An embryo at the stage following the blastula, when it is a hollow cup-shaped structure having three layers of cells.
- ‘Using light microscopy, he concluded that the embryo underwent gastrulation and that the gastrula consisted of three ‘cell elements’ on the outside, and two on the inside.’
- ‘During gastrulation, cells on the outside of the embryo move inwards and, in animals such as the sea urchin, gastrulation even transforms a hollow spherical blastula into a gastrula with a hole through the middle - the gut.’
- ‘Gastrulation in its broadest sense is the reorganization of the cells of the blastula to form a multilayered embryo, the gastrula.’
- ‘For example, most metazoans go through a developmental stage called a gastrula - a ball of cells with an infolding that later forms the gut.’
- ‘The nucleus must be taken from the blastula and gastrula stages of frog embryos (at this point no semblance or form of the creature is distinguishable).’
Late 19th century modern Latin, from Greek gastēr, gastr- ‘stomach’ + the Latin diminutive ending -ula.
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