Amphibians have two types of respiratory organs (not counting the skin): gills and lungs. The weakening of gill respiration and the emergence of pulmonary respiration are already observed in Dipnoi; changes in this direction are seen in Polypterus, and Lepidosteus. In amphibians, gill breathing is preserved primarily in larvae, and then in those Urodelas that spend their entire lives in water (Perennibranchiata in former systems). Gill slits are inherited by amphibians from fish-like ancestors. Gill arches are found in stegocephalians, in larvae, and in some adults (Branchiosauridae). All modern amphibians in the larval state breathe with gills. Normally, they have 5 visceral sacs and the 6th is underdeveloped. But not all of them open outward: 4 or even fewer gill slits are formed. Sometimes there are much fewer slots than arcs. The presence of cracks and arcs is proof of the origin of amphibians from fish. Internal gills, homologous to the gills of fish, are found, however, only in Anura larvae in the form of short outgrowths of integument on the arches separating the gill slits. A soft gill operculum (operculum), growing from the side of the hyoid arch, covers the gill region from the outside. The gill covers of the right and left sides merge with each other from the underside, leaving paired openings in some Anura, and one unpaired one on the left side of the body in most Anura.
In the early stages of development, the larvae of Anura and all other amphibians have only external gills, apparently homologous to the external gills of the larvae of Polypterini and Dipnoi. In Apoda and Anura, external gills exist only in the larval period, in the early stages of development, but in Urodela, which returned to aquatic life for the second time, they persist throughout life. Hence the name for these amphibians is permanent gill (Perennibranchiata), although this name, as has been said, embraces groups of amphibians having different origins. The external gills are probably inherited by amphibians from lobe-finned fishes.
Light amphibians look like long cylindrical bags with thin walls (in Urodela) or shorter ones (in Anura). In the legless, the right lung is much more developed than the left. Lungs appeared in the ancestors of tetrapods long before they landed. We see the same lungs in lungfish. They apparently appeared as an additional respiratory organ due to insufficient development of gill respiration, on the one hand, and possibly unfavorable conditions for breathing in dry and spoiled waters, on the other. The back part of the gill cavity developed in them into an additional respiratory organ. Initially, this organ, which looked like a bilobed sac that opened on the underside of the pharynx, was imperfect: its walls had to be slushy, although richly supplied with blood, with poorly developed or almost undeveloped partitions. Like all gill protrusions (slits), it had smooth visceral muscles and was innervated by the vagus first.
The lungs of amphibians have changed little in comparison: in aquatic Urodela, the lungs act more like a hydrostatic apparatus and have a smooth inner surface; the height of their organization is even lower than that of Dipnoi. Normally, in amphibians, the inner surface of the lungs is cellular due to the fact that a system of crossbars protrudes into the lung cavity (Fig. 253). It is very interesting that the more terrestrial a particular species is, the more developed are the crossbars in the lungs: in a toad, the lung is more cellular than frogs. In the genus Ascaphus, living in mountain streams, in oxygen-rich water, skin respiration is highly developed, while the lungs, on the contrary, are small and poorly supplied with blood. A number of amphibians from the suborder Salamandroidea (Salamandrina, Plethodon, Spelerpes, Batrachoseps, etc.) completely lost their lungs, instead of which pharyngeal and skin breathing developed strongly. .


In the simplest case, the lung sacs are interconnected in front, opening directly into the pharynx with a longitudinal slit supported on the sides by cartilaginous strips. These cartilaginous strips, with the help of muscles attached to them, can expand and narrow the laryngeal fissure.
These cartilages come from the last branchial arch and are found in their simplest form in some Urodela. From these cartilages, cartilages called cricoid cartilages can separate. They can be compared with the arytenoid cartilages (cartilagines arythenoidea) of higher vertebrates. Some Urodela and also Apoda have a rather long windpipe supported by cartilaginous rings. In Anura, the mucous membrane in the larynx forms the vocal cords. The larynx has complex muscles. At the bottom or at the corners of the mouth there are resonators that inflate when croaking.
The breathing mechanism of terrestrial amphibians is rooted in reflexes observed in fish and aquatic amphibians. Closest to fish breathing is the breathing of Anura larvae, which have internal gills, an opercular fold, and a gill cavity formed by their fusion, which opens outwards with one opening. In addition, in amphibian larvae, the oral cavity is abundantly supplied with blood. Taking water into the mouth and pushing it through the nostrils by lifting the jaws, the larvae increase the gas exchange in the oral cavity. When the larvae grow up, they rise to the surface, where they swallow air like a ceratod, and by raising the bottom of the oropharyngeal cavity they push air into the lungs. A similar act is observed in aquatic Urodela. When lowering the bottom of the oropharyngeal cavity and with the gill openings closed behind, water is sucked into the oral cavity through the mouth or nostrils, or through both. By subsequently raising the floor of the mouth with closed nostrils, water is pushed out through the gill slits. Thanks to these movements, the mucous membrane of the mouth and pharynx comes into contact with new masses of water, and the gills get a movement that renews the respiratory environment.
In terrestrial amphibians, the breathing mechanism is the act of swallowing air by lowering the muscular bottom of the mouth and pushing it into the lungs due to the bottom rising. Thus, the breathing of terrestrial amphibians is an act carried out according to the type of pressure pump that prevails in lower fish. The immediate basis on which it develops is the mechanism of respiration in perennial gill amphibians. This latter, seen in Necturus, for example, must have evolved in the distant fish-like ancestors of amphibians. A more complex type of terrestrial breathing has already developed from it - Anura.
In lungless salamanders, gas exchange of the intraoral and pharyngeal cavities is highly developed, which occurs with the help of frequent, up to 120-170 oscillations per minute of the diaphragm of the mouth (there are 30 in frogs).
In general, it should be said that lung respiration in amphibians as a whole is an auxiliary method of respiration. This also contains an indication of its phylogenetic origin.
The respiration of modern amphibians could by no means be the source of the development of respiration in the higher Tetrapoda (breathing by lifting the ribs, expanding the chest and thus sucking in air). The latter type could arise, in any case, be outlined in the most ancient extinct amphibians, which had long ribs.

Evolution of the respiratory system

Stages of the breathing process

Breath- a set of processes that ensure the supply of oxygen from the environment to the body, which is necessary for the oxidation of organic substances in the mitochondria of the cell, and the release of carbon dioxide

Breath types:



Breath type:

Cellular.
Organisms: unicellular animals (amoeba, green euglena, infusoria slipper); coelenterates (jellyfish, coral polyps); some worms.

Single-celled organisms absorb oxygen dissolved in water over the entire surface of the body by diffusion.

Oxygen is involved in the breakdown of complex organic substances, resulting in the release of energy, which is necessary for the life of the animal.
Carbon dioxide formed as a result of respiration is also released outward through the entire surface of the body.

Tracheal breathing is breathing with the help of a system of combined tracheal tubes that permeate the entire body.

Organisms: class Insects (beetles, butterflies, grasshoppers, flies)

The abdomen of an insect is divided into 5–11 parts (segments). Each of them has a pair of small holes - spiracle. From each spiracle branching tubules extend inward - trachea that permeate the entire body of the insect. Watching the cockchafer, you can see how its abdomen either decreases in volume or increases. These are breathing movements. When you inhale, air containing oxygen enters the body through the spiracles, and when you exhale, air saturated with carbon dioxide leaves.

In spiders (class Arachnids), the respiratory organs are represented not only by tracheae, but also by lung sacs that communicate with the external environment through respiratory openings.

Gill breathing is breathing with the help of specialized formations with a dense network of blood vessels.

Organisms: many aquatic life (fish, crayfish, mollusks)

Fish breathe oxygen dissolved in water with the help of special branched skin outgrowths called gills. Fish are constantly swallowing water. From the oral cavity, water passes through the gill slits, wash the gills and exits from under the gill covers. Gills consist of gill arches and gill filaments which are pierced by many blood vessels. From the water that washes the gills, oxygen enters the blood, and carbon dioxide is removed from the blood into the water. The gills inside the body are called internal gills.
Some animals, such as amphibians, have thick tufts of gills on the surface of the body. Such gills are called - outdoor. Such is the structure of Proteus, a blind cave animal from the western regions of Yugoslavia, and axolotls (which are similar in general appearance to newts) - their homeland is Mexico.

Gas exchange, or respiration, is expressed in the body's absorption of oxygen from the environment (water or atmosphere) and the release of carbon dioxide into the latter as the end product of the oxidative process occurring in the tissues, due to which the energy necessary for life is released. Oxygen is taken up by the body in a variety of ways; they can basically be characterized as: 1) diffuse breathing and 2) local breathing, that is, by special organs.

diffuse breathing consists in the absorption of oxygen and the release of carbon dioxide by the entire surface of the outer integument - skin respiration - and n and e - and the epithelial membrane of the digestive tube - to and cervical respiration, i.e. without organs specially adapted for this purpose. A similar method of gas exchange is characteristic of some types of primitive multicellular animals, such as sponges, coelenterates and flatworms, and is due to their lack of a circulatory system.

It goes without saying that diffuse respiration is inherent only in organisms in which the volume of the body is small, and its surface is relatively extensive, since it is known that the volume of the body increases in proportion to the cube of the radius, and the corresponding surface - only to the square of the radius. Therefore, with a large volume of the body, this method of breathing is insufficient.

However, even with more or less appropriate volume-to-surface ratios, diffuse respiration still cannot always satisfy organisms, since the more vigorously vital activity is manifested, the more intense the oxidative processes in the body should proceed.

With intensive manifestations of life, despite the small volume of the body, it is necessary to increase its area of ​​​​contact with the environment containing oxygen, and special devices to accelerate the ventilation of the respiratory tract. An increase in the area of ​​gas exchange is achieved by the development of special respiratory organs.

Special respiratory organs vary considerably in details of construction and location in the body. For aquatic animals, such organs are the gills, for terrestrial animals, the traxae and invertebrates, and for vertebrates, the lungs.

Gill breathing. Gills are external and internal. Primitive external gills represent a simple protrusion of villous offspring of the skin, abundantly supplied with capillary vessels. Such gills in some cases differ little in their function from diffuse respiration, being only its higher stage (Fig. 332- A, 2). Usually they are concentrated in the front parts of the body.

The internal gills are formed from the folds of the mucous membrane of the initial section of the digestive tube between the gill slits (Fig. 246-2-5; 332- 7). The skin adjacent to them forms abundant branching in the form of petals with a large number of capillary blood vessels. The internal gills are often covered with a special fold of the skin (gill cover), the oscillatory movements of which improve the conditions of exchange, increasing the flow of water and removing its used portions.

Internal gills are characteristic of aquatic vertebrates, and the act of gas exchange in them is complicated by the passage of portions of water to the gill slits through the oral cavity and the movements of the gill cover. In addition, their gills are included in the circulatory circle. Each gill arch has its own vessels, and thus, at the same time, a higher differentiation of the circulatory system is carried out.

Of course, with gill methods of gas exchange, skin respiration can also be preserved, but so weak that it is relegated to the background.

In describing the oropharynx of the digestive tract, it has already been said that the gill apparatus is also characteristic of some invertebrates, such as, for example, hemichordates and chordates.

Lung breathing- a very perfect way of gas exchange, easily serving the organisms of massive animals. It is characteristic of terrestrial vertebrates: amphibians (not in the larval state), reptiles, birds and mammals. A number of organs with other functions join the act of gas exchange concentrated in the lungs, as a result of which the pulmonary method of breathing requires the development of a very complex complex of organs.

When comparing aquatic and terrestrial types of respiration in vertebrates, one important anatomical difference should be kept in mind. During gill respiration, portions of water enter the primitive mouth one by one and are released through the gill slits, where oxygen is extracted from it by the vessels of the gill folds. Thus, the gill breathing apparatus of vertebrates is characterized by an inlet and a number of outlets. During pulmonary respiration, the same openings are used for the introduction and removal of air. This feature, of course, is associated with the need to take in and push out portions of air for faster ventilation of the gas exchange area, i.e., with the need to expand and contract the lungs.

It can be assumed that the distant, more primitive ancestors of vertebrates had independent muscle tissue in the walls of the swim bladder transforming into light; with its periodic contractions, air was pushed out of the bladder, and as a result of its expansion, fresh portions of air were collected due to the elasticity of the bladder walls. Elastic tissue, along with cartilage, now dominates as a support in the respiratory system.


In the future, with an increase in the vital activity of organisms, such a mechanism of respiratory movements became already imperfect. In the history of development, it was replaced by force concentrated either in the oral cavity and the anterior part of the trachea (amphibians), or in the walls of the chest and abdominal cavities (reptiles, mammals) in the form of a specially differentiated part of the trunk muscles (respiratory muscles) and, finally, diaphragm. The lung obeys the movements of this musculature, expanding and contracting passively, and retains the elasticity necessary for this, as well as a small muscular apparatus as an auxiliary device.

Skin respiration becomes so insignificant that its role is reduced almost to zero.

Gas exchange in the lungs in terrestrial vertebrates, as well as in aquatic ones, is closely connected with the circulatory system through the organization of a separate, respiratory, or small, circle of blood circulation.

It is quite clear that the main structural changes in the body during pulmonary respiration come down to: 1) an increase in the contact of the working area of ​​the lungs with air, and 2) a very close and no less extensive connection of this area with the thin-walled capillaries of the circulatory circle.

The function of the respiratory apparatus - to pass air into its many channels for gas exchange - speaks for the nature of its construction in the form of an open, gaping system of tubes. Their walls, in comparison with the soft intestinal tube, are composed of a harder supporting material; in places in the form of bone tissue (nasal cavity), and mainly in the form of cartilaginous tissue and easily pliable, but quickly returning to normal elastic tissue.

The mucous membrane of the respiratory tract is lined with a special ciliated epithelium. Only in a few areas does it change into a different form in accordance with other functions of these areas, such as, for example, in the olfactory region and in the places of gas exchange itself.

Throughout the pulmonary respiratory tract, three peculiar areas attract attention. Of these, the initial - n axial strip with t - serves for the perceived air, examined here for smell. The second section - the throat - is a device for isolating the respiratory tract from the digestive tract during the passage of the food coma through the pharynx, for making sounds and, finally, for producing cough shocks that eject mucus from the respiratory tract. The last section, lёg to and e-represent the organ of direct gas exchange.

Between the nasal cavity and the larynx is the cavity of the pharynx, common with the digestive apparatus, and between the larynx and the lung, the respiratory

throat, or trachea. Thus, the passing air is used by the described expanding areas in three different directions: a) perceived odors, b) devices for making sounds and, finally, in) gas exchange, of which the latter is the main one.

Reducing the number of gills.

An increase in the respiratory surface due to the formation of gill filaments.

Formation of gill capillaries.

In the lancelet, the side walls of the pharynx are pierced by numerous (up to 150 pairs) obliquely located gill slits. The afferent branchial arteries approach the interbranch septa, and the efferent branchial arteries depart. When water washes the interbranch septa, gas exchange occurs between the passing water and the blood that flows through the thin vessels of the septa. Gill arteries do not branch into capillaries. In addition, oxygen enters the animal's body through the capillaries of the skin.

In primary aquatic vertebrates (jawless and fish), as in the lower chordates, gill slits are formed that connect the pharyngeal cavity with the external environment. In cyclostomes, from the endoderm lining the gill slits, gill sacs are formed (in fish, the gills develop from the ectoderm). The inner surface of the bags is covered with numerous folds - gill filaments, in the walls of which a dense network of capillaries branches. The bag with an internal narrow channel opens into the pharynx (in adult lampreys - into the windpipe), and with an external one - on the lateral surface of the animal's body. Hagfishes have from 5 to 16 pairs of gill sacs, in the bdellostomatoe family each of them opens outward with an independent opening, and in the hagfish family all external gill passages on each side merge into one canal, which opens outwards with one opening located far behind. Lampreys have 7 pairs of gill sacs, each of which opens to the outside with an independent opening. Breathing is carried out by rhythmic contractions and relaxations of the muscular wall of the gill region. In non-feeding lampreys, water enters the respiratory tube from the oral cavity, then washes the petals of the gill sacs, providing gas exchange, and is removed through the external gill passages. In feeding cyclostomes, water enters and exits through the external openings of the gill sacs.

The respiratory system of fish has specialized gas exchange organs - ectodermal gills, which are either located on the intergill septa, as in cartilaginous fish, or directly extend from the gill arches, as in bony fish. The exchange of gases in the gills of vertebrates is built according to the type of "countercurrent systems": in the oncoming movement, the blood comes into contact with oxygen-rich water, which ensures its effective saturation. An increase in the oxygen absorption surface due to the formation of gills was accompanied by a decrease in the number of gill slits in vertebrates compared to lower chordates. In whole-headed (from cartilaginous fishes) the reduction of the intergill septa is outlined and a leathery gill cover is formed, covering the outside of the gills. In bony fish, a bone skeleton appears in the gill cover, and the intergill septa are reduced, which contributes to more intensive washing of the gill filaments with water. Along with gas exchange, the gills of fish are involved in water and salt metabolism, in the removal of ammonia and urea from the body. The skin, swim bladder, supraesophageal labyrinths, and specialized sections of the intestinal tube function as additional respiratory organs in certain groups of fish. In lung-breathing and multi-feathered fish, air-respiratory organs appear - the lungs. The lungs arise as paired outgrowths of the abdominal part of the pharynx in the region of the last branchial slit and are connected with the esophagus by a short canal. The walls of this outgrowth are thin and richly supplied with blood.


Directions of evolution of the pulmonary type of breathing

The emergence and differentiation of the respiratory tract.

Differentiation of the lung and an increase in the respiratory surface.

Development of auxiliary organs (thorax).

In amphibians, the following are involved in the absorption of oxygen and the release of carbon dioxide: in larvae - skin, external and internal gills, in adults - lungs, skin and mucous membrane of the oropharyngeal cavity. In some species of tailed amphibians (sirens, proteas) and in adults, gills are preserved and the lungs are underdeveloped or reduced. The ratio of pulmonary and other types of gas exchange is not the same: in species of humid habitats, skin respiration dominates in gas exchange, in inhabitants of dry places, most of the oxygen enters through the lungs, but the skin plays a significant role in the release of carbon dioxide. The respiratory system of adult amphibians includes the oropharyngeal, laryngeal-tracheal cavities and saccular lungs, the walls of which are braided with a dense network of capillaries. Tailless amphibians have a common laryngeal-tracheal chamber; in caudates, it is divided into the larynx and trachea. In the larynx, arytenoid cartilages appear, which support its wall and vocal cords. The lungs of tailed amphibians are two thin-walled bags that do not have partitions. Anurans inside the lung sacs have partitions on the walls that increase the surface of gas exchange (lungs are cellular). Amphibians do not have ribs, and the act of breathing occurs by forcing air during inhalation (due to an increase and then a decrease in the volume of the oropharyngeal cavity) and expelling air during exhalation (due to the elasticity of the walls of the lungs and abdominal muscles).

In reptiles, further differentiation of the respiratory tract and a significant increase in the functional surface of gas exchange in the lungs are noted. The airways are subdivided into the nasal cavity (it is combined with the oral cavity, but in crocodiles and turtles these cavities are separated by the bony palate), the larynx, trachea, and two bronchi. The walls of the larynx support the paired arytenoid and unpaired cricoid cartilages. In lizards and snakes, the inner walls of the lung sacs have a folded cellular structure. In turtles and crocodiles, a complex system of partitions protrudes into the internal cavity of the lung so deeply that the lung acquires a spongy structure. The chest is formed: the ribs are movably connected to the spine and sternum, the intercostal muscles develop. The act of breathing is carried out due to a change in the volume of the chest (costal type of breathing). Turtles retain the oropharyngeal type of air injection. In aquatic turtles in water, additional respiratory organs are capillary-rich outgrowths of the pharynx and cloacae (anal bladders). Reptiles do not have cutaneous respiration.

In birds, the airways are represented by the nasal cavity, the larynx, which is supported by the arytenoid and cricoid cartilages, the long trachea, and the bronchial system. The lungs are small, dense and slightly extensible attached to the ribs on the sides of the spinal column. Primary bronchi are formed when the lower part of the trachea is divided and enter the tissue of the corresponding lung, where they break up into 15–20 secondary bronchi, most of which end blindly, and some communicate with the air sacs. The secondary bronchi are interconnected by smaller parabronchi, from which many thin-walled cellular bronchioles depart. Bronchioles braided with blood vessels form the morphofunctional structure of the lung. Air sacs are connected with the lungs of birds - transparent elastic thin-walled outgrowths of the mucous membrane of the secondary bronchi. The volume of the air sacs is about 10 times the volume of the lungs. They play a very important role in the implementation of a peculiar respiratory act of birds: both inhalation and exhalation, air with a high oxygen content enters the lungs - “double breathing”. In addition to intensifying breathing, air sacs prevent the body from overheating during intense movement. An increase in intra-abdominal pressure during exhalation promotes defecation. Diving birds, by increasing the pressure in the air sacs, can reduce the volume and thereby increase the density, which makes it easier to dive into the water. There is no skin respiration in birds.

In mammals, further differentiation of the respiratory tract is observed. The nasal cavity, the nasopharynx are formed, the entrance to the larynx is covered by the epiglottis (in all terrestrial vertebrates except mammals, the laryngeal fissure is closed by special muscles), the thyroid cartilage appears in the larynx, then comes the trachea, which branches into two bronchi going to the right and left lung. In the lungs, the bronchi branch many times and end with bronchioles and alveoli (the number of alveoli is from 6 to 500 million), this significantly increases the respiratory surface. Gas exchange occurs in the alveolar passages and alveoli, the walls of which are densely braided with blood vessels. The morphofunctional unit of the mammalian lung is the pulmonary acinus, which is formed as a result of branching of the terminal bronchiole. The chest is formed, which is separated from the abdominal cavity by the diaphragm. The number of respiratory movements is from 8 to 200. Respiratory movements are carried out in two ways: due to a change in the volume of the chest (rib breathing) and due to the activity of the diaphragmatic muscle (diaphragmatic breathing). Higher mammals have developed skin respiration through the system of skin capillaries, which plays an important role in gas exchange.

Animal breath – set of processes that providehit into the body from the environmentoxygen , hiscell use for the oxidation of organic substances andbreeding from the body of carbon dioxide.This breathing is calledaerobic , and the organismsaerobes .

OK. No. 28. Biology.

green algae chlorella

Infusoria shoe

The process of respiration in animals is conditionally divided into three stages :

External respiration = gas exchange. Through this process, the animal receives oxygen and gets rid of carbon dioxide, which is the end product of metabolism.

Transport of gases in the body- this process is provided either by special tracheal tubes or internal body fluids (blood containing hemoglobin- a pigment that can attach oxygen and transport it to cells, as well as carry carbon dioxide out of cells).

internal breathing- occurs in cells. Simple nutrients (amino acids, fatty acids, simple carbohydrates) are oxidized and broken down with the help of cell enzymes, during which the ENERGY necessary for the life of the body is released.

The main significance of respiration is the release of energy from nutrients with the help of oxygen, which takes part in oxidation reactions.

Some of the simplest anaerobic organisms, i.e. organisms, not requiring oxygen. Anaerobes are optional and obligatory. Facultative anaerobic organisms are organisms that can live both in the absence of oxygen and in its presence. Obligate anaerobic organisms are organisms for which oxygen is poisonous. They can only live in the absence of oxygen. Anaerobic organisms do not need oxygen to oxidize nutrients.

Brachonella - anaerobic infusoria

Intestinal Giardia

human roundworm

By way of breathing and the structure of the respiratory apparatus in animals, 4 types of breathing are distinguished:

Skin respiration is the exchange of oxygen and carbon dioxide through the integument of the body. This process is based on the most important physical process - diffusion . Gases enter only in a dissolved state through the covers shallowly and at a low speed. Such breathing in organisms that are small in size, have wet covers, lead an aquatic lifestyle. It - sponges, coelenterates, worms, amphibians.

Tracheal breathing –

carried out with the help

connected systems

tubules - trachea , which

permeate the entire body

participation of fluids. FROM

their environment

connect special

holes - spiracles.

Organisms with tracheal

breathing is also small in size (no more than 2 cm, otherwise the body will not have enough oxygen). It - insects, centipedes, arachnids.

gill breathing - with the help of specialized formations with a dense network of blood vessels. These outgrowths are called gills . In aquatic animals polychaete worms, crustaceans, mollusks, fish, certain amphibian species. Invertebrates usually have external gills, while chordates have internal gills. Gill-breathing animals have additional forms of breathing through the skin, intestines, mouth surface, swim bladder.

Polychaete with gills

Crustacean gills

Nudibranch mollusk

Pulmonary respiration - this is breathing with the help of internal specialized organs - lungs.

Lungs– these are hollow thin-walled bags, braided with a dense network of tiny blood vessels - capillaries. Diffusion of oxygen from the air into the capillaries occurs on the inner surface of the lungs. Accordingly, the larger this inner surface, the more actively diffusion takes place.

Almost all terrestrial vertebrates breathe with lungs. reptiles, birds, some terrestrial invertebrates - spiders, scorpions, pulmonary mollusks, and some aquatic animals - lungfish. Air enters the lungs through Airways.

Lungs of a mammal


reptile lung

Respiratory system of birds

Breathing in animals is determined by their way of life and is carried out with the help of integument, trachea, gills and lungs.

Respiratory system – a set of organs for carrying air or water that contain oxygen, and gas exchange between the body and the environment.

Respiratory organs develop as outgrowths of the outer integument or walls of the intestinal tract. The respiratory system includes the respiratory tract and gas exchange organs. Vertebrates Airways – nasal cavity, larynx, trachea, bronchi ; a respiratory system -lungs .

Comparative characteristics of the respiratory organs.

Group

Characteristic features of the respiratory system

Coelenterates

Gas exchange across the entire surface of the body. There are no special respiratory organs.

annelids

External gills (polychaete worms) and entire body surface (oligochaete worms, leeches)

shellfish

Gills (bivalves, cephalopods) and lungs (gastropods)

arthropods

Gills (crustaceans), tracheae and lungs (arachnoids), tracheae (insects)

Fish

Gills. Additional organs for breathing: lungs (lungfish), parts of the oral cavity, pharynx, intestines, swim bladder

Amphibians

Lungs are cellular, gills (in larvae), skin (with a large number of vessels). Respiratory tract: nostrils, mouth, tracheo-laryngeal chamber

reptiles

Light honeycomb. Respiratory tract: nostrils, larynx, trachea, bronchi

Birds

Light spongy. Respiratory tract: nostrils, nasal cavity, upper larynx, trachea, lower larynx with vocal apparatus, bronchi. There are air bags.

mammals

Light alveolar. Respiratory tract: nostrils, nasal cavity, larynx with vocal apparatus, trachea, bronchi.

Functions of the respiratory system:

    Delivery of oxygen to the cells of the body and removal of carbon dioxide from the cells of the body and gas exchange(main function).

    Body temperature regulation(since water can evaporate through the surface of the lungs and airways)

    Purification and disinfection of incoming air(nasal mucus)

Questions for self-control.

Grade

Questions for self-control

1. What is breathing?

2. The main stages of breathing?

3. Name the main types of animal breathing.

4. Give examples of animals that breathe with their skin, gills, windpipes and lungs.

5. What is the respiratory system?

6. Name the main functions of the respiratory system.

7. What is the importance of breathing for the release of energy in animal cells?

8. What determines the type of breathing of animals?

9. What are the functions of the respiratory system?

10. Describe how vertebrates breathe.

Comparative characteristics of the respiratory organs of animals.

Respiratory system

Structural features

Functions

Examples

Gills

External(comb, filamentous and pinnate) or domestic(always associated with the pharynx) thin-walled outgrowths of the body that contain many blood vessels

Gas exchange in the aquatic environment

In fish, in almost all larvae of anurans, in most molluscs, some worms and arthropods

Trachea

Branched tubules that permeate the entire body and open outward with holes (stigmas)

Gas exchange in the air

In most arthropods

Lungs

Thin-walled bags that have an extensive network of vessels

Gas exchange in the air

In some molluscs and fish, terrestrial vertebrates