Embryonic Development in Frog Xenopus

Overview

• Embryo Stage: Blastula
• Structure: A ball of cells with a fluid-filled cavity.
• Cavity Name: Blastocele

Blastula Composition

• Vegetal Pole: Large yolk-filled cells.
• Animal Pole: Smaller cells.
• Tissue Layers (Colors):
  • Yellow: Endoderm
  • Red: Mesoderm
  • Blue: Ectoderm

Gastrulation Process

• Initiation: Surface cells, known as bottle cells, move into the embryo's interior.
• Cell Movement Tracking: Dye is used on surface cells to track their movement.

Formation of Dorsal Lip

• Description: Created as cells move inside the embryo over the dorsal lip.
• Ectoderm Movement: Extends around the embryo in a process called epiboly.

Archenteron and Blastocele

• Archenteron Formation: A cavity that forms, becoming the primitive gut.
• Blastocele Change: Gradually shrinks as gastrulation proceeds.
• Endoderm Role: Lines the archenteron and originates from the embryo's exterior.
• Blastopore: Connects the archenteron to the outside, eventually forming the animal's anus.

Formation of Ventral Lip

• New Bottle Cells: Form and migrate into the embryo, followed by other surface cells.
• Structure: Creates the ventral lip of the blastopore.

End of Gastrulation

• Ectoderm Position: Surrounds the embryo.
• Endoderm Position: Lines the inner side.
• Mesoderm Position: Lies between ectoderm and endoderm.
• Region Fates Determination:
  • Endoderm: Develops into the digestive and respiratory tracts and associated structures.
  • Mesoderm: Develops into the skeleton, circulatory system, muscles, excretory system, and most of the reproductive system.
  • Ectoderm: Develops into the skin, sense organs, and nervous system.