T.S. of blastula through permanent slides

Aim: T.S. of blastula through permanent slides (Mammalian)

Theory:

1. Soon after fertilization the zygote undergoes repeated division called cleavage.

2. Cleavage includes a series of successive and rapid mitotic division with transform single celled zygote into multicellular structure called blastula (blastocyst).

3. Cleavage occurs in upper portion of the fallopian tube. It results into a solid mass of cells called morula.

4. At the next stage of development which produces an embryo with aboutsixty four cells called blastula or blastodermic vesicle.

Material/Apparatus Required:

Permanente slide of blastula and microscope

Procedure:

Fix the slide of T.S of blastula under microscope. First observe the slide under low power and then under high power of the microscope.

Observation:

1. 1. It is a spherical mass of about sixty-four cells.
2. 2. It is composed of an outer envelope of cells, the trophoblast and inner cell mass (embryoblast).
3. 3. Within the envelope there is a fluid filled cavity called blastocoel.
4. 4. The side of the blastocyst to which the inner cell mass is attached is called the embryonic or animal pole, while the opposite side is the abembryonic pole.
5. 5. The inner cell mass is the precursor of the embryo.

Precautions:

1. First focus the slide under low power and then under the high power of the microscope.
2. Use fine adjustment while focusing the slide under high power of microscope.