Observations On The Morphology Of Hai Men Goat Embryos And Studies On The Genesis Of Their Urogenital Organs

This research used Hai Men Goats as materias. Four aspects were investigated and the main results were summarized as follows:1. During E10d8h-18d8h (Which means embryo development time from 10 days and 8 hours to 18 days and 8 hours after coitus), the germ layer of Hai Men Goats embryo occured. The embryo changed ball-shaped bursa into tube-shaped bursa. In fact the process of elongation was the coclusion of the elongation of the trophoblast. At E18d8h, the shape of the inner cell mass took place obvious change. The cells that located on the inner side of the inner cell mass separated from the inner cell mass obviously and entered the blastocoel. These cells formed the endoderm. At E12d8h, the inner cell mass was exposed in the surface of the blastocyst entirely. The hyperplasia of the inner cell mass formed the germinal disc. The endoderblast diffused outside and envolped archenteron. The mesoderm came from ectoderm. The mesodermblast separated from the primitive steak. After the mesodermblast formation the trophoblast changed from flat cells to cubic cells. At E18d8h, the axis apparatus erected. The embryo had four paires of somites. The somites had a hole. The neural tube was healed. The amnia kot was produced.2. The caul of the early embryo was made up of chorion, allantois, amnia and the chorion .The chorion cotyledon was produced at E29d14h- From 20d to 27d after coitus, the goat embry was in the stage of branchial arch. The head, neck and back all bent. The heart and liver projected, the projection of the heart was bigger than that of the liver. Because the projection of the liver developed fast, it was bigger than that of the liver at E25d14h.The hinder limb bud was produced, following the front limb bud. The limb budschanged their mound-shaped into pulp bord-shaped gradually. The tail bud was seen clearly at E24d8h. The morphology of the brain had formed basically. The digestive system and the circulatory system developed fast. All the organ' s buds had genesised. The stage of thumb web was 29-37d after coitus. The development of the face made great progress. The branchial crack has been healed. The limb-top was figner-shaped and there was a membrance between fingers. The later limb bud was longer than the front limb bud. The heart disappeared projection nearly. The genital projection appeared. The 42d embryo was in the artiodactyla stage. The face appeared rudiment and the charcteristic of the bread has manifested. The male and female embryo can be distinguished. The mamary buds were produced and the limb was node-shaped.3. The goat embryo re-acted the process of the system evolution, which passed through pronephros, mesonephros and metanephros. The pronephros exsisted shortly and transformed into the mesonephros rapidly. At E22d, the mesonephros became bannaner-shaped. The mesonephros processed towards the tail with days increasing. At E29d the metanephros appeared renal.The genital organ of the early goat embryo was mad up of mesonephric duct, gonad, Mulerian duct, urogenital sinus and genital tubercle. At E24d, the genital crest emerged on the inner side of the mesonephros. At E29d, the gonad had occured sex differentiation. The gonad separated from the mesonephros. The primary seminiferous tubule existed in the medulla.4.The growth of the embryo process in term of slowness-speediness-slowness -speediness circularly during E22d-47d. The goat embryo had 4 fast growth periods (22d-25d, 27d-33d, 35d-37d and 39d-47d).