Bilaminar Embryo: Embryology Quiz

29 Questions | Total Attempts: 74

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Bilaminar Embryo: Embryology Quiz

What do you know about the Bilaminar Embryo? The two-layered embryo describes the inner cell mass separating to form an initial two-layered structure. In human development, this occurs during the second week. The epiblast layer will then develop most of the embryo. Recreating the human embryo at implantation is essential for a successful pregnancy. This fascinating quiz will explain to you about the bilaminar embryo.


Questions and Answers
  • 1. 
    The blastocyst is weakly attached to the uterine wall during apposition via what structure(s)?
    • A. 

      Pinopodes

    • B. 

      Microvilli

    • C. 

      Sterocilia

    • D. 

      Pseudopodes

  • 2. 
    The strong attachment of the blastocyst to the uterine wall during adhesion is made via:
    • A. 

      Integrin proteins

    • B. 

      Extracellular matrix proteins

    • C. 

      Microvilli

    • D. 

      Proteases

  • 3. 
    Which of the following best describes a syncytium?
    • A. 

      A multinucleated mass of cytoplasm resulting from the fusion of mononucleated cells

    • B. 

      The formation of a hard mass of trophoblasts due to only paternal DNA present in zygote after fertilization

    • C. 

      Layer of mitotically active cells that line the embryoblast and blastocystic cavity

    • D. 

      A protein that facilitates the migration of the blastocyst through the uterine epithelium

  • 4. 
    What is the function of epiblast cells?
    • A. 

      Gives rise to embryo

    • B. 

      Forms amniotic membrane

    • C. 

      Secretes hCG and progesterone to maintain placenta

    • D. 

      To penetrate through the Fallopian tubes in order to implant into the uterus

  • 5. 
    At about what point does the primary yolk sac begin to develop?
    • A. 

      Day 8

    • B. 

      Day 2

    • C. 

      Day 15

    • D. 

      Day 14

  • 6. 
    Which of the following best describes what occurs during the epithelial to mesenchymal transformation?
    • A. 

      Cells become long, spindle shaped cells with invasive motility

    • B. 

      Cells become columnar to prepare for secretion of hormones

    • C. 

      Cells become cuboidal in order to create a protective lining for the developing embryo

    • D. 

      Cells become endothelial cells to line the newly forming placental blood vessels

  • 7. 
    What marker(s) differentiate mesenchymal cells from epithelial cells? (which are present on mesenchymal cells)
    • A. 

      Vimentin

    • B. 

      N-cadherin

    • C. 

      E-cadherin

    • D. 

      Desmoplakin

  • 8. 
    At about what point is the extraembryonic mesoderm formed?
    • A. 

      Day 11

    • B. 

      Day 35

    • C. 

      Day 4

    • D. 

      Day 7

  • 9. 
    The hypoblast cells can differentiate in which cell type(s)?
    • A. 

      Exocoelomic membrane

    • B. 

      Mesenchymal cells

    • C. 

      Extraembryonic endoderm

    • D. 

      Extraembryonic membrane

    • E. 

      Somatopleuric cells

    • F. 

      Syncytiotrophoblast cells

  • 10. 
    The secondary yolk sac is lined by:
    • A. 

      Extraembryonic endoderm

    • B. 

      Splanchnopleuric mesoderm

    • C. 

      Exocoelomic cysts

    • D. 

      Hypoblast cells

  • 11. 
    The chorionic plate consists of what structures?
    • A. 

      Extraembryonic somatopleuric mesoderm

    • B. 

      Cytotrophoblast

    • C. 

      Syncytiotrophoblast

    • D. 

      Connecting stalk

    • E. 

      Extraembryonic splanchnopleuric mesoderm

  • 12. 
    Where does the development of blood cells first begin in utero?
    • A. 

      Extraembryonic splanchnopleuric mesoderm

    • B. 

      Liver

    • C. 

      Bone marrow

    • D. 

      Proximal ends of long bones

  • 13. 
    Blood cell formation at week 6 begins where?
    • A. 

      Liver

    • B. 

      Extraembryonic splanchnopleuric mesoderm

    • C. 

      Bone marrow

    • D. 

      Distal ends of long bones

  • 14. 
    The primary stem villi begin to form by:
    • A. 

      Day 11

    • B. 

      Day 3

    • C. 

      Day 24

    • D. 

      Day 5

  • 15. 
    The placenta goes through a couple of stages to mature. At around which week is primitive placenta established?
    • A. 

      Week 3

    • B. 

      Week 1

    • C. 

      Week 2

    • D. 

      Week 4

  • 16. 
    The arteriocapillary networks that are formed in the primitive placenta become connected to the embryonic heart through:
    • A. 

      Vessels in the extraembryonic mesoderm of chorion and connecting stalk

    • B. 

      Cytotrophoblasts creating long vessels 

    • C. 

      Syncytiotrophoblasts lining long vessels

    • D. 

      Primary stem villi

  • 17. 
    What is a likely cause of ectopic pregnancy?
    • A. 

      Uterine damage caused by inflammation due to PID

    • B. 

      Ectopic pregnancies are spontaneous, random events

    • C. 

      Implantation of zygote in uterus

    • D. 

      Previous Cesarean sections

  • 18. 
    Most ectopic pregnancies occur where?
    • A. 

      Fallopian tubes

    • B. 

      Abdomen

    • C. 

      Placenta

    • D. 

      Cervix

  • 19. 
    What is the cause of placenta previa?
    • A. 

      Implantation of zygote occurs in the internal os of cervix

    • B. 

      Implantation of zygote in Fallopian tubes

    • C. 

      Complete blockage of vaginal opening due to disorganized mass of placental derivatives

    • D. 

      Severe abdominal pain

  • 20. 
    Complete hydatidiform moles are mostly composed of:
    • A. 

      Trophoblast cells

    • B. 

      Syncytiotrophoblast cells

    • C. 

      Blastocyst cells

    • D. 

      Hypoblast cells

  • 21. 
    The majority of complete hydatidiform mole cases are associated with:
    • A. 

      2 sets of paternal chromosomes

    • B. 

      2 sets of maternal chromosomes

  • 22. 
    What is the common cause of a partial hydatidiform mole?
    • A. 

      Dispermy

    • B. 

      Dipliody

    • C. 

      2 sets of chromosomes of maternal origin

    • D. 

      Methotrexate

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