Neurula

Part of speech: noun

Definitions

1. An early embryonic stage in vertebrates, following the gastrula, when the neural tube forms along the back of the developing body
2. The developmental phase in which a vertebrate embryo forms its primitive nervous system as a flat plate that folds into a tube
3. A stage of embryonic growth in backboned animals during which the nerve cord begins to take shape along the dorsal surface

Etymology: Early in embryonic development, before the body has taken its adult shape, a vertebrate embryo forms a flat plate of cells that folds into a hollow tube, and the stage is named after a tiny cord. The word "neurula" comes from New Latin, where it is a diminutive formed with the suffix "-ula" (a little one) from the Ancient Greek "neûron," meaning "sinew, tendon, cord." The Greek root gave English "neuron" and "nerve" as well, so the same ancient word for a cord of tissue lies behind both the nerve cells in the brain and this earlier stage of development. The name reflects the way the embryo's neural groove and folds look like a small, cord-like structure in its early form.