View source for Pharyngeal pouch (embryology)

{{Infobox Embryology |
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  Latin         = |
  GraySubject   = 13 |
  GrayPage      = 65 |
  Image         = Kiemenbogen.jpg |
  Caption       = Pattern of the branchial arches. I-IV branchial arches, 1-4 [[branchial pouches]] (inside) and/or [[pharyngeal grooves]] (outside)<BR>a [[Tuberculum laterale]]<BR>b [[Tuberculum impar]]<BR>c [[Foramen cecum]]<BR>d [[Ductus thyreoglossus]]<BR>e [[Sinus cervicalis]] |
  Image2        = Gray979.png |
  Caption2      = Floor of pharynx of human embryo about twenty-six days old. |
  System        = |
  CarnegieStage = 10 |
  Precursor     = |
  GivesRiseTo   = |
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  MeshNumber    =  |
  DorlandsPre   = p_31 |
  DorlandsSuf   = 12662655  |
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==Overview==
In the [[Embryogenesis|development]] of [[Vertebrate|vertebrate animals]], '''Pharyngeal''' or '''branchial pouches''' form on the endodermal side between the [[branchial arch]]es, and pharyngeal grooves (or clefts) form the lateral ectodermal surface of the neck region to separate the arches. The pouches line up with the clefts, and these thin segments become gills in [[fish]].

== The pouches ==
===First pouch===
This is the only pouch in which the endoderm and ectoderm remain close together, as the [[tympanic membrane]].  There is minimal mesoderm in the tympanic membrane.

*The [[endoderm]] lines the future [[auditory tube]], [[middle ear]], [[mastoid antrum]], and inner layer of the tympanic membrane.
*The [[ectoderm]] lines the future [[external acoustic meatus]] and outer layer of the tympanic membrane.
*[[Mesoderm ]] remains as the middle portion of the tympanic membrane, where the endoderm of the first pharyngeal pouch and the ectoderm of the first pharyngeal cleft have met. 
Other mesoderm derivatives include:  Meckel's cartilage (mandible, malleus, incus, sphenomandibular ligament), muscles (temporalis, masseter, later and medial pterygoids, mylohyoid, anterior belly digastric, tensor tympani, tensor veli palatini, anterior 2/3 tongue), and nerves (CN V2, CN V3).

===Second pouch===
*Contributes to the [[middle ear]], [[tonsils]], supplied by the [[facial nerve]].

===Third pouch===
*The third pouch possesses Dorsal and Ventral wings. Derivatives of Dorsal include the inferior [[parathyroid gland]]s, while the ventral wings fuse to form the cytoreticular cells of the [[thymus]]. The main nerve supply to the derivatives of this pouch is Cranial Nerve IX, glossopharyngeal nerve.

===Fourth pouch===
*Derivatives include the superior [[parathyroid gland]] and [[parafollicular]] C-Cells of the [[thyroid gland]].

===Fifth pouch===
*[[Rudimentary]] structure, becomes part of the fourth pouch contributing to thyroid C-cells.<ref>[http://www.mc.vanderbilt.edu/histology/labmanual2002/labsection3/ThyroidParathyroidIslets03.htm Endocrine Glands<!-- Bot generated title -->]</ref>

==See also==
* [[branchial arch]]
* [[DiGeorge syndrome]]

==References==
{{reflist}}

==External links==
* {{EmbryologySwiss|rrespiratory/korperhohlen01}} (Item #1 at Fig. 14)
* {{EmbryologyTemple|parch98/ARCHII97/sld017}}
* {{EmbryologyUNC|hednk|021}}
* {{EmbryologyUNC|hednk|022}}
* [http://www.med.howard.edu/anatomy/gas/wk7/Lecture%2024.htm Outline at howard.edu (scroll down to "III. THE PHARYNGEAL POUCHES")]

{{Embryology of head and neck}}
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[[Category:Animal anatomy]]
[[Category:Developmental biology]]
[[Category:Embryology]]
[[Category:Head and neck]]
[[pl:Kieszonki skrzelowe]]

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