- 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.
Origin of gastrula
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for gastrula
You know, from the second lecture, what a gastrula of our sea-urchin is.The Science and Philosophy of the Organism
The blastosphere determines the orientation of the gastrula, and so forth.The Biological Problem of To-day
A gastrula is established by a mixed process of embole and epibole.
Both the blastosphere and gastrula often swim freely by flagella.The Whence and the Whither of Man
John Mason Tyler
The formation of the gastrula and behaviour of the blastopore: together with the origin of the hypoblast.The Works of Francis Maitland Balfour, Volume III (of 4)
Francis Maitland Balfour
C19: New Latin: little stomach, from Greek gastēr belly
Word Origin and History for gastrula
1877, Modern Latin, from Greek gaster (genitive gastros) "stomach" (see gastric) + Latin -ula, diminutive suffix. Related: Gastrulation.
Online Etymology Dictionary, © 2010 Douglas Harper
- An embryo at the stage following the blastula, consisting of a hollow, two-layered sac of ectoderm and endoderm surrounding an archenteron that communicates with the exterior through the blastopore.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- 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.