Deck 6: Establishment of the Basic Embryonic Body Plan

Question 1

Which structure consists of ectoderm directly abutting endoderm?

A)Cloacal plate
B)Amniotic membrane
C)Yolk sac
D)Neural tube
E)Placental villus

Answer 1

A

Question 2

Splanchnic mesoderm acts as an inducer of all of the tissues or organs below except:

A)Teeth
B)Trachea
C)Liver
D)Lungs
E)Pancreas

Answer 2

A

Question 3

Sonic hedgehog,secreted by the notochord,induces the formation of the ___________.

A)Prechordal plate
B)Neural crest
C)Floor plate
D)Roof plate
E)Dorsal root ganglia

Answer 3

C

Question 4

Rhombomeres are segmental divisions of the _________________.

A)Forebrain
B)Hindbrain
C)Midbrain
D)Spinal cord

Question 5

The stomodeal plate (oropharyngeal membrane)consists of _____________.

A)Ectoderm + mesoderm
B)Ectoderm + mesoderm + endoderm
C)Mesoderm + endoderm
D)Ectoderm + endoderm
E)Ectoderm only

Question 6

The primordium of which structure is located in the septum transversum?

A)Pancreas
B)Lung
C)Liver
D)Thymus
E)Spleen

Question 7

The first blood cells arise from _______________.

A)Cardiogenic mesoderm
B)Sclerotome
C)Yolk sac endoderm
D)Hindgut endoderm
E)None of the above

Question 8

The otic placode arises through an inductive message given off by the _________________.

A)Prosencephalon
B)Mesencephalon
C)Rhombencephalon
D)All of the above
E)None of the above

Question 9

A major embryonic signaling center,producing fibroblast growth factor-8 and Wnt-1 and inducing gradients of En-1 and En-2,is located at the ____________.

A)Hensen's node
B)Midbrain-hindbrain junction
C)Notochord
D)Prechordal plate
E)None of the above

Question 10

A transcription factor characterizing cells that break away from an embryonic epithelium and become migratory as mesenchymal cells is called ____________.

A)Bone morphogenetic protein-4
B)Sonic hedgehog
C)Engrailed-1
D)Slug
E)None of the above

Question 11

_____________,produced in the notochord,induces both the floor plate and the ventromedial part of the somite.

A)Wnt-1
B)Hoxb-4
C)Chordin
D)Lim-1
E)Sonic hedgehog

Question 12

An inductive stimulus from the ____________ stimulates the transformation of the epithelial sclerotome into secondary mesenchyme.

A)Neural crest
B)Dorsal aorta
C)Ectodermal placode
D)Embryonic endoderm
E)Notochord

Question 13

The dorsal pancreatic bud is initially induced from duodenal endoderm by the ___________.

A)Liver
B)Notochord
C)Lung bud
D)Yolk sac
E)None of the above

Question 14

Which of the following is a morphological manifestation of the craniocaudal segmentation of the embryo?

A)Splanchnopleure
B)Wolffian (pronephric) duct
C)Neuromere
D)All of the above
E)None of the above

Question 15

Mediated by sonic hedgehog,the notochord induces the ventromedial somite to form _______________.

A)Limb myoblasts
B)Pronephros
C)Muscle of the body wall
D)Vertebral bodies
E)Neural crest

Question 16

The oropharyngeal membrane breaks down in the early embryo because it is lacking in ________________.

A)Ectoderm
B)Mesoderm
C)Endoderm
D)None of the above

Question 17

?Which molecule is important in stimulating the formation of the head?

A)Activin
B)Nodal
C)Oct-3
D)Lim-1
E)Noggin

Question 18

The cardiogenic plate arises from ________________.

A)Embryonic endoderm
B)Somatic mesoderm
C)Splanchnic mesoderm
D)Intermediate mesoderm
E)Neural crest

Question 19

Where in the embryo can you find rhombomeres?

A)Primitive node
B)Midbrain
C)Primitive streak
D)Mesoderm
E)None of the above

Question 20

The major signaling molecules produced by the midbrain/hindbrain signaling center (isthmic organizer)are __________________.

A)Sonic hedgehog/Hoxa-1
B)Bone morphogenetic protein-4/En-1
C)Fibroblast growth factor-8/Wnt-1
D)Sonic hedgehog/En-1
E)Wnt-1/bone morphogenetic protein-4

Question 21

Somites arise from _______________.

A)Somatopleure
B)Paraxial mesoderm
C)Splanchnopleure
D)Intermediate mesoderm
E)None of the above

Question 22

Blood islands form from the _______________.

A)Splanchnic mesoderm of the yolk sac
B)Endocardial tube
C)Yolk sac endoderm
D)Splanchnic mesoderm of the foregut
E)Cardiogenic mesoderm

Question 23

In the elongating spinal cord of the early embryo,which molecule stimulates neuronal differentiation?

A)Retinoic acid
B)Fibroblast growth factor-8
C)Lim-1
D)Cerberus
E)None of the above

Question 24

The ventromedial part of the sclerotome gives rise to the ________________.

A)Pedicle of the vertebra
B)Vertebral arch
C)Distal part of the rib
D)Connective tissue around the dorsal root ganglion
E)None of the above

Question 25

The sclerotome arises from cells that were located in the ______________.

A)Notochord
B)Paraxial mesoderm
C)Intermediate mesoderm
D)Lateral mesoderm
E)None of the above

Question 26

Segmental structures in the developing hindbrain are called _______________.

A)Rhombomeres
B)Dermatomes
C)Placodes
D)Somitomeres
E)Somites

Question 27

The oropharyngeal membrane is composed of __________________.

A)Ectoderm + splanchnic mesoderm
B)Endoderm + splanchnic mesoderm
C)Ectoderm + endoderm
D)Ectoderm + splanchnic mesoderm + endoderm
E)Ectoderm + somatic mesoderm + endoderm

Question 28

The "clock and wavefront" model refers to the formation of _________________.

A)Neural tube
B)Heart
C)Digestive tube
D)Somites
E)None of the above