A treatise on the science and practice of midwifery . Development of the membrane. 2. External layerof blastodermic membrane. •*. Internallayers forming the umbilical vesicle. vessels. .0. Projections Conn-ing amnion. 6. Allantoic 96 PREGNANCY. communication with the abdominal cavity of the foetus is throughthe constricted portion at the point of division called the vitellineduct (Fig. 52). An artery and vein, the omphalo-mesenteric, ramifyon the vesicle and its duct. Fig. I. Exo-chorion. 2. External layer ofblastodermic Amnion. 6. Embryon. 7. Alla
A treatise on the science and practice of midwifery . Development of the membrane. 2. External layerof blastodermic membrane. •*. Internallayers forming the umbilical vesicle. vessels. .0. Projections Conn-ing amnion. 6. Allantoic 96 PREGNANCY. communication with the abdominal cavity of the foetus is throughthe constricted portion at the point of division called the vitellineduct (Fig. 52). An artery and vein, the omphalo-mesenteric, ramifyon the vesicle and its duct. Fig. I. Exo-chorion. 2. External layer ofblastodermic Amnion. 6. Embryon. 7. Allautois increasing in size. 3. Umbilical vesicle. 4. Its vessels. Fig. 53, As the amnion increases in size, it pushes back the umbilicalvesicle towards the external membrane of the ovum, between whichand the amnion it lies (Fig. 53); and when the allantois is developed,it ceases to be of any use, and rapidly shrinks and dwindles most mammals no trace of it can be foundafter the fourth month of utero-gestation; insome, including the human female, it is said toexist as a minute vesicle at the placental end ofthe umbilical cord at the full period of preg-nancy. The umbilical vesicle is filled with ayellowish fluid, containing many oil and fatglobules, similar to the yelk of an egg. The Allantois.—Somewhere about the twen-tieth day after conception a small vesicle isformed towards the caudal extremity of thefoetus, which is called the allantois. It is welldeveloped and persistent in many of the
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Keywords: ., bookcentury1800, bookdecade1870, bookidtre, booksubjectobstetrics
