Chapter 5 & 6 Flashcards

1
Q

Greek for the little stomach

A

Grastula

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2
Q

Caudal migration of epiblasts forms the ______ at the caudal midline of the blastocyst.

A

primitive streak

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3
Q

Composition of Primitive Streak

A

Hensen’s node (primitive node or primitive knot)
Primitive groove (central depression)
Primitive folds (lateral elevations)

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4
Q

What are the 3 primary germ layers?

A

Ectoderm, Mesoderm, Endoderm

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5
Q

What happens to the remaining epiblasts of the primitive streak?

A

Give rise to ectoderm

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6
Q

Migrating cells from primitive streak entering the coelom will become ______

A

Mesoderm

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7
Q

Which germ layer forms the epidermis of skin, epithelium of oral and nasal cavities, nervous system and sense organs?

A

Ectoderm

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8
Q

Which germ layer forms the muscles, connective tissues including bones and components of circulatory, urinary and genital systems?

A

Mesoderm

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9
Q

Which germ layer forms the mucosal epithelium and glands of respiratory and digestive systems?

A

Endoderm

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10
Q

When does the primitive streak in avian embryo reach its maximum length?

A

18 hours of incubation

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11
Q

Continuous migration of epiblast from the primitive streak and non-addition of new epiblasts to the primitive streaks results to ________

A

regression of primitive streak

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12
Q

Primitive streak of avian embryo disappears by _________ of incubation

A

60 hrs (2.5 days)

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13
Q

True or false in most primitive vertebrates the notochord is the chief axial supporting structure of the body.

A

True

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14
Q

True or false the formation of notochord induces the formation of the head, nervous system and somite.

A

True

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15
Q

True or false the formation of notochord does not indicate the future location of vertebral column in higher vertebrates.

A

False

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16
Q

What is the ultimate fate of the notochord?

A

Nucleus pulposus of intervertebral disc.

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17
Q

What is the Morphogenic process that gives rise to the 3 primary germ layers: ectoderm, mesoderm and endoderm?

A

Gastrulation

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18
Q

What is the stage of early embryonic development characterized by early development of CNS, formation of the head process and foregut, formation of somites and formation of cardiac tube?

A

Neurulation

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19
Q

The depressed midregion of the neural plate is called

A

neural groove

20
Q

The raised edges at the neural plate

A

neural folds

21
Q

Cavity of neural tube

A

neural canal

22
Q

Bilaterally some cells from neuroectoderm excluded during fusion of neural folds lie dorsolateral to the neural tube and constitute the ________

A

neural crest

23
Q

The neural tube give rise to _______

A

CNS, brain and spinal cord

24
Q

development of 2 or more embryos in a dam that normally gives birth to
one offspring per gestation.

A

embryonic Duplication or Twinning

25
Q

result from fertilization of separate ova.

A

Free separate symmetrical dizygotic or polyzygotic twins

26
Q

from two separate zygotes.

A

Dizygotic twins

27
Q

similar to dizygotic twins except that the number of zygotes is more than two.
Ex: triplets

A

Polyzygotic twins

28
Q

derived from a single zygote

A

Free or conjoined, symmetrical, monozygotic twins

29
Q

the zygote duplicates itself and the twins separate completely.

A

Free symmetrical monozygotic twins or identical twins -

30
Q

– the zygote incompletely divides.

A

Conjoined or fused symmetrical monozygotic twins

31
Q

are identified according to the site of attachment

A

Diplopagus or Siamese twins

32
Q

twins are attached at the sternal region facing each other with partially
fused hearts.

A

Thoracopagus

33
Q

twins are attached at the abdomen, often with partially fused
intestines

A

Abdominopagus

34
Q

twins are attached at the pelvis or sacrum back-to-back

A

Pygopagus

35
Q

twins are attached in the head region.

A

Cephalopagus

36
Q

abnormally fused symmetrical monozygotic twins where the axial structures are
duplicated

A

Monster

37
Q

two heads

A

Dicephalus

38
Q

two faces

A

Diprosopus

39
Q

two tails

A

Dicaudatus

40
Q

four thoracic limbs

A

Tetrabrachius

41
Q

four pelvic limbs

A

Tetrascelus

42
Q

originate from monozygotic or dizygotic twins. Has one normal and one rudimentary twin

A

Free asymmetrical twins

43
Q

Fused twins with one normal individual called autosite and an extra body part, the parasite
attached to it

A

Conjoined asymmetrical twins

44
Q

where an extra pelvic limb is attached to the back of the normal twin

A

Notomelus

45
Q

elliptical region of specialized thickened ectoderm is referred to as

A

neural plate

46
Q

neural folds continue to elevate, appose in
the midline, and, eventually, fuse to create the

A

neural tube