Department By: Mohammad Rahawy
.1-The diffuse type :- This type is found in mare and saw the entire surface of the allantois chorion is covered with villi and microvilli that project in to crypts or pockets in the endometrium.
Surgery and Obstetrics Department By: Mohammad Rahawy
.Surgery and Obstetrics Department By: Mohammad Rahawy
.Surgery and Obstetrics Department By: Mohammad Rahawy
.Surgery and Obstetrics Department By: Mohammad Rahawy
2- The cotyledonary type :- Its also called multiplex type this found in ewe, goat and cow. In these structures the villi, secondary villi and microvilli of the cotyledon fit together closely with the maternal crypts and microvilli in more complex arrangement than in the diffuse type placenta. The caruncales are arranged in 4 rows, 2 ventral and 2dorsal, the length of each uterine horne. In cow the number of uterine caruncales in the pregnant uterus is 75-120 placentomes. the caruncales are convex in shape But in ewe the caruncales are concave in shape, about 80-90 placentomesSurgery and Obstetrics Department By: Mohammad Rahawy
Surgery and Obstetrics Department By: Mohammad Rahawy3- The zonary type :- This type is found in the dog and cat the placenta form a zonary band or girdle about 2.5-7.5 cm in the width around the circumference of the uterine lumen in the middle of the oval chorionic sac.
Surgery and Obstetrics Department By: Mohammad Rahawy
Surgery and Obstetrics Department By: Mohammad RahawySurgery and Obstetrics Department By: Mohammad Rahawy
4- The discoidal type :- This type is seen in the primates and rodents. There is a round to oval, disc-shaped placental area of the endometrium and allantois chorion.Surgery and Obstetrics Department By: Mohammad Rahawy
Surgery and Obstetrics Department By: Mohammad RahawyAnother method of classifying placenta type is by the tissues or structures that intervene between the maternal and fetal blood.(Histological type)
Surgery and Obstetrics Department By: Mohammad Rahawy
Surgery and Obstetrics Department By: Mohammad Rahawy1-The epithelochorial type of placenta:- This type is present in mare and sow. In this type six structures :endothelium, connective tissue, epithelium of the endometrium and the trophoblast or chorion, mesonchyme and endothelium of the fetal tissue separate the maternal and fetal blood.
Surgery and Obstetrics Department By: Mohammad Rahawy
2-The syndesmochorial type of placenta:- This type in cow, ewe and doe. In this type all the tissues of the preceding type are present exception of the maternal epithelium.Surgery and Obstetrics Department By: Mohammad Rahawy
3-The endotheliochorial type of placenta:- This type is present in bitch and cat which has the endothelium of uterine vessels and the chorion mesonchyme and endothelium of the fetal tissue or four structures separating the maternal and fetal bloodSurgery and Obstetrics Department By: Mohammad Rahawy
4-The hemochorial type of placenta:- This type is present in women and rodents has only the fetal tissue of the chorion, mesonchyme and endothelium that lie or bathe in a"lake" of maternal blood since all maternal tissue have been eliminatedSurgery and Obstetrics Department By: Mohammad Rahawy
Third more general classification which divided the placenta in to two type:-1-Deciduate placenta is present in women and rodents and in a slightly modified form in the bitch and cat. In this type the deciduas composed of portions of the maternal placenta and fetal placenta are shed at parturition leaving apportion of the endometrium denuded.