from The American Heritage® Dictionary of the English Language, 4th Edition
- n. See endoderm.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A type of tissue that forms from the inner cell mass and later is incorporated into the endoderm
from the GNU version of the Collaborative International Dictionary of English
- n. The inner or lower layer of the blastoderm; -- called also endoderm, entoderm, and sometimes hypoderm. See Illust. of blastoderm, delamination, and ectoderm.
from The Century Dictionary and Cyclopedia
- n. In botany, the flat dorsal cotyledon of a grass.
- n. In biology, the internal or inferior layer of cells of the embryo of metazoic animals, forming the endoderm or innermost membrane: the opposite of epiblast: correlated with mesoblast.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the inner germ layer that develops into the lining of the digestive and respiratory systems
The hypoblast is the lining of the intestine and of the glands which open into it; and the material of the notochord is also regarded, as hypoblast.
Entoderm: the innermost germ layer of the embryo, from which are derived the epithelium of the alimentary canal and accessory structures: = endoderm and hypoblast.
In this form, he says, the progaster is already developed, and its wall is differentiated for the first time into an animal or dermal layer (ectoblast), and into a vegetative or intestinal layer (hypoblast).
The blastosphere of the frog is like what the blastosphere of amphioxus would be, if the future hypoblast cells were enormously larger through their protoplasm being diluted with yolk.
But the notochord in the fowl is not so distinctly connected with the hypoblast, and so distinct from the mesoblast, as it is in the lower type, and no gills, internal or external, are ever developed.
Walls of the coelomic pouches, which form (a) an inner lining to the epiblast, (b) an outer coating to the hypoblast, and (c) the mesentery (m.), by which the intestine is supported.
Epiblast is indicated by a line of dashes, mesoblast by dots, and hypoblast, dark or black.
The true mouth is formed late by a tucking-in of epiblast, the stomodaeum (s.d.), which meets and fuses with the hypoblast, and is then perforated.
The former is often also called the ectoblast, or epiblast, and the latter the endoblast, or hypoblast.
But in all other animals the ovum first grows into two primary layers, the outer or animal layer (the ectoderm, epiblast, or ectoblast), and the inner or vegetal layer (the entoderm, hypoblast, or endoblast); and from these the tissues and organs are formed.