- Operculum (fish)
The operculum is composed of four fused bones; the opercle, preopercle, interopercle, and subopercle. These appear to be derived from the separate gill-slit covers of an elasmobranch ancestor of the teleost fishes. The posterior rim of the operculum is equipped with a flexible, ribbed structure which acts as a seal to prevent reverse water flow during respiration. The morphology of this anatomical feature varies greatly between species. For example, the bluegill (Lepomis macrochirus) has a posteriorly and dorsally oriented rounded extension with a small black splotch present. In some species, the operculum can push water from the buccal cavity through the gills.
For some fish, opercula are vital in obtaining oxygen. They open as the mouth closes, causing the pressure inside the fish to drop. Water then flows towards the lower pressure across the fish's gill lamellae, allowing some oxygen to be absorbed from the water.
Whereas the cartilaginous ratfishes have soft and flexible opercular flaps, the sharks, rays and relatives (elasmobranch fishes) lack opercula completely and respire instead through a series of gill slits perforating the body wall. Without opercula, other methods of getting water to the gills are required, such as ventilation.
Fish About fish Anatomy
- Fish anatomy
- Ampullae of Lorenzini
- Dorsal fin
- Swim bladder
- Gill slit
- Lateral line
- Leydig's organ
- Mauthner cell
- Pharyngeal teeth
- Shark cartilage
- Shark tooth
- Weberian apparatus
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Operculum — may refer to: Operculum (animal), a stiff structure resembling a lid or a small door that opens and closes Operculum (gastropod), a lid on the shell of some gastropods Operculum (bryozoa), a lid on the orifice of some bryozoans Operculum (fish),… … Wikipedia
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Fish — are aquatic vertebrate animals that are typically ectothermic (previously cold blooded), covered with scales, and equipped with two sets of paired fins and several unpaired fins. Fish are abundant in the sea and in fresh water, with species being … Wikipedia
operculum — ► NOUN (pl. opercula) Zoology 1) a flap of skin protecting a fish s gills, typically stiffened by bony plates. 2) a plate that closes the aperture of a gastropod mollusc s shell. ORIGIN Latin, lid, covering … English terms dictionary
operculum — [ō pʉr′kyo͞o ləm, ō pʉr′kyələm] n. pl. opercula [ō pʉr′kyo͞olə, ō pʉr′kyələ] or operculums [ModL < L, lid, dim. < operire, to close, shut: for IE bases see OB & APERTURE] any of various covering flaps or lidlike structures in plants and… … English World dictionary
fish — fishless, adj. /fish/, n., pl. (esp. collectively) fish, (esp. referring to two or more kinds or species) fishes, v. n. 1. any of various cold blooded, aquatic vertebrates, having gills, commonly fins, and typically an elongated body covered with … Universalium
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