Embry, Gastrulation

Question 1

What is the function of the second polar body?

Answer 1

Set up anterior-posterior axis and marks the axis of first cleavage.

Question 2

When is the left-right axis set up?

Answer 2

Following gastrulation

Question 3

When is the ventral-dorsal axis set up?

Answer 3

After the anterior-posterior axis is.

Question 4

What does delamination of the inner cell mass produce?

Answer 4

The bilaminar germ disk (epiblast and hypoblast)

Question 5

What are the two layers of the bilaminar disk?

Answer 5

Epiblast- embryo proper

Hypoblast- underneath the epiblast

Question 6

When is the bilaminar disk formed?

Answer 6

Day 8

Question 7

What tissues does the ectoderm form?

Answer 7

Epidermis, les, retina, internal ear, CNS, middle and posterior pituitary and pineal gland.

Question 8

What tissues does the mesoderm form?

Answer 8

Muscle, connective tissue, dermis, circulatory system, kidney, uterus, gonads

Question 9

What tissues does the endoderm form?

Answer 9

Midgut, bladder, lungs, liver, pancreas, thyroid, thymus, anterior pituitary

Question 10

Which layer of the bilaminar disks undergoes gastrulation?

Answer 10

Epiblast

Question 11

When does gastrulation occur?

Answer 11

Soon after implantation, 14-16 days.

Question 12

When is the primitive streak clearly visible?

Answer 12

15-16 days

Question 13

Is the primitive node near the anterior or posterior end?

Answer 13

Anterior

Question 14

Abnormalities in which layer give rise to caudal dysgenesis?

Answer 14

Mesoderm

Question 15

Disruption is which two genes in mice gives rise to caudal dysgenesis?

Answer 15

Brachyury, Wnt, engrailed

Question 16

When does gastrulation occur?

Answer 16

Week 2

Question 17

What organism has been used to study gastrulation?

Answer 17

Urchin, chicken

Question 18

When does gastrulation occur in chickens?

Answer 18

Within 5 hours of laying

Question 19

When is there full formation of all three germ layers?

Answer 19

Day 16

Question 20

When does germ layer formation occur?

Answer 20

Days 6-19

Question 21

What are the two major components of germ later formation?

Answer 21

Delamination and gastrulation

Question 22

How is the left-right axis establish?

Answer 22

Nodal cilia direct flow of fluid with signalling molecules to the left.

Question 23

What is the protein involved in left-right axis establishment by the node cilia?

Answer 23

Left-right dynein.

Question 24

What growth factors are involved in left-right axis establishment?

Answer 24

Shh and FGF8

Question 25

What is the effect of transplanting a node from one salamander to another salamander?

Answer 25

Another embryo body will form.

Question 26

What is the effect of transplanting a node from one chick to another chick?

Answer 26

Some important structures such as the neural tube will form.