operculum . The operculum of bony fishes (Osteichthyes) is a hard bony fin that covers and protects the gills . In most fishes, the posterior limit of the operculum marks the boundary between the head and the trunk.
Summary
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- 1 Parts of the operculum
- 2 Features
- 3 Fish breathing
- 1 Functioning of the gills
- 4 Curiosities
- 5 sources
operculum parts
The operculum is composed of four bones:
- operculum AND
- preoperculum
- interoperculum
- suboperculum
Characteristic
The base of the operculum may be flat or strongly convex. The apex is usually a long, thin beak , but it is also short and rounded. The morphology of this anatomical feature has large variations between species. For example, Lepomis macrochirus has a posteriorly and dorsally oriented rounded extension with a small black spot. in some speciesthe operculum can push water from the oral cavity through the gills. For some fish, the operculum is vital for obtaining oxygen. It opens when the mouth closes, causing negative pressure to the outer side of the gills so that water flows to the lower pressure through the gills, allowing oxygen exchange in the lamellae (lamellae). Cartilaginous fishes (Chondrichthyes) do not have an operculum. They have other methods for the passage of water through the gills.
fish breathing
Fish breathe through gills. The gills are extensions of the skin, through which the gaseous exchange that constitutes respiration takes place. They are formed by a branchial arch that has blood-rich filaments on the inner edge and, on the outer edge, some rough edges called gill rakers. The gills are located in “chambers” symmetrically located on both sides of the body, behind the head. In fish with bony skeletons, the water that irrigates the gills passes through the mouth, enters the pharynx, enters the chamber and leaves when the operculum is opened. In fish with a cartilaginous skeleton, the gills communicate directly with the outside.
gill function
The fish opens its mouth and absorbs the water. The operculum is closed. The fish then closes its mouth and opens the operculum. This forces water to pass through the gills.
Curiosities
Dactylogyritis: The metazoan Dactylogyrus settles in the gills and produces mucous that can seal the opercula. In many specimens, the opercula do not completely cover the gills, exposing them to all kinds of diseases. The males, in the mating season (recognizable by white “tubercles” on the operculum and main radius of the pectoral fins) can hurt females with their continuous pursuit.