How do fish breathe underwater?

How do fish breathe underwater?

Fish breathing methods

The fish breathes by entering water into its mouth and expelling it through the gill passages, and as the water passes over the thin walls of the gill passages, the oxygen dissolved in it is transferred into the blood of the fish, to be transferred later to its cells,[١] Here is an explanation of the different ways fish breathe:

Breathe through the skin

There are certain types of fish whose bodies lack gills and lungs, so they breathe through their skin, which is the main respiratory surface in most amphibians, so it must be kept moist, and studies indicate that the skin of amphibians contains many glands, and there are two basic types, namely: mucocutaneous glands and granular cutaneous glands.[٢]

The mucous glands are distributed all over the surface of the fish body and secrete sticky mucus, the importance of which lies in the following:

  • Keep the skin of the fish moist.
  • Make it easier for the fish to breathe through its skin.
  • Protects fish skin from abrasive shocks.
  • Prevent the entry of pathogens into the fish body.

It should be noted that the granular skin glands are less numerous than the mucous glands, which can be scattered on the body of the fish or gather at a specific point, and among the types of animals that breathe through the skin are frogs and catfish. (catfish)..[٢]

gill breathing

Fish exchange carbon dioxide and dissolved oxygen in water through gills located on both sides of the fish’s head.[١]

When water passes over the gills, the oxygen dissolved in the water quickly diffuses through them into the bloodstream, and then the circulatory system can transport the oxygenated blood to other parts of the body. Among the types of fish which breathe with gills, we find the common carp.[١]

Pulmonary respiration

A number of fish have developed special organs that help them breathe atmospheric air when they come out to the surface of the water, which are the lungs, and this type of fish has lungs that have been modified from of their air bladder, so they are connected to the digestive system of the fish.[٣]

It should be noted that the inner part of the lungs of fish consists of a huge number of cavities, which resemble a honeycomb with tiny blood vessels, and gas exchange takes place in small air sacs.[٣]

When the fish breathes, it raises its head to the edge of the water surface and opens its mouth, then takes in an appropriate amount of air, and this process is usually accompanied by a special sound for the fish, and among One type of fish that breathes using the lungs is the Australian lungfish, which breathes air through its nostrils while its mouth remains closed, unlike bony fish, which have an opening connecting the nasal cavity to the mouth.[٣]

How long do fish live out of water?

There are different types and sizes of fish, and they obviously don’t all have the same breathing abilities, so There is no specific time period for how long a fish can live out of water.It is important to note that the chances of a fish surviving out of water are determined by the conditions it lives in while out of water.[٤]

For example, if a fish jumps out of an aquarium and lands on a non-absorbent surface containing a small amount of water, it can survive by inhaling the dissolved oxygen content of the water, as long as its gills remain moist.[٤]

It should be noted that some fish can survive for a few minutes out of the water, some for a few hours and some for a few months, and it mainly depends on the species of fish, the environmental habitat and the duration of fish life. fight to survive.[٤]

the critic

  1. ^ a B J “The Respiratory System”, British, retrieved 2021-10-19. Edited.
  2. ^ a B “Skin Breathing”, sciencedirect, retrieved 2021-10-19. Edited.
  3. ^ a B J Adaptations for breathing British, retrieved 2021-10-19. Edited.
  4. ^ a B J “How long can fish survive out of water?”, a fishing story, retrieved 2021-10-19. Edited.





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