Book - Uterine and tubal gestation (1903) 1-13: Difference between revisions
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=Part I. The Essentials of Uterine Gestation= | =Part I. The Essentials of Uterine Gestation= | ||
==Chapter XIII. The Umbilical Vessels and Cord== | |||
===A. Umbilical Vessels=== | |||
The ovum possesses its fluid centre or yolk. It may possess a covering of discus proligerus and albumin. On embedding the trophoblast digests the decidual cells and is surrounded by the so-called symplasmatic fluid. The ovum develops and the trophoblast grows. During this time osmosis and the yolk are sources of nourishment. | |||
As the decidua is invaded capillaries are opened, and in the first few days trophoblast is acted on by blood of the mother. It changes trophoblast cells to syncytium and probably blood elements enter into the composition of the cells. Osmosis again serves to explain the growth of the ovum and its contents. On the interior of the ovum we have the embryo, consisting of ectoderm, mesoderm, and a lining of entoderm, which entodermal lining is a part of the entoderm of the yolk sac and abdominal vesicle. The ectoderm of the embryo, consisting of stratified epithelium, is continued into the single-layered amnion reflected over its dorsal aspect. The contents of the yolk sac thus line the entoderm of the embryo. A branch of the entoderm extends into the abdominal adherent band as the allantoic duct (Figs.30cZ,46&). | |||
As the ventral and caudal ends curve anteriorly, and the lateral walls also, they constrict the abdominal vesicle. The connection between extra-abdominal umbilical vesicle and intra-abdominal is through a resulting narrow canal, the ductus omphalo-entericus (Fig. 46 a and b). The duct is called omphalo-entericus because meanwhile mesoderm and entoderm have formed intestine and the duct enters into intestine instead of into a flat entodermal lining of the embryo. All this while arteries and veins have developed on the abdominal vesicle, the arterise and vena? omphalo-mesentericse. The arteries pass from the aorta to the vesicle, the veins from the vesicle to the venous end of the heart tube. In the first month develop two umbilical arteries and two umbilical veins. The arteries are branches of the aorta. They pass along the future lateral pelvic walls, along the later bladder, along the later anterior abdominal wall to the adherent band of mesoderm. Two umbilical veins develop, one of which atrophies. Their contents at first enter through the duct of Cuvier into the heart. | |||
The two venae omphalo-mesenterica? pass along the intestine and anastomose at the duodenum. They send branches to the budding liver, the future hepatic veins. These pass into the end area of the venae omphalo-mesentericse which empties into the primitive heart. The liver grows and thus needs more blood. Then develop the umbilical veins, which pass through the ducts of Cuvier to the venous sinus of the heart, passing over the liver. The right vein atrophies. Some branches of the left umbilical vein anastomose under the liver with the vena? omphalo-mesenterica;. This anastomosis under the liver soon becomes the important part and finally takes all the placental blood to the liver and through the hepatic veins. Thus the umbilical blood circulates with the yolk blood through the liver and then through the yolk veins to the heart, for the end piece of the yolk veins becomes the cardiac end of the future inferior vena cava. At first the umbilical vessels are small, while the omphalo-mesenteric are large. As the yoke is sucked up the omphalo-mesenteric vessels atrophy and the umbilical grow. The branches of the latter extend on through the abdominal pedicle, through the mesoderm of the membrana chorii into the villi, and join the capillaries there. At the end of the first month the fetal heart begins to beat, and in the first month circulation through the vessels begins, and for the first time there is an exchange between maternal blood and the contents of the chorionic vessels through the syncytium and cells of Langhans. As the liver grows the yolk veins atrophy and the umbilical veins grow larger. "When the liver can no longer take care of all the placental blood the ductus venosus Aurantii is formed, and so part of the blood goes directly into the inferior vena cava. The original yolk veins form the portal circulation, which becomes active in the latter part of the fetal nine months. After birth the portal circulation, carrying blood from the intestines, pancreas, and spleen, supplies the liver. The portal circulation, as said before, develops from the yolk veins. These changes are due to the change in size and importance of the yolk, placenta, and liver. After birth the umbilical vein becomes the ligamentum teres of the liver; the ductus venosus becomes the ligamentum venosum (Hertwig). | |||
===B. The Umbilical Cord=== | |||
The ductus omphalo-entericus enters the future ileum a1 a point lying subsequently near the cecum. It is obliterated in the eighth week and disappears. Sometimes it is retained and is known as the diverticulum of Meckel. It may be simply a diverticulum of the ileum. It may extend up to the umbilicus as a patent canal extending from the ileum. It may remain as a band extending between the ileum and the umbilicus. | |||
The umbilical artery of each side forms from its first part the common iliac. The remainder passing along the pelvic lateral wall to the side of the bladder, along the anterior surface of the abdominal wall to the adherent band and umbilicus, becomes the ligamentum vesico-umbilieale laterale. The intra-abdominal portion of the allantoic duct becomes a part of the bladder and the urachus, which extends from the summit of the bladder along the anterior abdominal wall to the navel. | |||
Fig. 46a. — Embryo with abdominal mesodermal pedicle and with umbilical vesicle, showing amnion still close to the embryo, a condition still found in the third week or even later. (Ahlfeld.) | |||
Of the umbilical veins, one atrophies. Early in its career it joins the veme omphalo-mesenterica?, which, in their later stages, are connected with the liver, and thus it enters the liver and subsequently becomes the ligamentum teres. Coming out of the abdomen of the fetus are : | |||
# The adherent band of mesoderm. | |||
# In it the allantoic duct. | |||
# In it the umbilical vein and umbilical arteries. | |||
# The atrophied umbilical vesicle and its duct, the omphaloenteric duct. | |||
# On the latter the atrophied omphalo-mesenterie vessels. | |||
===C. Amnion=== | |||
The amnion, even in the third week, may lie close upon the fetus. In it fluid is secreted which constantly distends it. As the cephalic and caudal ends take on a ventral curve, and as the lateral walls of the germinal plate curve upward and gradually approach, and as the points from which amnion begins thus approach, the amnion comes nearer and closer to the abdominal pedicle and the omphalo-enteric duct. "When the amnion is finally distended so that it is in contact with the inner lining of the membrana chorii (6th-10th week), it must envelop the abdominal pedicle and the atrophied umbilical vesicle. The vesicle is longer than the abdominal pedicle, so that its tip lies for a distance on the fetal surface of the membrana chorii. The point of attachment of the original adherent band to the membrana chorii is the point of attachment of the abdominal pedicle to the chorion frondosum and the point of attachment of the umbilical cord to the placenta. At the umbilicus the amnion, which thus covers the cord, goes over into the abdominal epidermis. The main substance of the'cord consists of "Wharton's jelly. A long, thin cord is characteristic of man. | |||
Fig. 46b. — Ovum (schematic), showing extra-embryonal chorion connected with the embryonal area by the mesoblastic umbilical pedicle. In the umbilical pedicle are the allantoic duct and the umbilical vessels. Passing from the umbilical vesicle to the intestine are the omphalo-enteric duct and its obliterated vessels. When the amnion becomes large enough to line the membrana chorii (sixth weevc or later), it presses these structures together and surrounds the then-formed umbilical cord. | |||
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Bandler SW. Uterine and tubal gestation. (1903) William Wood & Company, New York.
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Part I. The Essentials of Uterine Gestation
Chapter XIII. The Umbilical Vessels and Cord
A. Umbilical Vessels
The ovum possesses its fluid centre or yolk. It may possess a covering of discus proligerus and albumin. On embedding the trophoblast digests the decidual cells and is surrounded by the so-called symplasmatic fluid. The ovum develops and the trophoblast grows. During this time osmosis and the yolk are sources of nourishment.
As the decidua is invaded capillaries are opened, and in the first few days trophoblast is acted on by blood of the mother. It changes trophoblast cells to syncytium and probably blood elements enter into the composition of the cells. Osmosis again serves to explain the growth of the ovum and its contents. On the interior of the ovum we have the embryo, consisting of ectoderm, mesoderm, and a lining of entoderm, which entodermal lining is a part of the entoderm of the yolk sac and abdominal vesicle. The ectoderm of the embryo, consisting of stratified epithelium, is continued into the single-layered amnion reflected over its dorsal aspect. The contents of the yolk sac thus line the entoderm of the embryo. A branch of the entoderm extends into the abdominal adherent band as the allantoic duct (Figs.30cZ,46&).
As the ventral and caudal ends curve anteriorly, and the lateral walls also, they constrict the abdominal vesicle. The connection between extra-abdominal umbilical vesicle and intra-abdominal is through a resulting narrow canal, the ductus omphalo-entericus (Fig. 46 a and b). The duct is called omphalo-entericus because meanwhile mesoderm and entoderm have formed intestine and the duct enters into intestine instead of into a flat entodermal lining of the embryo. All this while arteries and veins have developed on the abdominal vesicle, the arterise and vena? omphalo-mesentericse. The arteries pass from the aorta to the vesicle, the veins from the vesicle to the venous end of the heart tube. In the first month develop two umbilical arteries and two umbilical veins. The arteries are branches of the aorta. They pass along the future lateral pelvic walls, along the later bladder, along the later anterior abdominal wall to the adherent band of mesoderm. Two umbilical veins develop, one of which atrophies. Their contents at first enter through the duct of Cuvier into the heart.
The two venae omphalo-mesenterica? pass along the intestine and anastomose at the duodenum. They send branches to the budding liver, the future hepatic veins. These pass into the end area of the venae omphalo-mesentericse which empties into the primitive heart. The liver grows and thus needs more blood. Then develop the umbilical veins, which pass through the ducts of Cuvier to the venous sinus of the heart, passing over the liver. The right vein atrophies. Some branches of the left umbilical vein anastomose under the liver with the vena? omphalo-mesenterica;. This anastomosis under the liver soon becomes the important part and finally takes all the placental blood to the liver and through the hepatic veins. Thus the umbilical blood circulates with the yolk blood through the liver and then through the yolk veins to the heart, for the end piece of the yolk veins becomes the cardiac end of the future inferior vena cava. At first the umbilical vessels are small, while the omphalo-mesenteric are large. As the yoke is sucked up the omphalo-mesenteric vessels atrophy and the umbilical grow. The branches of the latter extend on through the abdominal pedicle, through the mesoderm of the membrana chorii into the villi, and join the capillaries there. At the end of the first month the fetal heart begins to beat, and in the first month circulation through the vessels begins, and for the first time there is an exchange between maternal blood and the contents of the chorionic vessels through the syncytium and cells of Langhans. As the liver grows the yolk veins atrophy and the umbilical veins grow larger. "When the liver can no longer take care of all the placental blood the ductus venosus Aurantii is formed, and so part of the blood goes directly into the inferior vena cava. The original yolk veins form the portal circulation, which becomes active in the latter part of the fetal nine months. After birth the portal circulation, carrying blood from the intestines, pancreas, and spleen, supplies the liver. The portal circulation, as said before, develops from the yolk veins. These changes are due to the change in size and importance of the yolk, placenta, and liver. After birth the umbilical vein becomes the ligamentum teres of the liver; the ductus venosus becomes the ligamentum venosum (Hertwig).
B. The Umbilical Cord
The ductus omphalo-entericus enters the future ileum a1 a point lying subsequently near the cecum. It is obliterated in the eighth week and disappears. Sometimes it is retained and is known as the diverticulum of Meckel. It may be simply a diverticulum of the ileum. It may extend up to the umbilicus as a patent canal extending from the ileum. It may remain as a band extending between the ileum and the umbilicus.
The umbilical artery of each side forms from its first part the common iliac. The remainder passing along the pelvic lateral wall to the side of the bladder, along the anterior surface of the abdominal wall to the adherent band and umbilicus, becomes the ligamentum vesico-umbilieale laterale. The intra-abdominal portion of the allantoic duct becomes a part of the bladder and the urachus, which extends from the summit of the bladder along the anterior abdominal wall to the navel.
Fig. 46a. — Embryo with abdominal mesodermal pedicle and with umbilical vesicle, showing amnion still close to the embryo, a condition still found in the third week or even later. (Ahlfeld.)
Of the umbilical veins, one atrophies. Early in its career it joins the veme omphalo-mesenterica?, which, in their later stages, are connected with the liver, and thus it enters the liver and subsequently becomes the ligamentum teres. Coming out of the abdomen of the fetus are :
- The adherent band of mesoderm.
- In it the allantoic duct.
- In it the umbilical vein and umbilical arteries.
- The atrophied umbilical vesicle and its duct, the omphaloenteric duct.
- On the latter the atrophied omphalo-mesenterie vessels.
C. Amnion
The amnion, even in the third week, may lie close upon the fetus. In it fluid is secreted which constantly distends it. As the cephalic and caudal ends take on a ventral curve, and as the lateral walls of the germinal plate curve upward and gradually approach, and as the points from which amnion begins thus approach, the amnion comes nearer and closer to the abdominal pedicle and the omphalo-enteric duct. "When the amnion is finally distended so that it is in contact with the inner lining of the membrana chorii (6th-10th week), it must envelop the abdominal pedicle and the atrophied umbilical vesicle. The vesicle is longer than the abdominal pedicle, so that its tip lies for a distance on the fetal surface of the membrana chorii. The point of attachment of the original adherent band to the membrana chorii is the point of attachment of the abdominal pedicle to the chorion frondosum and the point of attachment of the umbilical cord to the placenta. At the umbilicus the amnion, which thus covers the cord, goes over into the abdominal epidermis. The main substance of the'cord consists of "Wharton's jelly. A long, thin cord is characteristic of man.
Fig. 46b. — Ovum (schematic), showing extra-embryonal chorion connected with the embryonal area by the mesoblastic umbilical pedicle. In the umbilical pedicle are the allantoic duct and the umbilical vessels. Passing from the umbilical vesicle to the intestine are the omphalo-enteric duct and its obliterated vessels. When the amnion becomes large enough to line the membrana chorii (sixth weevc or later), it presses these structures together and surrounds the then-formed umbilical cord.
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Reference: Bandler SW. Uterine and tubal gestation. (1903) William Wood & Company, New York.
Cite this page: Hill, M.A. (2024, April 18) Embryology Book - Uterine and tubal gestation (1903) 1-13. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_Uterine_and_tubal_gestation_(1903)_1-13
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
