endoderm (redirected from endoblast)

endoderm (ĕn`dədûrm'), in biology, inner layer of tissue formed in the gastrula stage of the developing embryo. At the end of the blastula stage, cells of the embryo are arranged in the form of a hollow ball. Cell movement results in an invagination of the bottom region, or vegetal hemisphere, of the embryo so that it resembles a double-walled cup. The inner layer of the cup is the endoderm; the outer layer is the ectoderm; a middle layer, the mesoderm, forms from a marginal zone. The endoderm is the germ layer from which are formed the digestive system, many glands, and part of the respiratory system. See embryo.

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endoderm [′en·dō‚dərm]

(embryology)

The inner, primary germ layer of an animal embryo; sometimes referred to as the hypoblast. Also known as entoderm; hypoblast.