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Where does the respiratory system begin? Respiratory organs and their functions: nasal cavity, larynx, trachea, bronchi, lungs

RESPIRATORY SYSTEM and breathing

The respiratory system includes the airways and lungs.

Gas-carrying (air-bearing) tracts are the nasal cavity, pharynx (the respiratory and digestive tracts intersect), larynx, trachea and bronchi. The main function of the airways is to carry air from outside into the lungs and from the lungs out. The gas-bearing pathways have a bone base (nasal cavity) or cartilage (larynx, trachea, bronchi) in their walls, as a result of which the organs maintain lumen and do not collapse. The mucous membrane of the airways is covered with ciliated epithelium; the cilia of their cells, with their movements, expel foreign particles that have entered the airways along with the mucus.

The lungs constitute the actual respiratory part of the system, where gas exchange occurs between air and blood.

The nasal cavity performs a dual function - it is the beginning of the respiratory tract and the organ of smell. The inhaled air, passing through the nasal cavity, is cleaned, warmed, and moistened. Odorous substances contained in the air irritate the olfactory receptors, where nerve impulses arise. From the nasal cavity, the inhaled air enters the nasopharynx, then into the larynx. Air can enter the nasopharynx and through the oral cavity. The nasal cavity and nasopharynx are called upper respiratory tract.

The larynx is located in the front of the neck. The skeleton of the larynx consists of 6 cartilages connected to each other by joints and ligaments. At the top, the larynx is suspended by ligaments to the hyoid bone, and at the bottom it is connected to the trachea. When swallowing, talking, coughing, the larynx moves up and down. The larynx contains vocal cords made of elastic fibers. As exhaled air passes through the glottis (the narrow space between the vocal folds), the vocal cords oscillate, vibrate, and produce sounds. Men's deeper voices are due to longer vocal cords than women and children.

The trachea has a skeleton in the form of 16–20 cartilaginous half-rings, not closed at the back and connected by annular ligaments. The back of the half rings is replaced by a membrane. In front of the trachea in its upper part there is the thyroid gland and the thymus, behind it is the esophagus. At the level of the V thoracic vertebra, the trachea is divided into two main bronchi - right and left. The right main bronchus is like a continuation of the trachea; it is shorter and wider than the left, and foreign bodies more often enter it. The walls of the main bronchi have the same structure as the trachea. The mucous membrane of the bronchi, like the trachea, is lined with ciliated epithelium and is rich in mucous glands and lymphoid tissue. At the gates of the lungs, the main bronchi are divided into lobar bronchi, which, in turn, are divided into segmental and other smaller ones. The branching of the bronchi in the lungs is called the bronchial tree. The walls of the small bronchi are formed by elastic cartilaginous plates, and the smallest ones are formed by smooth muscle tissue (see Fig. 21).



Rice. 21. Larynx, trachea, main and segmental bronchi

The lungs (right and left) are located in the chest cavity, to the right and left of the heart and large blood vessels (see Fig. 22). The lungs are covered with a serous membrane - the pleura, which has 2 layers, the first surrounds the lung, the second is adjacent to the chest. Between them is a space called the pleural cavity. The pleural cavity contains serous fluid, the physiological role of which is to reduce friction of the pleura during respiratory movements.

Rice. 22. Position of the lungs in the chest

The main bronchus, pulmonary artery, and nerves enter through the portal of the lung, and the pulmonary veins and lymphatic vessels exit. Each lung is divided into lobes by grooves; the right lung has 3 lobes, and the left lung has 2. The lobes are divided into segments, which consist of lobules. Each of them includes a lobular bronchus with a diameter of about 1 mm, it is divided into terminal (terminal) bronchioles, and the terminal ones into respiratory (respiratory) bronchioles. The respiratory bronchioles pass into the alveolar ducts, on the walls of which there are miniature protrusions (vesicles) - alveoli. One terminal bronchiole with its branches - respiratory bronchioles, alveolar ducts and alveoli is called pulmonary acinus. Under a microscope, a piece of lung tissue (respiratory bronchioles, alveolar ducts and alveolar sacs with alveoli) resembles a bunch of grapes (acinus), which was the reason for the name. The acini is a structural and functional unit of the lung; gas exchange occurs in it between the blood flowing through the capillaries and the air of the alveoli. In both human lungs there are approximately 600–700 million alveoli, the respiratory surface of which is about 120 m2.

Physiology of breathing

Breathing is the process of gas exchange between the body and the external environment. The body consumes oxygen from the external environment and releases carbon dioxide back. Oxygen is necessary for cells and tissues of the body to oxidize nutrients (carbohydrates, fats, proteins), resulting in the release of energy. Carbon dioxide is the end product of metabolism. Stopping breathing leads to immediate cessation of metabolism. Below in the table. Figure 4 shows the content of oxygen and carbon dioxide in inhaled and exhaled air. Exhaled air consists of a mixture of alveolar air and dead space air (gas-bearing air), the composition of which differs little from the inhaled air.

Table 4

in inhaled and exhaled air,%

The breathing process includes the following stages:

External respiration - gas exchange between the environment and the alveoli of the lungs;

Gas exchange between alveoli and blood. Oxygen entering the lungs through gas-bearing pathways through the walls of the pulmonary alveoli and blood capillaries enters the blood and is captured by red blood cells, and carbon dioxide is removed from the blood into the alveoli;

Transport of gases by blood - oxygen from the lungs to all tissues of the body, and carbon dioxide - in the opposite direction.

Gas exchange between blood and tissues. Oxygen from the blood through the walls of blood capillaries enters cells and other tissue structures, where it is included in metabolism.

Tissue or cellular respiration is the main link of the respiratory process; it involves the oxidation of a number of substances, resulting in the release of energy. The process of tissue respiration occurs with the participation of special enzymes.

Respiration is the process by which the body's cells are supplied with oxygen, which stimulates the metabolic reactions necessary for the absorption of nutrients. Cells convert oxygen into carbon dioxide (carbon dioxide) and return it to the blood to be eliminated from the body. This gas exchange (oxygen is inhaled, carbon dioxide is exhaled) is the main, vital function of the respiratory system, in addition, certain parts of it perform the function.

The respiratory system consists of the nose, pharynx, trachea, bronchi and lungs.

The nose is a structure of bone and cartilage covered by muscle tissue and skin. The inner surface of the nose, lined with mucous membrane, is connected to the nasopharynx by two canals of the nostrils. The air inhaled through the nose is warmed, humidified and filtered as it passes through three conchae - the exits of the bone, covered with a mucous membrane, which consists of cells that can trap dust and microbes.

Next, the filtered air enters the nasopharynx, located behind the internal nasal cavity. From the nasopharynx, air and mucus flow down into the throat, in addition, it is connected by the eustachian tubes to the inner ear, which allows equalizing the pressure on both sides of the eardrum. The throat is shaped like a “chimney” and has three functions: it passes air and food, and it also houses the vocal cords. The oral, middle part of the pharynx receives food, drink and air from the mouth, and the tonsils are also located here.

The lower part of the pharynx, the hypopharynx, also allows air, liquid, and food to pass through. It is separated from the larynx by two vocal cords. The air flow, entering the gap between them, creates vibration, so we hear ourselves and those around us.

The epiglottis is an elastic cartilage located at the base of the tongue and connected by a “trunk” to the Adam’s apple. The process of this cartilage can move freely up and down. When food is swallowed, the larynx rises, causing the cartilaginous “tongue” of the epiglottis to descend, covering it with a kind of lid. This allows food to enter the esophagus rather than the respiratory tract. The larynx continues with the trachea, or otherwise the windpipe, approximately 10 cm long. The walls of the trachea are supported by incomplete cartilaginous rings, which makes it rigid and at the same time flexible; When food passes through the nearby esophagus, the trachea moves slightly, bending.

The inner surface of the trachea is also covered with a mucous lining that traps dust particles and microorganisms, which are then expelled upward and outward. The trachea branches into the left and right pleural bronchi, similar in structure to the trachea, which lead respectively to the left and right lung. The bronchi branch into smaller canals, which branch into even smaller ones, and so on, until the air tubes turn into bronchioles.

The lungs are shaped like a cone, stretching from the collarbone to the diaphragm. The surface of each lung is rounded, which allows them to fit closely to the ribs, and is a pleural membrane, one surface of which is in contact with the walls of the chest cavity, and the second faces directly to the lungs. The pleural cavity, located behind the membrane, produces a lubricating fluid that prevents friction between the two membranes. Along the axis of the lung there is an area called the hilum, where nerves, blood and lymphatic vessels and primary bronchi enter the lung.

Each lung is divided into lobes: the left into two, and the right into three, which are divided into smaller lobules (there are ten in each lung). An arteriole, a venule, a lymphatic vessel and a branch of a bronchiole lead to each pulmonary lobule. Then the bronchioles branch into respiratory bronchioles, and these into alveolar ducts, which, in turn, are divided into alveolar sacs and alveoli. It is in the alveoli that gas exchange occurs. As the respiratory channels move into the lungs, the amount of muscle and cartilage in their structure decreases, which are replaced by thin connective tissue.

Physiology of respiration.

The respiratory process is one of the human processes, it is controlled by the respiratory center located in the brain stem, sending nerve impulses that are transmitted to the muscles involved in inhalation and exhalation. The diaphragm, in response to these impulses, contracts and straightens, increasing the volume of the chest cavity. As the diaphragm contracts, the external intercostal muscles also contract, expanding the rib cage outward and upward. Therefore, the walls of the lungs move behind the ribs, which leads to an increase in lung volume and a decrease in internal pressure, so air enters the windpipe.

When air reaches the alveoli, the process of gas exchange begins. The lining of the alveoli contains tiny capillaries. Gas diffusion occurs in the thin walls of capillaries and alveoli - oxygen enters the blood, which then transfers it to the tissues of the body, and carbon dioxide passes from the capillaries to the alveoli and is eliminated from the body when exhaled. It is believed that each lung contains approximately 300 thousand alveoli, the total surface of which is large enough for gas exchange to occur very quickly and efficiently.

When exhaling, the reverse process occurs. First, the intercostal muscles relax and the ribs move down, then the diaphragm relaxes and the volume of the thoracic cavity decreases. The elastic fibers surrounding the alveoli and the fibers in the alveolar ducts and bronchioles contract, reducing the volume of the lungs, and then air is “pushed” out of the body.

General characteristics of the respiratory system

The most important indicator of human vitality can be called breath. A person can live without water and food for some time, but life is impossible without air. Breathing is the link between a person and the environment. If air flow is obstructed, then respiratory organs The human body and the heart begin to work at an increased rate to provide the necessary amount of oxygen for breathing. The respiratory and respiratory system in humans is capable of adapt to environmental conditions.

Scientists have established an interesting fact. The air that enters respiratory organs person, conditionally forms two streams, one of which passes into the left side of the nose and penetrates left lung, the second stream penetrates the right side of the nose and supplies right lung.

Studies have also shown that in the artery of the human brain, the air received is also divided into two streams. Process breathing must be correct, which is important for normal life. Therefore, it is necessary to know about the structure of the human respiratory system and respiratory organs.

Breathing apparatus person includes trachea, lungs, bronchi, lymphatic, and vascular system. They also include the nervous system and respiratory muscles, pleura. The human respiratory system includes the upper and lower respiratory tract. Upper respiratory tract: nose, pharynx, oral cavity. Lower respiratory tract: trachea, larynx and bronchi.

The airways are necessary for the entry and exit of air from the lungs. The most important organ of the entire respiratory system is lungs, between which the heart is located.

Respiratory organs

Lungs- main respiratory organs. They are shaped like a cone. The lungs are located in the chest area, located on either side of the heart. The main function of the lungs is gas exchange, which occurs with the help of the alveoli. Blood enters the lungs from the veins thanks to the pulmonary arteries. Air penetrates through the respiratory tract, enriching the respiratory organs with the necessary oxygen. Cells need oxygen in order for the process to take place. regeneration, and the nutrients needed by the body were supplied from the blood. Covering the lungs is the pleura, consisting of two lobes separated by a cavity (pleural cavity).

The lungs include the bronchial tree, which is formed by bifurcation trachea. The bronchi, in turn, are divided into thinner ones, thus forming segmental bronchi. Bronchial tree ends in very small bags. These sacs are many interconnected alveoli. Alveoli provide gas exchange in respiratory system. The bronchi are covered by epithelium, which in its structure resembles cilia. The cilia remove mucus to the pharyngeal area. Promotion is facilitated by a cough. The bronchi have a mucous membrane.

Trachea is a tube connecting the larynx and bronchi. The trachea is approximately 12-15 see The trachea, unlike the lungs, is an unpaired organ. The main function of the trachea is to carry air into and out of the lungs. The trachea is located between the sixth vertebra of the neck and the fifth vertebra of the thoracic region. At the end trachea bifurcates into two bronchi. The bifurcation of the trachea is called bifurcation. At the beginning of the trachea, the thyroid gland adjoins it. At the back of the trachea is the esophagus. The trachea is covered by a mucous membrane, which is the basis, and it is also covered by muscle-cartilaginous tissue with a fibrous structure. The trachea consists of 18-20 rings of cartilage tissue that make the trachea flexible.

Larynx- a respiratory organ connecting the trachea and pharynx. The voice box is located in the larynx. The larynx is located in the area 4-6 vertebrae of the neck and is attached to the hyoid bone with the help of ligaments. The beginning of the larynx is in the pharynx, and the end is a bifurcation into two tracheas. The thyroid, cricoid and epiglottic cartilages make up the larynx. These are large unpaired cartilages. It is also formed by small paired cartilages: cornicular, wedge-shaped, arytenoid. The connection between the joints is provided by ligaments and joints. Between the cartilages there are membranes that also serve as a connection.

Pharynx is a tube that originates in the nasal cavity. The digestive and respiratory tracts intersect in the pharynx. The pharynx can be called the link between the nasal cavity and the oral cavity, and the pharynx also connects the larynx and esophagus. The pharynx is located between the base of the skull and 5-7 vertebrae of the neck. The nasal cavity is the initial section of the respiratory system. Consists of the external nose and nasal passages. The function of the nasal cavity is to filter the air, as well as cleanse and humidify it. Oral cavity- This is the second way air enters the human respiratory system. The oral cavity has two sections: posterior and anterior. The anterior section is also called the vestibule of the mouth.

Respiration is a complex and continuous biological process, as a result of which the body consumes free electrons and oxygen from the external environment, and releases carbon dioxide and water saturated with hydrogen ions.

The human respiratory system is a set of organs that provide the function of human external respiration (gas exchange between inhaled atmospheric air and blood circulating in the pulmonary circulation).

Gas exchange takes place in the alveoli of the lungs, and is normally aimed at capturing oxygen from the inhaled air and releasing carbon dioxide formed in the body into the external environment.

An adult, being at rest, takes an average of 15-17 breaths per minute, and a newborn baby takes 1 breath per second.

Ventilation of the alveoli is carried out by alternating inhalation and exhalation. When you inhale, atmospheric air enters the alveoli, and when you exhale, air saturated with carbon dioxide is removed from the alveoli.

A normal calm inhalation is associated with the activity of the muscles of the diaphragm and external intercostal muscles. When you inhale, the diaphragm lowers, the ribs rise, and the distance between them increases. Normal calm exhalation occurs largely passively, with the internal intercostal muscles and some abdominal muscles actively working. When you exhale, the diaphragm rises, the ribs move down, and the distance between them decreases.

Types of breathing

The respiratory system performs only the first part of gas exchange. The rest is done by the circulatory system. There is a deep relationship between the respiratory and circulatory systems.

There are pulmonary respiration, which provides gas exchange between air and blood, and tissue respiration, which provides gas exchange between blood and tissue cells. It is carried out by the circulatory system, since the blood delivers oxygen to the organs and removes decay products and carbon dioxide from them.

Pulmonary breathing. The exchange of gases in the lungs occurs due to diffusion. The blood entering from the heart into the capillaries that encircle the pulmonary alveoli contains a lot of carbon dioxide; there is little of it in the air of the pulmonary alveoli, so it leaves the blood vessels and passes into the alveoli.

Oxygen also enters the blood due to diffusion. But in order for this gas exchange to occur continuously, it is necessary that the composition of gases in the pulmonary alveoli be constant. This constancy is maintained by pulmonary breathing: excess carbon dioxide is removed outside, and oxygen absorbed by the blood is replaced with oxygen from a fresh portion of the outside air.

Tissue respiration. Tissue respiration occurs in the capillaries, where the blood gives off oxygen and receives carbon dioxide. There is little oxygen in the tissues, therefore, oxyhemoglobin breaks down into hemoglobin and oxygen. Oxygen passes into tissue fluid and is used there by cells for the biological oxidation of organic substances. The energy released in this case is used for the vital processes of cells and tissues.

If there is insufficient oxygen supply to the tissues: the function of the tissue is disrupted because the breakdown and oxidation of organic substances stops, energy ceases to be released, and cells deprived of energy supply die.

The more oxygen is consumed in the tissues, the more oxygen is required from the air to compensate for the costs. That is why during physical work both cardiac activity and pulmonary respiration simultaneously increase.

Types of breathing

Based on the method of chest expansion, two types of breathing are distinguished:

  • chest breathing(expansion of the chest is produced by raising the ribs), more often observed in women;
  • abdominal breathing(expansion of the chest is produced by flattening the diaphragm) is more often observed in men.

Breathing happens:

  • deep and superficial;
  • frequent and rare.

Special types of respiratory movements are observed during hiccups and laughter. With frequent and shallow breathing, the excitability of the nerve centers increases, and with deep breathing, on the contrary, it decreases.

System and structure of the respiratory organs

The respiratory system includes:

  • upper respiratory tract: nasal cavity, nasopharynx, pharynx;
  • lower respiratory tract: larynx, trachea, main bronchi and lungs covered with pulmonary pleura.

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. The respiratory tract provides connections between the environment and the main organs of the respiratory system - the lungs.

The lungs are located in the chest cavity, surrounded by the bones and muscles of the chest. The lungs are located in hermetically sealed cavities, the walls of which are lined with parietal pleura. Between the parietal and pulmonary pleura there is a slit-like pleural cavity. The pressure in it is lower than in the lungs, and therefore the lungs are always pressed against the walls of the chest cavity and take its shape.

Having entered the lungs, the main bronchi branch, forming a bronchial tree, at the ends of which there are pulmonary vesicles, alveoli. Along the bronchial tree, air reaches the alveoli, where gas exchange occurs between the atmospheric air that has reached the pulmonary alveoli (lung parenchyma), and the blood flowing through the pulmonary capillaries, which ensure the supply of oxygen to the body and the removal of gaseous waste products, including carbon dioxide. gas

Breathing process

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.

The maximum deep breath is about 2,000 ml of air. After maximum exhalation, about 1,200 ml of air remains in the lungs, called residual lung volume. After a quiet exhalation, approximately 1,600 ml remains in the lungs. This volume of air is called the functional residual capacity (FRC) of the lungs.

Thanks to the functional residual capacity (FRC) of the lungs, a relatively constant ratio of oxygen and carbon dioxide content is maintained in the alveolar air, since the FRC is several times larger than the tidal volume (TI). Only 2/3 of the DO reaches the alveoli, which is called the alveolar ventilation volume.

Without external respiration, the human body can usually survive up to 5-7 minutes (the so-called clinical death), after which loss of consciousness, irreversible changes in the brain and its death (biological death) occur.

Breathing is one of the few functions of the body that can be controlled consciously and unconsciously.

Functions of the respiratory system

  • Breathing, gas exchange. The main function of the respiratory organs is to maintain a constant gas composition of the air in the alveoli: remove excess carbon dioxide and replenish oxygen carried away by the blood. This is achieved through breathing movements. When you inhale, the skeletal muscles expand the chest cavity, followed by the lungs, the pressure in the alveoli drops and outside air enters the lungs. When you exhale, the chest cavity decreases, its walls compress the lungs and air leaves them.
  • Thermoregulation. In addition to ensuring gas exchange, the respiratory organs perform another important function: they participate in heat regulation. When breathing, water evaporates from the surface of the lungs, which leads to cooling of the blood and the entire body.
  • Voice formation. The lungs create air currents that vibrate the vocal cords of the larynx. Speech is achieved through articulation, which involves the tongue, teeth, lips and other organs that direct sound flows.
  • Air purification. The inner surface of the nasal cavity is lined with ciliated epithelium. It secretes mucus, which moisturizes the incoming air. Thus, the upper respiratory tract performs important functions: warming, humidifying and purifying the air, as well as protecting the body from harmful influences through the air.

Lung tissue also plays an important role in processes such as hormone synthesis, water-salt and lipid metabolism. In the abundantly developed vascular system of the lungs, blood is deposited. The respiratory system also provides mechanical and immune protection from environmental factors.

Breathing regulation

Nervous regulation of breathing. Breathing is regulated automatically by the respiratory center, which is represented by a collection of nerve cells located in different parts of the central nervous system. The main part of the respiratory center is located in the medulla oblongata. The respiratory center consists of inhalation and exhalation centers, which regulate the functioning of the respiratory muscles.

Nervous regulation has a reflex effect on breathing. The collapse of the pulmonary alveoli, which occurs during exhalation, reflexively causes inhalation, and the expansion of the alveoli reflexively causes exhalation. Its activity depends on the concentration of carbon dioxide (CO2) in the blood and on nerve impulses coming from receptors in various internal organs and skin.A hot or cold irritant (sensory system) of the skin, pain, fear, anger, joy (and other emotions and stressors), physical activity quickly change the nature of respiratory movements.

It should be noted that there are no pain receptors in the lungs, therefore, in order to prevent diseases, periodic fluorographic examinations are carried out.

Humoral regulation of respiration. During muscle work, oxidation processes intensify. Consequently, more carbon dioxide is released into the blood. When blood with excess carbon dioxide reaches the respiratory center and begins to irritate it, the activity of the center increases. The person begins to breathe deeply. As a result, excess carbon dioxide is removed, and the lack of oxygen is replenished.

If the concentration of carbon dioxide in the blood decreases, the work of the respiratory center is inhibited and involuntary holding of breath occurs.

Thanks to nervous and humoral regulation, in any conditions the concentration of carbon dioxide and oxygen in the blood is maintained at a certain level.

When problems with external respiration arise, certain

Vital capacity of the lungs

The vital capacity of the lungs is an important indicator of breathing. If a person takes the deepest breath and then exhales as much as possible, then the exchange of exhaled air will make up the vital capacity of the lungs. The vital capacity of the lungs depends on the age, gender, height, and also on the degree of training of the person.

To measure the vital capacity of the lungs, a device such as a Spirometer is used. For humans, not only the vital capacity of the lungs is important, but also the endurance of the respiratory muscles. A person whose lung vital capacity is small and whose respiratory muscles are also weak has to breathe frequently and shallowly. This leads to the fact that fresh air remains mainly in the airways and only a small part of it reaches the alveoli.

Breathing and exercise

During physical activity, breathing usually increases. Metabolism accelerates, muscles require more oxygen.

Instruments for studying breathing parameters

  • Capnograph- a device for measuring and graphically displaying the carbon dioxide content in the air exhaled by a patient over a certain period of time.
  • Pneumograph- a device for measuring and graphically displaying the frequency, amplitude and shape of respiratory movements over a certain period of time.
  • Spirograph- a device for measuring and graphically displaying the dynamic characteristics of breathing.
  • Spirometer- a device for measuring vital capacity (vital capacity of the lungs).

OUR LUNGS LOVE:

1. Fresh air(with insufficient oxygen supply to the tissues: tissue function is impaired because the breakdown and oxidation of organic substances stops, energy ceases to be released, and cells deprived of energy supply die. Therefore, staying in a stuffy room leads to headaches, lethargy, and decreased performance ).

2. Exercises(during muscular work, oxidation processes intensify).

OUR LUNGS DO NOT LIKE:

1. Infectious and chronic respiratory diseases(sinusitis, sinusitis, tonsillitis, diphtheria, influenza, sore throat, acute respiratory infections, tuberculosis, lung cancer).

2. Polluted air(car exhausts, dust, polluted air, smoke, vodka fumes, carbon monoxide - all these components have an adverse effect on the body. Hemoglobin molecules that have captured carbon monoxide are permanently deprived of the ability to transfer oxygen from the lungs to the tissues. There is a lack of oxygen in the blood and tissues, which affects the functioning of the brain and other organs).

3. Smoking(narcotic substances contained in nicotine are included in the metabolism and interfere with nervous and humoral regulation, disrupting both. In addition, substances in tobacco smoke irritate the mucous membrane of the respiratory tract, which leads to an increase in mucus secreted by it).

Now let's look at and analyze the respiratory process as a whole, and also trace the anatomy of the respiratory tract and a number of other features associated with this process.



Breathing is one of the most basic properties of any living organism. Its enormous importance cannot be overestimated. A person only thinks about how important normal breathing is when it suddenly becomes difficult, for example, when a cold appears. If a person can still live for some time without food and water, then without breathing - only a matter of seconds. In one day, an adult takes more than 20,000 inhalations and the same number of exhalations.

The structure of the human respiratory system - what it is, we will analyze in this article.

How a person breathes

This system is one of the most important in the human body. This is a whole set of processes that occur in a certain relationship and are aimed at ensuring that the body receives oxygen from the environment and releases carbon dioxide. What is breathing and how do the respiratory organs work?

The human respiratory organs are conventionally divided into airways and lungs.

The main role of the former is the unhindered delivery of air to the lungs. The human respiratory tract begins with the nose, but the process itself can also occur through the mouth if the nose is stuffy. However, nasal breathing is preferable, because when passing through the nasal cavity, the air is purified, but if it enters through the mouth, it is not.

There are three main processes in breathing:

  • external breathing;
  • transfer of gases through the bloodstream;
  • internal (cellular) respiration;

When you inhale through your nose or mouth, air first enters the throat. Together with the larynx and paranasal sinuses, these anatomical cavities belong to the upper respiratory tract.

The lower respiratory tract is the trachea, the bronchi connected to it, and the lungs.

All together they form a single functional system.

It is easier to visualize its structure using a diagram or table.

During respiration, sugar molecules are broken down and carbon dioxide is released.

The process of breathing in the body

Gas exchange occurs due to their different concentrations in the alveoli and capillaries. This process is called diffusion. In the lungs, oxygen flows from the alveoli into the vessels, and carbon dioxide flows back. Both alveoli and capillaries consist of a single layer of epithelium, which allows gases to easily penetrate them.

The transport of gas to the organs occurs as follows: first, oxygen enters the lungs through the airways. When air enters the blood vessels, it forms unstable compounds with hemoglobin in red blood cells, and together with it moves to various organs. Oxygen is easily detached and then enters the cells. In the same way, carbon dioxide combines with hemoglobin and is transported in the opposite direction.

When oxygen reaches cells, it penetrates first into the intercellular space and then directly into the cell.

The main purpose of respiration is the generation of energy in cells.

The parietal pleura, pericardium and peritoneum are attached to the tendons of the diaphragm, which means that during breathing there is a temporary displacement of the organs of the chest and abdominal cavity.

When you inhale, the volume of the lungs increases and when you exhale, it decreases accordingly. At rest, a person uses only 5 percent of the total lung capacity.

Functions of the respiratory system

Its main purpose is to supply the body with oxygen and remove waste products. But the functions of the respiratory system may be different.

During respiration, oxygen is constantly absorbed by the cells and at the same time they give off carbon dioxide. However, it should be noted that the organs of the respiratory system are also involved in other important functions of the body, in particular, they are directly involved in the formation of speech sounds, as well as the sense of smell. In addition, the respiratory organs are actively involved in the process of thermoregulation. The temperature of the air that a person inhales directly affects his body temperature. Exhaled gases reduce body temperature.

Excretory processes also partially involve the organs of the respiratory system. A certain amount of water vapor is also released.

The structure of the respiratory organs and the respiratory organs also provide the body’s defenses, because when air passes through the upper respiratory tract, it is partially cleansed.

On average, a person consumes about 300 ml of oxygen in one minute and emits 200 g of carbon dioxide. However, if physical activity increases, then oxygen consumption increases significantly. In one hour, a person is able to release from 5 to 8 liters of carbon dioxide into the external environment. Also, during the breathing process, dust, ammonia and urea are removed from the body.

The respiratory organs are directly involved in the formation of the sounds of human speech.

Respiratory organs: description

All respiratory organs are interconnected.

Nose

This organ is not only an active participant in the breathing process. It is also an organ of smell. This is where the respiratory process begins.

The nasal cavity is divided into sections. Their classification is as follows:

  • lower section;
  • average;
  • upper;
  • general.

The nose is divided into bony and cartilaginous sections. The nasal septum separates the right and left halves.

The inside of the cavity is covered with ciliated epithelium. Its main purpose is to clean and warm the incoming air. The viscous mucus found here has bactericidal properties. Its quantity increases sharply with the appearance of various pathologies.

The nasal cavity contains a large number of small venous vessels. When they are damaged, nosebleeds occur.

Larynx

The larynx is an extremely important component of the respiratory system, located between the pharynx and trachea. It is a cartilaginous formation. Laryngeal cartilages are:

  1. Paired (arytenoid, corniculate, wedge-shaped, granular).
  2. Unpaired (thyroid, cricoid and epiglottis).

In men, the junction of the plates of the thyroid cartilage protrudes greatly. They form the so-called “Adam's apple”.

The joints of the organ ensure its mobility. The larynx has many different ligaments. There is also a whole group of muscles that tense the vocal cords. The vocal cords themselves are located in the larynx and are directly involved in the formation of speech sounds.

The larynx is formed in such a way that the process of swallowing does not interfere with breathing. It is located at the level of the fourth to seventh cervical vertebrae.

Trachea

The actual extension of the larynx is the trachea. According to the location of the organs in the trachea, the cervical and thoracic parts are divided. The esophagus is adjacent to the trachea. The neurovascular bundle runs very close to it. It includes the carotid artery, vagus nerve and jugular vein.

The trachea branches into two sides. This point of separation is called a bifurcation. The posterior wall of the trachea is flattened. This is where the muscle tissue is located. Its special location allows the trachea to be mobile when coughing. The trachea, like other respiratory organs, is covered with a special mucous membrane - ciliated epithelium.

Bronchi

The branching of the trachea leads to the next paired organ - the bronchi. The main bronchi in the hilum area are divided into lobar bronchi. The right main bronchus is wider and shorter than the left.

At the end of the bronchioles are the alveoli. These are small passages, at the end of which there are special bags. They exchange oxygen and carbon dioxide with small blood vessels. The alveoli are lined from the inside with a special substance. They maintain their surface tension, preventing the alveoli from sticking together. The total number of alveoli in the lungs is approximately 700 million.

Lungs

Of course, all organs of the respiratory system are important, but the lungs are considered the most significant. They directly exchange oxygen and carbon dioxide.

The organs are located in the chest cavity. Their surface is lined with a special membrane called pleura.

The right lung is a couple of centimeters shorter than the left lung. The lungs themselves do not contain muscles.

There are two sections in the lungs:

  1. The top.
  2. Base.

And also three surfaces: diaphragmatic, costal and mediastinal. They face the diaphragm, ribs, and mediastinum respectively. The surfaces of the lung are separated by edges. The costal and mediastinal regions are separated by the anterior edge. The lower edge separates from the diaphragm area. Each lung is divided into lobes.

The right lung has three of them:

Upper;

Average;

The left one has only two: upper and lower. Between the lobes there are interlobar surfaces. Both lungs have an oblique fissure. It separates the lobes of the organ. The right lung additionally has a horizontal fissure separating the upper and middle lobes.

The base of the lung is expanded, and the upper part is narrowed. On the inner surface of each part there are small indentations called gates. The formations that create the root of the lung pass through them. Lymphatic and blood vessels and bronchi pass through here. In the right lung there is a bronchus, a pulmonary vein, and two pulmonary arteries. In the left there is a bronchus, a pulmonary artery, two pulmonary veins.

In the front of the left lung there is a small depression - the cardiac notch. From below it is limited by a part called the tongue.

The chest protects the lungs from external damage. The chest cavity is sealed, it is separated from the abdominal cavity.

Diseases associated with the lungs greatly affect the general condition of the human body.

Pleura

The lungs are covered with a special film - pleura. It consists of two parts: an outer and an inner petal.

The pleural cavity always contains a small amount of serous fluid, which ensures the wetting of the pleural lobes.

The human respiratory system is created in such a way that there is negative air pressure directly in the pleural cavity. It is thanks to this fact, as well as the surface tension of the serous fluid, that the lungs are constantly in an expanded state, and they also accept the respiratory movements of the chest.

Respiratory muscles

Respiratory muscles are divided into inspiratory (producing inhalation) and expiratory (working when exhaling).

The main inspiratory muscles are:

  1. Diaphragm.
  2. External intercostal.
  3. Intercartilaginous internal muscles.

There are also inspiratory accessory muscles (scalenes, trapezius, pectoralis major and minor, etc.)

The intercostal, rectus, hypocostal, transverse, external and internal oblique abdominal muscles are expiratory muscles.

Diaphragm

The diaphragm also plays a significant role in the breathing process. This is a unique plate that separates two cavities: the thoracic and abdominal. It is classified as a respiratory muscle. In the diaphragm itself there is a tendon center and three more muscle areas.

When contraction occurs, the diaphragm moves away from the chest wall. At this time, the volume of the chest cavity increases. The simultaneous contraction of this muscle and the abdominal muscles causes the pressure inside the chest cavity to become less than the external atmospheric pressure. At this moment, air enters the lungs. Then, as a result of muscle relaxation, exhalation occurs

Respiratory mucosa

The respiratory organs are covered with a protective mucous membrane - ciliated epithelium. On the surface of the ciliated epithelium there is a huge number of cilia, constantly carrying out the same movement. Special cells located between them, together with the mucous glands, produce mucus that wets the cilia. Like duct tape, tiny particles of dust and dirt inhaled stick to it. They are transported to the pharynx and removed. In the same way, harmful viruses and bacteria are eliminated.

This is a natural and quite effective self-cleaning mechanism. This shell structure and ability to be cleansed extends to all respiratory organs.

Factors affecting the state of the respiratory system

Under normal conditions, the respiratory system works clearly and smoothly. Unfortunately, it can be easily damaged. Many factors can influence its condition:

  1. Cold.
  2. Excessively dry air generated in the room as a result of the operation of heating devices.
  3. Allergy.
  4. Smoking.

All this has an extremely negative impact on the state of the respiratory system. In this case, the movement of the epithelial cilia can slow down significantly, or even stop altogether.

Harmful microorganisms and dust are no longer removed, resulting in a risk of infection.

Initially, this manifests itself in the form of a cold, and here the upper respiratory tract is primarily affected. There is a violation of ventilation in the nasal cavity, there is a feeling of nasal congestion and a general discomfort.

In the absence of correct and timely treatment, the paranasal sinuses will be involved in the inflammatory process. In this case, sinusitis occurs. Then other signs of respiratory diseases appear.

Cough occurs due to excessive irritation of cough receptors in the nasopharynx. The infection easily passes from the upper to the lower passages and the bronchi and lungs are affected. Doctors say in this case that the infection has “sank” lower. This is fraught with serious diseases such as pneumonia, bronchitis, and pleurisy. Medical institutions strictly monitor the condition of equipment intended for anesthesia and respiratory procedures. This is done to avoid infection of patients. There are SanPiN (SanPiN 2.1.3.2630-10) that must be observed in hospitals.

Like any other system of the body, the respiratory system should be taken care of: treated in a timely manner if a problem arises, and also avoid the negative influence of the environment, as well as bad habits.