Pharyngeal pouch (embryology)
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2008-06-11T21:25:06Z
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{{Infobox Embryology |
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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. |
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CarnegieStage = 10 |
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DorlandsPre = p_31 |
DorlandsSuf = 12662655 |
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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.
===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}}
[[Category:Animal anatomy]]
[[Category:Developmental biology]]
[[Category:Embryology]]
[[Category:Head and neck]]
[[pl:Kieszonki skrzelowe]]