Names of organs of the respiratory system. Respiratory system: physiology and functions of human breathing

The human respiratory organs include:

• nasal cavity;
• paranasal sinuses;
• larynx;
• trachea;
• bronchi;
• lungs.

Let's look at the structure of the respiratory organs and their functions. This will help to better understand how diseases of the respiratory system develop.

External respiratory organs: nasal cavity

The external nose, which we see on a person’s face, consists of thin bones and cartilage. On top they are covered with a small layer of muscle and skin. The nasal cavity is limited in front by the nostrils. WITH reverse side nasal cavity has openings - choanae, through which air enters the nasopharynx.

The nasal cavity is divided in half by the nasal septum. Each half has an inner and outer wall. On the side walls there are three projections - the turbinates, separating the three nasal passages.

There are openings in the two upper passages, through which there is a connection with the paranasal sinuses. The lower passage opens the mouth of the nasolacrimal duct, through which tears can enter the nasal cavity.

The entire nasal cavity is covered from the inside with a mucous membrane, on the surface of which lies ciliated epithelium, which has many microscopic cilia. Their movement is directed from front to back, towards the choanae. Therefore, most of the mucus from the nose enters the nasopharynx and does not come out.

In the area of ​​the upper nasal passage there is the olfactory region. Sensitive nerve endings are located there - olfactory receptors, which through their processes transmit the received information about odors to the brain.

The nasal cavity is well supplied with blood and has many small vessels carrying arterial blood. The mucous membrane is easily vulnerable, so nosebleeds are possible. Especially heavy bleeding appears when damaged by a foreign body or when the venous plexuses are injured. Such plexuses of veins can quickly change their volume, leading to nasal congestion.

Lymphatic vessels communicate with the spaces between the membranes of the brain. In particular, this explains the possibility of rapid development of meningitis in infectious diseases.

The nose performs the function of conducting air, smelling, and is also a resonator for the formation of voice. The important role of the nasal cavity is protective. The air passes through the nasal passages, which have a fairly large area, and is warmed and moistened there. Dust and microorganisms partially settle on the hairs located at the entrance to the nostrils. The rest are transmitted to the nasopharynx with the help of epithelial cilia, and are removed from there by coughing, swallowing, and blowing the nose. The mucus of the nasal cavity also has a bactericidal effect, that is, it kills some of the microbes that get into it.

Paranasal sinuses

The paranasal sinuses are cavities that lie in the bones of the skull and are connected to the nasal cavity. They are covered from the inside with mucous membranes and have the function of a vocal resonator. Paranasal sinuses:

• maxillary (maxillary);
• frontal;
• wedge-shaped (main);
• cells of the ethmoid bone labyrinth.

Paranasal sinuses

The two maxillary sinuses are the largest. They are located in the depth upper jaw under the orbits and communicate with the middle passage. The frontal sinus is also paired, located in the frontal bone above the eyebrow and has the shape of a pyramid, with the apex facing down. Through the nasofrontal canal it also connects to the middle passage. The sphenoid sinus is located in sphenoid bone on the back wall of the nasopharynx. In the middle of the nasopharynx, the openings of the cells of the ethmoid bone open.

The maxillary sinus communicates most closely with the nasal cavity, therefore, often after the development of rhinitis, sinusitis appears when the path of outflow of inflammatory fluid from the sinus to the nose is blocked.

Larynx

This is the top section respiratory tract, also involved in the formation of voice. It is located approximately in the middle of the neck, between the pharynx and trachea. The larynx is formed by cartilage, which is connected by joints and ligaments. In addition, it is attached to the hyoid bone. Between the cricoid and thyroid cartilages there is a ligament, which is cut in case of acute laryngeal stenosis to provide air access.

The larynx is lined with ciliated epithelium, and on the vocal cords the epithelium is stratified squamous, quickly renewed and allowing the ligaments to be resistant to constant stress.

Under the mucous membrane of the lower part of the larynx, below the vocal cords, there is a loose layer. It can swell quickly, especially in children, causing laryngospasm.

Trachea

The lower respiratory tract begins with the trachea. It continues with the larynx and then passes into the bronchi. The organ looks like a hollow tube consisting of cartilaginous half-rings tightly connected to each other. The length of the trachea is about 11 cm.

Below, the trachea forms two main bronchi. This zone is an area of ​​bifurcation (bifurcation), it has many sensitive receptors.

The trachea is lined with ciliated epithelium. Its feature is its good absorption ability, which is used for inhalation of drugs.

For laryngeal stenosis, in some cases a tracheotomy is performed - the anterior wall of the trachea is cut and a special tube is inserted through which air enters.

Bronchi

This is a system of tubes through which air passes from the trachea to the lungs and back. They also have a cleansing function.

The bifurcation of the trachea is located approximately in the interscapular area. The trachea forms two bronchi, which go to the corresponding lung and there are divided into lobar bronchi, then into segmental, subsegmental, lobular, which are divided into terminal bronchioles - the smallest of the bronchi. This entire structure is called the bronchial tree.

Terminal bronchioles have a diameter of 1–2 mm and pass into the respiratory bronchioles, from which the alveolar ducts begin. At the ends of the alveolar ducts there are pulmonary vesicles - alveoli.

Trachea and bronchi

The inside of the bronchi is lined ciliated epithelium. The constant wave-like movement of the cilia brings up the bronchial secretion - a liquid continuously produced by the glands in the wall of the bronchi and washing away all impurities from the surface. This removes microorganisms and dust. If thick bronchial secretions accumulate, or a large foreign body enters the bronchial lumen, they are removed using - defense mechanism, aimed at cleansing the bronchial tree.

In the walls of the bronchi there are ring-shaped bundles of small muscles that are able to “block” the flow of air when it is contaminated. This is how it arises. In asthma, this mechanism begins to work when the usual healthy person substance, such as plant pollen. In these cases, bronchospasm becomes pathological.

Respiratory organs: lungs

A person has two lungs located in the chest cavity. Their main role is to ensure the exchange of oxygen and carbon dioxide between the body and the environment.

How are the lungs structured? They are located on the sides of the mediastinum, in which the heart and blood vessels lie. Each lung is covered with a dense membrane - the pleura. Between its leaves there is normally a little fluid, which allows the lungs to slide relative to the chest wall during breathing. Right lung more than the left. Through the root located with inside organ, it contains the main bronchus, large vascular trunks, and nerves. The lungs consist of lobes: the right one has three, the left one has two.

The bronchi, entering the lungs, are divided into smaller and smaller ones. The terminal bronchioles become alveolar bronchioles, which divide and become alveolar ducts. They also branch out. At their ends there are alveolar sacs. Alveoli (respiratory vesicles) open on the walls of all structures, starting with the respiratory bronchioles. The alveolar tree consists of these formations. The branches of one respiratory bronchiole ultimately form the morphological unit of the lungs - the acinus.

The structure of the alveoli

The alveolar orifice has a diameter of 0.1 - 0.2 mm. The inside of the alveolar vesicle is covered thin layer cells lying on a thin wall - a membrane. Outside, a blood capillary is adjacent to the same wall. The barrier between air and blood is called aerohematic. Its thickness is very small - 0.5 microns. An important part of it is the surfactant. It consists of proteins and phospholipids, lines the epithelium and maintains the rounded shape of the alveoli during exhalation, preventing the penetration of microbes from the air into the blood and liquids from the capillaries into the lumen of the alveoli. Premature babies have poorly developed surfactant, which is why they often have breathing problems immediately after birth.

The lungs contain vessels from both circulation circles. Arteries great circle carry rich in oxygen blood from the left ventricle of the heart and directly feed the bronchi and lung tissue, like all other human organs. The arteries of the pulmonary circulation bring venous blood from the right ventricle to the lungs (this is the only example when venous blood flows through the arteries). It flows through the pulmonary arteries, then enters the pulmonary capillaries, where gas exchange occurs.

The essence of the breathing process

The exchange of gases between the blood and the external environment that takes place in the lungs is called external respiration. It occurs due to the difference in the concentration of gases in the blood and air.

The partial pressure of oxygen in air is greater than in venous blood. Due to the pressure difference, oxygen penetrates from the alveoli into the capillaries through the air-hematic barrier. There it joins red blood cells and spreads through the bloodstream.

Gas exchange across the air-blood barrier

The partial pressure of carbon dioxide in venous blood is greater than in air. Because of this, carbon dioxide leaves the blood and is released with exhaled air.

Gas exchange is a continuous process that continues as long as there is a difference in the content of gases in the blood and the environment.

During normal breathing, about 8 liters of air pass through the respiratory system per minute. With stress and diseases accompanied by increased metabolism (for example, hyperthyroidism), pulmonary ventilation increases and shortness of breath appears. If increased breathing fails to maintain normal gas exchange, the oxygen content in the blood decreases - hypoxia occurs.

Hypoxia also occurs in high altitude conditions, where the amount of oxygen in the external environment is reduced. This leads to the development of mountain sickness.

Respiratory system performs the function of gas exchange, but also takes part in such important processes as thermoregulation, air humidification, water-salt metabolism and many others. The respiratory organs are represented by the nasal cavity, nasopharynx, oropharynx, larynx, trachea, bronchi, and lungs.

Nasal cavity

Divided by the cartilaginous septum into two halves - right and left. On the septum there are three nasal conchae, which form the nasal passages: upper, middle and lower. The walls of the nasal cavity are lined with mucous membrane with ciliated epithelium. The cilia of the epithelium, moving sharply and quickly in the direction of the nostrils and smoothly and slowly in the direction of the lungs, trap and remove dust and microorganisms deposited on the mucus membrane.

The mucous membrane of the nasal cavity is abundantly supplied with blood vessels. The blood flowing through them warms or cools the inhaled air. The glands of the mucous membrane secrete mucus, which moisturizes the walls of the nasal cavity and reduces the activity of bacteria coming from the air. On the surface of the mucous membrane there are always leukocytes that destroy a large number of bacteria. In the mucous membrane upper section the nasal cavity ends nerve cells, forming the organ of smell.

The nasal cavity communicates with cavities located in the bones of the skull: the maxillary, frontal and sphenoid sinuses.

Thus, the air entering the lungs through the nasal cavity is cleaned, warmed and disinfected. This does not happen to it if it enters the body through oral cavity. From the nasal cavity through the choanae, air enters the nasopharynx, from it into the oropharynx, and then into the larynx.

It is located on the front side of the neck and from the outside its part is visible as an elevation called the Adam's apple. The larynx is not only an air-carrying organ, but also an organ of voice formation, sound speech. It is compared to a musical apparatus that combines elements of wind and string instruments. From above, the entrance to the larynx is covered by the epiglottis, which prevents food from entering it.

The walls of the larynx consist of cartilage and are covered on the inside with a mucous membrane with ciliated epithelium, which is absent on the vocal cords and part of the epiglottis. The cartilages of the larynx are represented in the lower section by the cricoid cartilage, in front and on the sides by the thyroid cartilage, on the top by the epiglottis, and in the back by three pairs of small ones. They are semi-movably connected to each other. Muscles are attached to them and vocal cords. The latter consist of flexible, elastic fibers that run parallel to each other.

Between the vocal cords of the right and left halves there is a glottis, the lumen of which varies depending on the degree of tension of the ligaments. It is caused by contractions of special muscles, which are also called vocal muscles. Their rhythmic contractions are accompanied by contractions of the vocal cords. As a result, the stream of air leaving the lungs acquires an oscillatory character. Sounds and voices appear. The shades of the voice depend on the resonators, the role of which is played by the cavities of the respiratory tract, as well as the pharynx and oral cavity.

Anatomy of the trachea

The lower part of the larynx passes into the trachea. The trachea is located in front of the esophagus and is a continuation of the larynx. The length of the trachea is 9-11 cm, diameter is 15-18 mm. At the level of the fifth thoracic vertebra it is divided into two bronchi: right and left.

The tracheal wall consists of 16-20 incomplete cartilaginous rings that prevent narrowing of the lumen, connected by ligaments. They extend 2/3 of a circle. Back wall trachea - membranous, contains smooth (non-striated) muscle fibers and is adjacent to the esophagus.

Bronchi

From the trachea, air enters the two bronchi. Their walls also consist of cartilaginous half-rings (6-12 pieces). They prevent the walls of the bronchi from collapsing. Together with blood vessels and nerves, the bronchi enter the lungs, where they branch to form the bronchial tree of the lung.

The inside of the trachea and bronchi are lined with mucous membrane. The thinnest bronchi are called bronchioles. They end in alveolar ducts, on the walls of which there are pulmonary vesicles, or alveoli. The diameter of the alveoli is 0.2-0.3 mm.

The alveolar wall consists of one layer of squamous epithelium and a thin layer of elastic fibers. The alveoli are covered with a dense network of blood capillaries in which gas exchange occurs. They form the respiratory part of the lung, and the bronchi form the airway section.

In the lungs of an adult there are about 300-400 million alveoli, their surface is 100-150 m2, i.e. the total respiratory surface of the lungs is 50-75 times greater than the entire surface of the human body.

Lung structure

The lungs are a paired organ. The left and right lungs occupy almost the entire chest cavity. The right lung is larger in volume than the left and consists of three lobes, the left - of two lobes. On the inner surface of the lungs are the hilum of the lungs, through which the bronchi, nerves, pulmonary arteries, pulmonary veins and lymphatic vessels pass.

On the outside, the lungs are covered with a connective tissue membrane - the pleura, which consists of two layers: the inner layer is fused with the air-bearing tissue of the lung, and the outer layer is fused with the walls of the chest cavity. Between the leaves there is a space - the pleural cavity. The contacting surfaces of the inner and outer layers of the pleura are smooth and constantly moistened. Therefore, their friction is not normally felt during breathing movements. IN pleural cavity pressure by 6-9 mm Hg. Art. below atmospheric. The smooth, slippery surface of the pleura and the reduced pressure in its cavities favor the movements of the lungs during the acts of inhalation and exhalation.

The main function of the lungs is gas exchange between the external environment and the body.

It is false to overestimate the importance of oxygen for the human body. A child still in the womb will not be able to fully develop if there is a lack of this substance, which enters through the maternal circulatory system. And when born, the baby emits a cry, making the first breathing movements that do not stop throughout life.

Oxygen hunger is not regulated by consciousness in any way. When there is a lack of nutrients or fluid, we feel thirsty or need food, but hardly anyone has felt the body's need for oxygen. Regular breathing occurs at the cellular level, since no living cell unable to function without oxygen. And to prevent this process from being interrupted, the body has a respiratory system.

Human respiratory system: general information

The respiratory, or respiratory, system is a complex of organs through which oxygen is delivered from the environment to the circulatory system and the subsequent removal of exhaust gases back into the atmosphere. In addition, it is involved in heat exchange, smell, formation of vocal sounds, synthesis hormonal substances and metabolic processes. However, it is gas exchange that is of greatest interest, since it is the most significant for maintaining life.

With the slightest pathology of the respiratory system, the functionality of gas exchange decreases, which can lead to activation of compensatory mechanisms or oxygen starvation. To assess the functions of the respiratory organs, it is customary to use the following concepts:

• Vital capacity of the lungs, or vital capacity, is the maximum possible volume atmospheric air, received in one breath. In adults, it varies from 3.5 to 7 liters depending on the degree of training and level of physical development.
• Tidal volume, or VT, is an indicator characterizing the average statistical intake of air per breath in calm and comfortable conditions. The norm for adults is 500‒600 ml.
• Inspiratory reserve volume, or ROVd, is the maximum amount of atmospheric air received in calm conditions in one breath; is about 1.5 – 2.5 liters.
• Expiratory reserve volume, or ERV, is the maximum volume of air that leaves the body at the moment of quiet exhalation; the norm is approximately 1.0 – 1.5 liters.
• Respiratory rate - the number of respiratory cycles (inhalation-exhalation) performed per minute. The norm depends on age and degree of load.

Each of these indicators has a certain meaning in pulmonology, since any deviation from normal numbers indicates the presence of a pathology that requires appropriate treatment.

Structure and function of the respiratory system

The respiratory system provides the body with a sufficient supply of oxygen, participates in gas exchange and the removal of toxic compounds (in particular carbon dioxide). Entering the airways, the air is warmed, partially purified, and then transported directly to the lungs - main body person's breath. This is where the main processes of gas exchange between the tissues of the alveoli and the blood capillaries occur.

Red blood cells contained in the blood include hemoglobin, a complex iron-based protein that is capable of attaching oxygen molecules and carbon dioxide compounds. Entering the capillaries of the lung tissue, the blood is saturated with oxygen, capturing it with the help of hemoglobin. Red blood cells then carry oxygen to other organs and tissues. There, the incoming oxygen is gradually released, and its place is taken by carbon dioxide - the final product of respiration, which at high concentrations can cause poisoning and intoxication, even death. After this, red blood cells deprived of oxygen are sent back to the lungs, where carbon dioxide is removed and the blood is re-oxygenated. This closes the cycle of the human respiratory system.

Regulation of the breathing process

The ratio of the concentration of oxygen and carbon dioxide is a more or less constant value and is regulated at an unconscious level. In calm conditions, the supply of oxygen is carried out in the optimal mode for a particular age and body, however, under loads - during physical training, with sudden severe stress, the level of carbon dioxide rises. In this case nervous system sends a signal to the respiratory center, which stimulates the mechanisms of inhalation and exhalation, increasing the level of oxygen intake and compensating for the excess of carbon dioxide. If this process is interrupted for some reason, the lack of oxygen quickly leads to disorientation, dizziness, loss of consciousness, and then irreversible brain disorders and clinical death. That is why the work of the respiratory system in the body is considered one of the most important.

Each inhalation is carried out due to a certain group of respiratory muscles, which coordinate the movements of the lung tissue, since it itself is passive and cannot change shape. Under standard conditions, this process is ensured thanks to the diaphragm and intercostal muscles, however, with deep functional breathing, the muscular frame of the cervical, thoracic and abdominals. As a rule, during each inhalation in an adult, the diaphragm lowers by 3–4 cm, which allows the total volume of the chest to increase by 1–1.2 liters. At the same time, the intercostal muscles, contracting, lift the costal arches, which further increases the final volume of the lungs and, accordingly, reduces the pressure in the alveoli. It is because of the pressure difference that air is pumped into the lungs and inhalation occurs.

Exhalation, unlike inhalation, does not require work muscular system. Relaxing, the muscles again compress the volume of the lungs, and the air is, as it were, “squeezed out” from the alveoli back through the airways. These processes occur quite quickly: newborns breathe on average once per second, adults – 16–18 times per minute. Normally, this time is enough for high-quality gas exchange and removal of carbon dioxide.

Organs of the human respiratory system

The human respiratory system can be conditionally divided into the respiratory tract (transportation of incoming oxygen) and the main paired organ - the lungs (gas exchange). The airways at the intersection with the esophagus are classified into upper and lower. The upper ones include openings and cavities through which air enters the body: nose, mouth, nasal, oral cavities and pharynx. To the lower ones are the paths along which air masses pass directly into the lungs, that is, the larynx and trachea. Let's look at what function each of these organs performs.

Upper respiratory tract

1. Nasal cavity

The nasal cavity is the link between the environment and the human respiratory system. Through the nostrils, air enters the nasal passages, which are lined with small villi that filter out dust particles. The inner surface of the nasal cavity is distinguished by a rich vascular-capillary network and a large number of mucous glands. Mucus acts as a kind of barrier for pathogenic microorganisms, preventing their rapid reproduction and destroying the microbial flora.

The nasal cavity itself is divided by the ethmoid bone into 2 halves, each of which, in turn, is divided into several more passages by means of bone plates. Open here paranasal sinuses- maxillary, frontal and others. They also relate to the respiratory system, since they significantly increase the functional volume of the nasal cavity and contain, although small, but still quite significant amount mucous glands.

The nasal mucosa is formed by ciliated epithelial cells that perform a protective function. By moving alternately, the cellular cilia form peculiar waves that keep the nasal passages clean, removing harmful substances and particles. The mucous membranes can change significantly in volume depending on the general condition of the body. Normally, the lumens of numerous capillaries are quite narrow, so nothing prevents full nasal breathing. However, at the slightest inflammatory process, for example during colds or flu, mucus synthesis increases several times, and the volume of the circulatory network increases, which leads to swelling and difficulty breathing. Thus, a runny nose occurs - another mechanism that protects the respiratory tract from further infection.

The main functions of the nasal cavity include:

• filtration from dust particles and pathogenic microflora,
• warming the incoming air,
• humidification of air flows, which is especially important in arid climates and during the heating season,
• protection of the respiratory system during colds.

2. Oral cavity

The oral cavity is a secondary respiratory opening and is not so anatomically designed to supply the body with oxygen. However, it can easily perform this function if nasal breathing for some reason it is difficult, for example, due to a nasal injury or runny nose. The path that air takes when entering through the oral cavity is much shorter, and the opening itself is larger in diameter compared to the nostrils, so the reserve volume of inhalation through the mouth is usually greater than through the nose. However, this is where the benefits of mouth breathing end. On the mucous membrane of the mouth there are neither cilia nor mucous glands that produce mucus, which means that the filtration function in this case completely loses its significance. In addition, the short path of air flow makes it easier for air to enter the lungs, so it simply does not have time to warm up to a comfortable temperature. Because of these features, nasal breathing is more preferable, and oral breathing is intended for exceptional cases or as compensatory mechanisms when it is impossible to get air through the nose.

3. Throat

The pharynx is the connecting area between the nasal and oral cavities and the larynx. It is conventionally divided into 3 parts: nasal, oral and laryngopharynx. Each of these parts is alternately involved in transporting air during nasal breathing, gradually bringing it to a comfortable temperature. Once in the laryngopharynx, the inhaled air is redirected to the larynx through the epiglottis, which acts as a kind of valve between the esophagus and the respiratory organs. During breathing, the epiglottis, adjacent to the thyroid cartilage, blocks the esophagus, ensuring air flow only into the lungs, and during swallowing, on the contrary, it blocks the larynx, protecting it from foreign bodies into the respiratory system and subsequent suffocation.

Lower respiratory tract

1. Larynx

The larynx is located in the anterior cervical region and is top part breathing tube. Anatomically, it consists of cartilaginous rings - the thyroid, the cricoid and two arytenoids. The thyroid cartilage forms the Adam's apple, or Adam's apple, which is especially pronounced in the stronger sex. The laryngeal cartilages are connected to each other using connective tissue, which, on the one hand, provides the necessary mobility, and on the other, limits the mobility of the larynx to a strictly defined range. The vocal apparatus, represented by vocal cords and muscles, is also located in this area. Thanks to their coordinated work, wave-like sounds are formed in a person, which are then transformed into speech. The inner surface of the larynx is lined with ciliated epithelial cells, and the vocal cords are flat epithelium devoid of mucous glands. Therefore, the main hydration of the ligamentous apparatus is provided by the outflow of mucus from the overlying organs of the respiratory system.

2. Trachea

The trachea is a tube 11–13 cm long, reinforced at the front with dense hyaline half rings. The posterior wall of the trachea is adjacent to the esophagus, so there is no cartilage tissue there. Otherwise, it would make it difficult for food to pass through. The main function of the trachea is to pass air through cervical spine further into the bronchi. In addition, the ciliated epithelium lining the inner surface of the respiratory tube produces mucus, which provides additional filtration of the air from dust particles and other pollutants.

Lungs

The lungs are the main organ that carries out air exchange. Paired formations of unequal size and shape are located in the thoracic cavity, bounded by the costal arches and the diaphragm. On the outside, each lung is covered with serous pleura, which consists of two layers and forms a sealed cavity. Inside it is filled with a small amount of serous fluid, which acts as a shock absorber and greatly facilitates breathing movements. The mediastinum is located between the right and left lungs. In this relatively small space, the trachea, thoracic lymph duct, esophagus, heart and large vessels extending from it are adjacent.

Each lung includes bronchial-vascular bundles formed by the primary bronchi, nerves and arteries. It is here that the branching of the bronchial tree begins, around the branches of which numerous The lymph nodes and vessels. The exit of blood vessels from the lung tissue occurs through 2 veins extending from each lung. Once in the lungs, the bronchi begin to branch depending on the number of lobes: in the right there are three bronchial branches, and in the left there are two. With each branch, their lumen gradually narrows down to half a millimeter in the smallest bronchioles, of which there are about 25 million in an adult.

However, the path of air does not end at the bronchioles: from here it enters even narrower and more branched alveolar ducts, which lead the air to the alveoli - the so-called “destination”. It is here that gas exchange processes occur through the contacting walls of the pulmonary sacs and the capillary network. The epithelial walls lining the inner surface of the alveoli produce a surfactant that prevents their collapse. Before birth, a child in the womb does not receive oxygen through the lungs, so the alveoli are in a collapsed state, but during the first breath and cry they straighten out. This depends on the full formation of surfactant, which normally appears in the fetus in the seventh month of intrauterine life. The alveoli remain in this state throughout life. Even with the most intense exhalation, some of the oxygen certainly remains inside, so the lungs do not collapse.

Conclusion

Anatomically and physiologically, the human respiratory system is a well-coordinated mechanism that maintains the vital functions of the body. Providing every cell human body the most important substance - oxygen - serves as the basis of life, the most significant process, without which not a single person can do. Regular inhalation of polluted air, low level ecology, smog and dust from city streets negatively affect the functions of the respiratory system, not to mention smoking, which kills millions of people around the world every year. Therefore, carefully monitoring your health, you need to take care not only of your own body, but also of the environment, so that in a few years a sip of clean, fresh air was not the ultimate dream, but the everyday norm of life!

The human respiratory system is actively involved during any type of physical activity, be it aerobic or anaerobic exercise. Any self-respecting personal trainer should have knowledge about the structure of the respiratory system, its purpose and the role it plays in the process of playing sports. Knowledge of physiology and anatomy is an indicator of a trainer’s attitude towards his craft. The more he knows, the higher his qualifications as a specialist.

The respiratory system is a set of organs whose purpose is to provide the human body with oxygen. The process of providing oxygen is called gas exchange. Oxygen inhaled by a person is converted into carbon dioxide when exhaled. Gas exchange occurs in the lungs, namely in the alveoli. Their ventilation is realized by alternating cycles of inhalation (inspiration) and exhalation (expiration). The process of inhalation is interconnected with physical activity diaphragm and external intercostal muscles. As you inhale, the diaphragm lowers and the ribs rise. The exhalation process occurs mostly passively, involving only the internal intercostal muscles. As you exhale, the diaphragm rises and the ribs fall.

Breathing is usually divided according to the method of expansion of the chest into two types: thoracic and abdominal. The first is more often observed in women (the expansion of the sternum occurs due to the elevation of the ribs). The second is more often observed in men (the expansion of the sternum occurs due to deformation of the diaphragm).

The structure of the respiratory system

The respiratory tract is divided into upper and lower. This division is purely symbolic and the boundary between the upper and lower respiratory tracts passes at the intersection of the respiratory and digestive systems at the top of the larynx. The upper respiratory tract includes the nasal cavity, nasopharynx and oropharynx with the oral cavity, but only partially, since the latter is not involved in the breathing process. The lower respiratory tract includes the larynx (although sometimes it is also referred to as upper paths), trachea, bronchi and lungs. Airways inside the lungs they form a kind of tree and branch approximately 23 times before oxygen reaches the alveoli, where gas exchange occurs. You can see a schematic representation of the human respiratory system in the figure below.

Structure of the human respiratory system: 1- Frontal sinus; 2- Sphenoid sinus; 3- Nasal cavity; 4- Nasal vestibule; 5- Oral cavity; 6- Pharynx; 7- Epiglottis; 8- Vocal fold; 9- Thyroid cartilage; 10- Cricoid cartilage; 11- Trachea; 12- Apex of the lung; 13- Upper lobe (lobar bronchi: 13.1- Right upper; 13.2- Right middle; 13.3- Right lower); 14- Horizontal slot; 15- Oblique slot; 16- Middle beat; 17- Lower lobe; 18- Aperture; 19- Upper lobe; 20- Lingular bronchus; 21- Carina of trachea; 22- Intermediate bronchus; 23- Left and right main bronchi (lobar bronchi: 23.1- Left upper; 23.2- Left lower); 24- Oblique slot; 25- Heart tenderloin; 26- Luvula of the left lung; 27- Lower lobe.

The respiratory tract acts as a link between the environment and the main organ of the respiratory system - the lungs. They are located inside the chest and are surrounded by the ribs and intercostal muscles. Directly in the lungs, the process of gas exchange occurs between oxygen supplied to the pulmonary alveoli (see figure below) and the blood that circulates inside the pulmonary capillaries. The latter deliver oxygen to the body and remove gaseous metabolic products from it. The ratio of oxygen and carbon dioxide in the lungs is maintained at a relatively constant level. Stopping the supply of oxygen to the body leads to loss of consciousness ( clinical death), then to irreversible disorders of brain function and ultimately to death (biological death).

Structure of the alveoli: 1- Capillary bed; 2- Connective tissue; 3- Alveolar sacs; 4- Alveolar duct; 5- Mucous gland; 6- Mucous lining; 7- Pulmonary artery; 8- Pulmonary vein; 9- Opening of the bronchiole; 10- Alveolus.

The breathing process, as I said above, is carried out by deforming the chest with the help of the respiratory muscles. Breathing itself is one of the few processes occurring in the body that is controlled by it both consciously and unconsciously. That is why a person continues to breathe during sleep, while in an unconscious state.

Functions of the respiratory system

The main two functions that the human respiratory system performs are breathing itself and gas exchange. Among other things, it is involved in such equally important functions as maintaining heat balance body, formation of voice timbre, perception of odors, as well as increasing the humidity of inhaled air. Lung tissue takes part in the production of hormones, water-salt and lipid metabolism. In the extensive vascular system of the lungs, blood is deposited (stored). The respiratory system also protects the body from mechanical factors. external environment. However, of all this variety of functions, we will be interested in gas exchange, since without it neither metabolism, nor the formation of energy, nor, as a consequence, life itself would occur.

During breathing, oxygen enters the blood through the alveoli, and carbon dioxide is removed from the body through them. This process involves the penetration of oxygen and carbon dioxide through the capillary membrane of the alveoli. At rest, the oxygen pressure in the alveoli is approximately 60 mmHg. Art. higher compared to the pressure in the blood capillaries of the lungs. Due to this, oxygen penetrates into the blood, which flows through the pulmonary capillaries. In the same way, carbon dioxide penetrates in the opposite direction. The gas exchange process occurs so quickly that it can be called virtually instantaneous. This process is shown schematically in the figure below.

Scheme of the gas exchange process in the alveoli: 1- Capillary network; 2- Alveolar sacs; 3- Opening of the bronchiole. I- Oxygen supply; II- Removal of carbon dioxide.

We've sorted out gas exchange, now let's talk about the basic concepts regarding breathing. The volume of air inhaled and exhaled by a person in one minute is called minute breathing volume. It provides the necessary level of gas concentration in the alveoli. The concentration indicator is determined tidal volume is the amount of air that a person inhales and exhales during breathing. And respiratory rate, in other words – breathing frequency. Inspiratory reserve volume- This is the maximum volume of air that a person can inhale after a normal breath. Hence, expiratory reserve volume- this is the maximum amount of air that a person can exhale additionally after a normal exhalation. The maximum volume of air that a person can exhale after a maximum inhalation is called vital capacity of the lungs. However, even after maximum exhalation, a certain amount of air remains in the lungs, which is called residual lung volume. The sum of vital capacity and residual lung volume gives us total lung capacity, which in an adult is equal to 3-4 liters of air per lung.

The moment of inhalation brings oxygen to the alveoli. In addition to the alveoli, air also fills all other parts of the respiratory tract - the oral cavity, nasopharynx, trachea, bronchi and bronchioles. Since these parts of the respiratory system are not involved in the process of gas exchange, they are called anatomically dead space. The volume of air that fills this space in a healthy person is usually about 150 ml. With age, this figure tends to increase. Since at the moment of deep inspiration the airways tend to expand, it must be borne in mind that the increase in tidal volume is simultaneously accompanied by an increase in the anatomical dead space. This relative increase in tidal volume usually exceeds that of the anatomical dead space. As a result, as tidal volume increases, the proportion of anatomical dead space decreases. Thus, we can conclude that the increase in tidal volume (with deep breathing) provides significantly better ventilation of the lungs, compared with rapid breathing.

Breathing regulation

For full provision oxygen supply to the body, the nervous system regulates the rate of ventilation of the lungs by changing the frequency and depth of breathing. Due to this, the concentration of oxygen and carbon dioxide in arterial blood does not change even under the influence of such active physical activity as working on a cardio machine or training with weights. The regulation of breathing is controlled by the respiratory center, which is shown in the figure below.

Structure respiratory center brain stem: 1- Varoliev Bridge; 2- Pneumotaxic center; 3- Apneustic center; 4- Pre-Bötzinger complex; 5- Dorsal group of respiratory neurons; 6- Ventral group of respiratory neurons; 7- Medulla oblongata. I- Respiratory center of the brain stem; II- Parts of the respiratory center of the pons; III- Parts of the respiratory center of the medulla oblongata.

The respiratory center consists of several discrete groups of neurons that are located on either side of the lower part of the brain stem. In total, there are three main groups of neurons: the dorsal group, the ventral group and the pneumotaxic center. Let's look at them in more detail.

• Dorsal respiratory group plays vital role in the implementation of the breathing process. It is also the main generator of impulses that set a constant breathing rhythm.
• The ventral respiratory group performs several functions at once important functions. First of all, respiratory impulses from these neurons take part in the regulation of the breathing process, controlling the level of pulmonary ventilation. Among other things, excitation of selected neurons in the ventral group can stimulate inhalation or exhalation, depending on the moment of excitation. The importance of these neurons is especially great since they are able to control the abdominal muscles that take part in the exhalation cycle during deep breathing.
• The pneumotaxic center takes part in controlling the frequency and amplitude of respiratory movements. The main influence of this center is to regulate the duration of the lung filling cycle, as a factor that limits tidal volume. An additional effect of such regulation is a direct effect on respiratory rate. When the duration of the inhalation cycle decreases, the exhalation cycle also shortens, which ultimately leads to an increase in the respiratory rate. The same is true in the opposite case. As the duration of the inhalation cycle increases, the exhalation cycle also increases, while the respiratory rate decreases.

Conclusion

The human respiratory system is primarily a set of organs necessary to provide the body with vital oxygen. Knowledge of the anatomy and physiology of this system gives you the opportunity to understand the basic principles of constructing the training process, both aerobic and anaerobic. The information provided here is special meaning when determining the goals of the training process and can serve as the basis for assessing the athlete’s health status during the planned construction of training programs.

In one day, an adult inhales and exhales tens of thousands of times. If a person cannot breathe, then he only has seconds.

The importance of this system for humans can hardly be overestimated. You need to think about how the human respiratory system works, what its structure and functions are, before health problems may arise.

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The structure of the human respiratory system

The pulmonary system can be considered one of the most significant in human body. It includes functions aimed at absorbing oxygen from the air and removing carbon dioxide. Normal operation breathing is especially important for children.

The anatomy of the respiratory organs stipulates that they can be divided into two groups:

• airways;
• lungs.

Upper respiratory tract

When air enters the body, it passes through the mouth or nose. It moves further through the pharynx, entering the trachea.

The upper respiratory tract includes the paranasal sinuses and the larynx.

The nasal cavity is divided into several sections: lower, middle, upper and general.

Inside, this cavity is covered with ciliated epithelium, which warms the incoming air and cleans it. There is a special mucus here that has protective properties that help fight infection.

The larynx is a cartilaginous formation that is located in the space from the pharynx to the trachea.

Lower respiratory tract

When inhalation occurs, air moves inward and enters the lungs. At the same time, from the pharynx at the beginning of its journey it ends up in the trachea, bronchi and lungs. Physiology classifies them as the lower respiratory tract.

In the structure of the trachea, it is customary to distinguish the cervical and thoracic parts. It is divided into two parts. It, like other respiratory organs, is covered with ciliated epithelium.

The lungs are divided into sections: apex and base. This organ has three surfaces:

• diaphragmatic;
• mediastinal;
• costal

The lung cavity is protected, in short, by the rib cage on the sides and the diaphragm below the abdominal cavity.

Inhalation and exhalation are controlled by:

• diaphragm;
• intercostal respiratory muscles;
• intercartilaginous internal muscles.

Functions of the respiratory system

The most main function respiratory organs is as follows: supply the body with oxygen in order to sufficiently ensure its vital functions, as well as remove carbon dioxide and other breakdown products from the human body by performing gas exchange.

The respiratory system also performs a number of other functions:

1. Creating air flow to ensure voice formation.
2. Obtaining air for odor recognition.
3. The role of breathing is also that it provides ventilation to maintain optimal body temperature;
4. These organs are also involved in the blood circulation process.
5. Provides a protective function against the threat of being hit pathogens along with the inhaled air, including when a deep breath occurs.
6. To a small extent external breathing promotes the removal of waste substances from the body in the form of water vapor. In particular, dust, urea and ammonia can be removed in this way.
7. The pulmonary system performs blood deposition.

IN the latter case The lungs, thanks to their structure, are able to concentrate a certain volume of blood, giving it to the body when the overall plan requires it.

Human breathing mechanism

The breathing process consists of three processes. The following table explains this.

The flow of oxygen into the body can occur through the nose or mouth. It then passes through the pharynx, larynx and into the lungs.

Oxygen enters the lungs as one of the components of air. Their branched structure allows O2 gas to dissolve in the blood through the alveoli and capillaries, forming unstable chemical compounds with hemoglobin. Thus, chemically bound oxygen moves through the circulatory system throughout the body.

The regulation scheme provides that O2 gas gradually enters the cells, being released from its connection with hemoglobin. At the same time, carbon dioxide exhausted by the body takes its place in transport molecules and is gradually transferred to the lungs, where it is removed from the body during exhalation.

Air enters the lungs because their volume periodically increases and decreases. The pleura is attached to the diaphragm. Therefore, when the latter expands, the volume of the lungs increases. By taking in air, internal respiration occurs. If the diaphragm contracts, the pleura pushes waste carbon dioxide out.

It is worth noting: a person needs 300 ml of oxygen within one minute. During the same time, there is a need to remove 200 ml of carbon dioxide outside the body. However, these figures are only valid in a situation where a person does not experience strong physical activity. If maximum inhalation occurs, they will increase many times over.

Different types of breathing may occur:

1. At chest breathing inhalation and exhalation are carried out due to the efforts of the intercostal muscles. Moreover, during inhalation rib cage expands and also rises slightly. Exhalation is performed in the opposite way: the cell contracts while simultaneously lowering slightly.
2. Abdominal breathing looks different. The inhalation process is carried out due to the expansion of the abdominal muscles with a slight rise of the diaphragm. When you exhale, these muscles contract.

The first of them is most often used by women, the second by men. In some people, both the intercostal and abdominal muscles may be used during breathing.

Diseases of the human respiratory system

Such diseases usually fall into one of the following categories:

1. In some cases, the cause may be an infectious infection. The cause may be microbes, viruses, bacteria, which, once in the body, have a pathogenic effect.
2. Some people have allergic reactions, which are expressed in various breathing problems. There can be many reasons for such disorders, depending on the type of allergy a person has.
3. Autoimmune diseases are very dangerous to health. In this case, the body perceives its own cells as pathogens and begins to fight them. In some cases, the result may be a disease of the respiratory system.
4. Another group of diseases are those that are hereditary. In this case, we are talking about the fact that at the genetic level there is a predisposition to certain diseases. However, by paying sufficient attention to this issue, in most cases the disease can be prevented.

To monitor the presence of a disease, you need to know the signs by which you can determine its presence:

• cough;
• dyspnea;
• pain in the lungs;
• feeling of suffocation;
• hemoptysis.

Cough is a reaction to mucus accumulated in the bronchi and lungs. In different situations, it can vary in nature: with laryngitis it can be dry, with pneumonia it can be wet. If we are talking about ARVI diseases, the cough can periodically change its character.

Sometimes when coughing, the patient experiences pain, which can occur either constantly or when the body is in a certain position.

Shortness of breath can manifest itself in different ways. Subjective intensifies at times when a person experiences stress. Objective is expressed in a change in the rhythm and force of breathing.

Importance of the respiratory system

The ability of people to speak is largely based on proper breathing.

This system also plays a role in the body's thermoregulation. Depending on the specific situation, this makes it possible to increase or decrease body temperature to the desired extent.

In addition to carbon dioxide, breathing also removes some other waste products from the human body.

In this way, a person is given the opportunity to distinguish different odors by inhaling air through the nose.

Thanks to this system of the body, gas exchange between a person and the environment takes place, supplies organs and tissues with oxygen and removes waste carbon dioxide from the human body.