In biology, the main respiratory organ of most fishes and immature amphibians, and of many aquatic invertebrates. In all types, water passes over the gills, and oxygen diffuses across the gill membranes into the circulatory system, while carbon dioxide passes from the system out into the water.
In aquatic insects, these gases diffuse into and out of air-filled canals called tracheae.
Respiratory organ of aquatic animals that breathe oxygen dissolved in water; SYN. branchia. + prikaži više