Practice Quiz - Embryonic Period (Weeks 3-8)

  1. Both the neurenteric canal and the notochordal plate are present in the conceptus at the same time.
    true
    false
  2. Much of the intraembryonic coelom forms within paraxial mesoderm.
    true
    false
  3. The primitive streak first appears at the beginning of the ___ week.
    first
    second
    third
    fourth
    fifth
  4. Which of the following structures is believed to be a primary organizer or inducer during organogenesis?
    somites
    notochord
    metanephric blastema
    lens placode
    none of the above
  5. Cells from the primitive streak DO NOT become:
    endoderm
    intermediate mesoderm
    paraxial mesoderm
    lateral plate mesoderm
    amnioblasts
  6. The primitive streak:
    is derived from the outer cells of the morula
    is formed during the second week in development
    persists as the cloacal membrane
    is the site of involution of epiblast cells to form mesoderm
    was done in a bathing suit, for those who remember streaking
  7. Teratomas are:
    the product of teratogens
    malformed fetuses
    a type of tumor containing tissue from all germ layers
    derived from trophoblast
    none of the above
  8. Identify the correct association:
    adrenal cortex - ectoderm
    blood vessels of the stomach - endoderm
    lung epithelium - mesoderm
    olfactory epithelium - brain
    liver parenchyma (functional cells) - endoderm
  9. 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
  10. 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
  11. At the caudal end of the primitive streak, ectoderm and endoderm fuse as the:
    notochordal canal
    coelom
    cloacal membrane
    neural groove
    notochord
  12. Intraembryonic mesoderm differentiates into the:
    yolk sac
    neural tube
    intermediate mesoderm
    primordial germ cells
  13. The lining of the _____________ forms the lining of the embryonic gut.
    ectoderm
    hypoblast
    blastocyst
    trophoblast
    syncytiotrophoblast
    cytotrophoblast
    blastocoele
    inner cell mass
    notochord
    extraembryonic mesoderm
    primary yolk sac
    amniotic cavity
    intraembryonic coelom
    secondary yolk sac
  14. All of the essential features of external body form are completed by the end of the ____ week.
    third
    fourth
    fifth
    sixth
    eighth
  15. "Quickening" or the period when fetal movements are commonly first felt by the mother occurs:
    near the end of the first trimester
    around the middle of the second trimester
    at the end of the second trimester
    at the end of the embryonic period
    at the end of the fetal period
  16. Mesoderm lateral to the notochord:
    is derived from hypoblast
    differentiates into ganglia
    migrates cranial to prochordal plate
    induces endoderm differentiation
  17. The following organs are derived from mesoderm EXCEPT:
    skeletal musculature
    musculature of blood vessels
    cardiac musculature
    suprarenal cortex
    suprarenal medulla
  18. Paraxial (somitic) mesoderm gives rise to:
    muscle in the stomach
    vertebrae
    muscles of mastication
    skeletal muscle in the trunk and extremities
    more than one of the above
  19. The endodermal germ layer gives rise to the epithelium and wall of the gastrointestinal tract.
    true
    false
  20. Somites:
    differentiate into myotomes which give rise to skeletal muscle in trunk and limbs
    differentiate into sclerotomes which give rise to vertebrae
    arise from segmentation of the paraxial mesoderm
    differentiate into myotomes which give rise to skeletal muscle of the limbs
    all of the above are correct
  21. Following are four structures together with a germ layer. Identify the INCORRECT association:
    epithelium of pancreas - endoderm
    hair - ectoderm
    bone - mesoderm
    heart - mesoderm
    epithelium of lung - mesoderm
  22. Of the following, which is derived from endoderm?
    muscle
    kidney
    gonads
    tonsils
    hair
  23. Which of the following structures is NOT derived from mesenchyme?
    muscle fiber
    cartilage of the limbs
    white blood cell precursor
    epidermis
    blood vessel
  24. Of the following, which is derived from endoderm?
    hypophysis
    epithelium of pharynx
    epithelium of anal canal
    enamel of the teeth
    muscle
  25. During the period of development of the major organ systems, development and differentiation appear first in what region?
    head
    tail
    mid-embryo
    distal third
    mid-third
  26. At the beginning of the fourth week, day 22, there are about 7-10 somites present. About how many are there at the end of the fourth week, day 28?
    7-10
    10-13
    20-23
    26-29
    42-44
  27. Almost all of the internal organs are well laid down at _________ months.
    1
    2
    3
    4
    5
  28. The space between the split layers of mesoderm is the:
    amniotic cavity
    blastocele
    foregut
    hindgut
    none of the above
  29. Which of the following are NOT distinctive characteristics of the fourth week of development?
    neuropores
    somites
    branchial arches
    lower limb buds
    hand plates
  30. During human embryonic development:
    the inner cell mass develops into the fetal portion of the placenta
    the yolk sac stores nutrients for the first four weeks of development
    the allantois stores waste products
    the location of cells in the morula dictates their fate
  31. Which of the following structures does not turn under onto the ventral surface of the embryo during folding of the head?
    prochordal plate
    heart
    notochord
    pericardial cavity
    septum transversum
  32. At birth, the crown-rump length of the newborn averages _______ cm.
    19
    28
    35
    44
    52
  33. The embryo is called a fetus after the:
    third week
    second month
    third month
    fourth month
    sixth month
  34. Lanugo covers the body, some head hairs show, and fetal movements are felt by the mother when the fetus is about how many months old?
    5
    6
    7
    8
    9
  35. Which of the following statements about fetal age and weight shows a normal relationship?
    8 weeks - 10 gm.
    12 weeks - 200 gm.
    20 weeks - 800 gm.
    26 weeks - 1000 gm.
    38 weeks - 4600 gm.
  36. Which of the following structures is derived from paraxial mesoderm of the cervical region?
    enamel of the teeth
    smooth muscle of the gut
    mucous lining of the larynx
    sympathetic chain ganglia
    ureter
    suprarenal medulla
    patella
    skeletal muscle of the upper limb
    heart
    lining of the lungs
    spinal cord
    parenchyma of the pancreas
    eleventh thoracic vertebra
    aortic arch
  37. Which of the following is derived from the splanchnic layer of the lateral plate mesoderm?
    enamel of the teeth
    smooth muscle of the gut
    mucous lining of the larynx
    sympathetic chain ganglia
    ureter
    suprarenal medulla
    patella
    skeletal muscle of the upper limb
    parietal peritoneum
    lining of the lungs
    spinal cord
    parenchyma of the pancreas
    eleventh thoracic vertebra
    aortic arch
  38. Which of the following is derived from the intermediate mesoderm?
    enamel of the teeth
    smooth muscle of the gut
    mucous lining of the larynx
    sympathetic chain ganglia
    ureter
    suprarenal medulla
    patella
    skeletal muscle of the upper limb
    parietal peritoneum
    lining of the lungs
    spinal cord
    parenchyma of the pancreas
    eleventh thoracic vertebra
    aortic arch
  39. During the fourth week in development, the growth of head, tail and lateral folds transform the flat germ disc into a tubular embryo.
    true
    false
  40. What process converts the bilaminar disc into the trilaminar embryonic disc consisting of ectoderm, mesoderm, and endoderm?
    somitogenesis
    transformation
    gastrulation
    neurulation
  41. What is the significance of primitive streak?
    It allows for the differentiation between the three layers of trilaminar disc.
    It allows for differentiation between caudal and cranial ends of epiblast.
    It specifically extends cranially and caudally to form oropharyngeal membrane and cloacal membrane.
    It forms the 4 limbs of the body.
    B and C
  42. At end of third week, somites begin to develop along the notochord and neural tube. What do they end up forming?
    axial skeleton
    brain
    spinal cord
    sympathetic chain ganglia
    limbs