Age-related features of breathing in children. · Airways include the nasal cavity, nasopharynx, larynx, trachea, bronchi. Hygienic requirements for the air environment of educational institutions

Fetal breathing. Respiratory movements in the fetus occur long before birth. The stimulus for their occurrence is a decrease in the oxygen content in the blood of the fetus.

The breathing movements of the fetus consist of a slight expansion of the chest, which is followed by a longer decline, and then an even longer pause. When inhaling, the lungs do not expand, but only a slight negative pressure appears in the pleural fissure, which is absent at the time of collapse chest. Meaning breathing movements The fetus is that they help increase the speed of blood movement through the vessels and its flow to the heart. And this leads to improved blood supply to the fetus and oxygen supply to tissues. In addition, fetal breathing movements are considered a form of lung function training.

Breathing of a newborn. The occurrence of the first breath of a newborn is due to a number of reasons. After ligation of the umbilical cord in a newborn, the placental exchange of gases between the blood of the fetus and mother stops. This leads to an increase in carbon dioxide in the blood, which irritates cells respiratory center And causing rhythmic breathing.

The reason for the first breath of a newborn is a change in the conditions of his existence. The action of various environmental factors on all body surface receptors becomes the irritant that reflexively contributes to the occurrence of inhalation. A particularly powerful factor is irritation of skin receptors.

A newborn's first breath is especially difficult. When it is carried out, the elasticity of the lung tissue is overcome, which is increased due to the surface tension forces of the walls of the collapsed alveoli and bronchi. The formation in the alveoli contributes to the reduction of surface tension forces. surfactant. It is believed that to stretch the lungs, a certain change in the shape of the chest with age is necessary, matching the force of contraction respiratory muscles and compliance of lung tissue. If the muscles are weak, stretching of the lungs will not occur and breathing movements will not occur.

After the first 1 to 3 respiratory movements occur, the lungs are fully expanded and evenly filled with air. During the first inspiration, the air pressure in the lungs becomes equal to atmospheric pressure and the lungs stretch to such an extent that the layers of the visceral and parietal pleura are in contact with each other.

The chest grows faster than the lungs, so negative pressure arises in the pleural cavity, creating conditions for constant stretching of the lungs. Creating negative pressure in the pleural cavity and maintaining it at a constant level also depends on the properties of the pleural tissue. It has high absorption capacity. Therefore, gas introduced into the pleural cavity and reducing the negative pressure in it is quickly absorbed, and the negative pressure in it is restored again.

The mechanism of breathing in a newborn. The child's breathing patterns are related to the structure and development of his chest. In a newborn, the chest has a pyramidal shape; by the age of 3 it becomes cone-shaped, and by the age of 12 it becomes almost the same as that of an adult. The upper ribs, the manubrium of the sternum, the collarbone and the entire shoulder girdle of a newborn are located high. All ribs lie almost horizontally, the respiratory muscles are weak. Due to this structure, the chest takes little part in the act of breathing. This is accomplished mainly by lowering the diaphragm.

Newborns have an elastic diaphragm, its tendon part occupies a small area, and the muscle part occupies a large area. As it develops, the muscular part of the diaphragm increases even more. It begins to atrophy from the age of 60, and in its place the tendon part increases.

Since infants mostly diaphragmatic breathing, then during inhalation the resistance of the internal organs located in abdominal cavity. In addition, when breathing, you have to overcome the elasticity of the lung tissue, which is still high in newborns and decreases with age. One also has to overcome bronchial resistance, which is much greater in children than in adults. Therefore, the work spent on breathing is much greater in children compared to adults.

Changes in breathing type with age. Diaphragmatic breathing persists until the second half of the first year of life. As the child grows, the chest moves down and the ribs become oblique position. In this case, infants experience mixed breathing (thoracic-abdominal), and stronger mobility of the chest is observed in its lower parts. Due to the development of the shoulder girdle (3–7 years), chest breathing begins to predominate. From 8 to 10 years of age, gender differences in the type of breathing arise: in boys, a predominantly diaphragmatic type of breathing is established, and in girls, a thoracic type of breathing is established.

Changes in the rhythm and frequency of breathing with age. In newborns and infants, breathing is arrhythmic. Arrhythmicity is expressed in the fact that deep breathing is replaced by shallow breathing, the pauses between inhalations and exhalations are uneven. The duration of inhalation and exhalation in children is shorter than in adults: inhalation is 0.5 - 0.6 s (in adults - 0.98 - 2.82 s), and exhalation - 0.7 - 1 s (in adults - from 1.62 to 5.75 s). From the moment of birth, the same relationship between inhalation and exhalation is established as in adults: inhalation is shorter than exhalation.

The frequency of respiratory movements in children decreases with age. In the fetus it ranges from 46 to 64 per minute. Up to 8 years of age, the respiratory rate (RR) is higher in boys than in girls. By the time of puberty, the respiratory rate in girls becomes greater, and this ratio remains throughout life. By the age of 14–15 years, the respiratory rate approaches the value of an adult.

The respiratory rate in children is much greater than in adults and changes under the influence of various influences. It increases with mental arousal, slight physical exercise, and a slight increase in body and environmental temperature.

Changes in the respiratory and minute volumes of the lungs and their vital capacity with age. The vital capacity of the lungs, tidal and minute volumes in children gradually increase with age due to the growth and development of the chest and lungs.

In a newborn baby, the lungs are inelastic and relatively large. During inhalation, their volume increases slightly, by only 10–15 mm. Providing the child's body with oxygen occurs by increasing the breathing rate. Tidal volume of the lungs increases with age along with a decrease in respiratory rate.

With age absolute value MOR increases, but relative MOR (ratio of MOR to body weight) decreases. In newborns and children of the first year of life it is twice as much as in adults. This is due to the fact that in children, with the same relative tidal volume, the respiratory rate is several times higher than in adults. In this regard, pulmonary ventilation is greater per 1 kg of body weight in children (in newborns it is 400 ml, at 5–6 years of age it is 210, at 7 years of age – 160, at 8–10 years of age – 150, 11 – for 13-year-olds – 130–145, for 14-year-olds – 125, and for 15–17-year-olds – 110). Thanks to this, the growing organism's greater need for O 2 is ensured.

The value of vital capacity increases with age due to the growth of the chest and lungs. In a 5-6 year old child it is 710-800 ml, in a 14-16 year old child it is 2500-2600 ml. From 18 to 25 years old vital capacity lungs is maximum, and after 35–40 years it decreases. The vital capacity of the lungs varies depending on age, height, type of breathing, gender (girls have 100–200 ml less than boys).

In children with physical work breathing changes in a peculiar way. During exercise, the RR increases and the RR remains almost unchanged. Such breathing is uneconomical and cannot ensure long-term performance of work. Pulmonary ventilation in children increases by 2–7 times when performing physical work, and by almost 20 times during heavy loads (middle-distance running). When performing maximum work, girls have less oxygen consumption than boys, especially at 8 - 9 years old and at 16 - 18. All this should be taken into account when practicing physical labor and sports with children of all ages.

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Breathing is a complex continuous process of maintaining redox processes in the human body at an optimal level. In the breathing process, it is customary to distinguish three parts: pulmonary respiration, transport of gases by blood, tissue respiration.

Pulmonary respiration is the exchange of gases between the body and the surrounding atmospheric air. It is divided into two stages: gas exchange between atmospheric and alveolar air, gas exchange between alveolar air and blood.

Pulmonary respiration is carried out due to the activity of the apparatus external respiration which includes the respiratory tract (nasopharynx, trachea, large bronchi), lungs, pleura, respiratory muscles, chest skeleton, diaphragm. The main function of the pulmonary breathing apparatus is the delivery of oxygen from the surrounding air and the release of excess carbon dioxide. Transport of gases is carried out by blood. It is provided by the difference in the partial pressure of gases along their path.

Regulation of breathing is carried out by the central nervous system, the special areas of which determine automatic breathing - alternating inhalation and exhalation and arbitrary breathing, providing adaptive changes in the respiratory system corresponding to a specific external situation and activity. Group nerve cells responsible for the respiratory cycle is called respiratory center. The respiratory center is located in medulla oblongata, its destruction leads to respiratory arrest.

In children early age the ribs have a slight bend and occupy almost horizontal position. The upper ribs and the entire shoulder girdle are located high, the intercostal muscles are weak. Therefore, in newborns, diaphragmatic breathing predominates with little participation of the intercostal muscles. This type of breathing persists until the second half of the first year of life. As the intercostal muscles develop and the child grows, the chest moves down and the ribs take on an oblique position. The breathing of infants now becomes thoraco-abdominal with a predominance of diaphragmatic breathing.

Between the ages of 3 and 7 years due to development shoulder girdle The chest type of breathing begins to predominate, and by the age of 7 it becomes pronounced.

At the age of 7–8 years, gender differences in the type of breathing begin: in boys it becomes predominant. abdominal type breathing, in girls - chest. Sexual differentiation of breathing ends by the age of 14–17 years.

The unique structure of the chest and the low endurance of the respiratory muscles make breathing movements in children less deep and frequent.

The depth of breathing is characterized by the volume of air entering the lungs in one breath - breathing air. The newborn's breathing is frequent and shallow, and its frequency is subject to significant fluctuations. In children school age a further decrease in breathing occurs.

The high frequency of respiratory movements in a child ensures high pulmonary ventilation.

The vital capacity of the lungs changes with age and depends on gender, the degree of development of the chest, and respiratory muscles. As a rule, it is greater in men than in women; athletes have more than untrained people. By the age of 16–17 years, the vital capacity of the lungs reaches values characteristic of an adult.

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Respiratory system.

Age-related characteristics of the respiratory system.

Breathing is a process of constant exchange of gases between the body and the environment, necessary for life. Breathing ensures a constant supply of oxygen to the body, which is necessary for the implementation of oxidative processes, which are the main source of energy. Without access to oxygen, life can last for several minutes. During oxidative processes, it is formed carbon dioxide which must be removed from the body. Blood is the carrier of oxygen from the lungs to the tissues, and carbon dioxide from the tissues to the lungs.

The act of breathing consists of three processes:

1. External or pulmonary respiration is the exchange of gases between the body and the environment.

2. Internal or tissue respiration occurring in cells.

3.Transport of gases by blood, i.e. transfer of oxygen from the blood to the tissues and carbon dioxide from the tissues to the lungs.

The human respiratory system is divided into:

The airways include the nasal cavity, nasopharynx, larynx, trachea, and bronchi.

The respiratory part or lungs - consists of a parenchymal formation, which is divided into alveolar vesicles in which gas exchange occurs.

All links respiratory system undergo significant structural transformations with age, which determines breathing patterns child's body at different stages of development.

The airways and respiratory part begin with the nasal cavity. Air enters through the nostrils, the nasal cavity is divided into two halves, and at the back, with the help of the choanae, it communicates with the nasopharynx. The walls of the nasal cavity are formed by bones and cartilage, lined with mucous membrane. The mucous membrane of the nasal cavity is abundantly supplied blood vessels and is covered with stratified ciliated epithelium.

Passing through nasal cavity, the air is warmed, humidified and purified. In the nasal cavity there are olfactory bulbs, thanks to which a person perceives smell.

By the time of birth, the child’s nasal cavity is underdeveloped; it is distinguished by narrow nasal openings and the virtual absence of paranasal sinuses, the final formation of which occurs in adolescence. The volume of the nasal cavity increases 2.5 times with age. The structural features of the nasal cavity of young children make it difficult nasal breathing, children breathe frequently open mouth, which leads to susceptibility to colds. Adenoids may be a factor in this. A “stuffy” nose affects speech - nasal sound. Mouth breathing causes oxygen starvation, congestion in the chest and cranium, deformation of the chest, decreased hearing, frequent otitis media, bronchitis, abnormal (high) development of the hard palate, violation of the nasal septum and shape lower jaw. Connected to the nasal cavity are the airborne sinuses of the adjacent bones - the paranasal sinuses. IN paranasal sinuses nose can develop inflammatory processes: sinusitis - inflammation of the maxillary, maxillary paranasal sinus; Frontal sinusitis is inflammation of the frontal sinus.

From the nasal cavity, air enters the nasopharynx, and then into the oral and laryngeal parts of the pharynx.

The child's pharynx is shorter and wider, as well as low position auditory tube. The structural features of the nasopharynx lead to the fact that diseases of the upper respiratory tract in children are often complicated by inflammation of the middle ear. Disease of the tonsil glands located in the pharynx also seriously affects the health of children. Tonsillitis is inflammation of the tonsils. Adenoids are one of the types of diseases of the tonsil glands - an enlargement of the third tonsil.

The next link in the airways is the larynx. The larynx is located on the front surface of the neck, at the level of 4-6 cervical vertebrae, on both sides of it are the lobes of the thyroid gland, and behind it is the pharynx. The larynx is shaped like a funnel. Its skeleton is formed by paired and unpaired cartilage, connected by joints, ligaments and muscles. Unpaired cartilages - thyroid, epiglottis, cricoid. Paired cartilages – corniculate, arytenoid. The epiglottis covers the entrance to the larynx during swallowing. The inside of the larynx is covered with a mucous membrane with ciliated epithelium. The larynx serves to conduct air and at the same time is an organ of sound production, in which two vocal cords participate, these are mucous folds consisting of elastic connective fibers. The ligaments are stretched between the thyroid and arytenoid cartilages, and limit the glottis.

In children, the larynx is shorter, narrower and higher than in adults. The larynx grows most intensively in the 1-3 years of life and during puberty - in boys an Adam's apple is formed, the vocal cords lengthen, the larynx becomes wider and longer than in girls, and the voice breaks. The mucous membrane of the airways is more abundantly supplied with blood vessels, is tender and vulnerable, and contains fewer mucous glands that protect it from damage.

The trachea extends from the lower edge of the larynx. The trachea is about 12 cm long (its length increases in accordance with the growth of the body, maximum accelerated growth at 14-16 years), consists of cartilaginous half-rings. The posterior wall of the trachea is soft and adjacent to the esophagus. The inside is lined with a mucous membrane containing glands that secrete mucus. From the neck area, the trachea passes into the chest cavity and is divided into two bronchi, wider and shorter on the left, and narrower and longer on the right. The bronchi enter the lungs and there they divide into bronchi of smaller diameter - bronchioles, which are divided into even smaller ones, forming bronchial tree, which in turn forms the gates of the lungs. IN chest cavity There are two lungs, they have the shape of a cone. On the side of each lung facing the heart, there are depressions - the gates of the lung, through which the bronchus, lung nerve, blood and lymphatic vessels. The bronchus branches in each lung. The bronchi, like the trachea, contain cartilage in their walls. The smallest branches of the bronchi are bronchioles; they do not have cartilage, but are equipped with muscle fibers and are capable of narrowing.

The lungs are located in the chest. Every lung is covered serosa– pleura. The pleura consists of two sheets: the parietal sheet is adjacent to the chest, the intranosal sheet is fused with the lung. There is space between two sheets - pleural cavity, filled with serous fluid, which facilitates the sliding of the pleural sheets during respiratory movements. There is no air in the pleural cavity and the pressure there is negative. The pleural cavity does not communicate with each other.

The right lung consists of three, and the left of two lobes. Each section of the lung consists of segments: in the right - 11 segments, in the left - 10 segments. Each segment in turn consists of many pulmonary lobes. The structural unit is the acenus - the terminal part of the bronchiole with alveolar vesicles. The bronchioles turn into expansion - alveolar ducts, on the walls of which there are protrusions - alveoli. which are the final part of the respiratory tract. The walls of the pulmonary vesicles consist of a single layer squamous epithelium and capillaries are adjacent to them. Gas exchange occurs through the walls of the alveoli and capillaries: oxygen enters the blood from the alveoli, and carbon dioxide returns back. There are up to 350 million alveoli in the lungs, and their surface reaches 150 m2. Large surface alveoli promotes better gas exchange.

In children, the lungs grow due to an increase in the volume of the alveoli (in newborns, the diameter of the alveoli is 0.07 mm, in adults it reaches 0.2 mm). Increased lung growth occurs up to three years of age. The number of alveoli by the age of 8 reaches the number in an adult. At the age of 3 to 7 years, the growth rate of the lungs is reduced. The alveoli grow especially vigorously after the age of 12; by this age the volume of the lungs increases 10 times compared to a newborn, and by the end of puberty 20 times. Accordingly, gas exchange in the lungs changes, an increase in the total surface of the alveoli leads to an increase in the diffusion capabilities of the lungs.

The exchange of gases between atmospheric air and the air in the alveoli occurs due to the rhythmic alternation of the acts of inhalation and exhalation.

There is no muscle tissue in the lungs, they actively contract, they cannot. The respiratory muscles play an active role in the act of inhalation and exhalation. When they are paralyzed, breathing becomes impossible, although respiratory organs however, they are not affected.

Inhalation is carried out as follows: under the influence of nerve impulses from the chest and diaphragm, the intercostal muscles lift the ribs and move them slightly to the side, thereby increasing the volume of the chest. When the diaphragm contracts, its dome flattens, which also leads to an increase in the volume of the chest. At deep breathing Other muscles of the chest and neck also take part. The lungs are located in a hermetically sealed chest and move passively behind its moving walls, since they are attached to the chest with the help of the pleura. This is facilitated by negative pressure in the chest. When you inhale, the lungs stretch, the pressure in them drops and becomes below atmospheric pressure, and outside air rushes into the lungs. When you exhale, the muscles relax, the ribs drop, the volume of the chest decreases, the lungs contract, the pressure in them increases and air rushes out. The depth of inspiration depends on the expansion of the chest during inhalation. The condition of the lung tissue is very important for the act of breathing. which has elasticity i.e. lung tissue has a certain resistance to stretching.

As the musculoskeletal apparatus of the respiratory system matures, and the characteristics of its development in boys and girls determine age and gender differences in breathing types. In young children, the ribs have a slight bend and occupy an almost horizontal position. The upper ribs and shoulder girdle are located high, the intercostal muscles are weak. In this regard, newborns breathe diaphragmatically. As the intercostal muscles develop and the child grows, the chest drops down, the ribs take on an oblique position - the child’s breathing becomes thoraco-abdominal with a predominance of diaphragmatic breathing. At the age of 3 to 7 years, chest breathing predominates. And at the age of 7-8 years, gender differences in the type of breathing are revealed. In boys, the abdominal type predominates, and in girls, the thoracic type predominates. Sexual differentiation ends by the age of 14-17 years. The types of breathing in boys and girls can change depending on sports and work activity.

Age-related features of the structure of the chest and muscles determine the features of the depth and frequency of breathing in childhood. IN calm state an adult makes 16-20 breathing movements per minute, 500 ml is inhaled per breath. air. The volume of air characterizes the depth of breathing.

The newborn's breathing is rapid and shallow. In children of the first year of life, the respiratory rate is 50-60 respiratory movements per minute, 1-2 years 30-40 respiratory movements per minute, 2-4 years 25-35 respiratory movements per minute, 4-6 years 23-26 respiratory movements per minute. In school-age children, there is a further decrease in the breathing rate, 18-20 respiratory movements per minute. The high frequency of respiratory movements in a child ensures high ventilation of the lungs. The volume of exhaled air in a child at 1 month of life is 30 ml, at 1 year - 70 ml, at 6 years - 156 ml, at 10 years - 240 ml, at 14 years - 300 ml. Minute breathing volume - This is the amount of air that a person exhales in 1 minute; the more often the breath, the higher the minute volume.

An important characteristic of the functioning of the respiratory system is the vital capacity of the lungs (VC) - greatest number air that a person can exhale after taking a deep breath. Vital capacity changes with age and depends on body length, the degree of development of the chest and respiratory muscles, and gender. At calm breathing In one breath, about 500 cm 3 of air enters the lungs - respiratory air. With maximum inhalation after a quiet exhalation, an average of 1500 cm 3 of air enters the lungs more than with a quiet inhalation - additional volume. With maximum exhalation after a normal inhalation, 1500 cm 3 more air can come out of the lungs than during a normal exhalation - the reserve volume. All these three types of volume - respiratory, additional, reserve - together make up vital capacity: 500 cm 3 +1500 cm 3 +1500 cm 3 = 3500 cm 3. After exhalation, even the deepest, about 100 cm 3 of air remains in the lungs - residual air, it remains even in the lungs of a corpse, a breathing child or an adult. Air enters the lungs with the first breath after birth. Vital vital capacity is determined using a special device - a spirometer. Typically, vital capacity is greater in men than in women. Trained people have a higher vital capacity than untrained people. A child's vital capacity can be determined with his conscious participation only after 4-5 years.

Regulation of breathing is carried out by the central nervous system, special areas of which determine automatic breathing - alternating inhalation and exhalation and voluntary breathing, providing adaptive changes in the respiratory system that correspond to the situation and type of activity. The activity of the respiratory center is regulated reflexively, by impulses coming from various receptors and humorally.

The respiratory center is a group of nerve cells that are located in the medulla oblongata; its destruction leads to respiratory arrest. In the respiratory center there are two sections: the inhalation section and the exhalation section, the functions of which are interconnected. When the inhalation department is excited, the exhalation department is inhibited and vice versa.

Special clusters of nerve cells in the pons and diencephalon are involved in the regulation of breathing. IN spinal cord there is a group of cells whose processes go into the spinal nerves to the respiratory muscles. In the respiratory center, excitation alternates with inhibition. When you inhale, the lungs expand and their walls stretch, which irritates the endings of the vagus nerve. Excitation is transmitted to the respiratory center and inhibits its activity. The muscles stop receiving stimulation from the respiratory center and relax, the chest drops, its volume decreases, and exhalation occurs. When relaxed, the centripetal fibers vagus nerve cease to be excited, and the respiratory center does not receive inhibitory impulses; it becomes excited again - another inhalation occurs. In this way, self-regulation occurs: inhalation causes exhalation, and exhalation causes inhalation.

The activity of the respiratory center is also regulated humorally, changing depending on the chemical composition of the blood. The reason for changes in the activity of the respiratory center is the concentration of carbon dioxide in the blood. It is a specific respiratory stimulant: an increase in the concentration of carbon dioxide in the blood leads to stimulation of the respiratory center - breathing becomes frequent and deep. This continues until the level of carbon dioxide in the blood decreases to normal. The respiratory center responds to a decrease in the concentration of carbon dioxide in the blood by decreasing excitability until it completely stops its activity for some time. The leading physiological mechanism affecting the respiratory center is reflex, followed by humoral. Breathing is subordinate to the cerebral cortex, as evidenced by the fact of voluntary holding of breath or changes in the frequency and depth of breathing, increased breathing during emotional states of a person.

Description of work

Breathing is a process of constant exchange of gases between the body and environment. Breathing ensures a constant supply of oxygen to the body, which is necessary for the implementation of oxidative processes, which are the main source of energy. Without access to oxygen, life can last for several minutes.

In this part we're talking about about the morphological development of the respiratory organs: about the antenatal development of the respiratory organs, about the postnatal development of the respiratory organs, about the nasopharynx, about the larynx, about the trachea, bronchi, lungs and pleura.

Morphological development of the respiratory organs.

Antenatal development of the respiratory system.

During the process of embryonic development, the respiratory organs are formed simultaneously with the digestive tube in the third week of the embryo’s life.

The development of the upper respiratory tract begins with the fact that the nasal openings, formed at the anterior end of the body of the embryo, open into the primary oral cavity. The nasal cavity develops from the upper part of the mouth by division by the palatine processes, from which the hard and soft palates are subsequently formed.

The respiratory organs are formed from an unpaired sac-like protrusion of the ventral part of the intestine, from which they are subsequently separated. From the upper part of this unpaired protrusion the larynx and trachea are subsequently formed, and its Bottom part divided by midline into two sacs from which the right and left lungs are formed.

The respiratory organs remain connected to the digestive apparatus only in the upper part in the pharynx area.

The lungs develop as a complex gland, in which the alveoli are secreting structures, and the bronchi are excretory ducts.

On early stages development, all respiratory organs (larynx, trachea, bronchi and pulmonary sacs) are formed only from endoderm cells. Later, mesenchymal cells penetrate into these formations. Mesenchyme forms the cartilage and muscles of the larynx, tracheal cartilage, cartilaginous plastics and smooth muscles of the bronchi, as well as the connective tissue base of the lungs, layers connective tissue, growing between the lobules of the lung, vascular system lungs.

Bronchi and bronchioles are formed from the pulmonary sacs at the end of the 4th and beginning of the 5th month of the intrauterine period of development. From the 6th month until birth, alveolar ducts develop in the lungs and alveoli appear. Throughout the entire period intrauterine development alveoli are collapsed vesicles with a thick wall. At the 6th month of fetal development, the outer and inner layers of the pleura are formed.

The lungs expand during the newborn's first breath, during which the alveoli expand, their cavities increase sharply and the thickness of the alveolar walls decreases.

Postnatal development of the respiratory organs.

The nasal cavity in newborns is very small. Its height is 17.5 mm with a length ethmoid bone 10.5 mm and upper jaw 7 mm. Nasal septum, dividing the nose into right and left parts, is very low. The nasal turbinates, extending from the outer side walls of the nasal cavity and dividing the nasal cavity into a series of slits (four nasal passages), are very thick. As a result, the nasal passages are narrow. The lower nasal passage is formed by 6 months and continues to grow until 13 years of age, and then changes little throughout life. A significant increase in the middle nasal meatus begins at age 2 and continues until age 20.

In newborns, the accessory nasal cavities are poorly developed: the frontal and sphenoid sinus are small protrusions of the mucous membrane. By the age of 14, they reach the size and shape of an adult’s sinuses. More developed than others maxillary cavity. The cells of the ethmoid bone in newborns are in their infancy. They grow most strongly in the first year. First they have round shape, by the age of 3 they become larger, by the age of 7 they lose their rounded outlines and their number increases, by the age of 14 they reach the size of the cells of an adult.

The lacrimal canal in a newborn is well defined, but very short, its outlet lies relatively close to the bottom of the nasal cavity. The mucous membrane of the nasal cavity is very delicate and richly supplied with blood vessels, and the lumen of the vessels is wider than in adults. This provides better air warming.

After birth, the outer cartilaginous part of the nose grows strongly, the size and shape of the nose changes (especially in the first 5 years of life), and the nasal cavity changes along with it.

Nasopharynx.

The nasopharynx in a newborn is low and does not form a semicircular arch, as in an adult. The width of the nasopharynx is relatively large. Choanae connecting the nasal cavity with the oral cavity, round or triangular shape. During the first year of life they grow very quickly, by the age of two their height doubles and their shape becomes oval.

The lower part of the nasopharynx (pharynx) in children is relatively large, wide and short Eustachian tube located low.

Diseases of the upper respiratory tract in children are often complicated by inflammation of the middle ear. This is due to the fact that the infection easily penetrates into the middle ear through the wide and short Eustachian tube.

Larynx.

The larynx in newborns is located higher than in adults. As a result, the child can breathe and swallow at the same time. The larynx at an early age has the shape of a funnel, with a frontal diameter larger than the sagittal one. With age, it takes on a cylindrical shape. The larynx and vocal target are narrow in newborns. Its length is relatively large: 1.53 cm, i.e. 1/32 body length. The larynx grows unevenly in different years. Up to 3 years of age it grows quickly, and at this time it is the same for boys and girls. From 3 to 12 years, its growth is insignificant, but the shape of the cartilage, its density, the structure of the mucous membrane, etc. change greatly.

The epiglottis in newborns is located close to the tongue, it is small, its edges are curved inward so that it looks like a groove. It is wide and short - width 1 cm, length 0.5 cm. The size of the epiglottis doubles by 16 years. The epiglottis gradually flattens and by the age of 10 in boys it acquires the same shape as in an adult. In women, this process ends by age 20.

The true vocal cords are attached at one-year-old children anteriorly to the thyroid cartilage higher than in adults. In young children they are shorter absolutely and in relation to the glottis than at a later time. Quite quickly, boys' vocal cords are longer (1.65 cm) than girls' (1.5 cm). Length vocal cords in a newborn 0.42-0.45 cm.

Sex differences in the development of the larynx up to 2 years of age were not found. After 2-3 years of age, the larynx in girls is stunted. This is even more pronounced at 10-15 years of age. Girls have a shorter and smaller larynx than boys. In boys, the anteroposterior diameter of the larynx increases from 3-5 years and becomes larger than in girls. This pattern persists in adults. Sex differences in the larynx are most noticeable in the thyroid cartilage and vocal cords.

The trachea in newborns and children in the first months of life has an ellipsoidal lumen, which gradually becomes round by the age of 15-20, and its circumference increases.

In newborns, like in the fetus, the trachea is located higher than in an adult. The growth of the trachea is carried out in accordance with the growth of the body. The trachea grows especially rapidly in the first 6 months of life and during puberty - 14-16 years. The length of the trachea by the age of 10 increases by 2 times, by the age of 25 - by 3 times.

In newborns and infants, the cartilaginous part of the tracheal rings is relatively small, and the connective tissue back wall, on the contrary, is great. The cartilage tissue of the trachea is elastic and soft, as a result of which it is easily compressed. In children, the trachea easily narrows and expands. From the age of 25, narrowing and expansion of the trachea becomes difficult, and from the age of 60 it becomes impossible.

The mucous membrane of the trachea, like the nasopharynx, is tender and rich in blood vessels, but relatively dry due to the insufficient development of the mucous glands.

Bronchi.

The bronchi in children are narrow, their cartilage tissue is soft, muscle and elastic fibers are poorly developed, the mucous membrane contains few mucous glands and is richly supplied with blood vessels. The growth of the bronchi is most vigorous in the first year of life and during puberty. The right bronchus is like a continuation of the trachea, and the left one departs from the trachea at a large angle. The left bronchus in newborns and young children is always longer and narrower than the right. In adolescents, due to the increased growth of the bronchi in length, their cartilaginous walls decrease and the development of muscle and elastic tissue increases. The bronchi of children contain much less cartilage tissue compared to adults.

Lungs.

The human lungs are divided into lobes (the right has three lobes, and the left has two). This division is expressed from the second month of fetal development.

The lungs of a newborn are relatively large: the weight of the lungs in children is related to body weight as 1: 43 or 1: 59. The lungs grow continuously until 16 years of age, but there are periods of strongest growth: at 3 months and from 13 to 16 years.

With age, the weight of the lungs changes: in a newborn - 50 g, in one year old child- 150 g, for a 12-year-old - 500 g, and for an adult - 1 kg. The relative weight of the lungs decreases throughout age periods. Lung volume increases significantly in the first year of life. In a 2-3 week old baby, the lungs occupy 2/3 of the volume of the chest. The growth of the lungs is carried out due to the branching of small bronchi, the formation of alveoli and an increase in their volume: in newborns, the size of the alveoli is 2 times smaller than in children 12 years old, and 3 times smaller than in adults. The process of lung differentiation ends by age 7.

In an adult, the alveolus is a ball with a surface of 0.126 mm and an internal volume of 4.14 ml. In the fetus, the alveoli in the collapsed lungs are roundish or oval shape, in a child’s lungs, filled with air, they have a multifaceted shape due to the pressure exerted on them.

During the development of the pulmonary alveolar epithelium at the time of birth, the fetus produces surfactant, a substance that stabilizes the surface tension of the lungs. It is produced by large cells of the alveolar epithelium - granular pneumocytes. If surfactant is not formed, the newborn's lungs will not expand.

Different parts of the lungs develop differently. In a newborn, the upper and middle lobes of the right lung are almost the same size, the lower one is larger than them. Up to 3 months, the upper lobe develops more slowly than the others, then - at the same rate as them. By the second year of a child’s life, the separate lobes of the right and left lungs acquire the same dimensions in relation to each other as in adults. Lung mass changes unevenly: from birth to 3 months of life right lung heavier than the left one. Accordingly, the volume of the right lung is larger. By the age of one year, the child’s lung volume is 250-280 ml. By the age of 16, it increases 20 times compared to the lung volume of a newborn.

Pleura.

The pleura of a newborn child contains many cellular elements and few elastic and connective tissue fibers up to 2-2.5 years. The structure of a child’s pleura approaches that of an adult by the age of 7 years.

AGE FEATURES OF THE RESPIRATORY ORGANS.

The concept of breathing and its meaning.

The concept of breathing includes the following processes :

external breathing - exchange of gases between external environment and lungs - pulmonary ventilation;

exchange of gases in the lungs between alveolar air and blood capillaries pulmonary respiration ;

transport of gases by blood - transfer of oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs;

exchange of gases in tissues - internal or tissue respiration - biological processes occurring in cell mitochondria.

11.2 Structure and functions of the respiratory organs.

All parts of the respiratory system are presented in Fig. 21. With age, they undergo significant structural transformations, which determine the breathing characteristics of the child’s body. different stages development.

Rice. 21. Airways of the human respiratory system.

1, 2, 3 - nasal turbinates; 4 - oral cavity; 5 - tongue; 6 - hard palate; 7-soft palate; 8 - nasopharynx; 9 - epiglottis; 10 - larynx; 11- esophagus.

The airways and respiratory tract begin nasal cavity. The mucous membrane of the nasal cavity is abundantly supplied with blood vessels and covered with stratified ciliated epithelium. The epithelium contains many glands that secrete mucus, which, together with dust particles penetrated with inhaled air, is removed by the flickering movements of the cilia. In the nasal cavity, the inhaled air is warmed, partially cleared of dust and moistened.

From the nasal cavity, air enters the nasopharynx - the upper part throats. The nasal cavity, larynx and auditory tubes connecting the pharyngeal cavity with the middle ear. The child's pharynx is shorter, wider and has a lower location of the auditory tube. The structural features of the nasopharynx lead to the fact that diseases of the upper respiratory tract in children are often complicated by inflammation of the middle ear, since the infection easily penetrates the ear through the wide and short auditory tube.

The next link of the airways is larynx. The skeleton of the larynx is formed by cartilage, connected by joints, ligaments and muscles.

The laryngeal cavity is covered with a mucous membrane, which forms two pairs of folds that close the entrance to the larynx during swallowing. The lower pair of folds cover the vocal cords. The space between the vocal cords is called glottis. Thus, the larynx not only connects the pharynx with the trachea, but also participates in speech function. The larynx in children is shorter, narrower and located higher than in adults. The larynx grows most intensively in the 1st-3rd years of life and during puberty. During puberty, gender differences appear in the structure of the larynx. In boys, an Adam's apple forms, the vocal cords lengthen, the larynx becomes wider and longer than in girls, and the voice breaks.

Extends from the lower edge of the larynx trachea. Its length increases in accordance with the growth of the body, the maximum acceleration of tracheal growth is noted at the age of 14 - 16 years. The circumference of the trachea increases according to the increase in the volume of the chest. The trachea branches into two bronchi, the right one of which is shorter and wider. The greatest growth of the bronchi occurs in the first year of life and during puberty.

The mucous membrane of the airways in children is more abundantly supplied with blood vessels, is tender and vulnerable, it contains fewer mucous glands that protect it from damage. These features of the mucous membrane lining the airways in childhood, combined with a narrower lumen of the larynx and trachea, make children susceptible to inflammatory diseases of the respiratory system.

Lungs. With age, the structure of the main respiratory organ - the lungs - changes significantly. The primary bronchus, having entered the gates of the lungs, is divided into smaller bronchi, which form the bronchial tree. Its thinnest branches are called bronchioles. Thin bronchioles enter the pulmonary lobules and within them are divided into terminal bronchioles.

The bronchioles branch into alveolar ducts with sacs, the walls of which are formed by many pulmonary vesicles - alveoli. Alveoli are the terminal part respiratory tract(Fig. 22). The walls of the pulmonary vesicles consist of a single layer of squamous epithelial cells. Each alveolus is surrounded on the outside by a dense network of capillaries. Gases are exchanged through the walls of the alveoli - oxygen passes from the air into the blood, and carbon dioxide and water vapor enter the alveoli from the blood.

Each lung is covered by a serous membrane called the pleura. The pleura has two layers. One is tightly fused to the lung, and the other is attached to the chest. Between the sheets there is a small pleural cavity filled with serous fluid (about 1-2 ml), which facilitates the sliding of the pleural sheets during respiratory movements.

Up to 3 years of age, increased growth of the lungs and differentiation of their individual elements occurs; by 8 years of age, the number of alveoli reaches the number in an adult. During puberty there is active growth lungs, mainly due to an increase in the total surface of the alveoli.

Rice. 22. Scheme of the structure of the lungs (A) and pulmonary alveoli (B)

A: - larynx; 2 - trachea; 3 - bronchi; 4 - bronchioles; 5 - light;

B: 1 - vascular network; 2, 3 - alveoli from the outside and in section; 4 - bronchiole; 5 - artery and vein.