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Unit 1 Embryo Question and Solutions Module

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Unit 1 Embryo Question and Solutions Module So you think you know embryology? Unit 1 Embryology Clinically Oriented Anatomy (COA) Texas Tech University Health Sciences Center Created by Boone Coleman, Fall 2019 [email protected] Solutions 1. D 10. E 21. C 31. D 2. A 11. A 22. D 32. A 3. E 12. A 23. D 33. C 13. C 24. B 34. C 4. E 14. C 25. B 5. C 15. A 26. D 6. D 16. D 27. B 7. B 17. A 28. D 8. A 18. C 29. C 9. D 19. E 30. D 20. G Overview of weeks 1-4 • Week 1: Fertilization and Implantation • Week 2: The Week of Twos • Week 3: Gastrulation and Notochord Formation • Weeks 3-4: Neurulation and Germ Layer Derivatives, Somite formation, Cardiac looping Week 1 1. Where does fertilization of the egg occur? A. Ovary B. Internal Os of the Uterus C. Fimbriae D. Ampulla E. Isthmus Question #1 A. Ovary: releases the egg B. Internal Os of the Uterus: opening from vagina into the uterus C. Fimbriae: grab released egg from ovary D. Ampulla: Fertilization occurs in the ampulla of the oviduct E. Isthmus: caudal end of the oviduct, is jointed to the uterus. 2. What implants into the nutrient-rich endometrium (i.e. decidua) about 8-9 days after ovulation? A. Blastocyst B. Morula C. Epiblast D. Hypoblast E. Bilaminar disk Question #2 A. Blastocyst: The term decidua refers to nutrient-rich endometrium and is where the blastocyst implants usually about 9 days after ovulation with the inner cell mass facing the uterine wall. B. Morula: 16 cell embryo. Morula enters uterus and becomes the blastocyst C. Epiblast D. Hypoblast E. Bilaminar disk: embryo differentiates into the hypoblast and epiblast forming the bilaminar disk 3. What structure has to degenerate so that implantation can occur? A. Syncytiotrophoblast B. Functional layer of the endometrium C. Basal layer of the endometrium D. Cytotrophoblast E. Zona Pellucida Question #3 A. Syncytiotrophoblast B. Functional layer of the endometrium C. Basal layer of the endometrium D. Cytotrophoblast E. Zona Pellucida 4. How soon after fertilization does implantation take place? A. By 12 hours B. By 30 hours C. Day 3 D. Day 4 E. Day 6 Question #4 A. By 12 hours B. By 30 hours C. Day 3 D. Day 4 E. Day 6 5. A 23-year-old woman presents at the emergency department with moderately severe abdominal pain on her right side. She is showing some signs of internal bleeding. She is sexually active but does not use any form of contraception and missed her last menstrual period. Based on this information, which of the following disorders should be included as an option in the diagnosis? A. Ovarian cancer B. Appendicitis C. Ectopic pregnancy D. Normal pregnancy E. HIV Question #5 A. Ovarian cancer B. Appendicitis C. Ectopic pregnancy: Ectopic tubal pregnancy must always be an option in the diagnosis when a woman in her reproductive years presents with such symptoms. About ten percent of ectopic implantations occur in the uterine tube. Ectopic tubal pregnancies result in rupture of the uterine tube and internal hemorrhage, which presents a major threat to the woman’s life. The uterine tube and embryo must be surgically removed. The symptoms may sometimes be confused with appendicitis. D. Normal pregnancy E. HIV Week 2 6. The second week of development is referred to as the week of two’s because…? A. The embryoblast divides into two layers B. Two cavities form, the amniotic cavity and yolk sac C. The trophoblast organizes into two layers, the cytotrophoblast and syncytiotrophoblast D. All of the above E. A & C Question #6 A. The embryoblast divides into two layers B. Two cavities form, the amniotic cavity and yolk sac C. The trophoblast organizes into two layers, the cytotrophoblast and syncytiotrophoblast D. All of the above: All of these occur in the week of two’s, hence the name E. A & C 7. Which two embryological structures together form the bilaminar disk? A. Cytotrophoblast and Hypoblast B. Hypoblast and Epiblast C. Epiblast and Cytotrophoblast D. Syncytiotrophoblast and Inner cell mass E. Epiblast and Embryoblast Question #7 A. Cytotrophoblast and Hypoblast B. Hypoblast and Epiblast: The inner cell mass or embryoblast differentiates into: 1) the hypoblast and the epiblast (together these form a bilaminar disk). C. Epiblast and Cytotrophoblast D. Syncytiotrophoblast and Inner cell mass E. Epiblast and Embryoblast 8. Chemotherapy treatment often targets mitotically active cells. Although this treatment is beneficial for cancer, it can negatively effect implantation and embryonic growth. Which of the following layers would be most affected by a slowed cell division rate? A. Cytotrophoblast B. Epiblast C. Amnioblast D. Syncytiotrophoblast E. Hypoblast Question #8 A. Cytotrophoblast: The trophoblast forms the fetal part of the placenta and is involved with implantation. The cytotrophoblast is the mitotically active inner part of the trophoblast, and provides the cells that migrate into the syncytiotrophoblast to allow it to expand. Thus, chemotherapy may directly affect mitotic activity in the cytotrophoblast possibly hindering implantation. B. Epiblast: The epiblast is not involved in implantation, it is the dorsal cell layer of the bilaminar germ disc which contributes to the formation of the embryo proper C. Amnioblast: Amnioblasts are not involved in implantation. Amnioblasts are Epiblast cells that line the amniotic cavity adjacent to the cytotrophoblast and are mitotically active in the growth of the amniotic membrane. D. Syncytiotrophoblast: The syncytiotrophoblast is a mitotically inactive outer, multinucleated part of the trophoblast that erodes the maternal endometrium and contributes to primitive uteroplacental circulation. E. Hypoblast: The hypoblast is the ventral cell layer of the bilaminar germ disc which contributes to the formation of the embryo proper 9. Which of the following develops from the multi- nucleated syncytium, the syncytiotrophoblast and serves as the beginnings of gas exchange between mother and embryo? A. Bilaminar disk B. Cytotrophoblast C. Amniotic cavity D. Lacunae Question #9 A. Bilaminar disk: made of the epiblast and hypoblast B. Cytotrophoblast: inner layer of mononucleated proliferative cells of the trophoblast and is not involved in gas exchange C. Amniotic cavity: a small cavity appears within the epiblast, which enlarges to become the amniotic cavity. Contains the amniotic fluid. D. Lacunae: part of the syncytiotrophoblast and are spaces that fill with maternal blood. Site of exchange of nutrients and gases. 10. The placenta is part of the chorion. The chorion consists of which of the following? A. Extraembryonic mesoderm B. Cytotrophoblast C. Hypoblast D. All of the above E. A & B Question #10 A. Extraembryonic mesoderm B. Cytotrophoblast C. Hypoblast D. All of the above E. A & B: The chorion consists of extraembryonic mesoderm, cytotrophoblast, and syncytiotrophoblast. 11. The amniotic cavity forms during the process of implantation of the blastocyst. The amniotic cavity forms within which of the following structures? A. Epiblast B. Cytotrophoblast C. Syncytiotrophoblast D. Maternal endometrium E. Hypoblast Question #11 A. Epiblast B. Cytotrophoblast C. Syncytiotrophoblast D. Maternal endometrium E. Hypoblast Week 3 12. Which of the following cells form endoderm and mesoderm? A. Migrating epiblast cells B. Migrating hypoblast cells C. Non-migrating epiblast cells D. Non-migrating hypoblast cells E. Neural crest cells Question #12 A. Migrating epiblast cells: Epiblast cells move into the primitive streak and primitive node to form endoderm and mesoderm. Non- migrating epiblast cells form ectoderm. B. Migrating hypoblast cells: hypoblast cells do not migrate C. Non-migrating epiblast cells D. Non-migrating hypoblast cells: are separated by epiblast cells to form endoderm E. Neural crest cells 13. The notochord develops from which of the following embryonic germ layers? A. Endoderm B. Ectoderm C. Mesoderm D. Neuroectoderm E. Neural crest cells Question #13 A. Endoderm B. Ectoderm C. Mesoderm: In addition to gastrulation, the notochord develops from the newly acquired mesoderm. This structure will induce the formation of the neural plate (neuroectoderm). D. Neuroectoderm E. Neural crest cells 14. Which week of embryonic development usually corresponds to the first missed menstrual period? A. Week one B. Week two C. Week three D. Week four E. None of the Above Question #14 A. Week one B. Week two C. Week three: High yield fact sheet - “During the third week of development, the process of gastrulation beginning with the formation of the primitive streak and primitive node at the cephalic (head) end of the embryo. Third week usually corresponds to first missed menstrual period.” D. Week four E. None of the Above Week 4 15. Neural crest cells develop during a process known as neurulation. These cells can ultimately form which of the following? A. Melanocytes B. Lymphocytes C. Somites D. All of the above Question #15 A. Melanocytes: During neurulation, neural crest cells develop. These cells will ultimately form melanocytes (pigmenting cells of the skin), sensory ganglia, Schwann’s cells, and others B. Lymphocytes: hematopoietic stem cells C. Somites: comes from paraxial mesoderm D. All of the above 16. The neural tube and plate forms from: A. Intermediate mesoderm B. Paraxial mesoderm C. Neural crest cells D. Neuroectoderm E. Endoderm Question #16 A. Intermediate mesoderm B. Paraxial mesoderm C. Neural crest cells D. Neuroectoderm E. Endoderm 17. Somites form from which of the following embryological derivations? A. Paraxial mesoderm B. Lateral plate mesoderm C. Neural crest cells D. Endoderm E. Ectoderm Question #17 A. Paraxial mesoderm: will become segmented into sclerotomes (head region) & somites (from occipital region onwards) B. Lateral plate mesoderm: bones of the shoulder and pelvic girdles and limbs come from parietal layer of lateral plate mesoderm), myotomes (muscle), and dermatomes (skin). C. Neural crest cells D. Endoderm E. Ectoderm 18. In a growing embryo, the vertebrae encase notochord and neural tube in a solid bone like structure.
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