. Cunningham's Text-book of anatomy. Anatomy. Anterior end of neural fold Plasmodial trophoblast Cellular trophoblast Amnion cavity [blast Mesoderm lining of tropho- Mesoderni of amnion Ectoderm of amnion Allantoic diverticulum of entoderm vesicle Body stalk mesoderm Entoderm Mesoderm covering of entoderm vesicle eurenteric canal "Cavity of entodermal vesicle Fig. 70.âSchema of Sagittal Section of Zygote along Line A / growth of foetal vessels into the foetal mesodermal cores. The secondary villi, therefore, consist of a mesodermal core covered by a layer of cellular trophoblast and a lay
. Cunningham's Text-book of anatomy. Anatomy. Anterior end of neural fold Plasmodial trophoblast Cellular trophoblast Amnion cavity [blast Mesoderm lining of tropho- Mesoderni of amnion Ectoderm of amnion Allantoic diverticulum of entoderm vesicle Body stalk mesoderm Entoderm Mesoderm covering of entoderm vesicle eurenteric canal "Cavity of entodermal vesicle Fig. 70.âSchema of Sagittal Section of Zygote along Line A / growth of foetal vessels into the foetal mesodermal cores. The secondary villi, therefore, consist of a mesodermal core covered by a layer of cellular trophoblast and a layer of plasmodium, the latter lying outside the former. Still later the secondary villi send out numer- ous branches into the blood spaces, and thus increase greatly in complexity (Figs. 75, 76, 77). As development progresses still further a part of the chorion is converted into the foetal portion of an organ called the Extra-embryonic cceiom placenta, and thus the chorion is divided into placental and non-placental regions. Upon the placental part the villi con- tinue to increase, but they dis- appear entirely from the non- placental part, which is then called the chorion laeve (Fig. 77). The Amnion, the Body- Stalk (Allantoic Stalk), and the Umbilical Cord.âThe amnion is formed from that portion of the wall of the larger of the two inner vesicles of the zygote, tbe ecto-mesodermal vesicle (p. 22), which does not take part in the formation of the embryo. It consists of ectoderm cells covered exter- nally by a layer of extra-em- bryonic mesoderm, and it is continuous with the margin of the embryonic area (Figs. 70, 71). The cavity of the ecto- mesodermal vesicle, enclosed between the amnion and the embryonic area, is the cavity of the amnion; it is filled with fluid, which raises the amnion in the form of a cupola over the embryonic region (Fig. 70). The Body-Stalk (Allantoic Stalk).âIt has been noted already that the mesoderm of the median part of the posterior portion of th
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
