Breath. The structure and functions of the respiratory system

Breathing is one of the most basic properties of any living organism. Its great importance is difficult to overestimate. About how important normal breathing is, a person thinks only when it suddenly becomes difficult, for example, when a cold has appeared. If without food and water a person is still able to live for some time, then without breathing - a matter of seconds. In one day, an adult makes more than 20,000 breaths and the same number of exhalations.

Structure respiratory system a person - what it is, we will analyze in this article.

How does a person breathe?

This system is one of the most important 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 environment and gave off carbon dioxide. What is respiration and how are the respiratory organs arranged?

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

The main role of the former is the unhindered delivery of air to the lungs. The respiratory tract of a person begins with the nose, but the process itself can also occur through the mouth if the nose is blocked. However, nasal breathing is preferable, because 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 respiration:

external respiration;
transport of gases with the bloodstream;
internal (cellular) respiration;

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

Lower Airways- this is the trachea, the bronchi connected to it, as well as the lungs.

Together they form a single functional system.

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

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

The process of respiration 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 enters from the alveoli into the vessels, and carbon dioxide returns back. Both alveoli and capillaries consist of a single layer of epithelium, which allows gases to easily penetrate into 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 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 the cells, it first penetrates into the intercellular space, and then directly into the cell.

The main purpose of respiration is the generation of energy in the 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 when you exhale, respectively, decreases. At rest, a person uses only 5 percent of the total volume of the lungs.

Functions of the respiratory system

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

In the process of 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 participants in other important functions organism, in particular, are directly involved in the formation of speech sounds, as well as 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 the temperature of his body. Exhaled gases lower body temperature.

Excretory processes also partially involve the organs of the respiratory system. Some water vapor is also released.

The structure of the respiratory organs, 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 releases 200 g of carbon dioxide. However, if it increases exercise stress, 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, in the process of breathing, dust, ammonia and urea are removed from the body.

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

Respiratory organs: description

All respiratory organs are interconnected.

Nose

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

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

lower section;
average;
upper;
general.

The nose is divided into bone and cartilage sections. The nasal septum separates the right and left halves.

From the inside, 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.

In the nasal cavity is a large number of small veins. 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. The cartilages of the larynx are:

Paired (arytenoid, corniculate, wedge-shaped, grain-shaped).
Unpaired (thyroid, cricoid and epiglottis).

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

The joints of the body provide its mobility. The larynx has many different ligaments. There is also a whole group of muscles that strain the vocal cords. In the larynx are the vocal cords themselves, which are most 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 from the fourth to the seventh cervical vertebrae.

Trachea

The actual continuation of the larynx is the trachea. According to the location, respectively, the organs in the trachea are divided into the cervical and thoracic parts. The esophagus is adjacent to the trachea. Very close to it passes the neurovascular bundle. 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 region of the gate are divided into lobar. 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 it is the lungs that are considered the most significant. They directly exchange oxygen and carbon dioxide.

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

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

The lungs are divided into two sections:

Top.
Base.

As well as three surfaces: diaphragmatic, costal and mediastinal. They are turned respectively to the diaphragm, ribs, mediastinum. The surfaces of the lung are separated by edges. The costal and mediastinal regions are separated by the anterior margin. The lower edge separates from the diaphragm area. Each lung is divided into lobes.

The right lung has three of them:

Upper;

Medium;

The left has only two: top and bottom. Between the lobes are interlobar surfaces. Both lungs have an oblique fissure. She shares shares in the body. 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 depressions called gates. Formations pass through them, creating the root of the lung. Here are the lymphatic and blood vessels, bronchi. In the right lung it is a bronchus, pulmonary vein, two pulmonary arteries. In the left - bronchus, pulmonary artery, two pulmonary veins.

In 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 - the pleura. It consists of two parts: outer and inner petal.

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

The human respiratory system is designed in such a way that negative air pressure is present directly in the pleural cavity. Due to this fact, as well as surface tension serous fluid, the lungs are constantly in a straightened state, and they also receive respiratory movements of the chest.

respiratory muscles

Respiratory muscles are divided into inspiratory (inhale) and expiratory (work during exhalation).

The main inspiratory muscles are:

Diaphragm.
External intercostal.
Intercartilaginous internal muscles.

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

Intercostal, rectus, hypochondrium, transverse, external and internal oblique muscles of the abdomen are expiratory muscles.

Diaphragm

The diaphragm also plays an important role in the breathing process. This is a unique plate that separates two cavities: chest and abdomen. It belongs to the respiratory muscles. In the diaphragm itself, a tendon center and three more muscle areas are distinguished.

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 leads to the fact that the pressure inside the chest cavity becomes less than the external one. atmospheric pressure. At this point, air enters the lungs. Then, as a result of muscle relaxation, exhalation is carried out

The mucous membrane of the respiratory system

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 that constantly carry 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 that have been inhaled by inhalation 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 fairly effective self-cleaning mechanism. This structure of the shell and the ability to cleanse 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 affect her condition:

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

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

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

At first, 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, a general uncomfortable condition.

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 paths to the lower ones and the bronchi and lungs are already affected. Doctors say in this case that the infection has "descended" below. This is fraught with serious diseases, such as pneumonia, bronchitis, pleurisy. In medical institutions, the condition of equipment intended for anesthetic and respiratory procedures is strictly monitored. 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: treat it in time if a problem occurs, and also avoid the negative influence of the environment, as well as bad habits.

As you know, breathing is life. And it is difficult to add anything to this statement, because even the need for water and food cannot be compared with the body's need for oxygen. Besides breath connects our body with the biosphere of the Earth, and all its living world. But the oxygen that penetrates the skin tissues is not enough to maintain all vital important processes. Therefore, it is the work of the entire respiratory system, and structure and functions of certain respiratory organs in particular, allows the heart to beat, supplying the blood with oxygen and subsequently removing carbon dioxide from the body.

The main anatomical components of the human respiratory system are:

upper respiratory tract (nasal cavity, nasopharynx and oropharynx, larynx);

lower respiratory tract (trachea with branching bronchi, lungs).

The air inhaled through the nose passes through the nasopharynx and oropharynx to the trachea, and then through the bronchial tree enters the lungs.

More details from work, structure and functions of the respiratory system, as well as the features of gas exchange in the body can be found in the anatomy section "Human Respiratory System". Now we consider the work and functions of the respiratory system from the point of view of respiratory gymnastics.

Nose and nasal cavity

The nasal cavity is the primary organ of respiration. The air entering it not only passes freely to the lungs, but is also cleaned of dust and heated. The ciliated epithelium of the nasal mucosa retains the smallest foreign particles, filtering the air.

Also, the mucous glands of the nasal cavity produce lysozyme, which performs two functions: moisturizing and bactericidal. Air heating occurs due to the blood vessels passing in the nasal cavity. So, already purified, moistened and heated air approaches the larynx. The larynx acts only as a connecting link between the nasopharynx and the trachea: no processes occur in it.

This is interesting! It is believed that when inhaled, the air passing through the right nostril goes to the right lung, and through the left - respectively, to the left.

Trachea and bronchi

Being a continuation of the larynx, the trachea, as it were, divides the incoming air into two parts, directing them to each lung along the right and left bronchi. They, in turn, branch out and spread over the entire area of the lungs and end in alveolar sacs, through which oxygen itself enters the blood.

Alveoli and lungs

The lungs are a paired organ that carries out gas exchange due to the smallest bubbles of the alveoli, the number of which reaches almost 700 million. Air enters the blood through the alveolar capillaries, and carbon dioxide exits back. Such difficult process occurs with each inhalation and exhalation of a person.

Functions of the respiratory organs

In addition to the main respiratory functions- ensuring the supply of oxygen to the blood and the removal of carbon dioxide from it - several more can be distinguished:

Thermoregulation. The temperature of the air entering the body affects the body temperature. Exhaling, a person gives off part of the heat external environment cooling the body.

Cleansing. On exhalation, not only carbon dioxide is removed from the body, but also water vapor or ethyl alcohol (if a person has consumed alcohol).

Maintenance of immunity. Lung cells are able to neutralize viruses and pathogenic bacteria.

This is interesting! The nasal cavity and nasopharynx are able to amplify the sound of the voice, give it a timbre and sonority. Therefore, when the nose is blocked, the person's voice changes.

Gas exchange occurs due to the alternation of acts of inhalation (inspiration) and exhalation (expiration). In the lungs muscle tissue no, therefore, the mechanism of respiration is carried out due to respiratory muscles. Its main components are the intercostal muscles, the diaphragm, and the accessory muscles of the neck and abdomen.

On inspiration, the chest rises due to the intercostal muscles. In this case, the seal and contraction of the diaphragm occurs. This action can be compared to the operation of a pump that pumps air into the lungs. On exhalation, the muscles relax, the diaphragm returns to its previous position, rising up, and displaces air filled with carbon dioxide from the body.

Continuous and permanent. During one breathing cycle (about 3-4 seconds), the air has time to go a long way, which can be divided into 4 stages:

1) ventilation of the lungs - the flow of air to the alveoli;

2) gas exchange between air and blood;

3) transfer of oxygen by erythrocytes to the tissues and carbon dioxide to the lungs;

4) biological oxidation - oxygen consumption by cells.

This indicator is very important for determining the state of the external respiration apparatus. For women lung capacity(VC) is approximately 3.5 liters; for men - from 4 to 5. Most high performance in athletes whose activities are associated with active breathing (skiers, rowers, swimmers, athletes).

VC can be determined using spirography. Simply put, a person must take the deepest possible breath, and then exhale through a tube connected to a machine called a spirograph.

Decrease in lung capacity can be affected by smoking, life in an ecologically unfavorable environment, lack of physical culture. With a chronic decrease in VC, there are pathological conditions pleural cavity or lung tissue, leading to respiratory failure. A person is forced to breathe more often, because. feels a constant lack of air. Lack of oxygen causes dizziness, weakness, and poor health. All of this can eventually lead to various diseases associated with the pulmonary apparatus (bronchitis, pleurisy, asthma, emphysema, etc.)

Breathing exercises

To maintain normal lung capacity and ensure proper breathing, special exercises aimed at adjusting the mechanism of the respiratory muscles help. The full use of the external respiration apparatus allows air to freely enter the lungs and provide oxygen to the entire body.

One way to train the lungs is to hold your breath.. The therapeutic effect of the exercise is the effect of vasodilation due to carbon dioxide, which, due to the lack of exhalation, lingered in the blood. With the next breath, the cells will receive more oxygen, because. he will be able to pass through the vessels more freely. This regular practice of short-term breath-holding allows you to gradually increase the useful amount of oxygen entering the body.

For more clarity on how respiratory function, as well as their structure and functions, below is given video, viewing which will supplement the above information.

Distinguish between external and internal. Internal (cellular) respiration is oxidative processes in cells, as a result of which energy is released. These processes necessarily involve oxygen, which enters the body as a result of external respiration. External respiration is the exchange of gases between the blood and atmospheric air. It occurs in the organs of the respiratory system. The respiratory system consists of the airways ( oral cavity, nasopharynx, pharynx, larynx, trachea, bronchi) and lungs. Each organ of the system has structural features in accordance with the functions performed.

I. The nasal cavity is divided into two halves by an osteochondral septum. It cleans, moisturizes, disinfects, warms the air and distinguishes odors. These various functions are provided by:

1) a large surface of contact with the inhaled air due to the winding passages that are in each half of the cavity;

2) ciliated epithelium, which consists of the mucous membrane of the nasal cavity. The cilia of the epithelium, moving, trap and bring dust and microorganisms out;

3) a dense network of capillary vessels penetrating the mucous membrane. Warm blood warms cold air;

4) mucus secreted by the glands of the mucous membrane of the nasal cavity. It moisturizes the air, reduces the vital activity of pathogenic bacteria;

5) olfactory receptors located in the mucous membrane.

II. The nasopharynx and pharynx conduct air into the larynx.

III. The larynx is a hollow air-bearing organ, the basis of which is cartilage; the largest of them is the thyroid. In addition to conducting air, the larynx performs the following functions:

1. Prevents food from entering the respiratory system. This is provided by movable cartilage - the epiglottis. It reflexively closes the entrance to the larynx at the moment of swallowing food.

IV. The trachea is located in the chest, in front of the esophagus, and consists of 16-20 cartilaginous semirings connected by ligaments. Half rings provide free passage of air through the trachea in any position of the human body. In addition, the posterior wall of the trachea is soft and consists of smooth muscles. This structure of the trachea does not interfere with the passage of food through the esophagus.

V. Bronchi. The left and right bronchi are formed by cartilaginous semirings. In the lungs, they branch into small bronchi, forming a bronchial tree. The thinnest bronchi are called bronchioles. They end in alveolar passages, on the walls of which there are alveoli, or pulmonary vesicles. The wall of the alveolus consists of a single layer of squamous epithelium and a thin layer of elastic fibers. The alveoli are densely entwined with capillaries and carry out gas exchange.

VI. The lungs are paired organs that occupy almost the entire chest cavity. The right is larger, consists of three lobes, the left - of two. Each lung is covered with a pulmonary pleura, consisting of two sheets. Between them is the pleural cavity, filled with pleural fluid, which reduces friction during respiratory movements. In the pleural cavity, the pressure is below atmospheric pressure. It promotes lung movement chest while inhaling and exhaling.

Thus, the structure of the organs of the respiratory system corresponds to the functions they perform.

2. Describe fungi and lichens. What is their significance in nature and human life?

Mushrooms are a separate kingdom of organisms that occupy an intermediate position between plants and animals. They are brought together with animals by the heterotrophic mode of nutrition, the presence of chitin in cell membranes, the supply of nutrients in the form of glycogen, and the formation of urea as a result of metabolism. At the same time, mushrooms, like plants, have unlimited growth, lead an immobile life, absorb nutrients by absorption. Mushrooms are divided into higher and lower. In the lower ones, the vegetative body - the mycelium - consists of one overgrown cell, in the higher ones - the mycelium is multicellular. Mushrooms reproduce by spores.

Some diseases of animals and humans (ringworm, thrush) also have a fungal nature.

Unicellular fungi - yeast - are used by humans in the baking and brewing industries. Antibiotics (penicillin) are obtained from moldy fungi.

Lichens also belong to the kingdom Mushrooms, because. their body is formed by filaments of mycelium and unicellular green algae. The combination of fungi and algae in one body has led to the fact that lichens have new morphological, physiological and ecological features. They can settle and grow on completely barren substrates, for example, on rocks, sand. Threads of mycelium absorb moisture from the atmosphere or from the surface of the substrate, and green algae provide lichen organic matter that are formed as a result of photosynthesis.

Lichens are the "pioneers" of vegetation, because. they are the first to settle in places where there is no soil (rocks, sand). During growth, they contribute to the destruction of rocks, and after dying off, they form humus on which other plants can grow. Lichens are the main food for reindeer. They are rich in sugars and proteins, so people have been eating some types of lichens for a long time. Man uses lichens as a raw material in the perfume industry, as well as to obtain alcohol, litmus, and dye. Lichens are very sensitive to atmospheric pollution: environmentalists determine the purity of the air by the frequency of occurrence of lichens.

Thus, fungi and lichens are peculiar organisms and play an important role in natural communities and human life.

3. What rules of mental hygiene should be followed?
Studying is the main activity of a student, therefore the rules of hygiene of mental activity are an integral part of his daily routine.

The daily routine is expediently organized, appropriate age characteristics the daily routine of activities, which provides for the automatism of life processes that repeats day after day.

The value of the daily routine is that the body eventually gets used to a certain work performed at a certain time, i.e. a system of conditioned reflexes is developed. This system unloads the cerebral cortex, because. automatic actions subcortex regulates. Thus, the cerebral cortex is maximally released for mental activity.

For maximum efficiency of mental activity it is necessary:

1. Be able to concentrate your attention on the work being done.

2. Correctly calculate the time of work: after an hour of work there should be a twenty-minute break with a change in the type of activity (physical activity).

3. Correctly choose the time of work. The most favorable for mental activity are the morning hours (1.5 hours after waking up), excluding periods of eating. At night, the productivity of the brain is reduced.

4. Effective mental work requires good lighting of the workplace and the absence of distractions.

5. Need to lead healthy lifestyle life, contributing to the optimal activity of all organ systems (including the brain).

Thus, mental activity is most effective if the daily regimen and hygiene rules are followed.

Ticket number 15
1. Explain the interdependence of the structure and functions of the digestive organs.
2. Give brief description gymnosperms and determine their significance in nature and human life.
3. What is the importance of hardening the body? Describe the methods of hardening.

Distinguish between external and internal. Internal (cellular) respiration is oxidative processes in cells, as a result of which energy is released. These processes necessarily involve oxygen, which enters the body as a result of external respiration. External respiration is the exchange of gases between the blood and atmospheric air. It occurs in the organs of the respiratory system. The respiratory system consists of airways (oral cavity, nasopharynx, pharynx, larynx, trachea, bronchi) and lungs. Each organ of the system has structural features in accordance with the functions performed.

I. The nasal cavity is divided into two halves by an osteochondral septum. It cleans, moisturizes, disinfects, warms the air and distinguishes odors. These various functions are provided by:

1) a large surface of contact with the inhaled air due to the winding passages that are in each half of the cavity;

2) ciliated epithelium, which consists of the mucous membrane of the nasal cavity. The cilia of the epithelium, moving, trap and bring dust and microorganisms out;

3) a dense network of capillary vessels penetrating the mucous membrane. Warm blood warms cold air;

4) mucus secreted by the glands of the mucous membrane of the nasal cavity. It moisturizes the air, reduces the vital activity of pathogenic bacteria;

5) olfactory receptors located in the mucous membrane.

II. The nasopharynx and pharynx conduct air into the larynx.

III. The larynx is a hollow air-bearing organ, the basis of which is cartilage; the largest of them is the thyroid. In addition to conducting air, the larynx performs the following functions:

1. Prevents food from entering the respiratory system. This is provided by movable cartilage - the epiglottis. It reflexively closes the entrance to the larynx at the moment of swallowing food.

VI. The lungs are paired organs that occupy almost the entire chest cavity. The right is larger, consists of three lobes, the left - of two. Each lung is covered with a pulmonary pleura, consisting of two sheets. Between them is the pleural cavity, filled with pleural fluid, which reduces friction during respiratory movements. In the pleural cavity, the pressure is below atmospheric pressure. This facilitates the movement of the lungs behind the chest during inhalation and exhalation.

Thus, the structure of the organs of the respiratory system corresponds to the functions they perform.

Breath - This is a set of physiological processes that provide gas exchange between the body and the external environment and oxidative processes in cells, as a result of which energy is released.

Respiratory system

Airways Lungs

nasal cavity

nasopharynx

The respiratory organs perform the following functions: air duct, respiratory, gas exchange, sound-forming, odor detection, humoral, participate in lipid and water-salt metabolism, immune.

nasal cavity formed by bones, cartilage and lined with a mucous membrane. The longitudinal partition divides it into right and left halves. In the nasal cavity, the air is warmed (blood vessels), moistened (tear), cleaned (mucus, villi), disinfected (leukocytes, mucus). In children, the nasal passages are narrow, and the mucous membrane swells at the slightest inflammation. Therefore, the breathing of children, especially in the first days of life, is difficult. There is another reason for this - the accessory cavities and sinuses in children are underdeveloped. For example, the maxillary cavity reaches full development only during the period of tooth change, the frontal cavity - up to 15 years. The nasolacrimal canal is wide, which leads to the penetration of infection and the occurrence of conjunctivitis. When breathing through the nose, irritation of the nerve endings of the mucous membrane occurs, and the act of breathing itself, its depth, intensifies in a reflex way. Therefore, when breathing through the nose, more air enters the lungs than when breathing through the mouth.

From the nasal cavity, through the choanae, air enters the nasopharynx, a funnel-shaped cavity that communicates with the nasal cavity and connects to the middle ear cavity through the opening of the Eustachian tube. The nasopharynx performs the function of conducting air.

Larynx - this is not only a department of the airways, but also an organ of voice formation. It also performs a protective function - it prevents food and liquid from entering the respiratory tract.

Epiglottis located above the entrance to the larynx and covers it at the time of swallowing. The narrowest section of the larynx is the glottis, which is limited to the vocal cords. The length of the vocal cords in newborns is the same. By the time of puberty in girls it is 1.5 cm, in boys it is 1.6 cm.

Trachea is a continuation of the larynx. It is a tube 10-15 cm long in adults and 6-7 cm in children. Its skeleton consists of 16-20 cartilaginous semirings that prevent its walls from falling off. Throughout the trachea is lined with ciliated epithelium and contains many glands that secrete mucus. At the lower end, the trachea divides into 2 main bronchi.

Walls bronchi are supported by cartilaginous rings and lined with ciliated epithelium. In the lungs, the bronchi branch to form the bronchial tree. The thinnest branches are called bronchioles, which end in convex sacs, the walls of which are formed by a large number of alveoli. The alveoli are braided with a dense network of capillaries of the pulmonary circulation. They exchange gases between the blood and the alveolar air.

Lungs - This is a paired organ that occupies almost the entire surface of the chest. The lungs are made up of the bronchial tree. Each lung has the shape of a truncated cone, with an expanded part adjacent to the diaphragm. The tops of the lungs extend beyond the collarbones into the neck area by 2-3 cm. The height of the lungs depends on sex and age and is approximately 21-30 cm in adults, and in children it corresponds to their height. Lung mass also has age differences. In newborns, approximately 50 g, junior schoolchildren- 400 g, in adults - 2 kg. The right lung is slightly larger than the left and consists of three lobes, in the left - 2 and there is a cardiac notch - the place where the heart fits.

Outside, the lungs are covered with a membrane - the pleura - which has 2 leaves - pulmonary and parietal. Between them is a closed cavity - pleural, with a small amount of pleural fluid, which facilitates the sliding of one sheet over another during breathing. There is no air in the pleural cavity. The pressure in it is negative - below atmospheric.

Breath. The structure and functions of the respiratory system

How does a person breathe?

The process of respiration in the body

Functions of the respiratory system

Respiratory organs: description