Content
- How fish breathe the oxygen that exists in the water
- fish respiratory system
- How do fish breathe, do they have lungs?
- Fish sleeps: explanation
Fish, as well as terrestrial animals or aquatic mammals, need to capture oxygen to live, this being one of their vital functions. However, fish do not obtain oxygen from the air, they are able to capture oxygen dissolved in water through an organ called brachia.
Want to know more about how do fish breathe? In this article by PeritoAnimal we will explain how the respiratory system of teleost fish is and how their breathing works. Keep reading!
How fish breathe the oxygen that exists in the water
At brachia of teleost fish, which are the majority of fish with the exception of sharks, rays, lampreys and hagfish, are found. on both sides of the head. You can see the opercular cavity, which is the part of the "fish face" that opens outward and is called the operculum. Within each opercular cavity are the brachia.
The brachia are structurally supported by four brachial arches. From each brachial arch, there are two groups of filaments called brachial filaments that have a "V" shape in relation to the arch. Each filament overlaps with the neighboring filament, forming a tangle. In turn, these brachial filaments they have their own projections called secondary lamellae. Here a gas exchange takes place, fish capture oxygen and release carbon dioxide.
The fish takes seawater through the mouth and, through a complex process, releases the water through the operculum, previously passing through the lamellae, where it is capture the oxygen.
fish respiratory system
O fish respiratory system receives the name of oro-opercular pump. The first pump, the buccal, exerts positive pressure, sending water to the opercular cavity and, in turn, this cavity, through negative pressure, sucks water from the oral cavity. In short, the oral cavity pushes water into the opercular cavity and this sucks it up.
During a breath, the fish opens its mouth and the region where the tongue is lowered, causing more water to enter because the pressure decreases and sea water enters the mouth in favor of the gradient. Afterwards, it closes the mouth increasing the pressure and causing the water to pass through the opercular cavity, where the pressure will be lower.
Then, the opercular cavity contracts, forcing the water to pass through the brachia where the gas exchange and leaving passively through the operculum. When opening its mouth again, the fish produces a certain return of water.
Find out how fish reproduce in this PeritoAnimal article.
How do fish breathe, do they have lungs?
Despite seeming contradictory, evolution has led to the appearance of lung fish. Within the phylogeny, they are classified in the class Sarcopterygii, for having lobed fins. These lungfishes are believed to be related to those first fish that gave rise to terrestrial animals. There are only six known species of fish with lungs, and we only know about the conservation status of some of them. Others do not even have a common name.
At species of fish with lungs are:
- Piramboia (Lepidosiren paradox);
- African lungfish (Protopterus annectens);
- Protopterus amphibius;
- Protopterus dolloi;
- Australian lungfish.
Despite being able to breathe air, these fish are very attached to water, even when it is scarce due to droughts, they hide under the mud, protecting the body with a layer of mucus that they are capable of producing. The skin is very sensitive to dehydration, so without this strategy they would die.
Discover the fish that breathe out of water in this article by PeritoAnimal.
Fish sleeps: explanation
Another question that raises many doubts among people is whether fish sleep, since they always have their eyes open. Fish have the neural nucleus responsible for allowing an animal to sleep, so we can say that a fish is capable of sleeping. However, it is not easy to identify when a fish is sleeping for the signs are not as clear as, say, in a mammal. One of the most obvious signs that a fish is sleeping is prolonged inactivity. If you want to know more information about how and when fish sleep, check out this article by PeritoAnimal.
If you want to read more articles similar to How fish breathe: explanation and examples, we recommend that you enter our Curiosities section of the animal world.