A Reproductive Lexicon


Ownership of this website has been transferred from Northwestern University to Michigan State University.
Please note that some site information may be inaccurate while adjustments to reflect this organizational change are made.

MOOC Advertisement

Learn More:
Get An Introduction to Reproduction

Learn more about the science of reproduction. Dr. Teresa Woodruff, creator of Repropedia, is offering a free online course exploring the world of reproduction.

Get Started!


The endoderm is the innermost layer of cells of a eukaryote or the innermost layer of cells in the developing embryo once it has reached the gastrula stage. This cell layer ultimately gives rise to the inner (epithelial) linings of the gut and associated glands, liver, respiratory tract, urinary bladder, ear passages, and the functional portions of the thyroid, parathyroid, pancreas, and thymus.