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Intraembryonic Coelom
In the development of the human embryo the intraembryonic coelom (or somatic coelom) is a portion of the conceptus forming in the mesoderm during the third week of development. During the third week of development, the lateral plate mesoderm splits into a dorsal somatic mesoderm (somatopleure) and a ventral splanchnic mesoderm (splanchnopleure). The resulting cavity between the somatopleure and splanchnopleure is called the intraembryonic coelom. This space will give rise to the thoracic and abdominal cavities. The coelomic spaces in the lateral mesoderm and cardiogenic area are isolated. The isolated coelom begins to organize into a horseshoe shape. The spaces soon join together and form a single horseshoe-shaped cavity: the intraembryonic coelom. It then separates the mesoderm into two layers. It briefly has a connection with the extraembryonic coelom. See also * Cavitation (embryology) Cavitation is a process in early embryonic development that follows cleavage. Cavitation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Plate Mesoderm
The lateral plate mesoderm is the mesoderm that is found at the periphery of the embryo. It is to the side of the paraxial mesoderm, and further to the axial mesoderm. The lateral plate mesoderm is separated from the paraxial mesoderm by a narrow region of intermediate mesoderm. The mesoderm is the middle layer of the three germ layers, between the outer ectoderm and inner endoderm. During the third week of embryonic development the lateral plate mesoderm splits into two layers forming the intraembryonic coelom. The outer layer of lateral plate mesoderm adheres to the ectoderm to become the somatic or parietal layer known as the somatopleure. The inner layer adheres to the endoderm to become the splanchnic or visceral layer known as the splanchnopleure. Development The lateral plate mesoderm will split into two layers, the somatopleuric mesenchyme, and the splanchnopleuric mesenchyme. * The ''somatopleuric layer'' forms the future body wall. * The ''splanchnopleuric laye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pericardial Cavity
The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made of serous membrane (serous pericardium). It encloses the pericardial cavity, which contains pericardial fluid, and defines the middle mediastinum. It separates the heart from interference of other structures, protects it against infection and blunt trauma, and lubricates the heart's movements. The English name originates from the Ancient Greek prefix "''peri-''" (περί; "around") and the suffix "''-cardion''" (κάρδιον; "heart"). Anatomy The pericardium is a tough fibroelastic sac which covers the heart from all sides except at the cardiac root (where the great vessels join the heart) and the bottom (where only the serous pericardium exists to cover the upper surface of the central tendon of diaphragm, central tendon of thoracic d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleural Cavity
The pleural cavity, pleural space, or interpleural space is the potential space between the pleurae of the pleural sac that surrounds each lung. A small amount of serous pleural fluid is maintained in the pleural cavity to enable lubrication between the membranes, and also to create a pressure gradient. The serous membrane that covers the surface of the lung is the visceral pleura and is separated from the outer membrane the parietal pleura by just the film of pleural fluid in the pleural cavity. The visceral pleura follows the fissures of the lung and the root of the lung structures. The parietal pleura is attached to the mediastinum, the upper surface of the diaphragm, and to the inside of the ribcage. Structure In humans, the left and right lungs are completely separated by the mediastinum, and there is no communication between their pleural cavities. Therefore, in cases of a unilateral pneumothorax, the contralateral lung will remain functioning normally unless there is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peritoneal Cavity
The peritoneal cavity is a potential space between the parietal peritoneum (the peritoneum that surrounds the abdominal wall) and visceral peritoneum (the peritoneum that surrounds the internal organs). The parietal and visceral peritonea are layers of the peritoneum named depending on their function/location. It is one of the spaces derived from the coelomic cavity of the embryo, the others being the pleural cavities around the lungs and the pericardial cavity around the heart. It is the largest serosal sac, and the largest fluid-filled cavity, in the body and secretes approximately 50 ml of fluid per day. This fluid acts as a lubricant and has anti-inflammatory properties. The peritoneal cavity is divided into two compartments – one above, and one below the transverse colon. Compartments The peritoneal cavity is divided by the transverse colon (and its mesocolon) into an upper supracolic compartment, and a lower infracolic compartment. The liver, spleen, stomach, and lesser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conceptus
A conceptus (from Latin: ''concipere'' to conceive) is an embryo and its appendages (adnexa), the associated membranes, placenta, and umbilical cord; the products of conception or, more broadly, "the product of conception at any point between fertilization and birth."''The American Heritage Dictionary of the English Language'' (2011), 5th ed., p. 381. The conceptus includes all structures that develop from the zygote, both embryonic and extraembryonic. It includes the embryo as well as the embryonic part of the placenta and its associated membranes: amnion, chorion (gestational sac), and yolk sac The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though ''yolk sac'' is far .... References Embryology Human pregnancy {{Developmental-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoderm
The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical Embryology, 11th edition. 2010. The mesoderm forms mesenchyme, mesothelium, non-epithelial blood cells and coelomocytes. Mesothelium lines coeloms. Mesoderm forms the muscles in a process known as myogenesis, septa (cross-wise partitions) and mesenteries (length-wise partitions); and forms part of the gonads (the rest being the gametes). Myogenesis is specifically a function of mesenchyme. The mesoderm differentiates from the rest of the embryo through intercellular signaling, after which the mesoderm is polarized by an organizing center. The position of the organizing center is in turn determined by the regions in which beta-catenin is protected from degradation by GSK-3. Beta-catenin acts as a co-factor that alters the activity of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatopleure
In the anatomy of an embryo, the somatopleure is a structure created during embryogenesis when the lateral plate mesoderm splits into two layers. The outer (or somatic) layer becomes applied to the inner surface of the ectoderm, and with it (partially) forms the somatopleure. The combination of ectoderm and mesoderm, or somatopleure, forms the amnion, the chorion and the lateral body wall of the embryo. The limbs are formed from the somatic mesoderm cells are induced by hox genes and the expression of other molecules to suffer and epithelial-mesenchyme transition. The embryonic somatopleure is then divided into 3 sections, the anterior limb bud formation, the posterior limb bud formation and the non limb forming wall. The bud forming sections grow in size at the somatic mesoderm under the ectoderm proliferate in mesenchyme form. In chicken, the extraembryonic tissues are separated into two layers: the splanchnopleure composed of the endoderm and splanchnic mesoderm, and the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Splanchnopleure
In the anatomy of an embryo, the splanchnopleuric mesenchyme is a structure created during embryogenesis when the lateral mesodermal germ layer splits into two layers. The inner (or splanchnic) layer adheres to the endoderm, and with it forms the splanchnopleure (mesoderm external to the coelom plus the endoderm). See also Post development the somato and splanchnopleuric junction lies at the duodeno-jejunal flexure. * somatopleure * mesenchyme References External links * * Overviewat Kennesaw State University Kennesaw State University (KSU) is a public research university located in the state of Georgia with two different campuses in the Atlanta metropolitan area, one in Kennesaw and the other in Marietta on a combined of land. The school was fou ... Embryology {{developmental-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelom
The coelom (or celom) is the main body cavity in most animals and is positioned inside the body to surround and contain the digestive tract and other organs. In some animals, it is lined with mesothelium. In other animals, such as molluscs, it remains undifferentiated. In the past, and for practical purposes, coelom characteristics have been used to classify bilaterian animal phyla into informal groups. Etymology The term ''coelom'' derives from the Ancient Greek word (), meaning 'cavity'. Structure Development The coelom is the mesodermally lined cavity between the gut and the outer body wall. During the development of the embryo, coelom formation begins in the gastrulation stage. The developing digestive tube of an embryo forms as a blind pouch called the archenteron. In Protostomes, the coelom forms by a process known as schizocoely. The archenteron initially forms, and the mesoderm splits into two layers: the first attaches to the body wall or ectoderm, forming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extraembryonic Coelom
The gestational sac is the large cavity of fluid surrounding the embryo. During early embryogenesis it consists of the extraembryonic coelom, also called the chorionic cavity. The gestational sac is normally contained within the uterus. It is the only available structure that can be used to determine if an intrauterine pregnancy exists until the embryo can be identified. On obstetric ultrasound, the gestational sac is a dark (anechoic) space surrounded by a white (hyperechoic) rim. Structure The gestational sac is spherical in shape, and is usually located in the upper part (fundus) of the uterus. By approximately nine weeks of gestational age, due to folding of the trilaminar germ disc, the amniotic sac expands and occupy the majority of the volume of the gestational sac, eventually reducing the extraembryonic coelom (the gestational sac or the chorionic cavity) to a thin layer between the parietal somatopleuric and visceral splanchnopleuric layer of extraembryonic mesoderm. Deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavitation (embryology)
Cavitation is a process in early embryonic development that follows cleavage. Cavitation is the formation of the blastocoel, a fluid-filled cavity that defines the blastula, or in mammals the blastocyst. After fertilization, cell division of the zygote occurs which results in the formation of a solid ball of cells (blastomeres) called the morula. Further division of cells increases their number in the morula, and the morula differentiates them into two groups. The internal cells become the inner cell mass, and the outer cells become the trophoblast. Before cell differentiation takes place there are two transcription factors, Oct-4 and nanog that are uniformly expressed on all of the cells, but both of these transcription factors are turned off in the trophoblast once it has formed. The trophoblast cells form tight junctions between them making the structure leakproof. Trophoblast cells have sodium pumps on their membranes, and pump sodium into the centre of the morula. This dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
