Question

On which stage, morphogenetic movements take place in embryos?
A.Blastula
B.Morula
C.Gastrula
D.Fertilized egg

Answer 1

Hint: In the early embryo, the movement of cells that change the shape or form of differentiating cells and tissues. As it is necessary to identify the embryo’s tissues and share the positional information in differentiation, it is very significant in embryogenesis.

Complete answer:
During embryonic development, the process where germ layers are formed is called gastrulation . Here many of the cells from the surface of the embryo move to a new interior location. It also involves changes in cell motility, cell shape, and cell adhesion. It is characterized by morphogenetic movements.

The primary germ layers are formed and organized in the proper location, during gastrulation. The endoderm(most internal germ layer) forms the lining of the gut and other internal organs. The exterior germ layer which forms the skin, brain, the nervous systems, and other external tissues is the ectoderm. The middle germ layer mesoderm forms the skeletal system and the circulatory system.

The major types of cell movement that occurs during gastrulation are,
Invagination: Epithelial sheets bent inward.
Ingression: Freely migrating mesenchyme cells forms when an individual cell leaves epithelial cells.
Involution: Epithelial cells roll inward to form the underlying layer.
Epiboly: By thinning, a sheet of cells were spread.
Intercalation: Longer array of cells is created when rows of cells move between one another.
Convergent extension: Here, the rows of cells intercalate which is highly directional.

Hence the correct answer is OPTION(C)

Note: Morphogenetic movements take place either
1.By infolding a monolayer or by growth, without altering its original arrangement.
2.Losing original contact by segregating the coherent cells arrays from monolayer into the interior of the embryo.