Question

A. Amnion

B. Anterior Visceral endoderm

C. BMP

D. Chorion

E. Columnarization

F. Cyclopy

G. Dorsal ventral mesoderm

H. Growth cone

I. Hensons’ node

J. Intermediate

K. Koller’s Sickle

L. Mantle

M. Marginal

N. Paraxial

O. Rhombomeres

P. Secondary

Q. Spina bifida

R. Wnt

1. The area which acts as the organizer in the mammalian embryo is _______.

2. The ____________, an extraembryonic membrane surrounds the embryo and is formed by the ectoderm and mesoderm.

3. In the vertebrates, the failure of the neural tube to close results in a condition known as ______________

4. In fish, the lumen of the neural tube forms after closure of the tube. This form of neurulation is called ______________ neurulation.

5. The process where by the neural plate cells elongate perpendicular to the surface of the embryo, while their apical and basal surfaces shrink is called ______________.

6. Cells formed by the first cell divisions of the neuroepithelium and migrate to take up position immediately outside the neuroepithelium and form the ________________ layer of the neural tube.

7. The __________ ________________(2 words) is the end of the axon which is being extended during pathfinding in development.

8. During the differentiation of the ectoderm, high levels of _______ will specify the keratinized layer.

9. ____________ are periodic swellings in the Rhombencephalon which represent separate territories in this area of the brain.

10. The region within the mesoderm that gives rise to the somite’s is the ___________ mesoderm.

Answer 1

1) The mammalian appear to have to signalling centres- one in the node and one in the anterior visceral endoderm.

So the blank can be filled with B.

Anterior visceral endoderm.

2) The amnion is formed above the embroyo and it consists of outer mesoderm and inner ectoderm.

So the blank can be filled with A.

Amnion.

3) Failure of the caudal end of the neural tube to close causes a condition which is known as spina bifida, in which the spinal cord fails to close.

so the blank can be filled with Q.

Spina Bifida.

4) Neurulation in fish proceeds only via the secondary form.

So the blank can be filled with P.

secondary.

5)