Question 1

________ Gives rise to the brain and spinal cord&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate

Accepted Answer

The neural plate is a thickened area of ectoderm that overlies and extends on each side of the notochord.The neural plate invaginates to form a neural groove.In later development,the neural folds meet dorsally and fuse to form the neural tube.The cranial part of the neural tube develops into the brain,and the longer remaining part forms the spinal cord.The notochord and paraxial mesoderm produce inductive substances that stimulate or induce the overlying ectoderm to thicken and form the neural plate.

Question 2

________ Neural groove&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The neural groove forms as the neural plate invaginates to form a neural fold on each side.The folds later fuse to form the neural tube,the primordium of the central nervous system (brain and spinal cord).The ectoderm lateral to the folds,surface ectoderm,gives rise to the epidermis of the skin.

Question 3

________ Derived from notochordal process&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The notochord arises by transformation of the notochordal process.The notochord is a cellular rod that defines the primordial axis of the embryo.Mesenchymal cells from the somites later surround it and give rise to the mesenchymal bodies of the vertebrae.The notochord within the developing vertebrae later degenerates.

Question 4

________ Embryonic ectoderm&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The embryonic ectoderm in the region indicated forms a neural fold.The neural folds soon fuse,converting the neural plate into the neural tube.

Question 5

________ Gives rise to an adult body cavity&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The intraembryonic coelom in the area indicated becomes part of the peritoneal cavity.The coelom appears here as a space within the lateral mesoderm,splitting it into somatic and splanchnic layers.The transverse section is cut through the caudal region of the lateral extensions of the horseshoe-shaped body cavity or coelom.

Question 6

________ Appears on extraembryonic membranes&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate

Accepted Answer

The blood islands first appear on the walls of the umbilical vesicle,allantois,and connecting stalk.These extraembryonic membranes are derived from the zygote,but they are not part of the embryo.Blood islands form in the embryo about 2 days after they appear on the umbilical vesicle.

Question 7

________ Diverticulum of umbilical vesicle (yolk sac)&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate

Accepted Answer

The allantois,a diverticulum of the umbilical vesicle,is a vestigial structure that later becomes the urachus (median umbilical ligament in an adult).It serves as a reservoir for excretory products in some species,but it is nonfunctional in human embryos.However,its blood vessels become the umbilical vessels.

Question 8

________ Derived from primitive streak&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The intraembryonic mesoderm is derived from the primitive streak.The primitive streak produces mesoderm rapidly during the third and fourth weeks.

Question 9

________ Derived from paraxial mesoderm&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The somites are paired cubical masses derived by segmentation of the paraxial mesoderm.The first pair of somites is formed a short distance caudal to the tip of the notochord,and successive somites are progressively formed from paraxial mesoderm.Most somites appear between days 20 and 30;they give rise to the axial skeleton and its associated musculature.

Question 10

________ Notochordal process&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The notochordal process is a rod-shaped structure composed of cells derived from the primitive node of the primitive streak.It is the primordium of the notochord,a cellular structure that defines the primordial axis of the embryo.

Question 11

________ Wall of amniotic sac&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Wall of amniotic sac&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 12

________ Fusing to form neural tube&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Fusing to form neural...

Question 13

________ Source of mesenchyme&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate

Accepted Answer

The answer of ________ Source of mesenchyme&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate...

Question 14

________ Aggregation of angioblasts&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate

Accepted Answer

The answer of ________ Aggregation of angioblasts&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate...

Question 15

________ Gives rise to most of the embryonic mesoderm&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Gives rise to most...

Question 16

________ Primitive pit

Accepted Answer

The answer of   ________ Primitive pit...

Question 17

________ Splanchnopleure&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Splanchnopleure&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 18

________ Site of the prechordal plate&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Site of the prechordal...

Question 19

________ Umbilical artery&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Umbilical artery&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 20

________ Forms the basis of the axial skeleton&#10;A)Allantois&#10;B)Primitive streak&#10;C)Notochord&#10;D)Blood island&#10;E)Neural plate

Accepted Answer

The answer of ________ Forms the basis of the axial...

Question 21

________ Tertiary chorionic villus&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Tertiary chorionic villus&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 22

________ Contains umbilical vessels&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Contains umbilical vessels&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 23

________ Sinus venosus&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Sinus venosus&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 24

________ Vitelline artery&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Vitelline artery&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Deck 3: Formation of Germ Layers and Early Tissue and Organ Differentiation