The inner layer of the three germ layers of the EMBRYO during its early development. The endoderm develops into the lining of the gastrointestinal tract and associated glands (LIVER; gall-bladder – see LIVER; PANCREAS), the lining of the bronchi and alveoli of the LUNGS and much of the URINARY TRACT.
The inner tissues of an organism.
n. the inner of the three *germ layers of the early embryo, which gives rise to the lining of most of the alimentary canal and its associated glands, the liver, gall bladder, and pancreas. It also forms the lining of the bronchi and alveoli of the lung and most of the urinary tract. —endodermal adj.