endoderm

(noun)

One of the three tissue layers in the embryo of a metazoan animal that produces tissue within the lungs, thyroid, pancreas, and the digestive system of the adult.

Related Terms

Examples of endoderm in the following topics:

  • Gastrulation

    • During gastrulation, the embryo develops three germ layers (endoderm, mesoderm, and ectoderm), which differentiate into distinct tissues.
    • These three germ layers are known as the ectoderm, mesoderm, and endoderm.
    • The mesoderm is found between the ectoderm and the endoderm, giving rise to somites.
    • The endoderm gives rise to the epithelium of the digestive and respiratory systems, and organs associated with the digestive system, such as the liver and pancreas.
    • However, some common features of gastrulation across triploblastic organisms include: (1) A change in the topological structure of the embryo, from a simply connected surface (sphere-like), to a non-simply connected surface (torus-like); (2) the differentiation of cells into one of three types (endodermal, mesodermal, or ectodermal); and (3) the digestive function of a large number of endodermal cells.

  • Development of Metabolism

    • The gut or gastrointestinal tract is an endoderm-derived structure.
    • As a result, a piece of the yolk sac (the endoderm-lined structure in contact with the ventral aspect of the embryo) is then "pinched off" to become the primitive gut.

  • Tissue Development

    • The endoderm produces tissue within the lungs, thyroid, and pancreas.
    • The endoderm is one of the germ layers formed during animal embryogenesis.
    • The endoderm consists at first of flattened cells, which subsequently become columnar.
    • Image illustrates the types of cells produced by the endoderm (inner germ layer) of the developing embryo.
    • Compare the three embryonic germ layers (endoderm, mesoderm, and ectoderm) from which all body tissues develop

  • Digestive System Development

    • The digestive system is an endoderm-derived structure that begins developing about the fourth week of embryogenesis.
    • The gut is an endoderm-derived structure.
    • The result is that a piece of the yolk sac, an endoderm-lined structure in contact with the ventral aspect of the embryo, begins to be pinched off to become the primitive gut .

  • Epithelial Membranes

    • The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion.

  • Blastocyst Formation

    • On the deep surface of the inner cell mass, a layer of flattened cells, called the endoderm, is differentiated and quickly assumes the form of a small sac, called the yolk sac.
    • This layer is derived from the inner cell mass and lies in opposition to the endoderm.

  • Neurulation

    • During gastrulation cells migrate to the interior of the embryo, forming the three germ layers the endoderm (the deepest layer), mesoderm (the middle layer), and ectoderm (the surface layer) from which all tissues and organs will arise.
    • In a simplified way, it can be said that the ectoderm gives rise to skin and nervous system, the endoderm to the intestinal organs, and the mesoderm to the rest of the organs.

  • Bilaminar Embryonic Disc Development

    • It is derived from the inner cell mass and lies adjacent to the endoderm.

  • Development of the Urinary System

    • It is lined with endoderm.

  • Yolk Sac Development

    • The yolk sac, situated on the ventral aspect of the embryo, is lined by extra-embryonic endoderm, outside of which is a layer of extra-embryonic mesenchyme derived from the mesoderm.