Teratogensis: Caudal Dysgenesis ( Sirenomelia)

Teratogensis: Caudal Dysgenesis ( sirenomelia) The third week of development is the period of superior sensitivity for teratogensis (Sadler 2010). In caudal dysgenesis (sirenomelia) genetic ab recipeities and toxins disrupt normal gastrulation. A more common name for sirenomelia is the mermaid syndrome. Sirenomelia is characterized by stingy mesoderm formed in the caudalmost region of the embryo. The mesoderm contributes to the institution of the lower limbs, urogenital system and the lumbosacral vertebrate. Defect varies from artless cutaneous fusion of the limbs to absence of all wide castanets but one femur. The defect of the feet is proportional to the defect of the long bones, with cutaneous defect commonly give uping a double amalgamate foot with ten toes, and more severe defect present with a more rudimentary foot and ectromelia. Thus, the fibulae when present argon between the tibia and the sole of the foot is oriented venturally sooner of dorsally (Sandra R. Silva, MD & Philippe Jeanty, MD, PhD 1999). Sirenomelia is thought to occur in about 1 in 65,000 livebirths (Oxford Medical Database; Dysmorphology). Sirenomelia may be caused by abnormalities in blastogenesis that affect the distribution of blood to the caudal region of the fetus.

The vascular steal theory indicates that a bingle large artery assumes the function of the umbilical arteries, thus amusive blood flow from the caudal portion of the embryo to the placenta (Bibhuti B Das et al 2001). The presence of paired femurs indicates that the condition is in all probability caused by failed lateralization of the lower limbs, arising at approximately 4 weeks. When single large umbilical artery is observed in direct continuation with the abdominal aorta, it is classified as a vascular anomaly. This type of vascular anomaly is considered a track of the vitelline artery complex and is almost always associated with sirenomelia (Haider 20001). Sirenomelia is fatal payable to severe pulmonary hypoplasia and... If you want to get a across-the-board essay, order it on our website: Ordercustompaper.com

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