BRAINCAKEVentilating the Gills
To keep a steep concentration gradient at the gills, a bony fish must keep a continuous, one-way flow of water over them, even when it is not swimming. It does this by changing the volumes, and so the pressures, of two cavities: the buccal cavity (mouth cavity) and the opercular cavity (the chamber containing the gills). Water, like air, flows from higher to lower pressure.
Taking water in
• The mouth opens and the floor of the buccal cavity is lowered.
• The volume of the buccal cavity increases, so its pressure decreases and water flows in through the mouth.
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More in Gas Exchange
- The Tracheal System
- Very Active Insects
- Gas Exchange in Fish
- Fish Gills
- The Countercurrent Exchange System
- Gas Exchange in Plants
- Stomata
- Opening and Closing the Stomata
All 23 lessons in Gas Exchange · All Edexcel AS-level Biology topics