Gill Arches


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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Gill Arches

 

the system of skeletal elements of the pharynx in cyclostomes and fish. Each gill arch embraces the pharynx in a half-ring. The majority of present-day fish have five gill arches; cyclostomes and some sharks have up to seven. In bony fish the number of gill arches may be reduced to three with the reduction of the posterior ones. Cyclostomes, cartilaginous fish, sturgeon, and dipnoans have cartilaginous gill arches; bony fish have bony gill arches.

Fully developed gill arches offish consist of four movably united segments. In bony fish the fifth gill arch, which is called the subpharyngeal bone, is usually rudimentary, but sometimes (in cyprinoids) bears teeth and is very powerful. In terrestrial vertebrates, the superior segments of the gill arches are reduced; the inferior ones participate in the formation of the subglossal apparatus and become the laryngeal cartilage.

REFERENCES

Severtsov, A. N. “Morfologiia vistseral’nogo apparata elasmobrankhii.” Sobr. soch., vol. 4. Moscow-Leningrad, 1948.
Gimmerreikh, G. A. “Vistseral’nyi apparat osetroobraznykh kak organ priema pishchi.” In Voprosy evoliutsionnoi morfologii pozvonochnykh. Moscow, 1963.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The initial anatomical regions with osteological development were mandible, pectoral fin (cleithrum), ceratobranchial and gill arches at 3 DPH in crimson snapper.
Later, as the gill arches enlarged, the gill rakers also enlarged, became longer, increased in number and became more complicated in shape due to the addition of side processes.
The rostral extremities of gill arches are united forming a wide interbranchial septum between the contra-lateral gills.
Densities increase slightly on the gill arches (approximately 1600 denticles per c[m.sup.2]); however, these are smaller denticles (length 132 [+ or -] 5 [micro]m, width 120 [+ or -] 2 [micro]m) with a mean surface area of 7092 [+ or -]32 [micro][m.sup.2] (n = 8).
There was also staining in the endothelium of vessels in the gill arches of the DR fish.
Approximately 460 million years ago, the anterior gill arches of some aquatic vertebrates evolved into jaws and their supporting structures, including the hyomandibular bone.
Consider the explanation that is often given for surprisingly deep and widespread homologies, such as the well known homologies in tetrapod skulls that derive from embryonic gill arches, or the newly discovered molecular homologies in the homeobox gene systems among all metazoa.
The piscinootest consists of the careful excision and removal of excess blood of gill arches from fish with provisional diagnosis of piscinoodiniasis (Figure 1A).
It is also noted that the cartilage acts as a model to form dental bone, which at the stage of ova (350 UTA) bars cartilaginous gill arches (mandibular included) are differentiated bone ossification and dental tissue begins adjacent mesenchymal.