2nd + 3rd weeks

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Marine
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2nd + 3rd weeks
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2015-02-08 07:48:11
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2nd + 3rd weeks
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  1. Much of intraembryonic coelom forms within
    paraxial mesoderm:

    True.

    False.
    false
  2. Both the neurenteric canal and the notochordal
    plate are present in the conceptus at the same time:
    A.True.
    B.False
    true
  3. The completion of interstitial implantation, so that the conceptus is
    entirely within the endometrium occurs:

    A)On about the 20 day.

    B)By about day 11.

    C)By the end of the first week.

    D)By erosion of the myometrial lining.

    E) As a result of endometrial proliferation.
    B
  4. The amniotic cavity develops:
    A)On the tenth day
    B)Within the outer cell mas.
    C)Within the inner cell mass near the cytotrophoblast.
    D)In extraembryonic mesoderm.
    E) around the 8th day
    C. E
  5. During the second week of development
    the trophoblast differentiates into:
    A)Syncytiotrophoblast.
    B)Ectoderm.
    C)Intraembryonic mesoderm.
    D)Yolk sac (secondary)
    E)Cytotrophoblast
    A. E
  6. Major events beginning on the second week of
    development include:

    a)Notochord differentiation.

    b)Somite formation.

    c)Angiogenesis.

    d)Yolk sac development.
    d) yolk sac development

    c)Angiogenesis ?
  7. The first two intraembryonic germ layers to
    differentiate are:

    Ectoderm and hypoblast.

    Epiblast and hypoblast.

    Ectoderm and ectoderm.

    Ectoderm and mesoderm.
    epiblast and hypoblast
  8. From where and when do epiblast+hypoblast develop?
    • from inner cell mass
    • 2nd week
  9. The blastocele becomes the:

    Amniotic cavity.

    Extraembryonic coelom.

    Primary yolk sac.

    Chorionic cavity.

    Secondary cavity.
    Primary yolk sac
  10. when and how is the exocoelomic or Heuser's membrane formed?
    • around the 9th day.
    • cells from the hypoblast spread around the blastocoele.
  11. how does the blastocoele become the primary yolk sac?
    when the blastocoele is surrounded by the exocoelomic membrane
  12. Extraembryonic somatic mesoderm is in
    close association with what?

    1.Syncytiotrophoblast.

    2.Cytotrophoblast and amnion.

    3.Yolk sac.

    4.Syncytiotrophoblast and
    Cytotrophoblast.
    2 .cytotrophoblast and amnion
  13. From what does the extraembryonic somatic mesoderm arise?
    • cytotropblast
    • hypoblast
  14. Extraembryonic SPLANCHNIC mesoderm is in close association with what?
    yolk sac
  15. Cytotrophoblast cells become what?

    1.Secondary yolk sac.

    2.Amnioblasts.

    3.Exocoelomic membrane.

    4.Syncytiotrophoblast.
    4. Syncytiotrophblast
  16. the secondary yolk sac comes from where?
    endoderm
  17. the amnioblasts come from where?
    epiblast
  18. the exocoelomic membrane comes from what?
    hypoblast
  19. The yolk sac in the human embryo...?

    Does not contribute to the embryonic gut.

    Is devoid of hematopoietic, or blood cell
    formation.

    Is the site of primordial germ cell production.

    Stores nutrients throughout pregnancy.

    the endodermal lining of the definitive yolk sac becomes the lining of gut tube
    is the site of primordial germ cell production

    the endodermal lining of the definitive yolk sac becomes the lining of gut tube
  20. when does the DEFINITIVE yolk sac form?
    end of the 2nd week
  21. The bilaminar germ disc:

    Consists of epiblast and mesoblast.

    Is derived from outer cells of the morula.

    Forms the embryo proper.

    Synthesizes human chorionic gonatropin.

    Develops from the inner cells of the morula and inner cells mass of blastocyst

    AKA embryoblast
    forms the embryo proper

    Develops from the inner cells of the morula and inner cells mass of blastocyst


    aka embryoblast because it becomes the embryo
  22. what's the composition of the bilaminar germ disc?
    epiblast and hypoblast
  23. The definitive yolk sac of the embryo appears by
    what day?

    13th.

    26th.

    72nd.

    94th.

    2nd.
    • 13 th day 
    •  the definitive yolk sac is formed by the hypoblast cells that line the inside of the exocoelomic membrane
  24. The amniotic cavity appears as a slit-like space
    near the embryonic polar trophoblast and within the:

    Extraembryonic cavity.

    Exocoelomic membrane.

    Inner cell mass.

    Connecting body stalk.

    Cytotrophoblast.

    begins to appear in the begining of the 8th day
    • inner cell mass
    • begins to appear in the begining of the 8th day
    • the cells that line this cavity are called amnioblasts and form the amnion
  25. During the second week of development, the
    embryonic disk is composed of:

    Ectoderm.

    Ectoderm and mesoderm.

    Endoderm.

    Epiblast and hypoblast.

    Ectoderm, mesoderm and endoderm.
    • epiblasts and hypoblast
    • in the 2nd week , you still have a bilaminar germ disc because the primitive streak has not yet formed, allowing for invagination and formation of mesoderm .
  26. The part of the 13th day embryoblast
    from which the embryo proper is formed:

     Lies between the amniotic cavity snd the yolk sac.

    Also contributes to the roof of the yolk sac.

    Is composed of two primary germ layers.

    Is attached to the amnion.
    • Lies between the amniotic cavity snd the yolk sac.
    • Also contributes to the roof of the yolk sac.
    • Is composed of two primary germ layers.
    • Is attached to the amnion.( amnion attaches to or is contunous with the margins of the epiblast layer )
  27. The cloacal membrane consists of what?

    Embryonic endoderm, mesoderm and ectoderm.

    Endoderm of the roof of the yolk sac and embryonic ectoderm.

    A spherical area of endoderm fused to embryonic mesoderm.

    The prechordal plate and the overlying embryonic endoderm.
    endoderm of the roof of the yolk sac and embryonic ectoderm
  28. what are the places at which the ectoderm and endoderm are in direct aposition ?
    • cloacal membrane
    • prochordal membrane
    • in this areas . the embryonic ectoderm is fused with the endoderm of the roof of the wolk sac and embryonic ectoderm
  29. The amniotic cavity develops:

    On the 10th day.

    Within the inner cell mass.

    Between inner cell mass and trophoblast.

    In the extraembryonic mesoderm.

    Between 2 layers of cytotrophoblast.
    within the inner cell mass
  30. Which statement about the 14-day blastocyst is
    NOT true?

    Villi are absent.

    Extraembryonic coelom surrounds the yolk sac.

    Primitive uteroplacental circulation is
    established.

    Extraembryonic mesoderm is split into two layers.
    villi are absent
  31. The primitive streak first appears at the
    beginning of the _____ week.

    First.

    Second.

    Third.

    Fourth.

    Fifth.
    third
  32. gastrulation occurs during which week?
    3rd week
  33. Which of the following structures is
    believed to be a primary organizer or inducer during organogenesis?

    Somites.

    Notochord.

    Metanephric
    blastema.

    Lens placode.
    notochord
  34. notochord is though to induce development , among others, of what?
    • nervous system
    • axial skeleton
  35. Cells from the primitive streak do not become:

    Endoderm.

    Intermediate mesoderm.

    Paraxial mesoderm.

    Lateral plate mesoderm.

    Amnioblasts.
    amnioblasts
  36. all mesoderm is a derivative of what?
    invaginating cells at the primitive streak
  37. The primitive streak:

    Is derived from the outer cells of the morula.

    Is formed during the second week of development.

    Persists as the cloacal membrane.

    Is the site of involution of epiblast cells to
    form mesoderm.

    Was done in bathing suit for those who remember streaking.
    • is the site of involution of epiblast cells to form mesoderm.
    • this process is known as gastrulation
  38. when and where does the primitive streak begin to form?
    • in the surface of the epiblast 
    • begining of the 3rd week
  39. Teratomas are:

    The products of teratogens.

    Malformed fetuses.

    A type of tumor containing tissue from all germ
    layers.

    Derived from trophoblast.

    Can be found in the sacrococcygeal area ( if they arise from remnants of the primitive streak)
    • a type of tumor containing tissue from all germ layers
    • can be found in the sacroccoxygeal area
  40. Identify the correct association:

    Adrenal cortex – ectoderm.

    Blood vessels of the stomach - endoderm.

    Lung epithelium – mesoderm.

    Olphactory epithelium – brain.

    Liver parenchyma (functional cells) – endoderm.
    liver parechyma ( functional cells)- endoderm.

    • the adrenal cortex and blood vessels of the stomach are derived from mesoderm.
    • the lung epithelium is endoderm
  41. In the third week of human embryonic development:

    The amnion appears.

    A bilaminar embryonic disc is formed.

    The body stalk moves ventrally and joins with the
    yolk sac stalk to form the umbilical cord.

    The neural plate is induced by the notochordal
    process and associated mesoderm.

    The uteroplacental circulation is established.
    the neural plate is induced by the notochordal process and associated mesoderm
  42. During development, the notochordal process:

    Arises from involuting endodermal cells.

    Extends from the prochordal plate to the
    primitive node.

    Is involved in the induction of the primitive
    gut.

    Becomes the appendicular skeleton.
    extends from the prochordal plate to the primitve node
  43. in adults, the notochord exists as what?
    nucleus pulposus of the intervertebral discs
  44. At the caudal end of the primitive
    streak, ectoderm and endoderm fuse as the:

    Notochordal canal. 

    Coelom.

    Cloacal membrane.

    Neural groove.

    Notochord.
    cloacal membrane
  45. At the cranial end of the primitive streak, ectoderm and endoderm fuse as the:

    Notochordal canal. 

    Coelom.

    Cloacal membrane.

    Neural groove.

    Notochord.

    prochordal membrane
    prochordal membrane
  46. Intraembryonic mesoderm differentiates into:

    Yolk sac.

    Neural tube.

    Intermediate mesoderm.

    Primordial germ cells.


    Somites

    Lateral plate mesoderm
    • intermediate mesoderm
    • somites
    • lateral plate mesoderm
  47. The lining of the _______ forms the lining of the embryonic gut.

    Ectoderm.

    Hypoblast.

    Blastocyst.

    Trophoblast.

    Syncytiotrophoblast.

    Cytotrophoblast.

    Blastocele.

    Inner cell mass.

    Notochord.

    Extraembryonic mesoderm.

    Primary yolk sac.

    Amniotic cavity.

    Intraembryonic coelom.

    Secondary yolk sac.
    secondary yolk sac
  48. The _____ gives rise to the extraembryonic mesoderm.

    Ectoderm.

    Hypoblast.

    Blastocyst.

    Trophoblast.

    Syncytiotrophoblast.

    Cytotrophoblast.

    Blastocele.

    Inner cell mass.

    Notochord.

    Extraembryonic mesoderm.

    Primary yolk sac.

    Amniotic cavity.

    Intraembryonic coelom.

    Secondary yolk sac.
    • cytotrophoblast
    • hypoblast
  49. Which layer of the bilaminar embryonic disc forms part of the lining of the amniotic cavity?

    se Ectoderm.

    Hypoblast.

    Blastocyst.

    Trophoblast.

    Syncytiotrophoblast.

    Cytotrophoblast.

    Blastocele.

    Inner cell mass.

    Notochord.

    Extraembryonic mesoderm.

    Primary yolk sac.

    Amniotic cavity.

    Intraembryonic coelom.

    Secondary yolk sac.
    epiblast
  50. What happens to the blastocyst during implantation?
    It collapses

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