swim bladder


swim bladder
n.
a gas-filled sac in the dorsal portion of the body cavity of most bony fishes, giving buoyancy to the body and used as an accessory, lunglike organ in lungfishes

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▪ fish anatomy
also called  air bladder,  

      buoyancy organ possessed by most bony fish. The swim bladder is located in the body cavity and is derived from an outpocketing of the digestive tube. It contains gas (usually oxygen) and functions as a hydrostatic, or ballast, organ, enabling the fish to maintain its depth without floating upward or sinking. It also serves as a resonating chamber to produce or receive sound. In some species the swim bladder contains oil instead of gas. In certain primitive fish it functions as a lung or respiratory aid instead of a hydrostatic organ. The swim bladder is missing in some bottom-dwelling and deep-sea bony fish (teleosts) and in all cartilaginous fish (sharks, skates, and rays).

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Universalium. 2010.

Look at other dictionaries:

  • Swim bladder — Swim Swim, n. 1. The act of swimming; a gliding motion, like that of one swimming. B. Jonson. [1913 Webster] 2. The sound, or air bladder, of a fish. [1913 Webster] 3. A part of a stream much frequented by fish. [Eng.] [1913 Webster] {Swim… …   The Collaborative International Dictionary of English

  • swim bladder — n. a gas filled sac in the dorsal portion of the body cavity of most bony fishes, giving buoyancy to the body and used as an accessory, lunglike organ in lungfishes …   English World dictionary

  • swim bladder — gas bladder (a thin membranous, sometimes alveolated sac in the dorsal portion of the abdominal cavity. Composed of three layers, the tunica externa, the submucosa or middle layer and the tunica interna, all q.v. Contains a varying mixture of… …   Dictionary of ichthyology

  • swim bladder — swim′ blad der n. ich air bladder 2) • Etymology: 1830–40 …   From formal English to slang

  • swim bladder — /ˈswɪm blædə/ (say swim bladuh) noun → air bladder (def. 2) …   Australian English dictionary

  • swim bladder — noun Date: 1837 the air bladder of a fish …   New Collegiate Dictionary

  • swim bladder. — See air bladder (def. 2). [1830 40] * * * …   Universalium

  • swim bladder — noun an air filled sac near the spinal column in many fishes that helps maintain buoyancy • Syn: ↑air bladder, ↑float • Hypernyms: ↑sac …   Useful english dictionary

  • swim bladder. — See air bladder (def. 2). [1830 40] …   Useful english dictionary

  • swim bladder — noun A gas filled sac within the bodies of most fish that variously acts as a float, lung, sound producing organ or an aid to hearing …   Wiktionary


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