Embryology USMLE Step 1 Quiz with complete solutions | Latest 2023/2024

Embryology USMLE Step 1 Quiz with complete solutions | Latest 2023/2024 where is sonic hedgehog gene produced? what axis is it responsible in patterning? -- base of limbs in the zone of polarizing activity; ant-post what gene is produced in the zone of polarizing activity? -- Sonic Hedgehog where is Wnt 7 gene produced? -- apical ectodermal ridge where is the apical ectodermal ridge? -- thickened ectoderm at end of each developing limb what axis is Wnt 7 responsible for developing? -- dorsal ventral axis where is the FGF gene produced? what is it responsible for- how does it do this? -- apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm what is the homeobox gene responsible in developing? (what axis) -- cranio-caudal; segmental where does fertilization occur? -- ampulla what is a zygote? -- sperm plus egg when does hCG secretion take place? with what event? -- day 6; with implantation where does the blastocyst implant in the uterus? during what phase of the menstrual cycle? -- post. sup wall; luteal phase what secretes hCG? -- synctiotrophoblast when does the blastocyst split into two disks? what is this disk called? what are the two germ layers called? -- week 2; bilaminar disk; epiblast and hypoblast within what week does gastrulation occur? what is gastrulation? -- week 3; primitive streak formation from the epiblast makes the three layers what is the primitive streak? from what layer does it form? -- mesoderm; epiblast what layer is the epiblast? hypoblast? -- ectoderm; endoderm what is the notochord? what does the notochord later become? -- mesoderm; nucleous pulposos what is the prochordal plate? -- where the epiblast and hypoblast fuse when does the notochord form? and when does the neural plate form? -- mesoderm; 3 week what is the neural plate and from what does it form? -- ectoderm when does the neural tube form and from what does it form? -- neural plate; closes by week 4 what are the neural crest cells and where do they come form? where do they go? -- they are the edge of neural plate folding; all over the body By what week is the neural tube supposed to be closed? when did it start forming? -- week 4; week 3 T/F the spinal cord is made from ectoderm -- ... T/F the neural crest cells are made from mesoderm -- false T/F the neural plate is mesoderm -- false T/F the notochord is mesoderm -- true what three layers form during gastrulation? from wh