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| Pharyngeal pouch (embryology) | |
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| Pattern of the branchial arches. I-IV branchial arches, 1-4 branchial pouches (inside) and/or pharyngeal grooves (outside) a Tuberculum laterale b Tuberculum impar c Foramen cecum d Ductus thyreoglossus e Sinus cervicalis |
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| Floor of pharynx of human embryo about twenty-six days old. | |
| Gray's | subject #13 65 |
| Carnegie stage | 10 |
In the development of vertebrate animals, pharyngeal or branchial pouches form on the endodermal side between the branchial arches, 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,[1] and these thin segments become gills in fish.
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Specific pouches
First pouch
The endoderm lines the future auditory tube (Pharyngotympanic " Eustachian " tube) , middle ear, mastoid antrum, and inner layer of the tympanic membrane.
Second pouch
- Contributes to the middle ear, palatine tonsils, supplied by the facial nerve.
Third pouch
- The third pouch possesses Dorsal and Ventral wings. Derivatives of the dorsal wings include the inferior parathyroid glands, 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 glands and ultimobranchial body which forms the parafollicular C-Cells of the thyroid gland.
Fifth pouch
- Rudimentary structure, becomes part of the fourth pouch contributing to thyroid C-cells.[2]
See also
References
External links
- Swiss embryology (from UL, UB, and UF) rrespiratory/korperhohlen01 (Item #1 at Fig. 14)
- Embryology at Temple parch98/ARCHII97/sld017
- hednk-021 — Embryology at UNC
- hednk-022 — Embryology at UNC
- Outline at howard.edu (scroll down to "III. THE PHARYNGEAL POUCHES")
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