Human Development Published on August 30, 2020 by ehudspeth Human Development Which of the following is NOT true regarding organogenesis? The primordial heart comes from the lateral mesoderm The epithelia of the bronchi come from the ectoderm The lumbar vertebrae come from the paraxial mesoderm The CNS comes from the ectoderm Blood and lymphatic cells come from the lateral mesoderm A spontaneously aborted fetus was found to have malformations in the development of the primordial heart and serous membranes of the pericardium and pleura. A defect is expected to have occurred in which of the following germ layers? Endoderm Surface Ectoderm Paraxial Mesoderm Lateral Mesoderm Neural Crest Ectoderm Sclerotome differentiate to form bones, cartilage, and tendon. From which mesodermal layer do sclerotomes arise? Paraxial mesoderm Intermediate mesoderm Lateral plate mesoderm Axial mesoderm Medial plate mesoderm This is the most common form of gestational trophoblastic disease. It is characterized by trophoblastic hyperplasia, villous edema, and the absence of embryo. This is the result of fertilization of an empty oocyte by a single sperm with duplication of paternal material. What is this referred to as? Vasculogenesis Teratogenesis Hydatidiform mole Hypervitaminosis A Hypovitaminosis A A woman, approximately 2 weeks pregnant, who had just missed her menstrual period was concerned that a glass of wine she had consumed the week before may have harmed her embryo. What would you tell your patient about Fetal Alcohol Syndrome, a neurodevelopmental disorder caused by environmental teratogens? Death of the embryo may occur due to consumption of alcohol during the first week of pregnancy, the period of maximal sensitivity to abnormal development. The central nervous system will begin to develop in the third embryonic week, therefore, the embryo was not in a critical developmental phase at the time of consumption. From weeks 3-8 of development, the embryo is least susceptible to external teratogens, so the embryo is not at risk for Fetal Alcohol Syndrome. Beginning the ninth week of development, the embryo is most susceptible to external teratogens, so the embryo is not at risk for Fetal Alcohol Syndrome. An embryo is visualized possessing midgut herniation, long upper limbs and webbed fingers. A crown to rump measurement of 20 mm is observed. What is the approximate age of the fetus? Week 8, Day 54-55 Week 7, Day 49-51 Week 6, Day 44-46 Week 5, Day 41-43 Delilah just found out she’s pregnant. She has struggled with migraines since college and was put on Depakote, a valproic acid derivative. Her doctor tells her that she can no longer take this medication. Which of the following is an explanation as to why? It affects the closing of the primitive streak resulting in a sacrococcygeal teratoma It causes the notochord to pinch off into three pieces essentially resulting in three non-functional spinal cords It could cause anencephaly from the neural tube not closing completely It could cause the fetus to not form an axial skeleton It could cause the fetus to form two extra arm buds in place of their leg buds Janis went into her OBGYN after getting a positive pregnancy test. Her hCG levels were elevated but a transvaginal ultrasound did not show an embryo. Upon further examination, a hydatidiform mole was discovered. How did this happen? The female pronucleus did not participate in development The male pronucleus did not participate in development More than one sperm got through the zona pellucida She has miscarried after the embryo was attached to the uterine lining The embryo did not form enough primary chorionic villi so it did not receive the proper nutrients for development A mother brings her baby to the clinic that you are working at. You take note of the fact that the baby displays thin lip, flat nose bridge, and a short nose. Following your observations, if the baby has fetal alcohol syndrome, what is the time period during which it was most likely exposed to ethanol? The entire first trimester Weeks 1-2 Weeks 3-8 Weeks 8-12 Ethanol would not have an impact on embryonic development Which of the following happens during week two of human development? Neural tube formation Gastrulation Hypoblast forms Amniotic cavity forms Fertilization Cleft lip is a common craniofacial defect in which the roof of the mouth and the lip does not fully fuse. Although it is easily identifiable appearance-wise it generally is asymptomatic. Which layer of the trilaminar disc is affected by this defect? Endoderm Head mesoderm Lateral mesoderm Neuroectoderm Intermediate mesoderm You and a classmate know that the bladder arises from the mesodermal layer of the embryo but are arguing over which division it comes from. Which of the following is the correct origin of the bladder? Paraxial mesoderm Intermediate mesoderm Mesodermal cells of the parietal layer (lateral plate) Mesodermal cells of the visceral layer (lateral plate) Cardiogenic mesoderm Defective enamel development can be the result of an inherited condition called amelogenesis imperfecta, or congenital enamel hypoplasia, which is estimated to affect about 1 in 14,000 people in the United States. This condition can also cause unusually small teeth and a variety of dental problems. Which layer of the trilaminar disc is affected by this defect? Endoderm Head mesoderm Lateral mesoderm Neuroectoderm Intermediate mesoderm The lining of the bronchi allows for the exchange of oxygen across the membrane through the function of epithelial cells. Which of the following is the origin of this layer? Endoderm Paraxial mesoderm Intermediate mesoderm Surface ectoderm Lateral mesoderm Time is Up!