Vertebrate Development I

Question 1

an embryonic stage at which all vertebrate embryos look rather similar … general body shape developed, neural tube/somites/notochord/head structures are present)

Answer 1

Phylotypic Stage (the development will diverge again)

Question 2

The Frog:

MI : complete with a polar body at the ___1.___

The cells deriving from cleavage divisions are called ___2.___

Inside the spherical mass of cells is a fluid-filled cavity called ___3.___

The embryo is called ___4.___. This formation ends after about ___5.___ cell divisions (several thousand cells)

Slowly the ___6.___ around the equator will give rise to the ___7.___

Answer 2

1. animal pole
2. blastomeres
3. blastocoel
4. blastula
5. 12 (way to remember: 12th day of Christmas lol)
6. marginal zone
7. mesoderm

Question 3

Gastrulation begins at the ___1.___ which forms on the ___2.___ side of the embryo

Answer 3

1. blastopore

2. dorsal

Question 4

The Zebra Fish:

After fertilization, cleavage does not extend into the yolk and results in a mound of ___1.___ (like the frog) perched above a large yolk cell … leads to the ___2.___ in which the embryo is in the form of a ___3.___ of around ___4.___ cells lying on top of the yolk cell

Answer 4

1. blastomeres
2. sphere stage
3. blastoderm
4. 1,000

Question 5

Birds and Mammals:

The blastula stage is not a hollow blastula but a layer of epithelium called ___1.___

The early chicken embryo develops as a flat disc of cells overlying a ___2.___

At 4 days after laying, ___3.___ have developed through which the embryo gets its nourishment from the yolk

Answer 5

1. epiblast
2. massive yolk
3. extra-embryonic membranes

Question 6

T or F: the mouse egg has no yolk and early development involves the allocation of cells to form the placenta and extra-embryonic membranes

Answer 6

TRUE

Question 7

The embryo naming for birds and mammals is ___1.___

Answer 7

1. blastocyst

Question 8

Humans

Early development similar to a mouse

Implantation usually occurs around Day ___1.___ of development, when about ___2.___ cell are present

Cells from the ICM of a human ___3.___ can be cultured as ___4.___

T or F : the processes of implantation and formation of the placenta differ from those in mice

Answer 8

1. 7
2. 256
3. blastocyst
4. embryonic stem cells

TRUE

Question 9

Formation of a flat bilaminar disc of cells ( ___1.___ and ___2.___ )

The ___3.___ lies above the epiblast and the ___4.___ lies below the ___5.___

The epiblast cells are thought to ingress through the ___6.___ in the same way as the epiblast cells in the chick embryo give rise to the ___7.___ and ___8.___

The epiblast cells that do not ingress form the ___9.___

Answer 9

1. epiblast
2. hypoblast
3. amniotic cavity
4. yolk sac cavity
5. hyboblast
6. primitive streak
7. mesoderm
8. endoderm
9. ectoderm

Question 10

Fluid from the amniotic cavity can be collected ( ___1.___ ) between ___2.___ weeks of gestation for prenatal diagnosis

The early stages in human development take longer than the same stages in the ___3.___

After ___4.___ , the human embryo is known as a ___5.___ and is accompanied by further maturation of the organs ( ___6.___ )

Answer 10

1. amniocentesis
2. 14 and 16
3. mouse
4. 8 weeks
5. fetus
6. organogenesis