MEDICAL EMBRYOLOGY PDF

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Sadler, T. W. (Thomas W.) Langman's medical embryology. — 12th ed. / T.W. Sadler. p. ; cm. Medical embryology. Includes index. ISBN 1. From The Developing Human. Moore and Persaud 6th Edition. From Langman's Medical Embryology 9th Edition. Lippincott Williams & Wilkins. Implanted. Sorry, this document isn't available for viewing at this time. In the meantime, you can download the document by clicking the 'Download' button above.


Medical Embryology Pdf

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About the author. Guus van der Bie MD () worked from to. as a lecturer at the Department of Medical. Anatomy and Embryology at Utrecht State. Second Week of Development: Bilaminar Germ Disc. 51 chapter 4. Third Week of Development Pages from PBF-FM longmogedwapor.ga 11/01/ PM Page i Aptara Embryology Ronald W . Dudek, PhD Professor Department of Anatomy a.

Langman’s Medical Embryology 13th Edition

They close together and form gap junctions , which facilitate cellular communication. This polarisation leaves a cavity, the blastocoel , creating a structure that is now termed the blastocyst. In animals other than mammals, this is called the blastula. The trophoblasts secrete fluid into the blastocoel.

The resulting increase in size of the blastocyst causes it to hatch through the zona pellucida, which then disintegrates. The embryo plus its membranes is called the conceptus , and by this stage the conceptus has reached the uterus.

The zona pellucida ultimately disappears completely, and the now exposed cells of the trophoblast allow the blastocyst to attach itself to the endometrium , where it will implant.

The formation of the hypoblast and epiblast , which are the two main layers of the bilaminar germ disc, occurs at the beginning of the second week. An erosion of the endothelial lining of the maternal capillaries by the syncytiotrophoblastic cells of the sinusoids will form where the blood will begin to penetrate and flow through the trophoblast to give rise to the uteroplacental circulation. These columns are known as primary villi.

At the same time, other migrating cells form into the exocelomic cavity a new cavity named the secondary or definitive yolk sac, smaller than the primitive yolk sac. It becomes thickened, with its secretory glands becoming elongated, and is increasingly vascular. This lining of the uterine cavity or womb is now known as the decidua , and it produces a great number of large decidual cells in its increased interglandular tissue. The blastomeres in the blastocyst are arranged into an outer layer called Trophoblast.

The trophoblast then differentiates into an inner layer, the cytotrophoblast , and an outer layer, the syncytiotrophoblast. The cytotrophoblast contains cuboidal epithelial cells and is the source of dividing cells, and the syncytiotrophoblast is a syncytial layer without cell boundaries.

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The syncytiotrophoblast implants the blastocyst in the decidual epithelium by projections of chorionic villi , forming the embryonic part of the placenta. The placenta develops once the blastocyst is implanted, connecting the embryo to the uterine wall. The decidua here is termed the decidua basalis; it lies between the blastocyst and the myometrium and forms the maternal part of the placenta.

The implantation is assisted by hydrolytic enzymes that erode the epithelium. The syncytiotrophoblast also produces human chorionic gonadotropin , a hormone that stimulates the release of progesterone from the corpus luteum. Progesterone enriches the uterus with a thick lining of blood vessels and capillaries so that it can oxygenate and sustain the developing embryo.

The trophoblasts secrete fluid into the blastocoel.

The resulting increase in size of the blastocyst causes it to hatch through the zona pellucida, which then disintegrates.

The embryo plus its membranes is called the conceptus , and by this stage the conceptus has reached the uterus. The zona pellucida ultimately disappears completely, and the now exposed cells of the trophoblast allow the blastocyst to attach itself to the endometrium , where it will implant.

The formation of the hypoblast and epiblast , which are the two main layers of the bilaminar germ disc, occurs at the beginning of the second week. An erosion of the endothelial lining of the maternal capillaries by the syncytiotrophoblastic cells of the sinusoids will form where the blood will begin to penetrate and flow through the trophoblast to give rise to the uteroplacental circulation.

These columns are known as primary villi. At the same time, other migrating cells form into the exocelomic cavity a new cavity named the secondary or definitive yolk sac, smaller than the primitive yolk sac. It becomes thickened, with its secretory glands becoming elongated, and is increasingly vascular.

This lining of the uterine cavity or womb is now known as the decidua , and it produces a great number of large decidual cells in its increased interglandular tissue. The blastomeres in the blastocyst are arranged into an outer layer called Trophoblast. The trophoblast then differentiates into an inner layer, the cytotrophoblast , and an outer layer, the syncytiotrophoblast. The cytotrophoblast contains cuboidal epithelial cells and is the source of dividing cells, and the syncytiotrophoblast is a syncytial layer without cell boundaries.

The syncytiotrophoblast implants the blastocyst in the decidual epithelium by projections of chorionic villi , forming the embryonic part of the placenta. The placenta develops once the blastocyst is implanted, connecting the embryo to the uterine wall. The decidua here is termed the decidua basalis; it lies between the blastocyst and the myometrium and forms the maternal part of the placenta.

The implantation is assisted by hydrolytic enzymes that erode the epithelium. The syncytiotrophoblast also produces human chorionic gonadotropin , a hormone that stimulates the release of progesterone from the corpus luteum. Progesterone enriches the uterus with a thick lining of blood vessels and capillaries so that it can oxygenate and sustain the developing embryo.

The uterus liberates sugar from stored glycogen from its cells to nourish the embryo. Other villi, called terminal or free villi, exchange nutrients.

Langman’s Medical Embryology – 14th edition

The embryo is joined to the trophoblastic shell by a narrow connecting stalk that develops into the umbilical cord to attach the placenta to the embryo.Development of the tongue A. Moore, Keith L. Moore, K.

Some hypoblast cells migrate along the inner cytotrophoblast lining of the blastocoel, secreting an extracellular matrix along the way. Because the brain continues to grow in size up until years of age, premature fusion of the sutures or fontanelles will result in abnormal shaping of the head as the brain will cause displacement of the bones that remain unfused.

Development of the skull anterior portions viscerocranium are derived primarily from neural crest mesenchyme that develop into bones via membranous ossification bones in the floors of the cranial fossae, aka the "chondrocranium" cribriform plate, sphenoid, petrous temporal and clivus of the occipital , are derived from paraxial somitic mesoderm that develop bone via endochondral ossification flat bones of the cranial vault, aka the "neurocranium" e.

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