Fish, like land animals or aquatic mammals, need to capture oxygen to live, this being one of their vital functions. However, fish do not take in oxygen from the air, instead they are able to capture dissolved oxygen in the water through an organ called gills
Do you want to know how fish breathe? Then don't miss this article on our site, we will talk about the respiratory system of teleost fish and we will learn how fish breathe.
The gills of the fish
The gills of teleost fish, which are most fish except sharks, rays, lampreys and hagfish, are found on both sides of the head From the outside we can see the opercular cavity, which is the part of the "fish face" that opens outwards and is called operculum. Inside each opercular cavity, we find the gills.
The gills are structurally supported by the branchial arches, of which there are four. From each branchial arch, two groups of filaments called branchial filaments come out, which are arranged in a "V" shape with respect to the arch. Each strand overlaps neighboring strands, forming a lattice. In turn, these branchial filaments have their own projections called secondary lamellae This is where the gaseous exchange, fish take in oxygen and release carbon dioxide.
The fish takes in water through its mouth and, through a complex process, releases the water through the opercula, first passing through the lamellae, where it is captured the Oxigen.
Respiratory system of fish
The respiratory system of fish is called bucco-opercular pump The first pump, the buccal, exerts positive pressure, so which sends the water towards the opercular cavity and, in turn, this cavity through negative pressure, sucks the water from the oral cavity. In short, the buccal cavity pushes water into the opercular cavity and the opercular cavity sucks it in.
During one breath, the fish opens its mouth and the area where the tongue is lowered, causing more water to enter, because the pressure decreases and water enters the mouth from the sea in favor of the gradient. Then closes the mouth and the buccal floor rises, increasing the pressure and causing the water to pass towards the opercular cavity, where the pressure is lower.
Then, the opercular cavity contracts, forcing the water to pass through the gills where the gas exchange will take place and exiting as Passive by operculum. When the fish opens its mouth again, some return of water may occur.
Also find out on our site why freshwater fish die in s altwater!
Do fish have lungs?
Although it may seem contradictory, evolution has caused the appearance of dipnoos or lungfish Within the phylogeny, they are classified in the class Sarcopterygii, for having lobed fins. These fish with lungs are thought to be closely related to those early fish that gave rise to land animals. There are only six known species of lungfish and we only know about some of them about their conservation status. Some don't even have a common name.
The species of fish with lungs are:
- American Mudfish (Lepidosiren paradoxa)
- African lungfish (Protopterus annectens)
- Marble Lungfish (Protopterus aethiopicus)
- Protopterus amphibius
- Protopterus dolloi
- Queensland or Australian lungfish (Neoceratodus forsteri)
Despite being able to breathe air, these fish are Very attached to water, even when water is scarce due to droughts, they hide in the mud protecting their body with a layer of mucus that they can manufacture. Their skin is very sensitive to desiccation, so without this strategy they would die.
