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swim bladder
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fish swim bladder internal structure of fishes
Study the roles of a fish's scales, swim bladder, and gills in its respiratory system
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Sea otter (Enhydra lutris), also called great sea otter, rare, completely marine otter of the northern Pacific, usually found in kelp beds. Floats on back. Looks like sea otter laughing. saltwater otters
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fish swim bladder
fish swim bladder The swim bladder expands and contracts so that a fish may achieve buoyancy.

swim bladder

fish anatomy
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Also known as: air bladder
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Also called:
air bladder
Related Topics:
baroreception
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swim 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).

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Adam Augustyn.