egnawer.blogg.se - Medical embryology

Histologic examination of the mass would reveal derivatives of which germ layer(s)?Ĭlick here to submit questions or comments about this site.COURSE DESCRIPTION: This course will provide a review of medical embryology in a lecture format that follows the material used in our medical student and allied health courses.ĮXAMINATIONS: A midterm and final examination over the didactic component of this course will be given as multiple choice questions in the format of the USMLE.

abnormal left-right patterning due to ciliary dysfunction.ĩ.

abnormal closure of the posterior (caudal) neuropore.

premature regression of the primitive streak during gastrulation.

abnormal persistence of primitive streak tissue after completion of gastrulation.

abnormal migration and proliferation of lumbosacral neural crest.

The MOST LIKELY cause for this congenital defect is: Gross image of the sacrococcygeal mass following cesarean section delivery of the neonate.Ĩ. MRI (T2 weighted images) of the maternal pelvis depicting a large cystic mass arising from the sacrococcygeal region of the fetus (the head of the fetus is down).įigure 2. Post-operatively, the mother and child both did well and were discharged home in stable condition.įigure 1. The neonate was subsequently taken to surgery where the lesion was resected and coccygectomy was performed. The mass had no solid components, and there was no involvement of the neural tube. At the time of delivery, the female neonate was noted to have a large, cystic sacrococcygeal mass (Fig. She was taken urgently to the operating room where a cesarean section was performed and the fetus was delivered without complication.

The patient was counseled and monitored until she presented in labor eight weeks later, with contractions every ten minutes, nausea, vomiting, and apparently decreased fetal activity. MRI showed large cystic mass arising from the sacrococcygeal region of the fetus (Fig. An MRI was obtained to further delineate the lesion found on sonography. She denied nausea, vomiting, acute abdominal pain, or recent trauma, and her pregnancy had been progressing well. A large fluid filled, intrauterine structure was found and she subsequently was referred to a tertiary care facility for further evaluation and management. For each of these questions, choose the SINGLE BEST answer.Ī 19-year-old pregnant woman at 29 weeks gestation underwent routine prenatal sonography. Questions 8 and 9 refer to the following case. The label indicating a space containing fluid that is produced by the kidneys in the developing fetus is The label indicating a space lined by endoderm is:ħ. The label indicating the amniotic cavity is:Ħ. For each of these questions, choose the SINGLE BEST answer.Ĥ. most of the placenta is derived from embryonic intermediate mesoderm.the placenta develops from the chorionic plate.

fetal blood vessels attach directly to materal vessels such that there is mixing of fetal and maternal blood.

syncytiotrophoblast cells invade the uterine wall.

cytotrophoblast cells divide and their progeny fuse to form syncytiotrophoblast cells.

epithelial lining of the respiratory tractģ.

endoneurial fibroblasts and Schwann cells of peripheral nerves.

Which of the following is derived from ENDODERM? at the same time as neural tube closureĢ.Implantation of human embryos typically occurs: Please identify all the correct answers.ġ. Any, all, or none of the answers to each question may be correct. Be able to list the derivatives of each subdivision of mesoderm:.Understand the formation and fate of the three embryonic germ layers ( ectoderm, mesoderm, and endoderm) AND be able to list the general derivatives of each layer (Note: the neural crest is sometimes considered a "4th germ layer" but recall that it is derived from the neural plate and is therefore ultimately derived from ECTODERM.).Understand the spatial relationship and functional role of extramembryonic structures such as:.Caudal agenesis (“sirenomelia”), (and VATER/VACTERL sequence).Understand the etiology of birth defects that would arise due to perturbation(s) in the processes listed above, such as:.Placentation and formation of embryonic membranes.Embryonic folding and body wall closure.Understand the general processes that occur in the early embryo AND the approximate time in development at which they occur such as:.Click here to launch the Simbryo Early Embryogenesis animation (and some really trippy music -you'll understand once the window opens.)