Air - the role of air in the life of humans, plants and animals. Modern views on the origin of life

Air is called a mixture natural gases- nitrogen, oxygen, argon, carbon dioxide, water and hydrogen. It is the primary source of energy for all organisms and the key to healthy growth and long life. Thanks to air, the process of metabolism and development occurs in organisms.

Air in the life of plants and animals

Air plays a huge role in plant life. The fundamental components necessary for the growth and life of plants are oxygen, carbon dioxide, water vapor and soil air. Oxygen is necessary for respiration, and carbon dioxide is necessary for carbon nutrition.

Oxygen is vital for all living things. Plants cannot germinate without oxygenation. The roots, leaves, and stems of plants need this element.

Carbon dioxide enters the plant by entering through its stomata into the leaf environment, entering the cells. The higher the concentration of carbon dioxide, the better plant life becomes.

Air contributes to the implementation of microbiological processes occurring in the soil. Thanks to these processes, elements necessary for the nutrition, growth and life of plants are formed in the soil - nitrogen, phosphorus, potassium and others.

Air also plays a special role in the formation of mechanical tissues in land plants. It serves as their environment, protecting them from exposure ultraviolet rays.

Air movement is important for favorable growth plants. Horizontal air movement dries out plants. And the vertical promotes the spread of fingers, seeds, and also regulates the thermal regime in different areas.

Animals, like plants, need air. Age, gender, size and physical activity are directly related to the amount of air consumed.

Animals' bodies are very sensitive to lack of oxygen. Due to the reduced oxygen concentration in animals, consumed proteins, fats and carbohydrates stop oxidizing. This leads to the accumulation of harmful toxic substances in the body.

Oxygen is necessary to saturate the blood and tissues of a living creature. Therefore, when there is a lack of this element in animals, breathing quickens, blood flow accelerates, oxidative processes in the body decrease, and the animal becomes restless. Prolonged lack of oxygen saturation causes: muscle fatigue, lack of pain factor, decreased body temperature and death.

Air in human life

Air is a vital factor for humans. It is carried by the blood throughout the body, saturating every organ and every cell of the body.

It is in the air that heat exchange occurs human body with the environment. The essence of this exchange is the convection transfer of heat and evaporation of moisture from the human lungs.

Air also performs a protective function for the body: it dilutes chemical pollutants to a safe concentration. This helps reduce the risk of poisoning the body with chemicals.

With the help of breathing, a person saturates the body with energy. Atmospheric air consists of many elements, but its composition can change. The reason for this is human production and technogenic activity.

During exhalation, a person returns a quarter less of the inhaled oxygen and a hundred times more carbon dioxide. A person needs to inhale 13-14 m3 of air daily. The oxygen content in the body of a healthy person remains virtually unchanged. But if this element is missing, then malfunctions occur in the body, the pulse quickens.

Carbon dioxide is also important for the body, but in certain quantities. An increase in gas concentration causes headache or tinnitus.

Oxygen helps rid the human body of carbon dioxide, which contains accumulated poisons and toxins. If a person rarely goes out Fresh air, breathes shallowly, or the air contains a low concentration of oxygen, the human body suffers poisoning, leading to various diseases.

Atmosphere pollution

There are a huge number of substances that pollute the atmosphere in the world. These substances are produced both by man and by nature itself. Sources of air pollution are: thermal power plants and heating plants, motor transport, non-ferrous and ferrous metallurgy, chemical production and others.

Human activity contributes to the release of ash, soot, and dust. Mineral acids and organic solvents also enter the atmosphere.

Natural disasters also release various substances into the atmosphere. During volcanic eruptions, dust storms and forest fires, dust, sulfur dioxide, nitrogen and carbon oxides are released.

In order to know the ways of the origin of life, it is necessary to first study the signs and properties of living organisms. Knowledge chemical composition, buildings and various processes, occurring in the body, makes it possible to understand the origin of life. To do this, let’s get acquainted with the features of the formation of the first inorganic substances V outer space and the emergence of a planetary system.

The atmosphere of the ancient Earth. According to the latest data from scientists and space researchers, celestial bodies were formed 4.5-5 billion years ago. At the first stages of the formation of the Earth, its composition included oxides, carbonates, metal carbides and gases that erupted from the depths of volcanoes. As a result of compaction earth's crust and the action of gravitational forces began to release a large amount of heat. The rise in Earth's temperature was influenced by the decay of radioactive compounds and ultraviolet radiation Sun. At this time, water on Earth existed in the form of steam. IN upper layers air, water vapor collected in clouds, which fell on the surface of hot stones in the form of torrential rains, then again, evaporating, rising into the atmosphere. Lightning flashed on Earth and thunder rumbled. This went on for a long time. Gradually, the surface layers of the Earth began to cool. Due to heavy rains, small ponds formed. Streams of hot lava that flowed from volcanoes and ash fell into primary reservoirs and continuously changed conditions environment. Such continuous environmental changes contributed to the emergence of formation reactions organic compounds.
Even before the emergence of life, the Earth's atmosphere contained methane, hydrogen, ammonia and water (1). As a result of the chemical reaction of combining sucrose molecules, starch and fiber were formed, and proteins were formed from amino acids (2,3). Self-regulating DNA molecules were formed from sucrose and nitrogen compounds (4) (Fig. 9).

Rice. 9. Approximately 3.8 billion years ago by chemical reactions the first complex compounds were formed

There was no free oxygen in the Earth's primary atmosphere. Oxygen was found in the form of compounds of iron, aluminum, and silicon and participated in the formation of various minerals in the earth’s crust. In addition, oxygen was present in water and some gases (for example, carbon dioxide). Hydrogen compounds with other elements formed poisonous gases on the surface of the Earth. Ultraviolet radiation from the Sun was one of the necessary sources of energy for the formation of organic compounds. Inorganic compounds widespread in the Earth's atmosphere include methane, ammonia and other gases (Fig. 10).

Rice. 10. The initial stage of the emergence of life on Earth. Formation of complex organic compounds in the primordial ocean

Formation of organic compounds by abiogenic means. Knowledge of environmental conditions in the initial stages of the Earth's development was of great importance for science. A special place in this area is occupied by the work of the Russian scientist A. I. Oparin (1894-1980). In 1924, he suggested the possibility of chemical evolution occurring in initial stages development of the Earth. The theory of A.I. Oparin is based on the gradual long-term complication of chemical compounds.
American scientists S. Miller and G. Ury carried out experiments in 1953, according to the theory of A.I. Oparin. By passing an electric discharge through a mixture of methane, ammonia and water, they obtained various organic compounds (urea, lactic acid, various amino acids). Later, many scientists repeated such experiments. The experimental results obtained proved the correctness of A.I. Oparin’s hypothesis.
Thanks to the conclusions of the experiments mentioned above, it was proven that as a result of chemical evolution primeval earth biological monomers were formed.

Formation and evolution of biopolymers. The totality and composition of organic compounds formed in various water spaces of the primordial Earth were of different levels. The formation of such compounds abiogenically has been proven experimentally.
The American scientist S. Fox in 1957 expressed the opinion that amino acids can form peptide bonds by connecting with each other without the participation of water. He noticed that when dry mixtures of amino acids were heated and then cooled, their protein-like molecules formed bonds. S. Fox came to the conclusion that in place of former water spaces, under the influence of the heat of lava flows and solar radiation, independent connections amino acids that gave rise to primary polypeptides.

The role of DNA and RNA in the evolution of life. Main difference nucleic acids from proteins - the ability to double and reproduce exact copies original molecules. In 1982, the American scientist Thomas Check discovered the enzymatic (catalytic) activity of RNA molecules. As a result, he concluded that RNA molecules are the very first polymers on Earth. Compared to RNA, DNA molecules are more stable in decomposition processes in slightly alkaline aqueous solutions. And the environment with such solutions was in the waters of the primordial Earth. Currently, this condition is preserved only within the cell. DNA molecules and proteins are interconnected. For example, proteins protect DNA molecules from harmful effects ultraviolet rays. We cannot call proteins and DNA molecules living organisms, although they have some characteristics of living bodies, because their biological membranes are not fully formed.

Evolution and formation of biological membranes. Parallel existence proteins and nucleic acids in space may have opened the way for the emergence of living organisms. This could only happen in the presence of biological membranes. Thanks to biological membranes, a connection is formed between the environment and proteins and nucleic acids. Only through biological membranes does the process of metabolism and energy take place. Over millions of years, primary biological membranes, gradually becoming more complex, added various protein molecules to their composition. Thus, through gradual complication, the first living organisms (protobionts) appeared. Protobionts gradually developed systems of self-regulation and self-reproduction. The first living organisms adapted to life in an oxygen-free environment. All this corresponds to the opinion expressed by A.I. Oparin. A. I. Oparin’s hypothesis is called the coacervate theory in science. This theory was supported in 1929 by the English scientist D. Haldane. Multimolecular complexes with a thin water shell on the outside are called coacervates or coacervate droplets. Some proteins in the coacervates played the role of enzymes, and nucleic acids acquired the ability to transmit information by inheritance (Fig. 11).

Rice. 11. Formation of coacervates - multimolecular complexes with an aqueous shell

Gradually, nucleic acids developed the ability to double. The connection of the coacervate droplet with the environment led to the implementation of the very first simple metabolism and energy on Earth.
Thus, the main provisions of the theory of the origin of life according to A.I. Oparin are as follows:

1. as a result of the direct influence of environmental factors, organic substances were formed from inorganic substances;
2. the formed organic substances influenced the formation of complex organic compounds (enzymes) and free self-reproducing genes;
3. the formed free genes combined with other high-molecular organic substances;
4. high-molecular substances gradually developed protein-lipid membranes on the outside;
5. As a result of these processes, cells appeared.

The modern view of the origin of life on Earth is called
the theory of biopoiesis (organic compounds are formed from living organisms). Currently it is called biochemical evolutionary theory emergence of life on Earth. This theory was proposed in 1947 by the English scientist D. Bernal. He distinguished three stages of biogenesis. The first stage is the emergence of biological monomers abiogenically. The second stage is the formation of biological polymers. The third stage is the emergence of membrane structures and the first organisms (protobionts). The grouping of complex organic compounds within coacervates and their active interaction with each other create conditions for the formation of self-regulating simple heterotrophic organisms.
In the process of the emergence of life, complex evolutionary changes occurred - the formation of organic substances from inorganic compounds. First, chemosynthetic organisms appeared, then gradually photosynthetic organisms appeared. Photosynthetic organisms played a huge role in the appearance of more free oxygen in the Earth's atmosphere.
Chemical evolution and the evolution of the first organisms (protobionts) on Earth lasted up to 1-1.5 billion years (Fig. 12).

Rice. 12. Scheme of the transition of chemical evolution to biological

Primary atmosphere. Biological membrane. Coacervate. Protobiont. The theory of biopoiesis.

1. Celestial bodies, including Earth, appeared 4.5-5 billion years ago.
2. During the period of the formation of the Earth, there was quite a lot of hydrogen and its compounds, but there was no free oxygen.
3. At the initial stage of the Earth's development, the only source of energy was ultraviolet radiation from the Sun.
4. A. I. Oparin expressed the opinion that in initial period Only chemical evolution occurs on Earth.
5. Biological monomers first appeared on Earth, from which proteins and nucleic acids (RNA, DNA) were gradually formed.
6. The first organisms to appear on Earth were protobionts.
7. Multimolecular complexes surrounded by a thin aqueous shell are called coacervates.
1. What is a coacervate?
2. What is the meaning of A.I. Oparin’s theory?
3. What poisonous gases were in the primordial atmosphere?
1. Describe the composition of the primary atmosphere.
2. What theory about the formation of amino acids on the surface of the Earth was presented by S. Fox?
3. What role do nucleic acids play in the evolution of life?

1. What is the essence of the experiments of S. Miller and G. Ury?
2. What was A.I. Oparin based on in his hypotheses?
3. Name the main stages in the emergence of life.

* Test your knowledge!
Review questions. Chapter 1. Origin and initial stages of development of life on Earth

1. The level of organization of life at which global problems are solved.
2. Individual development of individual organisms.
3. Sustainability internal environment body.
4. The theory of the origin of life through the chemical evolution of inorganic substances.
5. Historical development organisms.
6. The level of organization of life, consisting of cells and intercellular substances.
7. The ability of living organisms to reproduce their own kind.
8. A standard of living characterized by the unity of the community of living organisms and the environment.
9. A standard of living characterized by the presence of nucleic acids and other compounds.
10. The property of changes in the vital activity of living organisms according to annual cycles.
11. A look at the introduction of life from other planets.
12. The level of organization of life, represented by the structural and functional unit of all living organisms on Earth.
13. The property of close connection between living organisms and the environment.
14. A theory that connects the origin of life with the action of “vital forces.”
15. The property of living organisms to ensure the transmission of characteristics to their offspring.
16. The scientist who proved with the help simple experience the theory of the spontaneous generation of life is incorrect.
17. Russian scientist who proposed the theory of the origin of life through abiogenic means.
18. A gas necessary for life that was not present in the primary atmosphere.
19. A scientist who expressed the opinion that a peptide bond is formed by connecting amino acids together without the participation of water.
20. The very first living organisms with a biological membrane.
21. High molecular weight complexes surrounded by a thin aqueous shell.
22. The scientist who first defined the concept of life.
23. The ability of living organisms to respond to various influences environmental factors.
24. The property of changing the signs of heredity of living organisms under the influence various factors environment.
25. The level of organization of life at which the first simple evolutionary changes are noticeable.

All life on Earth exists for a hundred years solar heat and energy reaching the surface of our planet. All animals and humans have adapted to extract energy from organic substances synthesized by plants. To use the solar energy contained in the molecules of organic substances, it must be released by oxidizing these substances. Most often, air oxygen is used as an oxidizing agent, since it makes up almost a quarter of the volume of the surrounding atmosphere.

Single-celled protozoa, coelenterates, free-living flatworms and roundworms breathe the entire surface of the body. Special respiratory organs - feathery gills appear in marine annelids and aquatic arthropods. The respiratory organs of arthropods are trachea, gills, leaf-shaped lungs located in the recesses of the body cover. The respiratory system of the lancelet is presented gill slits piercing the wall of the anterior intestine - the pharynx. In fish, under the gill covers there are gills, abundantly penetrated by the smallest blood vessels. In terrestrial vertebrates, the respiratory organs are lungs. The evolution of respiration in vertebrates followed the path of increasing the area of ​​the pulmonary partitions involved in gas exchange and improving transport systems delivery of oxygen to cells located inside the body, and the development of systems that provide ventilation to the respiratory system.

Structure and functions of the respiratory organs

A necessary condition for the life of the body is constant gas exchange between the body and the environment. The organs through which inhaled and exhaled air circulate are combined into a breathing apparatus. The respiratory system consists of the nasal cavity, pharynx, larynx, trachea, bronchi and lungs. Most of them are airways and serve to conduct air into the lungs. Gas exchange processes take place in the lungs. When breathing, the body receives oxygen from the air, which is carried by the blood throughout the body. Oxygen is involved in complex oxidative processes of organic substances, which releases the energy needed by the body. The final products of decomposition - carbon dioxide and partly water - are removed from the body into the environment through the respiratory system.

Functions of the respiratory system

• Providing the body cells with oxygen O 2.
• Removing carbon dioxide CO 2 from the body, as well as some end products of metabolism (water vapor, ammonia, hydrogen sulfide).

Nasal cavity

The airways begin with nasal cavity, which connects with the environment through the nostrils. From the nostrils, air passes through the nasal passages, which are lined with mucous, ciliated and sensitive epithelium. The external nose consists of bone and cartilage formations and has the shape of an irregular pyramid, which varies depending on the structural features of the person. The bony skeleton of the external nose includes the nasal bones and the nasal part of the frontal bone. The cartilaginous skeleton is a continuation of the bony skeleton and consists of hyaline cartilage various shapes. The nasal cavity has a lower, upper and two side walls. The lower wall is formed by the hard palate, the upper by the cribriform plate of the ethmoid bone, the lateral wall by the upper jaw, lacrimal bone, orbital plate of the ethmoid bone, palatine bone and sphenoid bone. The nasal septum divides the nasal cavity into right and left parts. The nasal septum is formed by the vomer, perpendicular to the plate of the ethmoid bone, and anteriorly supplemented by the quadrangular cartilage of the nasal septum.

The turbinates are located on the side walls of the nasal cavity - three on each side, which increases the inner surface of the nose with which the inhaled air comes into contact.

The nasal cavity is formed by two narrow and tortuous nasal passages. Here the air is warmed, humidified and freed from dust particles and microbes. The membrane lining the nasal passages consists of cells that secrete mucus and ciliated epithelial cells. By the movement of the cilia, mucus, along with dust and germs, is directed out of the nasal passages.

The inner surface of the nasal passages is richly supplied with blood vessels. The inhaled air enters the nasal cavity, is heated, humidified, cleaned of dust and partially neutralized. From the nasal cavity it enters the nasopharynx. Then air from the nasal cavity enters the pharynx, and from it into the larynx.

Larynx

Larynx- one of the sections of the airways. Air enters here from the nasal passages through the pharynx. There are several cartilages in the wall of the larynx: thyroid, arytenoid, etc. At the moment of swallowing food, the neck muscles raise the larynx, and the epiglottic cartilage lowers and closes the larynx. Therefore, food only enters the esophagus and does not enter the trachea.

Located in the narrow part of the larynx vocal cords, in the middle between them there is a glottis. As air passes through, the vocal cords vibrate, producing sound. The formation of sound occurs during exhalation with human-controlled air movement. The formation of speech involves: the nasal cavity, lips, tongue, soft palate, facial muscles.

Trachea

The larynx goes into trachea(windpipe), which has the shape of a tube about 12 cm long, in the walls of which there are cartilaginous half-rings that do not allow it to fall off. Its posterior wall is formed by a connective tissue membrane. The cavity of the trachea, like the cavity of other airways, is lined with ciliated epithelium, which prevents the penetration of dust and other foreign bodies into the lungs. The trachea occupies a middle position, at the back it is adjacent to the esophagus, and on the sides of it there are neurovascular bundles. Front cervical region the trachea covers the muscles, and at the top it is also covered by the thyroid gland. The thoracic section of the trachea is covered in front by the manubrium of the sternum, the remains of the thymus gland and blood vessels. The inside of the trachea is covered with a mucous membrane containing a large amount of lymphoid tissue and mucous glands. When breathing, small particles of dust adhere to the moist mucous membrane of the trachea, and the cilia of the ciliated epithelium push them back to the exit from the respiratory tract.

The lower end of the trachea is divided into two bronchi, which then branch repeatedly and enter the right and left lungs, forming a “bronchial tree” in the lungs.

Bronchi

In the chest cavity, the trachea divides into two bronchus- left and right. Each bronchus enters the lung and there is divided into bronchi of smaller diameter, which branch into the smallest air tubes - bronchioles. Bronchioles, as a result of further branching, transform into extensions - alveolar ducts, on the walls of which there are microscopic protrusions called pulmonary vesicles, or alveoli.

The walls of the alveoli are built from a special thin single-layer epithelium and are densely intertwined with capillaries. The total thickness of the alveolar wall and the capillary wall is 0.004 mm. Gas exchange occurs through this thinnest wall: oxygen enters the blood from the alveoli, and carbon dioxide enters back. There are several hundred million alveoli in the lungs. Their total surface in an adult is 60–150 m2. Thanks to this, a sufficient amount of oxygen enters the blood (up to 500 liters per day).

Lungs

Lungs occupy almost the entire cavity of the thoracic cavity and are elastic, spongy organs. In the central part of the lung there is a gate where the bronchus, pulmonary artery, and nerves enter, and the pulmonary veins exit. The right lung is divided by grooves into three lobes, the left into two. The outside of the lungs is covered with a thin connective tissue film - the pulmonary pleura, which passes to the inner surface of the wall of the chest cavity and forms the wall pleura. Between these two films there is a pleural gap filled with fluid that reduces friction during breathing.

There are three surfaces on the lung: the outer, or costal, the medial, facing the other lung, and the lower, or diaphragmatic. In addition, in each lung there are two edges: anterior and inferior, separating the diaphragmatic and medial surfaces from the costal surface. At the back, the costal surface, without a sharp border, passes into the medial surface. Front edge the left lung has a cardiac notch. The hilum is located on the medial surface of the lung. The gateway of each lung includes the main bronchus, the pulmonary artery, which carries venous blood to the lung, and the nerves that innervate the lung. Two pulmonary veins emerge from the gates of each lung, which carry arterial blood and lymphatic vessels to the heart.

The lungs have deep grooves dividing them into lobes - upper, middle and lower, and in the left there are two - upper and lower. The lung sizes are not the same. The right lung is slightly larger than the left, while it is shorter and wider, which corresponds to the higher position of the right dome of the diaphragm due to the right-sided location of the liver. Color of normal lungs childhood pale pink, and in adults they acquire a dark gray color with a bluish tint - a consequence of the deposition of dust particles that enter them with the air. Lung tissue is soft, delicate and porous.

Gas exchange of the lungs

In the complex process of gas exchange, there are three main phases: external respiration, gas transfer by blood and internal, or tissue, respiration. External respiration combines all processes occurring in the lung. It is carried out breathing apparatus, which includes the chest with the muscles that move it, the diaphragm and the lungs with the airways.

The air entering the lungs during inhalation changes its composition. The air in the lungs gives up some of its oxygen and is enriched with carbon dioxide. The carbon dioxide content in venous blood is higher than in the air in the alveoli. Therefore, carbon dioxide leaves the blood into the alveoli and its content is less than in the air. First, oxygen dissolves in the blood plasma, then binds to hemoglobin, and new portions of oxygen enter the plasma.

The transition of oxygen and carbon dioxide from one environment to another occurs due to diffusion from higher to lower concentrations. Although diffusion is slow, the surface of contact between blood and air in the lungs is so large that it completely ensures the necessary gas exchange. It is estimated that complete gas exchange between blood and alveolar air can occur in a time that is three times shorter than the time the blood remains in the capillaries (i.e., the body has significant reserves of providing tissues with oxygen).

Venous blood, once in the lungs, gives off carbon dioxide, is enriched with oxygen and turns into arterial blood. In a large circle, this blood disperses through the capillaries to all tissues and gives oxygen to the cells of the body, which constantly consume it. There is more carbon dioxide released by cells as a result of their vital activity than in the blood, and it diffuses from the tissues into the blood. Thus, arterial blood, having passed through the capillaries of the systemic circulation, becomes venous and the right half of the heart is sent to the lungs, here it is again saturated with oxygen and gives off carbon dioxide.

In the body, breathing is carried out using additional mechanisms. Liquid media, which are part of the blood (its plasma), have low solubility of gases in them. Therefore, in order for a person to exist, he would need to have a heart 25 times more powerful, lungs 20 times more powerful, and pump more than 100 liters of fluid (not five liters of blood) in one minute. Nature has found a way to overcome this difficulty by adapting a special substance - hemoglobin - to carry oxygen. Thanks to hemoglobin, blood is able to bind oxygen 70 times, and carbon dioxide - 20 times more than the liquid part of the blood - its plasma.

Alveolus- a thin-walled bubble with a diameter of 0.2 mm filled with air. The alveolar wall is formed by one layer of flat epithelial cells, along the outer surface of which a network of capillaries branches. Thus, gas exchange occurs through a very thin septum formed by two layers of cells: the capillary wall and the alveolar wall.

Exchange of gases in tissues (tissue respiration)

The exchange of gases in tissues occurs in capillaries according to the same principle as in the lungs. Oxygen from tissue capillaries, where its concentration is high, passes into tissue fluid with a lower oxygen concentration. From the tissue fluid it penetrates into the cells and immediately enters into oxidation reactions, so there is practically no free oxygen in the cells.

Carbon dioxide, according to the same laws, comes from cells, through tissue fluid, into capillaries. The released carbon dioxide promotes the dissociation of oxyhemoglobin and itself combines with hemoglobin, forming carboxyhemoglobin, is transported into the lungs and released into the atmosphere. In the venous blood flowing from the organs, carbon dioxide is found both in a bound and dissolved state in the form of carbonic acid, which easily breaks down into water and carbon dioxide in the capillaries of the lungs. Carbonic acid may also combine with plasma salts to form bicarbonates.

In the lungs, where venous blood enters, oxygen saturates the blood again, and carbon dioxide moves from a zone of high concentration (pulmonary capillaries) to a zone of low concentration (alveoli). For normal gas exchange, the air in the lungs is constantly replaced, which is achieved by rhythmic attacks of inhalation and exhalation, due to the movements of the intercostal muscles and the diaphragm.

Transport of oxygen in the body

The meaning of breathing.

Breath- is a set of physiological processes that ensure gas exchange between the body and the external environment ( external breathing), and oxidative processes in cells, as a result of which energy is released ( internal breathing). Exchange of gases between blood and atmospheric air (gas exchange) - carried out by the respiratory system.

The source of energy in the body is food substances. The main process that releases the energy of these substances is the process of oxidation. It is accompanied by the binding of oxygen and the formation of carbon dioxide. Considering that the human body has no reserves of oxygen, its continuous supply is vital. Stopping the access of oxygen to the body's cells leads to their death. On the other hand, carbon dioxide formed during the oxidation of substances must be removed from the body, since the accumulation of a significant amount of it is life-threatening. The absorption of oxygen from the air and the release of carbon dioxide occurs through the respiratory system.

The biological significance of breathing is:

• providing the body with oxygen;
• removing carbon dioxide from the body;
• oxidation of organic compounds of BZHU with the release of energy necessary for human life;
• removal of metabolic end products ( water vapor, ammonia, hydrogen sulfide, etc.).

Breath- this is such a natural process for us that probably few people think about how we breathe and with what. I thought about this back in childhood, when my breathing was impaired by a cold. Then my stuffy nose simply didn’t let me think about anything else.

What we all breathe

We all know from school that for a person to breathe oxygen needed. He is one of the most important elements, necessary to maintain life on our planet in the form we are familiar with. Oxygen is not only found in the air. It is also a component of the Earth's hydrosphere. It is thanks to this fact that there is also life in water.

How chemical element oxygen was discovered Karl Schele back in 1773.

Facts about oxygen

Oxygen is not only vital, but also a very interesting element. I'll give you a selection interesting facts that you may not have heard of yet:

What happens if you breathe pure oxygen?

As I said above, oxygen in pure form and in high concentrations it is dangerous and even poisonous. What will happen to a person if he breathes it for some time?

Familiar to us normal oxygen content in the air approximately 21% . Poisoning of the body occurs if this content increases to 50%. This can lead to increased levels of carbon dioxide in the body, seizures, coughing, loss of vision and ultimately death.

The art of breathing is to exhale almost no carbon dioxide and lose as little of it as possible. As an example, the reaction of plant biosynthesis is the absorption of carbon dioxide, the utilization of carbon and the release of oxygen, and it was at that time that very lush vegetation existed on the planet. Carbon dioxide CO2 is constantly formed in the cells of the body.

Respiration is the exchange of gases, on the one hand, between the blood and the external environment (external respiration), on the other, the exchange of gases between the blood and tissue cells (internal or tissue respiration).

Why does a person need carbon dioxide?

Oxygen is involved in metabolism. Therefore, the cessation of oxygen supply leads to the death of tissues and the body. The main part The respiratory system of the human body is the lungs, which perform the main function of respiration - the exchange of oxygen and carbon dioxide between the body and the external environment. This exchange is possible due to a combination of ventilation, diffusion of gases through the alveolar-capillary membrane and pulmonary circulation.

How does carbon dioxide spread through the Earth's atmosphere?

During external respiration, oxygen from external environment delivered to the alveoli of the lungs. The process of external respiration begins with the upper respiratory tract, which cleans, warms and humidifies the inhaled air. Ventilation of the lungs depends on respiratory exchange and respiratory rate. Oxygen diffusion occurs through the acinus - structural unit lung, which consists of the respiratory bronchioles and alveoli.

Oxygen is necessary for organisms to breathe. The lack of oxygen in the air affects the functioning of living organisms. If the amount of oxygen in the air decreases to 1/3 of it, then a person loses consciousness, and if it decreases to 1/4 of it, breathing stops and death occurs.

It is blown into blast furnaces to speed up the smelting of metals. Carbon dioxide is formed during combustion (wood, peat, coal, oil). Organisms, including humans, release a lot of it into the air when they breathe. Being heavier than air, carbon dioxide more located in the lower layers of the atmosphere, accumulates in depressions of the Earth (caves, mines, gorges).

Man widely uses carbon dioxide to carbonate fruit and mineral water when bottling it. Carbon dioxide, like oxygen, under strong compression and low temperature transforms from a gaseous state into a liquid and solid state. Carbon dioxide in solid form is called dry ice. It is used in refrigeration chambers when preserving ice cream, meat and other products.

Carbon dioxide does not support combustion and is heavier than air, which is why it is used to extinguish fires. Why can’t people and other living organisms live without oxygen? Why is there always oxygen in the air? How is liquid oxygen produced and where is it used?

Where do the bubbles (carbon dioxide) come from in soda?

Air is a mixture of natural gases - nitrogen, oxygen, argon, carbon dioxide, water and hydrogen. It is the primary source of energy for all organisms and the key to healthy growth and long life. Thanks to air, the process of metabolism and development occurs in organisms. The fundamental components necessary for the growth and life of plants are oxygen, carbon dioxide, water vapor and soil air. Oxygen is necessary for respiration, and carbon dioxide is necessary for carbon nutrition.

The roots, leaves, and stems of plants need this element. Carbon dioxide enters the plant by entering through its stomata into the leaf environment, entering the cells. The higher the concentration of carbon dioxide, the better plant life becomes. Air also plays a special role in the formation of mechanical tissues in land plants.

Age, gender, size and physical activity are directly related to the amount of air consumed. Animals' bodies are very sensitive to lack of oxygen. This leads to the accumulation of harmful toxic substances in the body. Oxygen is necessary to saturate the blood and tissues of a living creature. Therefore, when there is a lack of this element in animals, breathing quickens, blood flow accelerates, oxidative processes in the body decrease, and the animal becomes restless.

Carbon dioxide is not to blame for global warming

Air is a vital factor for humans. It is carried by the blood throughout the body, saturating every organ and every cell of the body. It is in the air that heat exchange between the human body and the environment occurs. The essence of this exchange is the convection transfer of heat and evaporation of moisture from the human lungs. With the help of breathing, a person saturates the body with energy. The reason for this is human production and technogenic activity.

An adult, at rest, makes an average of 14 respiratory movements per minute, but the respiratory rate can undergo significant fluctuations (from 10 to 18 per minute). An adult takes 15-17 breaths per minute, and a newborn baby takes 1 breath per second. Normal calm exhalation occurs largely passively, with the internal intercostal muscles and some abdominal muscles actively working.

There are upper and lower respiratory tracts. The symbolic transition of the upper respiratory tract to the lower one occurs at the intersection of the digestive and respiratory systems in the upper part of the larynx. Inhalation and exhalation are carried out by changing the size of the chest using the respiratory muscles. During one breath (at rest), 400-500 ml of air enters the lungs. This volume of air is called tidal volume (TI). The same amount of air enters the atmosphere from the lungs during a quiet exhalation.

After maximum exhalation, about 1,500 ml of air remains in the lungs, called residual lung volume. Breathing is one of the few functions of the body that can be controlled consciously and unconsciously. Types of breathing: deep and superficial, frequent and rare, upper, middle (thoracic) and lower (abdominal).

The lungs (Latin pulmo, ancient Greek πνεύμων) are located in the chest cavity, surrounded by the bones and muscles of the chest. Besides, respiratory system participates in such important functions as thermoregulation, voice formation, smell, and humidification of inhaled air.

When the ambient temperature decreases, gas exchange in warm-blooded animals (especially small ones) increases as a result of increased heat production. In humans, when working at moderate power, it increases after 3-6 minutes. after its start, it reaches a certain level and then remains at this level throughout the entire period of operation. Studies of changes in gas exchange under standard physical work used in the physiology of work and sports, in the clinic to assess the functional state of systems involved in gas exchange.

What uses does oxygen have in industry? It turned out that carbon dioxide, to a certain extent, promotes a more complete absorption of oxygen by the body. Carbon dioxide is also involved in the biosynthesis of animal protein, and some scientists see this as possible reason the existence of giant animals and plants many millions of years ago.