home Aquarium How Fish Gills Work

How Fish Gills Work

Water entering the gills

The normal life of fish is ensured by the continuous supply of oxygenated water to the gills. In most bony fish, the mouth and gills work in concert according to the principle of a pump: first, the gills close tightly, the mouth opens, and its walls expand, drawing water inward. Then the mouth contracts, the mouth closes, and the gills open, pushing the water out of the mouth. This breathing pattern, which allows water to enter the gills, even when the fish is at rest, is typical of sedentary fish such as carp, flounder and halibut.

Breathing begins when the fish’s mouth opens and the mouth expands to suck in water.

Then the fish’s mouth closes and the operculums open, pushing water out of the gill cavity through the gills.

How fish breathe underwater?

Like all living things, fish need oxygen. Most fish get it through special grating organs called gills.

The gills are located just behind the oral cavity on either side of the head and are usually protected by a translucent plate. the operculum, or operculum. Below the operculum are four rows of partially overlapping blood-red gills. The gills are made up of bony arches that support numerous gill lobes. a pair of thin, soft processes that resemble the tightly set teeth of a comb. Each petal contains tiny membranes, or lamellae, woven from billions of blood capillaries. The walls of the membranes are so thin that the blood flowing through them extracts oxygen directly from the water stream that washes the gills. Then the lamellae remove carbon dioxide from the blood into the water. Water, like air, is 1/30 of oxygen, and this gas exchange. oxygen and carbon dioxide is a key component of underwater life.

Rigid gill rakers located on the branchial arch filter the incoming water. The blood vessels in the gill lobes supply blood and drain the capillaries in the lamella.

The water passing through the gill lobes enriches the arterial blood with oxygen. After that, the blood flows through the venous vessels into the membrane, where it is freed from carbon dioxide.

It is better to breathe through the mouth

Active fish. mackerel, tuna, and some shark species. need more oxygen than their slower counterparts such as flounder, eel, electric ray and seahorses. This is why underwater fish often swim with their mouths open: this allows them to pass a much larger volume of water through their gills, and therefore oxygen. In addition, the gills of these fish species are larger and thicker, with closely spaced membranes, which markedly increases their respiratory capacity. These fish are forced to swim even during sleep, otherwise they will die from lack of oxygen (from suffocation).

How gills work

Fish gills are visible when looking at their heads. These are the lines on the sides of the fish’s head. The gills are also found inside the body of fish, but they cannot be seen from the outside. just like our own lungs. The fish can be seen breathing in the water because its head gets bigger as it draws water. Just like when a person swallows a large piece of food.

First, water enters the fish’s mouth and flows through the gills. When the water leaves the gills, it returns to the reservoir. In addition, the carbon dioxide produced by the fish is also removed with the water when it leaves the gills.

Fun fact: fish and other animals with gills breathe oxygen because their blood flows through the gills in the opposite direction from the water. If the blood flowed through the gills in the same direction as the water, the fish would not receive the necessary oxygen from it.

The gills are like a filter, and they collect oxygen from the water, which the fish needs to breathe. After the gills absorb oxygen (oxygen cycle), the gas travels through the blood and nourishes the body.

This is why it is so important to leave fish in the water. Without water, they won’t get the oxygen they need for health.

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One of the most encouraging aspects of modern fishing is the fact that once caught, the fishermen are very careful with the fish they catch. In order for the fish to be released healthy and unharmed, a basic knowledge of the internal structure of the fish body is required. We hope that this information will help you not to harm and safely release the fish you just caught.

Gills. The gills in fish are located behind the operculum. In healthy fish, they are bright red. With the help of gills, fish extract oxygen from the water, which they need for normal functioning. The gills of fish can extract more than 80% of oxygen from the water (on average, humans extract only 4%). The tissue that makes up the gills is very, very thin, about seven thousandths of a millimeter thick. This makes the gills very, very “tender”. In water, gill covers serve as reliable protection for them. Rough handling of fish can easily damage the gills. When releasing, try not to touch the gills and areas near them. Fish uses oxygen to digest food and provide energy for life.

Swimming bladder. Its main function is to compensate the body weight of the fish in water. This means that the fish will remain in the water column even when they are not moving their fins. In fact, it provides the fish with neutral buoyancy. For slow movement, the fish uses ribs, not fins and still remains in the desired water horizon.

Weberian Ossicles. These bones are found only in carp fish. It is a chain of small bones that connect the hearing system and the swim bladder. This bundle provides fish with the ability to hear in a much wider range of audio frequencies. Fish such as perch and pike do not have such bones and, as a result, have much less sensitive hearing.

Ears. Fish have inner ears that have nothing to do with the outside world. The reason for this is simple. they don’t need an external ear. Sounds are transmitted much better in water than in air. As a result, fish can easily perceive sounds and can detect their source. Fish hear low-frequency sounds much better than humans, but high-frequency sounds are practically indistinguishable for them. Remember this when stomping loudly or making noise on the shore.

A heart. Like humans, it is a pump that pumps blood. In fish, blood, leaving the heart, is delivered directly to the gills. When it enters the gills, the blood pressure rises. it flows very quickly. This helps the gills extract oxygen more efficiently and quickly drain waste away. From the gills, blood flows to other organs. This means that if the gills are damaged, the fish will lose a lot of blood. Try not to touch the gill area. The heart of the fish is located under the gills in a V-shaped depression formed by the gill covers. Thus, the heart makes minimal effort to pump blood to the gills.

Brain The brain of a fish is small but functional. It is especially good at processing information from the organs of sight, hearing and smell.

Liver. Most fish have large liver. Typically, the liver is connected to the pancreas. It serves to process harmful chemicals. The liver is also connected to the intestines. If the liver is damaged, the fish will not be able to properly process their food and will die. So far, there is no evidence that feeding fish with artificial feed (compound feed, pellets, etc.) does not harm the fish body.

Stomach and intestines. The stomach of predatory fish is designed to digest prey. Fish such as carp or roach have virtually no stomach at all. They just have long intestines. This is explained by the fact that they feed more often than predators and small particles most often become their food. This means that they simply do not need the stomach. the whole process of digestion takes place in the intestines. Food enters it and is digested through chemicals. It is absorbed by the intestines or transported by the blood to the liver, or stored to be used later.

Kidneys. 2 kidneys in fish are combined into one and are located under the spine. The main function of the kidneys is filtration. And this function is very well developed in all freshwater fish. The kidneys filter the blood and allow the fish to get rid of water that enters the body through the gills or intestines. If the kidneys are damaged as a result of the disease, water will accumulate in the fish.

Spleen. A dark red organ located in the center of the fish body. The spleen creates and stores blood and helps fight infections.

Gallbladder Produces bile, which is found in the intestines to neutralize stomach acids and help digest fats.

Any use of materials without reference is prohibited

Dogs, humans, and fish breathe for the same reason. Everyone needs oxygen. Oxygen is a gas that bodies use to generate energy.

Living things experience two feelings of hunger. stomach and oxygen. Unlike the breaks between meals, the breaks between breaths are much shorter. People take about 12 breaths per minute.

It may seem that they breathe only oxygen, but there are many other gases in the air. When we breathe in, the lungs are filled with these gases. The lungs separate oxygen from the air and release other gases that the bodies do not use.

Everyone exhales the carbon dioxide that bodies produce when they generate energy. Just like the body sweats when we exercise, the body also emits carbon dioxide when we breathe.

Fish also need oxygen to move their bodies, but the oxygen they use is already in the water. Their bodies are not the same as those of humans. Humans and dogs have lungs, fish have gills.

Fish gills photo for children

Human lungs, mammalian lungs must be dry. We cannot breathe underwater. But fish live in water and they cannot live on land. How do they then breathe in water? Why fish can breathe underwater?

Humans and mammals need oxygen to breathe. We breathe air and we breathe oxygen. Fish need oxygen to breathe too! In order to release oxygen from the water, fish have gills that are located on either side of the head.

The gills are a porous organ with a mass of blood vessels.

The fish swallows water, water passes through the thin walls of the gills.

The oxygen concentration in the blood of fish is always less than in water, due to this diffusion occurs. Oxygen dissolved from water passes into the blood.

Oxygen is picked up by hemoglobin in red blood cells and then transported throughout the fish’s body.

Oxygen is absorbed by tissues and used in important cellular functions. This is how fish extract oxygen from the water and breathe it in.

You may be wondering why dolphins and whales swim near the surface of the water and don’t swim deep. Because these are not fish at all! Whales and dolphins are mammals, just like humans. They have lungs to breathe. They need air to breathe.

For reference

Water is hydrogen oxide. A water molecule consists of two hydrogen atoms and one oxygen atom. Chemical formula of water: H2O.

Other respiratory mechanisms in fish

Many fish breathe through their skin, especially when they are born, because they are so small that they do not have specialized organs. As it grows, gills develop because there is not enough diffusion through the skin. 20% or more cutaneous gas exchange observed in some adult fish.

Some fish species have developed cavities behind the gills that are filled with air. In others, complex organs developed from the irrigated branchial arch form and act as a lung.

Some fish breathe air without special adaptation. American eel covers 60% of oxygen needs through the skin and 40% is swallowed from the atmosphere.

It is better to breathe through the mouth

Active fish. mackerel, tuna, and some shark species. need more oxygen than their slower counterparts such as flounder, eel, electric ray and seahorses. This is why underwater fish often swim with their mouths open: this allows them to pass a much larger volume of water through their gills, and therefore oxygen. In addition, the gills of these fish species are larger and thicker, with closely spaced membranes, which markedly increases their respiratory capacity. These fish are forced to swim even during sleep, otherwise they will die from lack of oxygen (from suffocation).

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How fish breathe underwater?

Date Category: Underwater World

Like all living things, fish need oxygen. Most fish get it through special grating organs called gills.

The gills are located just behind the oral cavity on either side of the head and are usually protected by a translucent plate. the operculum, or operculum. Below the operculum are four rows of partially overlapping blood-red gills. The gills are made up of bony arches that support numerous gill lobes. a pair of thin, soft processes that resemble the tightly set teeth of a comb. Each petal contains tiny membranes, or lamellae, woven from billions of blood capillaries. The walls of the membranes are so thin that the blood flowing through them extracts oxygen directly from the water stream that washes the gills. Then the lamellae remove carbon dioxide from the blood into the water. Water, like air, is 1/30 of oxygen, and this gas exchange. oxygen and carbon dioxide is a key component of underwater life.

Rigid gill rakers located on the branchial arch filter the incoming water. The blood vessels in the gill lobes supply blood and drain the capillaries in the lamella.

The water passing through the gill lobes enriches the arterial blood with oxygen. After that, the blood flows through the venous vessels into the membrane, where it is freed from carbon dioxide.

How fish gills work

Municipal autonomous preschool educational institution Kindergarten “Alenka” s. Kudara of the municipal formation “Kabansky district” of the Republic of Buryatia

Summary of the lesson on the topic: “What fish breathe” Senior group

Speech therapist: Novolodskaya Marina Gennadievna

Creation of conditions for the development of cognitive and research activities of children through familiarization with the inhabitants of Lake Baikal and their habitat.

To acquaint children with the inhabitants of Lake Baikal, to give general information about the representatives of (name).

2.Give children an idea of ​​how fish breathe.

By observation and experiment, determine in what form the air is in the water.

Contribute to the development of logical thinking, observation, attention, the ability to identify the living conditions of the inhabitants of the lake (cognitive development).

Create conditions for encouraging children to speech activity (speech development).

To promote the development of interaction skills of children with adults and peers (social and communicative development).

Words-names of fish, epischura, macrohectopus, names of respiratory organs of fish-gills.

Expected results: Children will learn that fish need air to live. They breathe the air in the water with the help of special organs. gills. Through the experiment, children learn that air in water is in the form of bubbles, it is everywhere, in all objects and materials, it is easy to detect it if objects are immersed in water.

Types of children’s activities: communicative, play, cognitive and research.

Materials and equipment: a model of Lake Baikal, models of fish, pictures with the image of fish from Baikal, a glass jar with water, stones, an aquarium with fish.

Organized activities of children

Children sit in a semicircle near the table on which the visual material is located.

-Guys, listen to the riddle:

There is a lake in Buryatia,

Where the water in it is clear, pure.

We call the lake. the sea,

We call it. Baikal.

Examining a poster depicting Lake Baikal, fish of Baikal.

Educator: children, look at this model of Lake Baikal. Who knows where this lake is? (children’s answers). A large number of fish live in Baikal, and do you know what fish live in Baikal? Try to guess:

Silver, mobile, flexible,

It tastes better than many fish

Starts with O (omul)

Cold water is needed.

And the fish melts in the sun,

Fish oil expires (golomyanka)

She is the most dangerous of all

Cunning, gluttonous, strong

over, such a spiteful person

Of course it is. (pike)

Some graze in an open field,

Others are free to swim.

Some were met all over the land,

Others are found in Baikal.

Broad forehead, decent tail,

What is their name- question!

Silver, mobile, flexible,

It tastes better than many fish

Gives the ear a special taste

We list the names of the fish, children attach them to the model of the lake.

And also crustaceans live in Lake Baikal, they are called Epishura, Macrohectopus.

-And now I suggest you play the game “Fisherman”.

-Who loves to fish with a rod? (Children “catch” fish, remembering its name).

And what else fish cannot live without (heat, light and air)?

A fish cannot live without air, just like a person. How do we breathe (children’s answers)? How fish breathe, we now find out.

Look, the fish have gills on their heads that constantly open and close. The fish swallows water through the mouth, the air remains in the fish, and the water exits through the gills.

The teacher offers to see how the fish breathe in the aquarium

Air is everywhere, but invisible. Now we will see how the air is in the water.

Children are standing near the table where there is a can of water. The teacher shows the stones to the children, asks if there is air in them (children’s answers).

Suggests looking closely at the water can to see what will happen. He throws one stone into the water, he drowns (the teacher asks what the guys saw, what kind of bubbles they were and where did they come from). Explains that the bubbles are air, it was in the stone and came out of it when the stone hit the water.

The teacher invites the children to take one stone at a time and throw it into the water and observe what is happening, notes the air bubbles that appear, this is what fish cannot live without in the water.

What we talked about today in class?

What is the air in the water?

The lesson is over, thanks for the work, it was very interesting to me with you, goodbye.

Water entering the gills

The normal life of fish is ensured by the continuous supply of oxygenated water to the gills. In most bony fish, the mouth and gills work in concert according to the principle of a pump: first, the gills close tightly, the mouth opens, and its walls expand, drawing water inward. Then the mouth contracts, the mouth closes, and the gills open, pushing the water out of the mouth. This breathing pattern, which allows water to enter the gills, even when the fish is at rest, is typical of sedentary fish such as carp, flounder and halibut.

Breathing begins when the fish’s mouth opens and the mouth expands to suck in water.

Then the fish’s mouth closes and the operculums open, pushing water out of the gill cavity through the gills.

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Why gills need to be removed?

The answer to this question is simple, but first, we note that getting rid of gills is not always necessary. When it comes to river and lake fish, as a rule, you should protect yourself from the smell of mud. It is in the gills that the center of an unpleasant odor is located, which can also affect the taste of the finished dish. Therefore, when cooking perch, silver carp, pike, it is always necessary to remove the gills.

The gills of marine fish can also fill the food with an unpleasant aftertaste. If you plan to bake the fish whole or put your heads in your ear, you must get rid of the gills. They can also contain all kinds of garbage: duckweed, fragments of aquatic plants and even living creatures.

When boiled, the gills give the broth a disgusting unappetizing shade and completely unnecessary smells. This is the answer to the question of why to remove gills from fish for fish soup.

How to remove gills from fish: a step by step guide

Today, many retail outlets, where you can buy seafood delicacies, offer customers not only fresh fish, but also a cleaning service. Sellers usually charge very little for their work. On average, 10 to 30% of the purchase price. Not wanting to stain the kitchen with scales and trying to save time, many buyers are happy to use this additional service.

Therefore, everyone who plans to pamper their family with an exquisite dish should know not only the recipe for cooking, but also how to remove the gills from fish.

Our article will tell you about this.

Precautions

Before removing the gills from a fish, pay attention to the following. Some species have acquired a variety of protective devices. For example, pike perch has grown sharp spines on its fins in the process of evolution. The gills can also have spiny edges.

Pulling out the gills by hand, especially when cleaning large fish, runs the risk of injury. To prevent this from happening, inspect the surface, do not jerk. Even ordinary pliers can be used to remove the gills, but you need to pull not by the middle of the arc, but by the very edge. Otherwise, the gills will break, and you will have more work: getting rid of torn flaps is more difficult than from a whole organ.

Gill removal process

Our step-by-step instructions will help you overcome any gills. The process should start after cleaning the fish from the scales. Consider how to remove gills from fish:

  • Turn the carcass with its belly towards you. Peel back the operculum on one side and make an incision near the frontal gill arch. For this, you can use both a sharp knife and culinary scissors.
  • Do the same with the second branchial arch.
  • Fold back the bridle that connects the gill arches under the fish’s mouth. Slide a sharp knife through, cut both gill arches from the bridle.
  • Pull out the gills carefully.
  • Rinse the carcass under running water, placing under the stream the place to which the gill arches were attached.

That’s all the wisdom. If this is your first time thinking about how to remove the gills from a fish, then most likely you have presented a complex and time-consuming process. Perhaps on the first try it will turn out to be like that. But with a little stuffing your hand, you can easily cope with the task.

Is it always necessary to remove gills from fish?

Some saltwater fish, especially small ones, do not have a pungent smell. You don’t have to mess with the gills of herring, mackerel, saury. Even when salting the whole, extraneous odors will not arise.

Of course, you shouldn’t waste time fighting gills if you don’t plan on using fish heads in your cooking.

Poisoning

One of the most common causes of reddening of the gills in aquarium fish is nitrite or ammonia poisoning. In this case, the color of the gills becomes more likely even scarlet, or purple, than bright red. A particularly deplorable situation can be if the fish have been living in such an environment for a long time. Goldfish are a separate topic, as they are often kept in aquariums without living plants, and the latter can cope well with the remains of food and fish life, which significantly naturally reduces the level of nitrite. Also, with a high level of nitrates, fish can scratch on various objects. this can also speak in favor of the version with water quality.

How to solve the problem I think you have already guessed. To begin with, be sure to make tests of water for nitrites, ammonia. The latter must be zero! If there are doubts about the quality of the water, then the only correct treatment option will be to change the water to clean and settled according to all the rules. If there are a lot of nitrites and ammonia, then it may be necessary to resort to the use of special water conditioners. Change water every day at 10-15% for several days. Then you do tests again and adjust your actions based on them. Here you can read about how to get a lot of water for your aquarium quickly.

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Insufficient volume

Volume is a very important factor that affects the health of the fish and their longevity. For example, oranda need an aquarium of 60-100 liters, depending on their quantity. It is also necessary to take into account other fish living in the aquarium and their total number.

Providing this condition, the fish can feel comfortable, it can be stress-free, and it can have good immunity. However, in a larger aquarium with a sufficient number of plants, the level of nitrates and nitrites can be naturally reduced.

Disease

The gills can be irritated and affected also as a result of illness. these can, as a rule, be some kind of parasites. Usually they can be noticed if you take a good look at what is happening in the fish under the gill cover. Parasites are treated only with special drugs. But without strong evidence, we do not recommend starting to pour the medicine into the aquarium or planting fish for treatment. Better to work out the poisoning version first due to poor water quality.

Answer

Reddening of the gills in aquarium fish (goldfish) is quite common. It occurs in a wide variety of species. regardless of their size. There may also be many reasons for the appearance of such symptoms. these can be both serious diseases and not so.

It is difficult to give any assumptions and make predictions without additional information, so you will have to disassemble this disease from all sides.

The gills of goldfish turn red

Question from Oksana

Say oranda has red gills and very rapid breathing. What can this beat? Before that, two weeks ago, several fish died. Help, otherwise everyone will die.

Why can goldfish gills blush?

In general, pink or even red gills are normal for a fish. But extreme colors, such bright scarlet and pale white. these are already problems. Also, the open gill covers, as well as translucent ones, through which these very red gills are visible, can be a cause for concern. Take a close look at the fish, as the lower part of the head (under the gills) can also turn red.

So, here are some reasons for this problem:

  • Increased levels of nitrites, ammonia.
  • Insufficient aquarium volume.
  • Disease.
  • Defect; there may be a lack of pigment in the fish scales, so the gills are clearly visible through the lid.

Defects

It is quite possible that the operculum is visible through the fish due to some defects. In addition to any problems with pigments, there may also be defects in the structure of the gill covers, due to which part of the reddened gills is visible. Of course, fish do not die from the fact that they are missing part of the operculum, but death may well occur as a result of poisoning. In some cases. in the later stages of the disease. the fish may not even be able to be saved if the gills are already badly burned.

Carefully monitor the quality of the aquarium water, make changes in time, and, if possible, plant live plants in the aquarium. And of course, don’t forget about aeration. In case of ammonia poisoning, aeration should be set to almost the maximum level.

How do fish breathe? What do fish breathe? What devices for breathing do they have??

Fish can be found in swamps, lakes, seas and rivers of all geographic zones of the planet. They spend their whole life under water, without experiencing any difficulties with breathing. Most of them do not need to float to the surface in order to swallow the next portion of air. What do fish breathe? What mechanisms help them survive in the aquatic environment? We will talk about the internal structure of fish and the natural tricks of these aquatic animals in our article.

Oxygen demand

In the aquatic environment, fish are the predominant group of animals. In rivers and oceans, they go through all stages of their biological development. from eggs to adults. At the same time, only a few species can emerge from time to time and inhale atmospheric air, while most have adapted to live without it.

But what do fish breathe when they are constantly in the water? Like other vertebrates, they need oxygen for normal life. They “extract” it not from the air, but directly from the water, literally filtering it. To get enough gas, they have to “process” a huge amount of liquid.

Oxygen in the reservoir is extremely important for their normal functioning, and a lack of oxygen causes starvation and death in animals. However, the norms of gas concentration are different for each species. For example, tench and carp live in stagnant water bodies and are able to survive even in the weak presence of oxygen (from 4 cm 3 / l to 0.5 cm 3 / l). Trout, salmon, pike perch, on the contrary, are very demanding. They need a gas concentration of more than 7 cm 3 / l.

The perception of fish changes with their age, with the transition from season to season, and also depending on their activity. So, the younger and more mobile the individual, the more it needs oxygen. The needs increase greatly before spawning, when the fish needs a lot of strength and energy. In the heat and during the winter freezing of the reservoir, there is a lack of oxygen, which makes the animals have difficulty breathing.

Other respiratory mechanisms in fish

Many fish breathe through their skin, especially when they are born, because they are so small that they do not have specialized organs. As it grows, gills develop because there is not enough diffusion through the skin. 20% or more cutaneous gas exchange observed in some adult fish.

Some fish species have developed cavities behind the gills that are filled with air. In others, complex organs developed from the irrigated branchial arch form and act as a lung.

Some fish breathe air without special adaptation. American eel covers 60% of oxygen needs through the skin and 40% is swallowed from the atmosphere.

How fish breathe under water. video. Features of respiration in fish. How fish breathe

RESPIRATORY ORGANS OF FISH

Fishes are characterized by two types of respiration: water (with the help of gills and skin) and air (with the help of the skin, swim bladder, intestine and supra-gill organs). Respiratory organs of fish are divided into: 1) main (gills); 2) additional (all others).

The main respiratory organs. The main function of the gills is gas exchange (absorption of oxygen and the release of carbon dioxide), they also participate in water-salt metabolism, secrete ammonia and urea.

In cyclostomes, the respiratory organs are represented by gill sacs (endodermal origin), which are formed as a result of separation from the pharynx. Lampreys have seven pairs of gill sacs with two openings in each of them: external and internal, leading to the respiratory tube and capable of closing. The breathing tube was formed as a result of the division of the pharynx into two parts: the lower respiratory and upper digestive. The tube ends blindly, and is separated from the oral cavity by a special valve. The larva of the lamprey (sandworm) does not have a respiratory tube, and the internal gill openings open directly into the pharynx. In most myxines, the external gill openings on each side are combined into a common canal, which opens further than the last branchial sac. In addition, the nasal opening of myxins communicates with the pharynx. In cyclostomes, water enters through the mouth opening into the pharynx or respiratory tube (in adult lampreys and myxins), then into the gill sacs, from where it is pushed out. When feeding, water is sucked in and excreted through the external gill openings. In mixins buried in silt, water enters the gill sacs through the nasal opening.

In fish embryos, respiration is carried out due to a developed network of blood vessels in the yolk sac and in the fin fold. As the yolk sac is absorbed, the number of blood vessels on the fin folds, sides, and head increases. In the larvae of some fish, external gills develop. outgrowths of the skin, supplied with blood vessels (lungs, mnogoper, loach, etc.).

The main respiratory organs of adult fish are gills (ectodermal origin).

Most cartilaginous fish have five pairs of branchial openings (some have 6–7) and the same number of branchial arches. There is no operculum, with the exception of whole-headed (chimeras), in which the gill slits are covered with a skin fold. In sharks, gill openings are located on the sides of the head, in rays. on the lower surface of the body.

Each gill of cartilaginous fish consists of: 1) the branchial arch; 2) gill petals; 3) gill stamens.

The interbillary septum extends from the outer side of the branchial arch, the gill petals cover it on both sides, while the posterior edge of the septum remains free and covers the external branchial opening (Fig. 18). The branchial septa are supported by cartilaginous support rays. The branchial stamens are located on the inner surface of the branchial arch. At the base of the intergill septum, there are blood vessels: 1) the branchial artery that carries venous blood; 2) two outflowing branchial arteries with arterial blood.

The branchial petals, located on one side of the septum, form a semi-gill. Thus, the gill consists of two semi-gills located on one branchial arch, and the aggregate of two semi-gills facing one branchial cleft forms a branchial sac. On the first four of the five branchial arches, there are two semi-gill arches, and on the last branchial lobes, there are no gill lobes, but in the first branchial sac on the hypogillary arch there is one more semi-gill. Hence, cartilaginous fish have four and a half gills.

In cartilaginous fish, the spithagus, which is a rudimentary branchial cleft, can be classified as the respiratory organs. They are located behind the eyes and communicate with the oropharyngeal cavity. On the front wall of the sprinkler there are valves, and on the back wall there is a false gill, which supplies the organs of vision with blood. Squid are found in cartilaginous and sturgeon. In cartilaginous fish, unlike bony fish, the gills do not secrete nitrogen metabolism products and salt.

In sharks, when breathing, water enters through the mouth opening and exits through the external gill slits. In stingrays, water enters the oropharyngeal cavity through the open valves of the sprinkler, and when the valves are closed, it comes out through the gill slits.

fish, gills, work

Sturgeon fishes in their gills have short intergill septa. Their reduction is associated with the appearance of the operculum, from which the gill membranes extend, covering the gills from below. Sturgeons (like cartilaginous fishes) have five pairs of branchial arches; on the last branchial arch, hidden under the skin, there are no branchial petals. The anterior row of gill petals is located on the inner surface of the operculum and forms a semi-gill arch (opercular gill). Sturgeons, like cartilaginous ones, have four and a half gills. On the inner surface of the branchial arch, the branchial stamens are located in two rows.

Teleost fishes have four branchial arches and the same number of full gills (the posterior, fifth, branchial arch does not bear gills). Each gill consists of two semi-gills, but due to the presence of a developed gill cover, the intergill septum is completely reduced, and the gill petals are attached directly to the gill arch, which increases the respiratory surface of the gills. The base of the gill is the bony branchial arch, on which the gill petals are triangular in shape. Gill lobes on both sides are covered with gill lobes (or respiratory folds), where gas exchange takes place. At the base of the gill lobes are chloride cells that remove salts from the body. A supporting cartilaginous ray passes along the inner edge of the branchial lobe, along which the petal artery stretches, and on the opposite side. the petal vein. At the base of the branchial lobes are the inflowing and outflowing branchial arteries. On the inner surface of the branchial arch there are branchial stamens of various sizes and shapes.

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During the gill breathing of bony fish, water enters the pharynx through the mouth, passes between the gill lobes, gives oxygen to the blood, receives carbon dioxide and leaves the gill cavity to the outside. Gill respiration can be: 1) active, water is sucked into the pharynx through the mouth opening and washes the gill petals due to the movement of the gill covers (in all fish); 2) passive, fish swim with open mouth and gill covers, and the water flow is created by the movement of the fish itself (in fish living in water with high oxygen).

Additional respiratory organs. In the process of evolution, bony fish living in water bodies where there is a deficiency of oxygen, developed additional respiratory organs.

Cutaneous respiration is characteristic of almost all fish. In fish of warm stagnant water bodies, about 20% of consumed oxygen enters through the skin, sometimes this value can rise to 80% (carp, crucian carp, tench, catfish). In fish living in reservoirs with a high oxygen content, skin respiration does not exceed 10% of the total oxygen consumption. Juveniles tend to breathe skin more intensively than adults.

Some species are characterized by air breathing, which is carried out with the help of the supragillary organs, which have a different structure. In the upper part of the pharynx, many of them develop paired hollow chambers (supragillary cavities), where the mucous membrane forms numerous folds, penetrated by blood capillaries (snakeheads). In creeper (labyrinth) fish, the folds of the mucous membrane are supported by labyrinthine bent bony plates extending from the first branchial arch (creeper, cockerels, gourami, macropods).

In clarius catfish, an unpaired treelike branched supragillary organ located above and behind the gills departs from the gill cavity. In sacgill catfish, additional respiratory organs are paired long blind sacs that extend from the gill cavity and stretch under the spine to the tail. Fish that have supragillary organs have adapted to breathing atmospheric oxygen and, deprived of the opportunity to rise and swallow air at the surface, die from suffocation even in water rich in oxygen.

Some fish have intestinal respiration. The inner surface of part of the intestine is devoid of digestive glands and is permeated with a dense network of blood capillaries, where gas exchange takes place. Air swallowed through the mouth passes through the intestines and out through the anus (loach) or is pushed back and out through the mouth (tropical catfish). A number of tropical fish use the stomach or a special blind outgrowth of the stomach filled with air to breathe air.

The swim bladder of fish is also involved in gas exchange. In lungfish, it has transformed into a kind of lungs, they have a cellular structure and communicate with the pharynx. Breathing air enters the lungs through the mouth or nose. Among lung-breathing fish there are one-lung (cattle-toothed) and two-lung (protopter, lepidosiren). In one-lungs, the lung is divided into two parts and the gills are well developed, so they can equally breathe with the lungs and gills. In bipulmonary animals, the swim bladder is paired, the gills are underdeveloped. When fish are in the water, the lungs are additional respiratory organs, and in dry bodies of water, when they burrow into the ground, the lungs become the main respiratory organ.

The swim bladder is an additional respiratory organ in some other open-bubble fishes (polypere, amia, carapace pike, haracin). It is permeated with a dense network of blood capillaries, and in some, cellularity appears, which increases the inner surface.

N.V. ILMAST. INTRODUCTION TO ICHTIOLOGY. Petrozavodsk, 2005

What do fish breathe? Gas exchange devices

In the same way as in our country, fish exchange gas through the circulatory system. For this, most of them have only one circle of blood circulation and a two-chambered heart, in lung-breathing species there are two such circles. Oxygen enters the heart through the vessels, and enters them through the gills, which filter gas from the water.

The respiratory system of fish is, in fact, more efficient than a human. It is able to filter from water two to three times more oxygen than the lungs separate from the atmosphere. Basically, fish breathe with gills, but sometimes their work is insufficient or conditions do not allow their normal use. In this case, other special bodies are connected to them.

There are quite a few additional or alternative ways of breathing in fish. Absolutely all species help themselves, partially carrying out gas exchange through the skin. Some also use the swim bladder, others use the intestines or a cecum in the stomach. Some species have adapted to breathing air of the atmosphere, for this they use labyrinth or supra-gill organs.

Why and how fish breathe underwater

Dogs, humans, and fish breathe for the same reason. Everyone needs oxygen. Oxygen is a gas that bodies use to generate energy.

Living things experience two feelings of hunger. stomach and oxygen. Unlike the breaks between meals, the breaks between breaths are much shorter. People take about 12 breaths per minute.

It may seem that they breathe only oxygen, but there are many other gases in the air. When we breathe in, the lungs are filled with these gases. The lungs separate oxygen from the air and release other gases that the bodies do not use.

Everyone exhales the carbon dioxide that bodies produce when they generate energy. Just like the body sweats when we exercise, the body also emits carbon dioxide when we breathe.

Fish also need oxygen to move their bodies, but the oxygen they use is already in the water. Their bodies are not the same as those of humans. Humans and dogs have lungs, fish have gills.

Variety of aquatic organisms

These respiratory organs develop in a huge variety of aquatic organisms, we can find different types of gills in molluscs, worms, crustaceans, echinoderms, fish and even reptiles at certain stages of their life cycle.

Characteristic gills, functions, types and importance

Gills or gills. These are the respiratory organs of aquatic animals that perform the function of exchanging human oxygen with the environment. They range from very simple forms in invertebrates to complex structures that have developed in vertebrates, consisting of thousands of specialized plates located inside the gill cavity, ventilated by a continuous flow of water.

Cells require energy to function, this energy is obtained from the breakdown of sugar and other substances in a metabolic process called cellular respiration. In most species, oxygen in the air is used as energy and carbon dioxide is emitted as waste.

The way organisms exchange gases with their environment depends on both the shape of the body and the environment in which it lives.

Aquatic environments have less oxygen than terrestrial ones and diffusion of oxygen is slower than in air. The amount of oxygen dissolved in water decreases with increasing temperature and decreasing current.

Less developed species do not need specialized respiratory structures to perform their basic functions. However, in larger systems, it is vital to have more sophisticated metabolic systems so that they can adequately cover their metabolic needs.

Gills are found in invertebrates and vertebrates, can be in the form of filaments, laminar or treelike, endowed with many capillaries, we also observe them internally or externally.

The coastal area is home to animals such as molluscs and crabs, which can actively breathe gills in the water and air as long as they remain moist. Unlike other aquatic organisms, which suffocate when leaving the water, despite the abundance of available oxygen.

  • 1 General characteristics
  • 2 functions
  • 3 How they work?
  • 4 types (external and internal)
  • 4.1 External gills
  • 4.2 Internal gills
  • 5 Importance
  • 6 References
  • External gills

    External gills are observed mainly in less developed invertebrate species and temporarily in the early stages of reptile development, since they lose them after undergoing metamorphosis.

    This type of gill has certain disadvantages, firstly, because they are delicate appendages, prone to abrasions and attract predators. In organisms that have movement, they impede their movement.

    Being in direct contact with the external environment, they are usually very susceptible and can easily be exposed to adverse environmental factors such as poor water quality or the presence of toxic substances.

    If the gills are damaged, it is very likely that bacterial, parasitic or fungal infections will develop, which, depending on the severity, can lead to death.

    Sensitive organs

    Gills. These are very sensitive organs prone to physical injury and disease caused by parasites, bacteria and fungi. For this reason, it is generally believed that the less developed gills are of the external type.

    Injury

    In teleost fish, gills exposed to high concentrations of chemical pollutants such as heavy metals, suspended solids and other toxic substances suffer from morphological damage or trauma called edema.

    They cause necrosis of the branchial tissue, and in severe cases can even lead to the death of the body due to changes in respiration.

    Due to this characteristic, fish gills are often used by scientists as important biomarkers of pollution in the aquatic environment.

    Variety of shapes

    As a result, they vary greatly in shape, size, location, and origin, resulting in specific adaptations for each species.

    For the most developed aquatic animals, the increase in size and mobility led to a greater demand for oxygen. One of the solutions to this problem was to increase the area of ​​the gills.

    Fish, for example, have a large number of folds that are separated from each other by water. This gives them a large gas exchange surface, which allows them to achieve maximum efficiency.

    Types (external and internal)

    Gills can appear in the outside or inside of the body. This differentiation is mainly a consequence of the degree of evolution, the type of habitat in which it develops, and the specific characteristics of each species.

    How do they work?

    In general, the gills act as filters that trap oxygen or2 which is contained in the water, which is necessary for its vital functions and the removal of carbon dioxide CO2 wastes that are present in the body.

    To achieve this filtration, a constant flow of water is required, which can be caused by movements of the external gills in worms, human movements performed by sharks, or pumping of an opercula into a bony fish.

    Gas exchange occurs through contact diffusion between water and blood contained in the gills.

    The most efficient system is called countercurrent, in which the blood that flows through the gill capillaries comes into contact with oxygen-rich water. A concentration gradient is created that allows oxygen to flow through the gill plates and diffuse into the bloodstream, while carbon dioxide diffuses outward.

    If the flow of water and blood were in the same direction, the same oxygen uptake rates would not be achieved, because the concentrations of this gas would quickly equalize along the gill membranes.

    Internal gills

    Internal gills, because they are more efficient than external gills, are found in larger aquatic organisms, but have different levels of specialization depending on how the species evolved.

    They are usually located in chambers that protect them, but require currents that allow them to be in constant contact with the external environment to match the exchange of gases.

    The fish also developed a layer of lime called the opercula, which acts as a guard for the gills, acts as a gate that restricts the flow of water, and also pumps water.