- This animation shows the migration of mesoderm throughout the embryonic disc during gastrulation.
- The pink arrow show how mesodermal cells spread out between the ectoderm and endoderm layers, forming the third (middle) layer of the trilaminar embryo.
- Axial process - the arrow running from the primitive node upward is the axial process which will later form the notochord.
- 2 regions where no mesoderm is found, at the upper and lower ends of the gastrointestinal tract.
- cranial (top) - buccopharyngeal membrane
- caudal (bottom) - cloacal membrane.
- Prechordal plate - lies above the buccopharyngeal membrane and is the cardiogenic mesoderm, that will form the heart.