View source for Endoderm

{{Short description|Inner germ layer of embryonic development}}
{{Infobox embryology
| Name          = Endoderm
| Latin         =
| Image         = Embryonic_origin_of_endoderm.png
| Caption       = Tissues derived from endoderm.
| System        =
| CarnegieStage =
| Days          = 16
| Precursor     = [[Epiblast]]
| GivesRiseTo   = 
}}
'''Endoderm''' is the innermost of the three primary [[germ layer]]s in the very early [[embryo]]. The other two layers are the [[ectoderm]] (outside layer) and [[mesoderm]] (middle layer).<ref>Langman's Medical Embryology, 11th edition. 2010.</ref> Cells migrating inward along the [[archenteron]] form the inner layer of the [[gastrulation|gastrula]], which develops into the endoderm.<ref>{{cite journal |last1=Fukuda |first1=Kimiko |last2=Kikuchi |first2=Yutaka |title=Endoderm development in vertebrates: fate mapping, induction and regional specification |journal=Development, Growth and Differentiation |date=August 2005 |volume=47 |issue=6 |pages=343–355 |doi=10.1111/j.1440-169X.2005.00815.x |pmid=16109032 |s2cid=26241717 |url=https://onlinelibrary.wiley.com/doi/full/10.1111/j.1440-169X.2005.00815.x |access-date=10 March 2023 |language=en |issn=0012-1592|doi-access=free }}</ref>

The endoderm consists at first of flattened cells, which subsequently become columnar. It forms the [[epithelial]] lining of multiple systems.

In [[plant biology]], endoderm corresponds to the innermost part of the [[Cortex (botany)|cortex]] ([[Bark (botany)|bark]]) in young [[Shoot (botany)|shoots]] and young [[root]]s often consisting of a single [[Cell (biology)|cell]] layer. As the [[plant]] becomes older, more endoderm will [[Lignification|lignify]].

==Production==

The following chart shows the [[tissue (biology)|tissue]]s produced by the endoderm.
The embryonic endoderm develops into the interior linings of two tubes in the body, the digestive and respiratory tube.<ref>{{cite web|last=Gilbert|first=SF|title=Endoderm|url=https://www.ncbi.nlm.nih.gov/books/NBK10107/|publisher=Sinauer Associates|access-date=14 March 2013}}</ref>
{| class="wikitable"
! Layer !! Category !! System !!
|-
| General<ref>The '''General''' category denotes that all or most of the [[animal]]s containing this layer produce the adjacent product.</ref> || [[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 [[Vertebrate trachea|trachea]], [[bronchi]], and [[Pulmonary alveolus|alveoli]] of the [[lungs]]
|-
| General || [[Endocrine]] glands and organs || the lining of the follicles of the [[thyroid gland]] and the epithelial component of the [[thymus|thymus (i.e. thymic epithelial cells).]]
|-
|  || [[Auditory system]] || the [[epithelium]] of 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.<ref name="pmid11532400">{{cite journal |author=Zaret KS |title=Hepatocyte differentiation: from the endoderm and beyond |journal=Curr. Opin. Genet. Dev. |volume=11 |issue=5 |pages=568–74 |date=October 2001 |pmid=11532400 |doi= 10.1016/S0959-437X(00)00234-3}}</ref>

In humans, the endoderm can differentiate into distinguishable organs after 5 weeks of [[embryogenesis|embryonic development]].

==Additional images==
<gallery>
 File:Gray21.png|Section through the embryo.
 File:Gray32.png|Section through ovum imbedded in the uterine decidua
 Transcription factor network in endoderm induction..jpg|[[Signaling pathway]] to inducing endoderm
</gallery>

== See also ==
{{col div|colwidth=40em}}
*[[Hypoblast]] of primitive endoderm
*[[Ectoderm]]
*[[Germ layer]]
*[[Histogenesis]]
*[[Mesoderm]]
*[[Organogenesis]]
*[[Endodermal sinus tumor]]
*[[Gastrulation]]
*[[Cell differentiation]]
*[[Triploblasty]]
*[[List of human cell types derived from the germ layers]]
{{colend}}

== References ==
{{Gray's}}
{{reflist}}

{{wiktionary|endoderm}}

{{Embryology}}

{{Portal bar|Anatomy}}

[[Category:Endoderm| ]]
[[Category:Germ layers]]
[[Category:Developmental biology]]
[[Category:Embryology]]
[[Category:Gastrulation]]