Gas bladder意思

"Gas bladder" is a term used in anatomy to refer to the swim bladder of fish. It is also known as the air bladder. The gas bladder is an internal organ that helps fish stay buoyant in the water. It is filled with gas, usually oxygen, and can be adjusted in size to control the fish's buoyancy. This allows the fish to maintain its position in the water column without having to swim constantly. Some fish use their gas bladders for other purposes as well, such as breathing air at the surface or making sounds.