Deck 5: Formation of Germ Layers and Early Derivatives

Question 1

Which of the following tissues is not dependent on the proper functioning of the primitive streak?

A)Ectoderm
B)Notochord
C)Endoderm
D)Mesoderm
E)Amnion

Answer 1

E

Question 2

The principal inductor in primary neural induction is the ____________.

A)Hypoblast
B)Primitive streak
C)Extraembryonic mesoderm
D)Notochordal process
E)Embryonic ectoderm

Answer 2

D

Question 3

The major organizing center of the gastrulating embryo is the ___________.

A)Inner cell mass
B)Primitive streak
C)Primitive node
D)Oropharyngeal membrane
E)Paraxial mesoderm

Answer 3

C

Question 4

In the early embryo,what molecule facilitates the migration of mesenchymal cells between the ectoderm and the endoderm?

A)Chondroitin sulfate
B)Hyaluronic acid
C)ZP3
D)Interleukin-2
E)Oct-3

Question 5

Induction of the central nervous system is brought about by the action of the ___________ on the overlying ectoderm.

A)Hypoblast
B)Chordamesoderm (notochord)
C)Primitive streak
D)Embryonic endoderm
E)Body stalk

Question 6

Which cell adhesion molecule(s)rely(ies)heavily on Ca++ for its function?

A)N-CAM
B)E-cadherin
C)Integrin
D)All of the above
E)None of the above

Question 7

Precursor cells of which of the following embryonic tissues pass through the primitive streak?

A)Cytotrophoblast
B)Neural crest
C)Yolk sac endoderm
D)Amniotic ectoderm
E)None of the above

Question 8

Precursor cells of which of the following embryonic tissues pass through the primitive streak?

A)Cytotrophoblast
B)Syncytiotrophoblast
C)Yolk sac endoderm
D)Amniotic ectoderm
E)None of the above

Question 9

A key molecule in the determination of body asymmetry is ________________.

A)Retinoic acid
B)Notch
C)Nodal
D)Bone morphogenetic protein
E)None of the above

Question 10

Neural induction molecules act by blocking the inhibitory action of _________ in the dorsal ectoderm.

A)Bone morphogenetic protein-4
B)Noggin
C)Chordin
D)Fibroblast growth factor
E)Lim-1

Question 11

The absence of which molecule results in an embryo missing the anterior part of the head?

A)Retinoic acid
B)Lim-1
C)Bone morphogenetic protein-4
D)Chordin
E)None of the above

Question 12

Which of the following tissues arise from cells passing through the primitive streak?

A)Embryonic endoderm
B)Hypoblast
C)Cytotrophoblast
D)Primary yolk sac
E)Amnion

Question 13

Neural induction occurs through the blocking of what inhibitory molecule?

A)Bone morphogenetic protein-4
B)Activin
C)Sonic hedgehog
D)N-CAM
E)Chordin

Question 14

As embryonic mesodermal cells pass through the primitive streak,they find themselves in an extracellular environment that is rich in _____________.

A)Histones
B)Hyaluronic acid
C)Protamines
D)All of the above
E)None of the above

Question 15

Which of the structures below will induce a secondary body axis if implanted in a host embryo?

A)Hensen's node
B)Hypoblast
C)Cytotrophoblast
D)Syncytiotrophoblast
E)Amnion

Question 16

The principal inductor in primary neural induction is the _____________.

A)Hypoblast
B)Primitive streak
C)Extraembryonic mesoderm
D)Notochordal process
E)Embryonic ectoderm