The lateral line is developed. Lateral line of fish. Lateral line in fish

Linea lateralis ll is a peculiar sensory organ of fish that perceives low-frequency vibrations of water; it is a subcutaneous canal lined with sensitive epithelial cells with nerve endings approaching it. The channel communicates with the external environment through holes piercing the scales or integument of the body. The lateral line has a systematic meaning. Her appearance is very diverse. In most fish, the lateral line runs in the form of a straight line along the sides of the body from the head to the caudal fin (bream, carp, perch, etc.). This lateral line is called complete. In some species of fish, the lateral line forms a sharp bend above the pectoral fins (sichel fish, halibut). In smelt and verkhovkas the lateral line is incomplete; it occupies several scales. The lateral line can be located on the belly (garfish) or on the back (gerbil). Terpugidae have 4-5 pairs of lateral lines, but toteniaceae have 1-3. Herrings, gobies and some other fish do not have a lateral line. Its function is performed by a highly developed system of sensory channels on the head or genipora. Fishes with a lateral line (cod, navaga) also have sensory canals and genipores (Fig. 21). The characteristic of the lateral line can be written by the formula. To compile the lateral line formula, the number of scales along the lateral line, above and below it is calculated. So, the formula for the ide line is:

What does it mean: 56 – the smallest number of scales along the lateral line for the species; 61 – the largest number of scales along the lateral line for the species; 8-9 – number of scales above the lateral line to the dorsal fin; 4-5 – number of scales under the lateral line to the ventral fins. It is not always possible to accurately calculate the scales above and below the side line, so sometimes they are limited to calculating the scales only along the side line. In this case, the ide formula will look like this: ll =56-61.

Figure 21 – Genipores and sensory canals:

1 – on the head of the cod; 2 - on the head of navaga.

Side line is the oldest sensory formation, which, even in evolutionarily young groups of fish, simultaneously performs several functions.

Taking into account the exceptional importance of this organ for fish, let us dwell in more detail on its morphofunctional characteristics.

Different ecological types of fish exhibit different variations of the lateral system. The location of the lateral line on the body of fish is often a species-specific feature. There are species of fish that have more than one lateral line. For example, the greenling has 4 lines on each side. This is where its second name comes from - eight-line chir.

In most bony fishes, the lateral line stretches along the body (without interruption or interruption in some places), extends onto the head, where it forms a complex system of canals. The lateral line channels are located either deep in the skin or open on the surface of the skin.

An example of the open surface arrangement of neuromasts - structural units of the lateral line - is the lateral line of the minnow.

Despite the obvious diversity in the morphology of the lateral system, it should be emphasized that the observed differences concern only the macrostructure of this sensory formation. The organ's receptor apparatus itself (the chain of neuromasts) is surprisingly the same in all fish, both morphologically and functionally.

The lateral line system responds to compression waves of the aquatic environment, to flow currents, to chemical stimuli and to electromagnetic fields with the help of neuromasts - structures that unite several hair cells. The neuromast consists of a mucous-gelatinous part - a capsule, into which the hairs of sensitive cells are immersed. Closed neuromasts communicate with the external environment through small holes that pierce the scales.

Open neuromasts are characteristic of the canals of the lateral system extending onto the head of the fish.

Channel neuromasts stretch from head to tail along the sides of the body, usually in one row (fishes of the family Hexagramidae have six or more rows). The term “lateral line” in common usage refers specifically to canal neuromasts. However, in the world of fish, neuromasts are also described, separated from the canal part and looking like independent organs.

The labyrinth and canal and free neuromasts, located in different parts of the fish’s body, do not duplicate, but functionally complement each other.

It is believed that the sacculus and lagena of the inner ear are responsible for sound sensitivity from a great distance, and the lateral system allows you to localize the source of sound at close range. It has been experimentally proven that the lateral line perceives low-frequency vibrations, both sound and those arising from the movement of other fish, i.e. low-frequency vibrations arising from a fish hitting the water with its tail are perceived by other fish as low-frequency sounds.

Waves arising on the surface of the water have a noticeable influence on the activity of fish and the nature of their behavior. The causes of this physical phenomenon are many factors: the movement of large objects (large fish, birds, animals), wind, tides, earthquakes. Water disturbance serves as an important channel for informing aquatic animals about events both in the reservoir itself and beyond. Moreover, the disturbance of the reservoir is perceived by both pelagic fish and bottom fish. The reaction to surface waves on the part of fish is of two types: the fish sinks to greater depths or moves to another part of the reservoir.

The stimuli acting on the body of the fish during the period of disturbance of the reservoir is the movement of water relative to the body of the fish. The movement of water when it is agitated is sensed by the acoustic-lateral system. Moreover, the sensitivity of the lateral line to waves is extremely high. Thus, for afferentation to occur from the lateral line, a displacement of water relative to the cupula by 0.1 μm is sufficient. At the same time, the fish is able to very accurately localize both the source of wave formation and the direction of wave propagation.

As a rule, waves on the surface of a reservoir generate rolling motion. Therefore, when excited, not only the lateral line of the fish, but its labyrinth becomes excited. Experiments have shown that the semicircular canals of the labyrinth respond to rotational movements in which water currents involve the body of the fish. The utriculus receives the linear acceleration that occurs during the rolling process.

Observations of marine fish indicate that during a storm, fish, both solitary and schooling, change their behavior. During a weak storm, pelagic species in the coastal zone descend to the bottom layers. When the waves are strong, fish migrate to the open sea and go to greater depths, where the influence of waves is less noticeable. It is obvious that strong excitement is assessed by fish as an unfavorable or even dangerous factor. Disturbance suppresses feeding behavior and forces fish to migrate. Similar changes in feeding behavior are observed in fish species inhabiting inland waters. Anglers know this: when there is excitement, the fish stop biting.

If you find an error, please select a piece of text and press Ctrl+Enter.

In contact with

Classmates

The sense organs have a huge influence in the life of a fish, which also affects their behavior. This is a seismosensory system, or otherwise it is called the lateral line. This line unites all receptor cells located not only in the head, but also in other parts of the body.

This sensitive organ, meaning the lateral line, is also present in some amphibians and their larvae, and not only in fish. Such an organ is used for several purposes, namely:

• so that the fish can navigate;
• and also for hunting.

If you look closely, this organ looks like a thin line that exists on both one and the other side of the body and it stretches, starting from the gill slits, and ending at the tail. Some species of fish have a certain part of the receptors in the lateral line, which are converted into so-called electroreceptors, which allow them to catch electrical vibrations produced by the environment.

Anatomy of the lateral line

Each channel of the seismosensory system on the head has a genipore in length - nerve endings, and in large numbers. Also, such channels can open outward. For example, cod has as many as 26 such channels.

The lateral line can be either continuous or interrupted.

This complex system allows fish to perfectly navigate in the depths of water, in pitch darkness. Also, using their seismic sensor system, they:

• find food;
• can move in a coordinated manner while in a flock;
• running away from enemies or other danger.

If visibility is poor, then the lateral line helps to look for moving food, usually small fish. But with the help of tactile senses, such as touch and taste, she finds motionless food - licking or a shellfish. There are several examples where a blind fish can perfectly take care of its food, which is achieved by the presence of such a complex seismosensory system.

There is such a species of fish as the blind cave fish, although it does not have vision by nature - these are anopgihi. And thanks to its seismosensory system, it perfectly provides itself with good conditions not only for existence, but also for reproduction. There is another type of fish - blind-eyes, which live in the so-called karst waters. They have a well-developed lateral line, as well as organs of touch, which are present on the head, as well as on the body, and also on the tail. All this replaces not only the organs of vision, but also some other organs.

It is worth saying that the lateral line also plays an important role during spawning. It helps attract a female. There are species of fish in which the male builds a nest house, and then sends specialized acoustic-mechanical signals to the female, inviting her to visit such a “house.” Some males direct the water flow towards their opponent. This makes him understand that this spawning site has already been occupied.

So we can safely say that the seismosensory system is a unique natural invention that allows fish to detect water vibrations, which are still very poorly understood in relation to the schooling behavior of marine individuals.

Side line

Anatomy[ | code]

Lateral line in fish[ | code]

Astyanax mexicanus

Links[ | code]

Scorpis violacea from the kyphosis family Esox lucius

Waves run in front of a swimming fish, reflecting from underwater objects, and, returning to the fish, are perceived by its lateral line.

Free neuromasts and canal organs of the lateral line are mechanoreceptors that perceive flows of water and sound as vibrations. With their help, the fish picks up tiny vibrations (from 6 vibrations per second or more), determining the direction of the flow of water and sound, the proximity of neighbors, obstacles, etc. By sensing water currents with their lateral line - strong or barely noticeable - fish can distinguish the size of an obstacle or objects moving in the water.

The lateral line organs, as displacement receptors, function effectively in the near acoustic field. Sources of mechanical stimuli are also determined by the lateral line organs at close range. Fish have two types of sound receptors: pressure receptors (hearing organs), which allow them to sense sound waves over long distances, and displacement receptors - lateral line organs, which allow them to subtly analyze the acoustic situation.

Fish can use skin receptors for these purposes, which are also displacement receivers.

The topography of the displacement receptors of the seismosensory system is extremely important for determining the direction and distance from the source of mechanical, acoustic, and electromagnetic vibrations. Almost all fish that have a well-developed seismosensory system are perfectly oriented with its help when moving in schools, in feeding fields and spawning areas. Displacement receptors, directly related to the fish’s hearing, function simultaneously with vision. So, for example, when attacking prey, a pike is guided by vision and displacement receptors - the organs of the lateral line, which are well developed on its head, especially on the lower jaw and on the sides of the body. These are, of a kind, small primitive radars that determine the location of the victim target with great accuracy. It is thanks to this “guidance” that the pike does not make idle throws at the hunted victim.

The lateral line also functions well in sea eels. This voracious predator of the sea, like pike in fresh water, lies in wait for its prey in ambush, from where it rushes at the victim according to the indications of the displacement organs.

In monkfish, the lateral line organs are located in the grooves of the skin on the upper surface of the strongly flattened body, which allows it to perceive vibrations and currents of water coming mainly from above. This fish lies motionless on the ground, and the leathery brush of a separate dorsal ray moves above its head. This lazy predator “invites” its prey. As soon as the trusting fish saw the “worm-shaped tip” and approached it, it instantly finds itself in the huge toothy mouth of the monkfish.

The seismosensory system of cyprinid fish is well developed. For many of them, the sense of the lateral line, along with the sense of smell and touch, is leading in the search for food. Cod and many other cod fish have a well-developed lateral line on both sides of the body, and it is especially complexly branched on the head. On each side of the head, the lateral line forms many canals: preopercular-mandibular, infraorbital and supraorbital with a short commissure connecting the right and left canals. The interorbital commissure of the supraorbital canal is located in a special depression, the frontal - mucus fossa, the external shape of which varies greatly among different cod fish; in cod, haddock and pollock, the mucus pit is closed. In some cod it is open.

Along each of the channels of the lateral line system on the head there are multi-membered groups of nerve endings - genipores, or these channels open outwards with a number of pores. Cod, for example, has 26-27. Moreover, single genipores are also present in this case. The lateral line of some cod representatives is continuous (haddock, pollock), while in others it is discontinuous (cod). In some codfish, such as cod, the lateral line is continuous on the body and discontinuous on the caudal peduncle. Such a complex seismosensory system—displacement receptors—allows cod, cod and other cod fish to navigate in the complete darkness of the sea depths, find food, move in a coordinated manner in schools, and avoid enemies, including getting caught in trawl fishing gear. In conditions of poor visibility, cod uses the senses of the lateral line organs to find moving food (mainly small fish), and with the senses of smell and tactile senses (taste, touch) it looks for stationary, favorite food (mollusks, licks). Thus, in the Barents Sea, a blind cod was caught with a lot of food in its stomach - capelin. The fat content of the cod (the ratio of liver weight to body weight as a percentage) was quite high, which indicates good feeding conditions.

This example, as, by the way, other similar catches, indicates that cod, being blind, finds and obtains enough food for itself thanks to a well-developed sense of smell and touch, and the presence of a complex seismosensory system.

There are naturally blind cave fish - anopgichi, which, with the help of a seismosensory system, provide themselves with normal conditions of existence and reproduction. In underground karst waters live blind-eyes, which have highly developed lateral line organs and organs of touch on the head, body and caudal peduncle. They replace not only vision for these fish, but also other remote sensory organs.

The lateral line plays a significant role in spawning waters to attract a female or in competition between males over her. In some species of fish, the male, having built a nest house, sends acoustic-mechanical signals, which the female takes as an invitation to “enter the house” as a “young mistress.” In other species, the male, with an energetic movement of his tail, directs the flow of water towards his opponent and, thus, influences his lateral line, informing the enemy that the spawning area is occupied.

The functions of the lateral line and other displacement receptors, which allow fish to detect water vibrations in a certain frequency spectrum, have been poorly studied from the point of view of their significance in the schooling behavior of fish. Thus, the seismosensory system of fish is a unique invention of nature. It provides fish with the opportunity to adequately change their behavior depending on the biotic and abiotic environment, and in each specific case - and how, and is the most important sensory organ in the struggle for life.
read/viewed 14998 times Facebook - post a comment on the article

Side line- a sensitive organ in fish, as well as in the larvae of amphibians and some adult amphibians, perceiving movement and vibrations of the surrounding water. Used for orientation and also for hunting. Externally it looks like a thin line on both sides of the body, stretching from the gill slits to the base of the tail. In some species, some of the lateral line receptors are converted into electroreceptors and can detect electrical vibrations in the environment. Some representatives of crustaceans and cephalopods have similar organs.

Anatomy

The lateral line receptors are called neuromasts, each of which consists of a group of hair cells. The hairs are located in a convex jelly-like cupule, about 0.1-0.2 mm in size. Hair cells and cupules of neuromasts are usually found in the lower part of the grooves and pits that make up the lateral line organs. The hair cells of the lateral line are similar to the hair cells of the inner ear, suggesting that these organs have a common origin.

The lateral line organs of bony fishes and elasmobranchs usually have the form of canals, in which the neuromasts are not directly connected to the external environment, but through canal pores. In the lateral lines of some fish and various parts of the fish's body surface, free-standing neuromasts not associated with the canals may also be present.

Lateral line in fish

The development of the lateral line organs is associated with the animal’s lifestyle. For example, in actively swimming fish, neuromasts are usually located in canals. The lateral line itself is located at the maximum distance from the pectoral fins, which may reduce the distortion that occurs when the fish moves.

The lateral line organs help fish navigate, sense the direction and speed of currents, and detect prey or enemies. For example, in the blind cave fish Astyanax mexicanus There are rows of neuromasts on the head, which are used for precise detection of food objects. Some carp-toothed fish are able to sense ripples that occur when an insect moves on the surface of the water. Experiments with pollock have shown that the lateral line is of key importance in the schooling movement of fish.

Links

Tubular scales of the lateral line of roach.
A clearly visible dark lateral line running from the gills to the tail in fish of the species Scorpis violacea from the kyphosis family Small holes on the pike's head ( Esox lucius) belong to the seismosensory channels of the lateral line.

Surrounding water. Used for orientation and also for hunting. Externally it looks like a thin line on both sides of the body, stretching from the gill slits to the base of the tail. In some species, some of the lateral line receptors are transformed into electroreceptors and can detect electrical vibrations in the environment. Some representatives of crustaceans and cephalopods have similar organs.

Anatomy

The lateral line receptors are called neuromasts, each of which consists of a group of hair cells. The hairs are located in a convex jelly-like cupule, about 0.1-0.2 mm in size. Hair cells and neuromast cupules are usually found in the lower part of the grooves and pits that make up the lateral line organs. The hair cells of the lateral line are similar to the hair cells of the inner ear, suggesting that these organs have a common origin.

The lateral line organs of bony fishes and elasmobranchs have the form of canals, in which the neuromasts are connected to the external environment not directly, but through canal pores. Additional neuromasts may be present at various points on the surface of the fish's body.

Lateral line in fish

The development of the lateral line organs is associated with the animal’s lifestyle. For example, in actively swimming fish, neuromasts are usually found in canals rather than openings. The lateral line itself is located at the maximum distance from the pectoral fins, which may reduce the distortion that occurs when the fish moves.

Lateral line organs help fish avoid collisions, navigate water currents, and detect prey. For example, the blind cavefish Astyanax mexicanus has rows of neuromasts on its head that are used to accurately detect food in the absence of vision. Some carp-toothed fish are able to sense ripples that occur when an insect moves on the surface of the water. Experiments with pollock have shown that the lateral line is of key importance in the schooling movement of fish.

Links

• Lateral organs- article from
• Side line- article from the Great Soviet Encyclopedia
• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional ones). - St. Petersburg. , 1890-1907.

Wikimedia Foundation. 2010.

See what the “Lateral Line Organ” is in other dictionaries:

Lateral line in a shark The lateral line in fish, as well as in the larvae of amphibians and some adult amphibians, is a sensitive organ that perceives movement and vibrations of the surrounding water. Used for orientation and also for hunting. Externally it looks... ... Wikipedia

organ- 19.3 authority: A legal or administrative entity that has specific tasks and structure. Source … Dictionary-reference book of terms of normative and technical documentation

Organ of Corti ... Wikipedia

Sphyrna lewini ... Wikipedia

Tailless ... Wikipedia

CHOKRAK LAKE- CHOKRAK LAKE, a complex that includes: a resort, a mud lake, mineral springs, and in the future probably a sea coast. Lately only the lake has been used. Ch. about. located 14 km to the village. h. from the city of Kerch, belongs to... ... Great Medical Encyclopedia

A specimen of the human brain, the cerebellum highlighted in red... Wikipedia

Placodes, or epidermal placodes, are derivatives of the ectoderm, formed at the point of contact of the neural tube with the ectoderm. Placodes are formed by thickening or invagination of the ectoderm, migration of cells from it, or in a mixed way. From placodes... ... Wikipedia

Placodes, or epidermal placodes, are derivatives of the ectoderm, formed at the point of contact of the neural tube with the ectoderm. Placodes are formed by invagination of the ectoderm, migration of cells from it, or in a mixed way. The lens is formed from the placodes... ... Wikipedia

External openings of the ampullae of Lorenzini on the face of a tiger shark The ampullae of Lorenzini is a sensory organ in several orders of fish, responsible for electroreception and achieving the greatest development ... Wikipedia

Tests

755-01. The lateral line organs present in fish perform the functions
A) supports and movements
B) sense of smell
B) sensations of water temperature
D) sensations of the direction and strength of water flow

Answer

755-02. What adaptations that allow movement in water with the least energy consumption have arisen in the process of evolution in fish?
A) paired pectoral and ventral fins
B) dorsal and anal fins
B) gills covered with gill covers
D) streamlined body shape, mucus on the skin

Answer

755-03. The main significance of the mucus secreted by the skin glands of fish is
A) reducing the friction of the fish’s body on the water
B) supplying scales with nutrients
C) protecting the scales from the settlement of unicellular algae on it
D) increased sensitivity of the lateral line organs

Answer

755-04. What function do the lateral line organs perform in the animal body?
A) help in finding a partner during reproduction
B) signal the onset of seasonal changes in water
C) allow you to sense proximity to underwater objects
D) determine the light source

Answer

Which of the following characteristics are characteristic of most representatives of the class Bony fish? Choose three correct answers.
A) cartilaginous skeleton
B) no swim bladder
B) have gill covers
D) are found mainly in seas and oceans
D) the notochord is present only in embryos
E) very fertile, eggs are small

Answer

What features are typical for representatives of bony fish? Choose three correct answers out of six.
A) The heart is formed by three chambers and there is one circle of blood circulation.
B) They breathe oxygen dissolved in water.
B) There are no glands in the skin.
D) They have gill covers.
D) They have a swim bladder.
E) They have a constant body temperature.

Why do fish have a “lateral line”?

nature has rewarded fish with a special organ for perceiving vibrations and movement of water - the lateral line.

It is known that the acoustic pressure in water is 2 times greater than the acoustic pressure in air. Water is practically incompressible, its density is 800 times greater than the density of air. All this creates favorable conditions for the propagation in the aquatic environment of vibrations, vortices, and jets caused by the movement of various bodies. The lateral line organs of fish are designed to capture both mechanical displacements of water particles and sounds (mainly low frequencies). Any creature moving near a fish causes at least a small movement of the water and thereby reveals itself. The sensitivity of the lateral line of fish is amazing: in experiments, fish detect the movement of a glass hair 0.25 mm thick at a distance of 20 to 50 cm.

What are the lateral line organs and how do they function? On both sides of the fish’s body, dotted lines are visually detected, running from the head to the tail of the fish. If you look closely, you will find that each dotted line represents a channel or groove filled with mucus. Sensitive cells of the lateral line are collected in kidney-shaped groups and hidden in canals that are washed by water.

The bodies of the sensitive cells contain a hair, which, when water acts on the mucus in the canal, bends and sends a signal to the auditory center of the fish. These hair cells are called neuromasts. Neuromasts of the lateral line organs densely cover the head and lateral surface of slow-swimming bottom-dwelling fish. A juvenile bream, for example, has almost 2000 such cells. They allow the fry to perceive a detailed picture of jet currents, learn about the direction of waves on the surface of the water, navigate (without the help of vision) the bottom topography, the movements of prey or school neighbors, even become familiar with the shape of objects by fanning them from a distance of 3-4 cm with fins .

In fact, the lateral line serves as a distant sense of touch. For fish it is more necessary than vision. Avid fishermen rightfully claim that when fishing for pike, it doesn’t matter what the spoon looks like - it’s enough that it just sparkles in the water. Much more important is how it moves and vibrates during wiring. It has been established that the lateral line of both predators and peaceful fish perfectly captures infrasounds, which are formed as a result of the disruption of vortices from the surface of any streamlined bodies (fish, baits, boats, underwater hunters, etc.). Infrasonic noises are very “loud” during sudden changes in fish speeds (throws, turns, accelerations) and are most intense in fish with a poorly streamlined body shape.