Gillilõhed

Gillilõhed, also known as gill slits, are external openings that lead to the gills of many aquatic animals, particularly fish and some amphibians. These slits are a crucial part of the respiratory system, allowing water to pass over the delicate gill filaments where oxygen is extracted from the water and carbon dioxide is released. In most bony fish, the gill slits are covered by a protective bony flap called the operculum. Sharks and rays, on the other hand, typically have multiple, visible gill slits that are not covered by an operculum. The number and arrangement of gill slits can vary significantly between different species, serving as a distinguishing characteristic for taxonomic purposes. Some larval amphibians, such as tadpoles, also possess external gill slits as part of their aquatic larval stage, which are often lost or covered as they metamorphose into terrestrial or semi-aquatic adults. The efficiency of gas exchange through gill slits is vital for the survival of these organisms in their aquatic environments.