Medical Definition of Endoderm

Endoderm: One of the three primary germ cell layers -- the other two are the mesoderm and ectoderm -- in the very early embryo. The endoderm is the innermost of the three layers. It differentiates to give rise first to the embryonic gut and then to the linings of respiratory and digestive tracts and the liver and pancreas.

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What causes tooth decay? See Answer