An air-filled sac in many fish that helps maintain buoyancy or, in some species, helps in respiration, sound production, or hearing.
American Heritage Science
Other Word Forms of Air Bladder
Air Bladder Sentence Examples
The oesophagus is provided often with caeca which in Syllids and Hesionidae have been found to contain air, and possibly therefore perform the function of the fish's air-bladder.
European mackerel are of two kinds, of which one, the common mackerel, Scomber scomber, lacks, while the other possesses, an air-bladder.
But, on the ground of their air-bladder being closed, or deprived of a pneumatic duct communicating with the digestive canal, such as is characteristic of the Malacopterygians, they were removed from them and placed with the flat-fishes, or Pleuronectidae, in a suborder Anacanthini, regarded as intermediate in position between the Acanthopterygians, or spiny-finned fishes, and the Malacopterygians.
These are a chain of small bones belonging to the first four vertebrae, which are much modified, and connecting the air-bladder with the auditory organs.
The air-bladder may be so reduced as to lose its hydrostatic function and become subservient to a sensory organ, its outer exposed surface being connected with the skin by a meatus between the bands of muscle, and conveying the thermobarometrical impressions to the auditory nerves.