Gastrulation

Definition

Gastrulation is a critical phase in early embryonic development where the single-layered blastula reorganizes into a multilayered structure known as the gastrula. This process establishes the three primary germ layers: ectoderm, mesoderm, and endoderm.

5 Must Know Facts For Your Next Test

1. Gastrulation marks the beginning of significant cell differentiation and tissue formation.
2. The three germ layers formed during gastrulation are crucial for developing all tissues and organs in an organism.
3. In most animals, gastrulation follows the stages of cleavage and blastulation.
4. Key movements during gastrulation include invagination, involution, ingression, delamination, and epiboly.
5. Disruptions in gastrulation can lead to severe developmental defects or embryonic lethality.

Review Questions

• What are the three primary germ layers formed during gastrulation?
• Describe one key cell movement that occurs during gastrulation.
• Why is gastrulation considered a critical phase in embryonic development?

Related terms

Cleavage:

Series of rapid mitotic divisions following fertilization that leads to the formation of a multicellular embryo.

Blastula: The stage of an embryo characterized by a hollow ball of cells prior to gastrulation.

Organogenesis: The process where the three germ layers develop into internal organs of an organism.