nounmass nounZoology Embryology
The innermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the lining of the gut and associated structures.
- ‘In this tissue, therefore, the fate of some of the cells has been changed from prospective gut endoderm to mesoderm and ectoderm.’
- ‘These cells, usually seen as being mesodermal, apparently represent another cell line originating from endoderm.’
- ‘In addition, they act as messengers, bearing molecular orders to the mesoderm and endoderm which they contact on arrival.’
- ‘At a tissue level, an adult hydra is essentially a tube composed of two tissue layers, the ectoderm and the endoderm, which extend throughout the animal.’
- ‘Other asymmetric anatomical features - such as placement of the heart and liver - are products of different layers, the mesoderm and endoderm.’
Mid 19th century from endo-‘within’ + Greek derma ‘skin’.
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