Endoderm

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Endoderm
Tissues derived from endoderm.
Details
Days16
Precursorepiblast
Identifiers
MeSHD004707
FMA69071
Anatomical terminology

Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer).[1] Cells migrating inward along the archenteron form the inner layer of the gastrula, which develops into the endoderm.[2]

The endoderm consists at first of flattened cells, which subsequently become columnar. It forms the

epithelial
lining of multiple systems.

In

lignify
.

Production

The following chart shows the tissues produced by the endoderm. The embryonic endoderm develops into the interior linings of two tubes in the body, the digestive and respiratory tube.[3]

Layer Category System
General[4] Gastrointestinal tract the entire
alimentary canal except part of the mouth, pharynx and the terminal part of the rectum (which are lined by involutions of the ectoderm), the lining cells of all the glands which open into the digestive tube, including those of the liver and pancreas
General Respiratory tract the
lungs
General
Endocrine
glands and organs		 the lining of the follicles of the
thyroid gland and the epithelial component of the thymus (i.e. thymic epithelial cells).
Auditory system the
auditory tube and tympanic cavity
Urinary system the
urinary bladder and part of the urethra

Liver and pancreas cells are believed to derive from a common precursor.[5]

In humans, the endoderm can differentiate into distinguishable organs after 5 weeks of

embryonic development
.

Additional images

  • Section through the embryo.
    Section through the embryo.
  • Section through ovum imbedded in the uterine decidua
    Section through ovum imbedded in the uterine decidua
  • Signaling pathway to inducing endoderm
    Signaling pathway
    to inducing endoderm

See also

References

Public domain This article incorporates text in the public domain from page 49 of the 20th edition of Gray's Anatomy (1918)

  1. ^ Langman's Medical Embryology, 11th edition. 2010.
  2. S2CID 26241717
    . Retrieved 10 March 2023.
  3. ^ Gilbert, SF. "Endoderm". Sinauer Associates. Retrieved 14 March 2013.
  4. ^ The General category denotes that all or most of the animals containing this layer produce the adjacent product.
  5. PMID 11532400
    .
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