OBJECTIVE LIFE SCIENCE
DEVELOPMENTAL BIOLOGY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Area vitellina
|
|
|
Area pellucida
|
|
|
Embryo proper
|
|
|
None of the above
|
Detailed explanation-1: -4.1 Blastodisc Thus, development starts as a flat disc on top of the yolk. Cleavage occurs as the zygote is passing along the oviduct before the egg is laid. The cytoplasm is concentrated in the blastodisc at the opposite pole to the yolk mass. The blastodisc is a pale area several millimeters across.
Detailed explanation-2: -CHICK BLASTULA Discoblastula consists of a disc-shaped mass of blastomeres overlying a large yolk mass. 3. This blastula is the result of meroblastic discoidal cleavage 4. There is no blastocoel, instead a slit like cavity called subgerminal cavity appears in between the blastoderm and the yolk mass.
Detailed explanation-3: -Between the area pellucida and the area opaca is a thin layer of cells called the marginal zone (or marginal belt) (Eyal-Giladi 1997; Arendt and Nübler-Jung 1999).