gastrula

[ gas-troo-luh ]

noun

, Embryology.

, plural gas·tru·las, gas·tru·lae [gas, -tr, oo, -lee].

1. 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.

gastrula

/ ˈɡæstrʊlə /

noun

1. See endoderm, mesoderm, ectoderm
   a saclike animal embryo consisting of three layers of cells (ectoderm, mesoderm, and endoderm) surrounding a central cavity (archenteron) with a small opening (blastopore) to the exterior See also ectoderm mesoderm endoderm

gastrula

/ găs′trə-lə /

, Plural gastrulas găs′trə-lē′

1. 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.
2. ◆ The development of an embryo from blastula to gastrula is called gastrulation.
3. Compare blastula

Derived Forms

• ˈgastrular, adjective

Other Words From

• gastru·lar adjective
• pre·gastru·lar adjective

Word History and Origins

Origin of gastrula¹

From New Latin, dating back to 1875–80; gastro-, -ule

Word History and Origins

Origin of gastrula¹

C19: New Latin: little stomach, from Greek gastēr belly

Example Sentences

A view of the gastrula stage after the larva has become fixed is given in fig. 2.

From Project Gutenberg

At the same time they become clearer and permit a view of the interior of the gastrula.

From Project Gutenberg

This gastrula is the simplest form of the "person," and the two germinal layers are its sole organs.

From Project Gutenberg

In the further development of the various tissue-forming animals from the gastrula we have to distinguish two principal groups.

From Project Gutenberg

The two-layered young stage of higher creatures, when it has a free-swimming existence, is called a Gastrula (Fig. 6).

From Project Gutenberg