swim bladder(redirected from Swim bladders)
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a gas-filled sac that is present in most fish and functions as a hydrostatic organ; it is located beneath the vertebral column primarily in the anterior abdomen and is connected with the esophagus in some species (for example, goldfish). Oxygen is transferred from a rich venous sinus into the swim bladder to increase buoyancy.
Synonym(s): swim bladder
A gas-filled structure in many fishes that functions to maintain buoyancy and, in some species, to aid in respiration or to produce sound. Also called air bladder, gas bladder.