blastula

Examples of blastula in the following topics:

• Cleavage, the Blastula Stage, and Gastrulation

  • After the cleavage has produced over 100 cells, the embryo is called a blastula.
  • Each cell within the blastula is called a blastomere.
  • In mammals, the blastula forms the blastocyst in the next stage of development.
  • The typical blastula is a ball of cells.
  • During gastrulation, the blastula folds upon itself to form the three layers of cells.

• Gastrulation

  • Gastrulation is a phase early in the embryonic development of most animals during which the single-layered blastula is reorganized into a trilaminar (three-layered) structure known as the gastrula.
  • Gastrulation takes place after cleavage and the formation of the blastula and primitive streak.

• Animal Reproduction and Development

  • After further cell division and rearrangement of existing cells, a 6–32-celled hollow structure called a blastula is formed.
  • Next, the blastula undergoes further cell division and cellular rearrangement during a process called gastrulation.
  • During embryonic development, the zygote undergoes a series of mitotic cell divisions, or cleavages, to form an eight-cell stage, then a hollow blastula.
  • During a process called gastrulation, the blastula folds inward to form a cavity in the gastrula.

• Cleavage of the Zygote

  • The different cells derived from cleavage up to the blastula stage, are called blastomeres.
  • Fluid collects between the trophoblast and the greater part of the inner cell mass, and thus the morula is converted into the blastodermic vesicle (blastocyst or blastula).

• Fertilization

  • Nondisjunction during the completion of meiosis or problems with early cell division in the zygote to blastula stages can lead to problems with implantation and pregnancy failure.

• Cellular Differentiation

  • A pathway that is guided by the cell adhesion molecules is created as the cellular blastomere differentiates from the single-layered blastula to the three primary layers of germ cells in mammals, namely the ectoderm, mesoderm and endoderm (listed from most distal, or exterior, to the most proximal, or interior).

• Tissue Development

  • During the next stage, termed cleavage, mitotic cell divisions transform the zygote into a tiny ball of cells, called a blastula.

• Phylum Cnidaria

  • After fertilization, the zygote develops into a blastula and then into a planula larva.

• Animal Characterization Based on Features of Embryological Development

  • Each of the three germ layers in a blastula, or developing ball of cells, becomes particular body tissues and organs.