Frames of fish are paired and unpaired. To the pair belongs to the chest P (Pinna Pectoralis) and the abdominal V (Pinna Ventralis); Unparalleled - spinal d (Pinna Dorsalis), anal A (Pinna Analis) and tail with (Pinna Caudalis). The outer skeleton of the fins of bony fish consists of rays that can be branches and Nursery. The upper part of branched rays is divided into separate rays and has the kind of tassels (branched). They are soft and are located closer to the caudal end of the fin. Nursery rays lie closer to the front edge of the fin and can be divided into two groups: articular and non-grindy (thorny). Shleniy Rays are separated along the length of individual segments, they are soft and can bend. Nehleniy - solid, with acute vertex, rigid, can be smooth and served (Fig. 10).

Figure 10 - Rays of fins:

1 - Brownless shaded; 2 - branchy; 3 - spiny smooth; 4 - spiny served.

The number of branched and non-bright rays in the fins, especially in the unpaired, is an important systematic sign. Rays are calculated, and their number is recorded. Nehlenic (thorny) are denoted by Roman numbers, branched - Arabic. Based on the miscalculation of the rays, the fin formula is compiled. So, Sudak has two dorsal fins. In the first of these, 13-15 prickly rays (in different individuals), in the second 1-3 spines and 19-23 branched beams. The formula of the spinal fin is the following form: D XIII-XV, I-III 19-23. In the anal fins of Sudak, the number of prickly rays I-III, branches 11-14. The formula of the anal fins of Sudak looks like this: and II-III 11-14.

Paired fins. These fins have all true fish. The absence of them, for example, in Muren (Muraenidae) is a secondary phenomenon, the result of late loss. Circumphous (Cyclostomata) do not have pair fins. This is the primary phenomenon.

Breast fins are behind the gill grams of fish. At sharks and sturgeon, breast fins are located in a horizontal plane and sediments. In these fish, the convex surface of the back and the glued abdominal side of the body gives them similarity with the profile of the aircraft wing and when moving creates lifting force. Such asymmetry of the case causes the appearance of the rotational moment, aspiring turn, the head of fish down. Breast fins and Rostrum sharks and sturgeon fishes in functionality are a single system: directed under a small (8-10 °) angle to movement they create an additional lifting force and neutralize the rotational torque (Fig. 11). If sharp remove breast fins, it will raise your head up to keep the body in a horizontal position. In sturgeon fish, the removal of thoracic fins is not compensated for due to poor body flexibility in the vertical direction, which the bugs interfere, therefore, in amputation of breast fins, the fish falls on the bottom and cannot rise. Since thoracic fins and Rostrum at sharks and sturgeon fish are functionally connected, the strong development of Rostrum, as a rule, is accompanied by a decrease in the size of the breast fins and the removal of them from the front of the body. This is well noticeable at the hammer shark (Sphyrna) and the pilon shark (Pristiophorus), the Rostrum of which is developed strongly, and the chest fins are small, whereas the marine fox (alopiias) and blue sharks (prionace) are well developed, and Rostrum is small.

Figure 11 is a diagram of vertical forces arising in the progressive movement of shark or sturgeon fish in the direction of the longitudinal axis of the body:

1 - center of gravity; 2 - dynamic pressure center; 3 - the power of the residual mass; V. 0 - lifting force generated by the case; V. R - lifting force created by pectoral fins; V R. - lifting force created by Rostrum; V V. - lifting force created by abdominal fins; V. from - lifting force created by the tailflower; Curved arrows show the action of the rotational torque.

Breast fins of bony fish, unlike fins sharks and sturgeon, are located vertically and can make rowing movements back and forth. The main function of the chest fins of bony fish are the movements of a small stroke, allowing to accurately maneuver when searching for feed. Breast fins together with abdominal and tail allow you to maintain balance of fish with immobility. Breast fins at the rods, evenly focusing their body, perform the function of the main movements when swimming.

Breast fins in fish are very diverse both in shape and size (Fig. 12). At the battlefish, the length of the rays can be up to 81% of the body length, which allows

Figure 12 - Molds of pectoral fins of fish:

1 - flying fish; 2 - perch-slider; 3 - Cylebryushka; 4 - bodywork; 5 - sea cock; 6 - angler.

fish float in the air. Freshwater fish of Celebryushki from a family of haracin enlarged breast fins allow the fish to fly, resembling birds. Sea Roosters (Trigla) The first three rays of chest fins turned into finger-shaped grows, relying on which the fish can move along the bottom. Representatives of the detachment of Russian (Lophiiformes), thoracic fins with fleshy bases are also adapted to moving on the ground and quick instillation into it. Movement on a solid substrate with chest fins made these fins very movable. When moving on the soil, the riders can rely on both the chest and on the abdominal fins. Somov genus Clarias and sea dogs genus Blennius breast fins serve as additional supports in the serpentic movements of the body during moving along the bottom. Peerophthalmidae (Periophthalmidae) are peculiar. Their bases are equipped with a special muscles, which makes it possible to make the movement of the fin forward and backward, and have a bend that resembles the elbow joint; At an angle to the base is the replenish itself. Upgraded on coastal shallows, jumped with chest fins are capable not only to move on land, but also rise up on plants' stems, using the tail fin with which they wrap the stem. With the help of chest fins move on land and fish-sliders (Anabas). Stripping the tail and clinging to breast fins and spikes of a gill cap for the stalks of plants, these fish are capable of traveling from the reservoir to the reservoir, spelled to hundreds of meters. Such bottom, fish, like stone perch (Serranidae), barley (GASTEROSTEIDAE), and lubandae (labridae), breast fins are usually wide, rounded, fan-shaped. When they work, the ability is moving vertically down, the fish turns out to be suspended in the thickness of the water and can rise up like a helicopter. Fishes of a decay of needle-shaped (Tetraodontiformes), sea needles (Syngnathidae) and skates (hyppocampus), having small gill gaps (a gill lid hidden under the skin), can make circular movements with breast fins, creating an outflow of water from the gills. With amputation of breast fins, these fish are choking.

Abdominal fins are mainly performed by the equilibrium function and therefore, as a rule, are located near the center of gravity of the body of the fish. Their position changes with a change in the center of gravity (Fig. 13). Low-organized fish (cemoda-shaped, carpets) abdominal fins are located on bracles for breast fins, occupying Abdominal position. The center of gravity of these fish is on the belly, which is associated with the uncompact position of the internal organs occupying a large cavity. At high-organized fish, abdominal fins are in front of the body. This position of abdominal fins is called Thoracic and characteristic mainly for most perch-like fish.

Abdominal fins can be placed in front of chest - on the throat. This location is called Yugular, and it is characteristic of large-scale fish with a compact location of the internal organs. The sigular position of the abdominal fins is characteristic of all Fishes of the Cracke Fishes, as well as the Bolshable Fishes of the Ochneumy-shaped Fish: StarzoP (UranoScopidae), Nototheniyidae, doggy (Blenniidae), and others. In ernevous (ophidioidei) fish having a belt-angled body shape, abdominal fins are on the chin and perform the function of the touch of the touch.

Figure 13 - The position of abdominal fins:

1 - abdominal; 2 - thoracic; 3 - Yugular.

Abdominal fins can be modified. Using their some fish are attached to the soil (Fig. 14), forming either a sterling funnel (bullshop), or a suction disk (Pinagorovy, slug). Various in spines typuster bars carry a protective function, and in spinors, abdominal fins have the appearance of barbed spikes and along with the spiny ray of the dorsal fins are the protection authority. In the males of cartilage fish, the last rays of abdominal fins are transformed into a pternigopody - the cooler bodies. At sharks and sturgeon, abdominal fins, like breasts, perform the function of carrier planes, but their role is less than the chest, as they serve to increase the lifting force.

Figure 14 - modification of abdominal fins:

1 - a pleasant funnel in the bile; 2 - Sleeping dial for slug.



Neparal fins include the dorsal, anal and tail.

The dorsal and the anal fins perform the function of stabilizers, resistance to the lateral displacement of the body when the tail is operated.

A large dorsal fins of sailboats with sharp turns acts as a steering wheel, strongly increasing fish maneuverability when pursuing production. The dorsal and anal fins in some fish act as the propulsions that inform the fishing movement (Fig. 15).

Figure 15 - the form of abandoning fins in various fish:

1 - sea Horse; 2 - Suncher; 3 - Fish-moon; 4 - bodywork; 5 - Sea needle; 6 - Kambala; 7 - Electric eel.

At the heart of the locomotion with the help of the crimson movements of the fins lie wave-like movements of the plane of the fin, due to successive transverse deviations of the rays. This method of movement is usually characterized by fish with a small body length, unable to curb the body, - body, fish-moon. Only due to the edge of the spinal fin moves sea skates and marine needles. Such fish, like camebaloid and sunny, along with the adulting movements of the dorsal and anal fins float, laterally flexing the body.

Figure 16 - Topography of the passive locomotor function of unpaired fins from various fish:

1 - eel; 2 - Crack; 3 - Studum; 4 - Tuna.

In slow-laying fish with a coherent body shape, the dorsal and anal fins, merging with the tail, form in the functional sense a single focusing body of the fin, carry a passive locomotor function, as the main work falls on the body body. In rapidly moving fish with an increase in the speed of movement, the locomotor function is concentrated in the rear section of the housing and on the rear parts of the spinal and anal fins. The increase in speed leads to the loss of locomotor function with spinal and anal fins, the reductions of their rear departments, the front departments perform functions that are not related to locomotion (Fig. 16).

In the rapid rolling rich-fledged fish, the dorsal fin at movement is placed in the groove passing along the back.

Salm-shaped, sargano-shaped and other fish have one dorsal fin. In highly organized squads of bony fish (perch-like, kefow-shaped), as a rule, two dorsal fins. The first consists of barbed rays that give it certain transverse stability. These fish are called prickle. Cracic-like three dorsal fins. In most fish, only one anal fin, and the bit-like fish are two.

The dorsal and anal fins in a number of fish are absent. For example, the spinal fin is not at an electric eel, the locomotor abstraction of which is a strongly developed anal fin; There is no His Skat-tapes. Anal fin do not have Squaliformes squads and sharks.

Figure 17 - a modified first dorsal fin at fish-prishi ( 1 ) and a rude ( 2 ).

The dorsal fin can be modified (Fig. 17). So, the fish-sticky, the first dorsal fin moves his head and turned into a suction disk. He seemed to be divided by partitions on a number of self-active smaller, and therefore relatively more powerful suckers. Partitions are homologous to the rays of the first dorsal fin, they can bend back, taking almost a horizontal position, or straighten. At the expense of their movement and creates an effect of suction. In rude, the first disconnected rays of the first dorsal fins turned into a fishing rod (ilicium). The barley dozen fins have the appearance of separate spines performing a protective function. In fish-smoking fish of the Balistes, the first beam of the spinal fin has a lock system. It straightens and fixed motionless. You can bring it out of such a position by pressing the third barrel ray of the spinal fin. With this beam and the prickly rays of abdominal fins, the fish in danger is covered in crevices, fixing the body in the floor and the shelter ceiling.

Some sharks have rear elongated spine blades create a certain lifting force. A similar, but more substantial, supportive force is created by an anal fin with a long base, for example, in Somov fish.

The tail fin serves as the main propulsioner especially with a comb-shaped type of movement, being a force that informs the fish translation forward. It provides high maneuverability of fish when turning. Several forms of the tail fin (Fig. 18) are isolated.

Figure 18 - Forms of the tail fin:

1 - Protoxnarkal; 2 - heterocerkal; 3 - homocerkal; 4 - Difsercal.

Protocrekal, i.e., primary equally-bladed, has a view of a kayma, supported by thin cartilage rays. The end of the chord is included in the central part and divides the fin for two equal half. This is the most ancient type of fin, it is characteristic of the headup and larval stages of fish.

Difsercal - symmetrical outward and internally. The spine is located in the middle of equal blades. He is inherent in some two-way and cyzer. From bony fish such a fin is served in sargan and creak.

Heterocercal, or asymmetrical, inquisitive. The upper blade grows up, and the end of the spine, bending, enters it. This type of fin is characteristic of many cartilaginous fish and cartilage ganoids.

Homocerkal, or false symmetric. This fin externally can be attributed to an equally-blade, but the axial skeleton is distributed in the blades of Nonodynakovo: the last vertebra (Urgel) enters the upper blade. This type of fin is widespread and is characteristic of most bony fish.

By the ratio of the size of the upper and lower blades, tail fins may be epi, hypo and Estabutated (churches). With epibate (epitercian) type, the upper blade is longer (sharks, sturgeon); With a hypobate (hypertercal), the upper blade in shorter (volatile fish, czech), with an extensional (isoocrecal), both blades have the same length (herring, tuna) (Fig. 19). The division of the tail fin for two blades is associated with the features of the flow of the body of fish by the oncoming water currents. It is known that a layer of friction is formed around moving fish - a layer of water, which a moving body is reported to some additional speed. With the development of the speed fish, the boundary layer of water is possible from the surface of the body of the fish and the formation of the vortex zone. With a symmetrical (relative to its longitudinal axis), the body of the fish arising from behind the vortex zone is more or less symmetrical relative to this axis. At the same time, to exit the vortex zone and the friction layer of the blade of the tail fins to be extended to equally - intensity, isoocereka (see Fig. 19, a). With an asymmetric body: a convex back and a flattened abdominal side (shark, sturgeon), a vortex zone and a friction layer are shifted up with a relatively longitudinal axis of the body, therefore the upper blade is extended - epibacy, epitizkia (see Fig. 19, b). If there are more convex abdominal and direct spinal surfaces (Czech), the lower blade of the tail fin, as the vortex zone and the friction layer are more developed from the bottom side of the body - hypobacy, hypo-mersion (see Fig. 19, B). The higher the speed of movement, the more intense the process of the vortex formation and the thicker of the friction layer and the stronger the blades of the tail fin, the ends of which should go beyond the zone of the vortex and the friction layer, which ensures high speeds. In fast-playing fish, the tail fin has either a durable form - short with well-developed crescently elongated blades (combroids), or WilChatu - the tail notation comes to almost the base of the body of the fish (stavrid, herring). In sedental fish, with a slow motion of which the vortex processes almost do not have the place, the tail blade is usually short - a leaked tail fin (Sazan, perch) is either not differentiated - rounded (lifting), truncated (solar, butterfly fish), pointed ( Captain hornbies).

Figure 19 - The layout of the tailflower blades relative to the vortex zone and the friction layer with different body shape:

but - with a symmetrical profile (isoocereka); B. - with a more convex profile circuit (epitizkia); in - with a more convex lower profile circuit (Hympocerkia). The zone of the vortex and the friction layer is shaded.

The magnitude of the blades of the tail fin, as a rule, is associated with the height of the body of the fish. The higher the body, the longer the blade of the tail fin.

In addition to the main fins on the body of fish there may be additional floats. It belongs to them fatty The fin (Pinna Adiposa), located behind the spinal fin above the anal and represents the skin fold without rays. It is characteristic of Salmon Family Fishes, Koryushkov, Harius, Haracinov and Some Somovoids. On the tail stem, a number of rapid fish for the dorsal and anal fins are often small floors consisting of several rays.

Figure 20 - Kiel on the tail stem from the fish:

but - at the village shark; B. - At the mackerel.

They perform the function of curvatures that are generated during the movement of the fish, which contributes to an increase in fish speed (combroids, machelishek). On the tail fins, the elongated scales (Alae) perform the function of fairing. On the sides of the tail stem, the shark, stavride, skumbrid, sword fish are located side keels, which help to reduce the lateral bending of the tail stem, which improves the locomotor function of the tail fin. In addition, side keels serve horizontal stabilizers and reduce the vortex formation when swimming fish (Fig. 20).



Fish living medium are all sorts of reservoirs of our planet: ponds, lakes, rivers, seas and oceans.

Fish occupy very extensive territories, in any case, the ocean area exceeds 70% of the earth's surface. Add to this that the deepest depressions goes to the ocean deposits by 11 thousand meters and will become clear what spaces are owned by fish.

Life in water is distinguished by an extreme manifold, which could not not affect the appearance of the fish, and led to the fact that their form of their bodies is diverse, as the underwater life itself.

On the head of the fish there are gill wings, lips and mouth, nostrils and eyes. The head goes into the body very smoothly. Starting from gill wings and to anal fin is a torso, which ends with the tail.

Furnaces serve as fishes. In fact, they are skin grows, which are based on bone faded rays. The most important for fish is the tail fin. On the sides of the body, in its lower part there are paired abdominal and chest fins, which correspond to the rear and front limbs of vertebrate animals inhabitants. In different species of fish, pair fins can be located differently. At the top of the body of the fish is a dorsal fin, and below, next to the tail - anal. Moreover, it is important to note that the number of anal and dorsal fins from fish can vary.

Most fish on the sides of the body is a body that perceives the flow of water and which is called the "lateral line". Thanks to it, even blind fish can catch moving mining without bumping on the obstacles. The visible part of the side line consists of having holes of the scales.

Through these holes in the channel stretching along the body penetrates the water, where it is perceived by the ending channel of nerve cells. The side line in fish can be solid, intermittent or absent at all.

FDI functions from fish

Due to the presence of fins, fish are capable of moving and retain equilibrium in water. If the fish is devoid of fins, it will simply turn up with a belly, as the center of gravity of the fish is located in its spinal part.

The spinal and the anal fins provide the fishes of the stable body position, and the tail fin almost all fish is a kind of propulsion.


As for paired fins (abdominal and chest), they perform mainly stabilizing function, since they provide an equilibrium position of the body during immobility. With these fins, the fish can take the body position right. In addition, they are carriage planes during the movement of fish, and perform the function of the steering wheel. What to chest fins, then this is a kind of little motor, with which the fish moves during slow navigation. Abdominal fins are mainly used to maintain equilibrium.

Form of Body Fish

For fish, the streamlined shape of the body is characteristic. This is a consequence of its lifestyle and habitat. For example, in those fish that are adapted to long and fast swimming in the water thicker (for example, salmon, cod, herring, mackerel or tuna) body shape looks like a torpedo. Predators who practice lightning throws on very short distances (for example, sarah, sargan, time or) body shape sweatshop.


Some kinds of fish that are adapted to long-term location at the bottom, such as flaming or skate, have a body of a flat form. Separate fish types and have bizarre body forms, which can resemble a chess horse, as it can be seen from, whose head is located perpendicular to the axis of the body.

Seahorse inhabit almost all the marine waters of the Earth. His body as an insect concluded a shell, a taiga tail like a monkey, the eyes are able to rotate like a chameleon, and complements the picture of the bag, like that what a kangaroo has. And although this strange fish can swim, keeping the vertical position of the body, using the oscillation of the dorsal fin, the swimmer from it is still nikudny. It uses his tubular straight of the sea horse as a "hunting pipette": when prey is shown nearby, the horse is sharply inflated and pulls the prey in the mouth from a distance of 3-4 centimeters.


The smallest fish is considered the phillipsky bull Pandaku. The length of it is about seven millimeters. It was even that fashionista wore this bull in their ears using earrings-aquariums made from crystal.

But the biggest fish is, the length of the body of which is sometimes about fifteen meters.

Additional organs from fish

Fish has some species such as som or carp, a mustache can see around the mouth. These organs perform a tactile function and are used, also, to determine the taste of food. Many deep-water fish, such as Photoblefaron, Anchov, fish-hatchets and have luminous organs.


On Czech, fish sometimes you can meet protective spikes that can be in different parts of the body. For example, the body of the fish-hedge is covered with spikes almost completely. Separate fish species, such as warts, sea dragon and possess special attack and protection bodies - poisonous glands, which are located at the base of the finishing rays and the base of spikes.

Pockes of the body of fish

From the outside, the skin of the fish is covered with thin translucent plates - scales. The ends of the scales are listed on each other, sitting like a tiled. On the one hand, this provides animal solid protection, and on the other, it does not interfere with free movement in water. It is formed by scales with special skin cells. The size of the scales can be different: it has almost microscopic, whereas Indian Usach has several centimeters in diameter. Scales are distinguished by a large variety of both its strength and quantity, composition and a number of other characteristics.


In the skin of fish, chromatophores (pigment cells) are lied, with the expansion of which, pigment grains spread to a significant space, making the body color brighter. If chromatophores are reduced, the pigment grains are asked in the center and most of the cell will remain unpainted, thanks to which the body of the fish becomes paler. When the pigment grains of all colors are uniformly distributed inside chromatophores, the fish has a bright coloring, and if they are assembled in centers of cells, the fish will be so colorless that it may even seem transparent.

If only yellow pigment grains are distributed in chromatophoras, the fish will change its painting on light yellow. All variety of fish coloring is determined by chromatophoras. This is especially typical for tropical waters. In addition, in the skin of fish there are organs that perceive the chemical composition and water temperature.


Of all the above, it becomes clear that the skin of the fish performs many functions at once, among which is outer protection, and protection against mechanical damage, and communication with the external environment, and communication with relatives, and alleviating slip.

Role coloring among fish

Pelagic fish often has a dark back and a brystone of a light shade, for example, like a representative of the Codra Fishes of Abadejho. Many fish inhabitants in the middle and upper layers of water coloring the top of the body is much darker than the lower part. If you look at such fish from below, then its light abdomen will not stand out on a translucent through the thickness of the water with a bright background of the sky, which masks the fish from the seafront of her marine predators. In the same way, when viewed from above, her dark back is merged with a dark background of the seabed, which protects not only from predatory marine animals, but also from various bird-fishermen.


If you analyze the color of fish, then it will be possible to notice how it is imitated and disguised with other organisms. Thanks to this, the fish demonstrates a danger or failure, and also gives signals to other fish. In the marriage, many species of fish tend to acquire a very bright color, whereas the rest of the time they try to merge with the environment or imitate a completely different animal. Often, such a color disguise complements the form of fish.

Internal structure of fish

The muscular muscular system of fish, like terrestrial animals, consists of muscles and skeleton. The skeleton is based on the spine and skull consisting of separate vertebra. Each vertebra has a thickened part, which is called the body of the vertebra, as well as the lower and upper arcs. Together, the upper arcs form a channel in which there is a spinal cord that protects against injuries with arcs. In the upper direction from the arcs, long oestic processes are departed. In the trunk part, the lower arcs are open. In the tail part of the spine, the lower arcs form a channel inside which the blood vessels pass. The ribs are adjacent to the side of the vertebrals and perform a number of functions, primarily the protection of the internal organs, and the creation of the necessary support for the muscles of the body. The most powerful muscles of fish is in the field of tail and back.


The skeleton of fish includes bones and bone rays both pair and unpaired fins. For unpaired fins, the skeleton consists of a variety of fastened muscles of elongated bones. In the abdominal belt is a single bone. The free abdominal fin skeleton consists of many long bones.

The skeleton of the head includes a small cranial box. The skull bones serve as protection for the brain, but most of the skeleton of the head occupy the bones of the upper and lower jaws, the bones of the gill apparatus and the eye. Speaking of a gill apparatus, it can be noted primarily gill lids of large size. If the gill lids raise a bit, then under them you can see the paired gill arches: left and right. The gills are placed on these arcs.

As for the muscles, in the head part of them, they are located for the most part in the area of \u200b\u200bthe gill covers, on the back of the head and jaws.


Skeletal bones are attached to ensuring their work the movement of the muscle. The main part of the muscles is evenly located in the dorsal part of the body of the animal. The most developed muscles moving tail.

The functions of the musculoskeletal system in the organism of fish are the most different. The skeleton serves as protection for internal organs, bone fed rays protect fish from rivals and predators, and the entire skeleton in combination with muscles allows this inhabitant of water to move and protect against collisions and beats.

Fish digestive system

The digestive system begins with a large mouth, which is located in the front of the head and armed with jaws. There are large small teeth. Behind the oral cavity there is a cavity of the pharynx, in which you can see the gill slots, which are separated by interjaceous partitions, on which the gills are located. Outside, the gills are covered with gill lids. Next is the esophagus, followed by a rather bulky stomach. There is a gut behind him.


The stomach and the intestine using the effect of digestive juices, digest food, and the gastric juice acts in the stomach, and in the intestine there are several juices that excrete glands of the intestinal walls, as well as the walls of the pancreas. Also participates in this process and coming from the liver and gallbladder bile. The water digested in the intestines and food is absorbed into the blood, and the unfulfilled residues through the anus are thrown out.

A special body, which is only in binding fish, are a swimming bubble, which is under the spine in the body cavity. The swimming bubble occurs during the embryonic development as a spinal growth of the intestinal tube. In order for the bubble to be filled with air, the magnitude that appeared to the light pops up to the surface of the water and swallows the air into their esophagus. After some time, the connection between the esophagus and the swimming bubble is interrupted.


It is of interest, the fact that some fish use a swimming bubble as a means with the help of which they enhance the sounds published by them. True in some fish, there is no swimming bubble. These are usually those fish that live at the bottom, as well as those for which the vertical quick movements are characteristic.

Thanks to the swimming bubble, the fish is not sinking under his weight. This organ made of one or of two chambers and is filled with a mixture of gases, which in its composition is close to air. The volume of gases contained in the swimming bubble may vary when the walls of the swimming bubble walls are absorbed through the blood vessels, as well as when the air is swallowed. Thus, the proportion of fish and the volume of its body and can change in one direction or another. The swimming bubble provides a fish equilibrium between the mass of its body and acting on it at a certain depth of the ejecting force.

Gill fish

As a skeletal support of a gill apparatus, fishes are four pairs of gill arcs located in the vertical plane, which are attached by the gill plates. They consist of loyal petals like a fringe.


Circuit vessels are undergoing inside gill petals, which are branched to capillaries. A gas exchange occurs through the walls of the capillaries: oxygen is absorbed from the water, and carbon dioxide is distinguished. Thanks to the reduction of the muscles of the pharynx, as well as thanks to the movements of the gill covers, the water moves between the gill petals, which possess the gill stamens that protect the gentle soft gills from clogging by the food parts.

Blood system at fish

Schematically, the blood circuit system can be depicted as a vascular circle consisting of vessels. The main body of this system is a two-chamber, consisting of atrium and a ventricle, which provides blood circulation in the body of the animal. Moving along the vessels, blood provides gas exchange, as well as the transfer of nutrients in the body, and some other substances.

In fish, the circulatory system includes one circle circulation. The heart sends blood into the gills, where it is enriched with oxygen. Such oxygen-saturated blood is called arterial, and spread over the body, spreading oxygen by cells. At the same time, it is saturated with carbon dioxide (in other words it becomes venous) after which the blood returns back to the heart. It should be recalled that all vertebrates from the heart vessels are called arteries, while returning to it - veins.


Fish selection authorities are responsible for the elimination of finite metabolism products from the body, blood filtering and water removal from the body. They are presented with paired kidneys, which are located along the spine with uretera. Some fish have a bladder.

In the kidneys, extraction of unnecessary liquid, harmful products of exchange and salts occurs from blood vessels. Ureachers urine enters the bladder, where it strikes out. Outside the urinary channel opens with a hole, which is located just behind the anal hole.

Through these organs, the fish removes excess salts, water and harmful products for the body of metabolism.


Fish metabolism

The metabolism is called a combination of chemical processes occurring in the body. The basis of the metabolism of any organism is the construction of organic substances and their decay. When complex organic substances come to the body of the fish together with food, they are transformed into less complicated in the digestion process, which, absorbing blood, is spread through the cells of the body. There, it is formed by the required organism proteins, carbohydrates and fats. Of course, the energy released during breathing is spent. At the same time, many substances in cells are disintegrated into urea, carbon dioxide and water. Consequently, the metabolism is a combination of the process of constructing and decay of substances.

The intensity with which the metabolism in the body of the fish, depends on the temperature of its body. Since fish are animals with variable body temperature, that is, cold-blooded, then their temperature is in close proximity to the ambient temperature. As a rule, the body temperature of the fish does not exceed the ambient temperature by more than one degree. True, some fish, for example, the tunzic difference can be about ten degrees.


Nervous fish system

The nervous system is responsible for the coherence of the work of all organs and systems of the body. It also provides the body's response to certain changes in the environment. It consists of a central nervous system (spine and brain) and the peripheral nervous system (leaving the branches from the head and spinal cord). It consists of a fish brain of five departments: front, which includes visual shares, medium, intermediate, cerebellum and an oblong brain. All leading an active lifestyle of pelagic fish, cerebellum and visual shares are quite large, as they need fine coordination and good vision. An oblong brain in fish is moving into a spinal cord, ending in the tail of the spine.

With the help of the nervous system, the body of the fish responds to irritation. These reactions are called reflexes that can be divided into conditional reflexes and unconditional. The latter are also called congenital reflexes. Unconditional reflexes in all belonging to alone animals are the same, while conditional reflexes are individual and produced during the life of a particular fish.

Fish feelings

Fish sense organs are developed very well. Eyes can clearly recognize objects at close range and distinguish between colors. The sounds of fish are perceived through the inner ear located inside the skull, and the smells recognize through the nostrils. In the oral cavity, the skin of the lips and mustaches are taste, which allow the fish to distinguish with salt, sour and sweet. The side line due to the sensitive cells located in it sensitively reacts to the change in water pressure and transmits the corresponding signals into the brain.

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Finnish

water animal movement organs. Among the invertebrates P. have pelagic forms of the buchelogs and challenges of mollusks and bristle-jaws. In the bucculets of mollusks P. are a modified leg, in puddling - side folds of the skin. For bristles, the side and tail of P., formed by the folds of the skin. Among modern vertebrates P. have round, fish, some amphibious and mammals. Circlav - only unparalleled p.: Front and rear spinal (at Midnog) and the tail.

The fish distinguish pair and unpaired P. Paired are represented by front (thoracic) and rear (abdominal). In some fish, for example, gravestone and sea dogs, abdominal P. Sometimes arranged in front of the chest. The skeleton of pair P. consists of cartilage or bone rays, which are born to the skeleton of limb belt (see the limb belts) ( fig. one ). The main function of the paired P.- The direction of the movement of the fish in the vertical plane (depth steering). A number of fish pair P. perform the functions of active diving organs (see swimming) or serve for planning in the air (volatile fish), crawling on the bottom or movement on land (in fish, periodically emerging from the water, for example, from representatives of the tropical PERIOPHTALMUS which with the help of chest P. may even climb on the trees). The skeleton of the unpaired P.-spinal (often separated by 2, and sometimes on 3 parts), the rear-intensive (sometimes separated by 2 parts) and the tail - consists of cartilage or bone rays lying between the sidelines of the body ( fig. 2. ). The skeletal rays of the tail P. are associated with the rear end of the spine (in some fish they are replaced with spinning process of vertebrae).

Peripheral parts of P. are supported by thin rays from coronary or bone tissue. In the prickly fishes, the front of these rays thicken and form solid spines, sometimes associated with poisonous glands. To the base of these rays, the muscles stretching the blade P. The dorsal and rear-point P. are attached to regulate the direction of movement of the fish, but sometimes they can be the organs of progressive movement or perform additional functions (for example, reducing production). Tail P., very much varies in the form of various fish, is the main body of movement.

In the process of the evolution of vertebrates P. Fish, it was probably from a solid skin fold, which took place along the back of the animal, enveloped the back end of his body and continued on the abdominal side to the rear-ground opening, then divided into two side folds, which lasted to gill slots; Such is the position of the fetal folds of the modern primitive chord - Lancing A. It can be assumed that in the process of animal evolution, skeletal elements were formed in some places of such folds and in the intervals of the folds disappeared, which led to the emergence of the unpaired P. near the heads and fish and pairs of fish. This is in favor of the lateral folds or poison of spikes in the ancient vertebrals (some frantic, acanthody) and the fact that modern fish P. P. has a greater length of the early stages of development than in an adult state. Among the amphibious unpaired P. in the form of a skin fold, deprived of a skeleton, there are both permanent or temporary formations in the majority of larvae living in water, as well as in adult tailed and larvae of adult amphibians. Among the mammals P. are available in the secondary way to the water lifestyle of cetaceous and lilac. Unpaired P. Catto-shaped (vertical spinal and horizontal tail) and lilac (horizontal tail) do not have a skeleton; These are secondary formations, not homologous (see Homology) Unpaired P. Fish. Paired P. Catto-shaped and Sirens, represented only by front P. (rear reduced), have an internal skeleton and homologous to the front limbs of all other vertebrates.

Lit. Management on zoology, vol. 2, M.- L., 1940; Schmalgausen I. I., the foundations of the comparative anatomy of vertebrate animals, 4 ed., M., 1947; Suvorov E. K., Basics of ichthyology, 2 ed., M., 1947; DoHel V. A., Zoology of invertebrates, 5 ed., M., 1959; Aleev Yu. G., Functional foundations of the external structure of fish, M., 1963.

V. N. Nikitin.


Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

Watch what is "fins" in other dictionaries:

    - (Pterigiae, Pinnae), motion or regulation of the body of aquatic animals. Among the invertebrates P. has Pelagich. Forms of certain mollusks (modified leg or skin fold), bristles. In undepair and larvae of Fish Fish P. ... ... Biological Encyclopedic Dictionary

    Movement or regulation of the body position of aquatic animals (some mollusks, bristles, lunks, lancing, round, fish, some amphibious and mammals cetaceous and lilac). May be pair and unpaired. * * * Fins ... ... encyclopedic Dictionary

    Movement or regulation of water animals (some mollusks, bristles, lunks, lancing, fish, fish, some amphibious and mammals cetaceous and lilac). Distill steam and unpaired fins ... Big Encyclopedic Dictionary

; their organs regulating movement and position in water, and in some ( flying fish) - also planning in the air.

Finns are cartilage or bone rays (radialia), which have top-to-skin-epidermal covers.

The main types of fis fins are spinal, anal, tail, abdominal and chest pair.
Some fish have also fat plants (They are devoid of fin rays), located between the dorsal and tail fins.
Finns are driven by muscles.

Often, different types of fish fins are modified for example, males niphey fish Anal fin is used as an organ for mating (the main function of the anal fin is similar to the function of the dorsal - it is a keel when moving fish); W. gurura Modified filamentous typhoid fins are special tentacles; Strongly developed thoracic fins allow some fish to jump out of the water.

Folders of fish are actively involved in motion, balancing the body of fish in water. At the same time, the motor moment begins from the tail fin, which pushes forward with a sharp movement. The tail fin is a kind of fish propulsion. The dorsal and anal fins balance the body of fish in water.

In different species of fish, the amount of dorsal fins is different.
Seld-shaped and carpeuts have one dorsal fin, kefale-shaped and perch-like - Two, cracic - three.
They are located too, can be different: pike - shifted far back, seldow-shaped carpets - in the middle of the ridge, perch and cod. - closer to the head. W. mackerel, Tuna and Sairi There are small additional floats for spinal and anal fins.

Breast fins are activated by fish with slow swimming, as well as with abdominal and tail fins support the balance of the body of fish in water. Many bottom fish move on the ground with chest fins.
However, some fish ( muren For example) breast and abdominal fins are absent. Some species have no tail: anthemids, ramphicht, seahorse, skate, fisher-moon and other types.

Kolyushu Trechilla

In general, the more developed by the fish fins, the more it is adapted for swimming in calm water.

In addition to movement in water, air, on the soil; jumps, packers, fins help different types of fish attached to the substrate (fins-sucker bychkov), search for food ( trigla), have protective functions ( kolyushki.).
Some types of fish ( skorenova) There are poisonous glands at the bases of the spiny fins. There are and fish without fins: a discount.