a metazoan embryo in an early state of germ layer formation following the blastula stage, consisting of a cuplike body of two layers of cells, the ectoderm and endoderm, enclosing a central cavity, or archenteron, that opens to the outside by the blastopore: in most animals progressing to the formation of a third cell layer, the mesoderm.
Click for a side-by-side comparison of meanings. Use the word comparison feature to learn the differences between similar and commonly confused words.
- gas·tru·lar, adjective
- pre·gas·tru·lar, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use gastrula in a sentence
A view of the gastrula stage after the larva has become fixed is given in fig. 2.The Works of Francis Maitland Balfour, Volume 1 | Francis Maitland Balfour
At the same time they become clearer and permit a view of the interior of the gastrula.The Works of Francis Maitland Balfour, Volume 1 | Francis Maitland Balfour
This gastrula is the simplest form of the "person," and the two germinal layers are its sole organs.The Wonders of Life | Ernst Haeckel
In the further development of the various tissue-forming animals from the gastrula we have to distinguish two principal groups.
The two-layered young stage of higher creatures, when it has a free-swimming existence, is called a gastrula (Fig. 6).Stories of the Universe: Animal Life | B. Lindsay
British Dictionary definitions for gastrula
- gastrular, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for gastrula
An animal embryo at the stage following the blastula. The gastrula develops from the blastula by invagination (inpocketing), forming an inner cavity with an opening and causing the cells to be distributed into an outer layer (ectoderm) and an inner layer (endoderm). In complex animals such as vertebrates, a third layer (mesoderm) also forms. These layers later develop into the organs and tissues of the body. In vertebrates and other deuterostomes, the opening of the gastrula becomes the anus, while in protostomes (such as arthropods), it becomes the mouth.♦ The development of an embryo from blastula to gastrula is called gastrulation. Compare blastula.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.