Age-related features of the respiratory system briefly. Age-related features of a child’s breathing. All parts of the respiratory system undergo significant structural transformations with age, which determines the breathing characteristics of the child’s body at different stages.
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- The meaning of breathing
- Breathing movements
- Conclusion
- Literature
The meaning of breathing
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.
Oxygen from the external environment enters the lungs. There, as is already known, the transformation takes place venous blood into the arterial Arterial blood flowing through capillaries great circle blood circulation, gives oxygen through tissue fluid to cells that are washed by it, and carbon dioxide secreted by cells enters the blood. The release of carbon dioxide by the blood into the atmospheric air also occurs in the lungs.
It is clear that stopping the supply of oxygen to cells at least for a very long time a short time leads to their death. That is why the constant supply of this gas from the environment - necessary condition life of the organism.
The importance of breathing for a person is enormous. In fact, a person can live without food for several weeks, without water for several days, and without oxygen for only 5 minutes.
The act of breathing consists of three processes:
1. External or pulmonary respiration - 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.
breathing alveoli respiratory organ
Structure and functions of the respiratory organs and their age-related characteristics
The human respiratory system is divided into:
· Airways include the nasal cavity, nasopharynx, larynx, trachea, bronchi.
· Respiratory part or lungs - consists of a parenchymal formation, which is divided into alveolar vesicles in which gas exchange occurs.
All parts of the respiratory system undergo significant structural transformations with age, which determines the characteristics of breathing child's body on different stages 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 the nasal cavity, the air is warmed, moistened and purified. In the nasal cavity there are olfactory bulbs, thanks to which a person perceives smell.
By the time of birth, the baby’s nasal cavity is underdeveloped; it is characterized by narrow nasal openings and virtually no paranasal sinuses, the final formation of which occurs in adolescence. The volume of the nasal cavity increases 2.5 times with age. Structural features of the nasal cavity of children early age 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 chest, decreased hearing, frequent otitis media, bronchitis, abnormal (high) development of the hard palate, violation of the nasal septum and the shape of the lower jaw. Connected to the nasal cavity are the airborne sinuses of the adjacent bones - the paranasal sinuses. Inflammatory processes can develop in the paranasal sinuses: sinusitis - inflammation of the maxillary, maxillary paranasal sinus; frontal sinusitis - 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 old), consists of cartilaginous half-rings. Back wall 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. There are two lungs in the chest cavity; 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 a space between the two sheets - the pleural cavity, filled serous fluid, which facilitates the sliding of pleural sheets during breathing movements. There is no air in the pleural cavity and the pressure there is negative. The pleural cavity does not communicate with each other.
Right lung consists of three, and the left one 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 single-layer squamous epithelium and are adjacent to capillaries. 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.
Breathing movements
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. Active Role in the act of inhalation and exhalation belongs to the respiratory muscles. When they are paralyzed, breathing becomes impossible, although the respiratory organs are not affected.
Inhalation is carried out as follows: under the influence nerve impulses The chest and diaphragm 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. When breathing deeply, other muscles of the chest and neck are also involved. 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. Condition is very important for the act of breathing lung tissue, which has elasticity i.e. Lung tissue has a certain resistance to stretching.
Types breathing. 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. Upper ribs and shoulder girdle located high, the intercostal muscles are weak. In this regard, newborns breathe diaphragmatically. As the intercostal muscles develop and the child grows, the chest moves down and the ribs take on 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 characteristics The structure of the chest and muscles determines the characteristics of the depth and frequency of breathing in childhood. At rest, an adult does 16-20 breathing movements per minute, 500 ml is inhaled in one 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 children school age 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 is the amount of air that a person exhales in 1 minute; the more often the breathing, the higher the minute volume.
Life capacity lungs. 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.
Respiratory center. 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. IN spinal cord there is a group of cells whose processes go into the composition spinal nerves to the respiratory muscles. In the respiratory center, excitation alternates with inhibition. When you inhale, the lungs expand, their walls stretch, which irritates the endings 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 of the vagus nerve cease to be excited, and the respiratory center does not receive inhibitory impulses; it is excited again - the next inhalation occurs. Thus, a kind of 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. Leading physiological mechanism, affecting the respiratory center is reflex, followed by humoral. Breathing is subordinated to the cerebral cortex, as evidenced by the fact of voluntary holding of breath or a change in the frequency and depth of breathing, increased breathing when emotional states person. Excitation of the respiratory center can also cause a decrease in oxygen levels in the blood. Defensive acts such as coughing and sneezing are also associated with breathing; they are carried out reflexively. A cough occurs in response to irritation of the mucous membrane of the larynx, pharynx or bronchi. And sneezing is due to irritation of the nasal mucosa. Gas exchange increases sharply during physical activity, since during work the metabolism in the muscles increases, which means oxygen consumption and carbon dioxide release. Features of breathing regulation in childhood. By the time a child is born, his respiratory center is able to ensure a rhythmic change in the phases of the respiratory cycle (inhalation and exhalation), but not as perfectly as in older children. This is due to the fact that at the time of birth the functional formation of the respiratory center has not yet completed. This is evidenced by the great variability in the frequency, depth, and rhythm of breathing in young children. The excitability of the respiratory center in newborns and infants is low. Formation functional activity respiratory center occurs with age. By the age of 11, the ability to adapt breathing to different conditions life activity. It should be noted that during puberty, temporary disturbances in the regulation of breathing occur, and the body of adolescents is less resistant to oxygen deficiency than the body of an adult.
As the cerebral cortex matures, the ability to voluntarily change breathing improves - to suppress respiratory movements or produce maximum ventilation of the lungs. Children cannot significantly change the depth of breathing during physical activity, but rather increase their breathing speed. Breathing becomes even more frequent and shallow. This results in lower ventilation efficiency, especially in young children.
Hygienic requirements for the air environment of educational institutions
The hygienic properties of the air environment are determined not only by its chemical composition, but also by its physical state: temperature, humidity, pressure, mobility, atmospheric electric field voltage, solar radiation, etc. For normal human life, the constancy of body temperature and the environment is of great importance, which has influence on the equilibrium of heat generation and heat transfer processes. High ambient temperatures make it difficult to transfer heat, which leads to an increase in body temperature. At the same time, the pulse and breathing increase, fatigue increases, and performance decreases. A person’s presence in conditions of high relative humidity also complicates heat transfer and increases sweating. At low temperatures, there is a large loss of heat, which can lead to hypothermia. With high air humidity and low temperatures, the risk of hypothermia and colds increases significantly. In addition, heat loss by the body depends on the speed of air movement and the body itself (riding an open car, bicycle, etc.). Electrical and magnetic field atmospheres also affect humans. For example, negative air particles have a positive effect on the body (relieve fatigue, increase performance), while positive ions, on the contrary, depress breathing, etc. Negative air ions are more mobile and are called light, while positive ions are less mobile and are called heavy. In clean air, light ions predominate, and as it becomes polluted, they settle on dust particles and water droplets, turning into heavy ones. Therefore, the air becomes warm, stuffy and stuffy. The air contains impurities of various origins: dust, smoke, various gases. All this negatively affects the health of people, animals and plant life. In addition to dust, the air also contains microorganisms - bacteria, spores, molds, etc. There are especially many of them in indoors.
Microclimate of school premises. Microclimate is the totality of physicochemical and biological properties of the air environment. For a school, this environment consists of its premises, for a city - its territory, etc. Hygienically normal air At school - important condition student performance and performance. When 35-40 students stay in a classroom or office for a long time, the air ceases to meet hygienic requirements. Change it chemical composition, physical properties and bacterial contamination. All these indicators increase sharply towards the end of the lessons.
An indirect indicator of indoor air pollution is the carbon dioxide content. The maximum permissible concentration (MPC) of carbon dioxide in school premises is 0.1%, but at a lower concentration (0.08%) in children younger ages there is a decrease in the level of attention and concentration.
The most favorable conditions in the classroom are a temperature of 16-18°C and a relative humidity of 30-60%. With these standards, students’ working capacity and well-being are maintained for the longest time. In this case, the difference in air temperature vertically and horizontally should not exceed 2-3°C, and the air speed should not exceed 0.1-0.2 m/s.
In the gym, recreational areas, and workshops, the air temperature should be maintained at 14-15°C. The calculated norms of air volume per student in a class (the so-called air cube) usually do not exceed 4.5-6 cubic meters. m. But to ensure that the concentration of carbon dioxide in the classroom air during the lesson does not exceed 0.1%, a 10-12 year old child needs about 16 cubic meters. m of air. At the age of 14-16 years, the need for it increases to 25-26 cubic meters. m. This value is called the volume of ventilation: the older the student, the greater it is. To ensure the specified volume, a three-fold change of air is required, which is achieved by ventilation (ventilation) of the room.
Natural ventilation. The flow of outside air into the room due to the difference in temperature and pressure through pores and cracks in the building material or through specially made openings is called natural ventilation. To ventilate classrooms of this type, windows and transoms are used. The latter have an advantage over vents, since the outside air first flows upward through the open transom, to the ceiling, where it warms up and descends warmly. At the same time, people in the room do not become hypothermic and feel an influx of fresh air. Transoms can be left open during classes, even in winter.
The area of open windows or transoms should not be less than 1/50 of the classroom floor area - this is the so-called ventilation coefficient. Airing of classrooms should be carried out regularly, after each lesson. The most effective is through ventilation, when during recess the vents (or windows) and classroom doors are opened simultaneously. Through ventilation allows you to reduce the CO2 concentration to normal in 5 minutes, reduce humidity, the number of microorganisms and improve the ionic composition of the air. However, with such ventilation there should be no children in the room. Special attention attention is paid to ventilation of offices, chemical, physical and biological laboratories, where toxic gases and vapors may remain after experiments.
Artificial ventilation. This is supply, exhaust and supply and exhaust (mixed) ventilation with natural or mechanical impulse. Such ventilation is most often installed where it is necessary to remove exhaust air and gases generated during experiments. It is called forced ventilation, since the air is exhausted outside using special exhaust ducts that have several holes under the ceiling of the room. Air from the premises is directed to the attic and through pipes removed outside, where to enhance the air flow in the exhaust ducts, thermal stimulators of air movement - deflectors or electric fans - are installed. The installation of this type of ventilation is provided during the construction of buildings. Exhaust ventilation should work especially well in restrooms, wardrobes, and the cafeteria, so that the air and odors of these rooms do not penetrate into classrooms and other main and service areas.
Conclusion
· Breathing is one of the basic processes of functioning and vital activity of the human body; without breathing, life can last only a few minutes.
· The breathing process is a complex system of gas exchange between the body and the environment and includes mechanisms for partial processing of inhaled gases by the human respiratory system.
· The human respiratory organs change during a person’s growing up and life, as well as under the influence of external factors.
Literature
1. A.G. Khripkova, M.V. Antropova, D.A. Farber "Age physiology and school hygiene" Enlightenment 1990
2. Yu.A. Ermolaev "Age physiology" Enlightenment 1976
3. N.N. Leontyeva, K.V. Marinova, E.G. Kaplun "Anatomy and physiology of the child's body" Higher school 1985
4. N.V. Poltavtseva, N.A. Gordova" Physical Culture in preschool childhood"
5. E.A. Vorobyova, A.V. Gubar, E.B. Safyannikov "Anatomy and Physiology" Medicine 1975
6. http://med-tutorial.ru/med-books/book/59/
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Breathing is a complex continuous process of maintaining redox processes in the human body at an optimal level. In the process of breathing, it is customary to distinguish three parts: pulmonary respiration, gas transport 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. The group of nerve cells responsible for the respiratory cycle is called respiratory center. The respiratory center is located in the medulla oblongata, its destruction leads to respiratory arrest.
In young children, the ribs have a slight bend and occupy an almost horizontal position. The upper ribs and the entire shoulder girdle are located high, the intercostal muscles are weak. Therefore, in newborns it predominates diaphragmatic breathing with minor involvement 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.
At the age of 3 to 7 years, due to the development of the 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, the abdominal type of breathing becomes predominant, in girls - thoracic. 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 - respiratory air. The newborn's breathing is frequent and shallow, and its frequency is subject to significant fluctuations. In school-age children, breathing decreases further.
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.
The main vital function of the respiratory organs is to provide tissues with oxygen and remove carbon dioxide.
The respiratory organs consist of air-conducting (respiratory) tracts and paired respiratory organs - the lungs. The respiratory tract is divided into upper (from the opening of the nose to the vocal cords) and lower (larynx, trachea, lobar and segmental bronchi, including intrapulmonary branches of the bronchi).
By the time of birth, the respiratory organs of children not only have an absolutely smaller size, but, in addition, they also differ in some incomplete anatomical and histological structure, which is also associated with the functional features of breathing.
Intensive growth and differentiation of the respiratory organs continues during the first months and years of life. The formation of the respiratory organs ends on average by the age of 7 years and subsequently only their sizes increase (Fig. 1).
Fig.1. The structure of the respiratory organs in children
Features of the morphological structure of OD in children of the first years of life:
1) thin, tender, easily wounded dry mucous membrane with insufficient development of glands, reduced production secretory immunoglobulin A (SIg A) and surfactant deficiency;
2) rich vascularization of the submucosal layer, represented mainly by loose fiber and containing few elastic and connective tissue elements;
3) softness and pliability of the cartilaginous frame of the lower respiratory tract, the absence of elastic tissue in them and the lungs.
These features reduce the barrier function of the mucous membrane, contribute to more easy penetration infectious agent into the bloodstream, and also create the preconditions for narrowing of the respiratory tract due to rapidly occurring swelling or compression of the pliable respiratory tubes from the outside (the thymus gland, abnormally located vessels, enlarged tracheobronchial lymph nodes).
Nose and nasopharyngeal the space in young children is small, the nasal cavity is low and narrow due to insufficient development of the facial skeleton. The shells are thick, the nasal passages are narrow, the lower one is formed only by 4 years. The mucous membrane is delicate and rich in blood vessels. Even slight hyperemia and swelling of the mucous membrane during a runny nose makes the nasal passages obstructed, causes shortness of breath, and makes breastfeeding difficult. The submucosa in the first years of life is poor in cavernous tissue, which develops by 8-9 years, so nosebleeds in young children are rare and caused by pathological conditions. During puberty they are observed more often.
Accessory nasal cavities in young children they are very poorly developed or even completely absent.
By the birth of the child, only the maxillary (maxillary) sinuses are formed; The frontal and ethmoid are open protrusions of the mucous membrane, taking shape in the form of cavities only after 2 years; the main sinus is absent. All paranasal sinuses develop completely by the age of 12-15, however, sinusitis can also develop in children in the first two years of life.
Nasolacrimal duct short, its valves are underdeveloped, the outlet is located close to the corner of the eyelids, which facilitates the spread of infection from the nose to the conjunctival sac.
Pharynx in children it is located higher, has a shorter length than in adults, is relatively narrow and has a more vertical direction, the mucous membrane is relatively dry and well supplied with blood. The auditory tube connecting the pharyngeal cavity with the middle ear in young children is wide and short, located low, which often leads to complications of diseases of the upper respiratory tract manifested by inflammation of the middle ear
The palatine tonsils are clearly visible at birth, but do not protrude due to well-developed arches. Their crypts and vessels are poorly developed, which to some extent explains rare diseases sore throat in the first year of life. By the end of 4-5 years of life, the lymphoid tissue of the tonsils, including the nasopharyngeal (adenoids), often hyperplasias, especially in children with exudative and lymphatic diathesis. Their barrier function at this age is low, like that of lymph nodes.
IN puberty The pharyngeal and nasopharyngeal tonsils begin to undergo reverse development, and after puberty it is relatively rare to see their hypertrophy.
With hyperplasia of the tonsils and the colonization of them with viruses and microbes, sore throats can be observed, which subsequently lead to chronic tonsillitis. With the growth of adenoids and the penetration of viruses and microorganisms, nasal breathing disorders, sleep disturbances, and adenoiditis may develop. In this way, foci of infection are formed in the child’s body.
Larynx in very young children has, funnel-shaped, with a distinct narrowing in the area of the subglottic space, limited by the rigid cricoid cartilage. The diameter of the larynx in this place in a newborn is only 4 mm and increases slowly (6-7 mm at 5-7 years, 1 cm by 14 years), its expansion is impossible. Narrow lumen, abundance of vessels and nerve receptors in the subglottic space, easily occurring swelling of the submucosal layer can cause severe breathing problems even with minor manifestations respiratory infection(croup syndrome).
The larynx in children is shorter, narrower and located higher than in adults, it is mobile, the mucous membrane is relatively dry and well supplied with blood, its lower end in newborns is at level IV cervical vertebra(in adults 1-1 1/2 vertebrae lower ).
The most vigorous growth of the transverse and anteroposterior dimensions of the larynx is observed in the 1st year of life and at the age of 14-16 years; With age, the funnel-shaped shape of the larynx gradually approaches cylindrical. The larynx in young children is relatively longer than in adults.
The cartilage of the larynx in children is delicate, very pliable, the epiglottis is relatively narrow until 12-13 years of age and in infants it can be easily seen even with a routine examination of the pharynx.
The glottis in children is narrow; the true vocal cords are relatively shorter than in adults; their growth is especially vigorous in the 1st year of life and at the beginning of puberty. The false vocal cords and mucous membrane are delicate, rich in blood vessels and lymphoid tissue.
Gender differences in the larynx in boys and girls begin to emerge only after 3 years, when the angle between the plates of the thyroid cartilage in boys becomes more acute. From the age of 10, boys already have quite clearly identified features characteristic of the male larynx.
Trachea in newborns it is about 4 cm long , To 14-15 years old reaches approximately 7 cm, and in adults it is 12 cm . In children of the first months of life, it has a somewhat funnel-shaped shape; at older ages, cylindrical and conical shapes predominate. In newborns, the upper end of the trachea is at the level of the IV cervical vertebra, in adults - at the level of VII.
The bifurcation of the trachea in newborns corresponds to the ΙΙΙ-ΙV thoracic vertebrae, in 5-year-old children - IV-V and 12-year-olds - V-VI vertebrae.
The growth of the trachea is approximately parallel to the growth of the trunk. There is an almost constant relationship between the width of the trachea and the circumference of the chest at all ages. The cross section of the trachea in children in the first months of life resembles an ellipse, in subsequent ages it resembles a circle.
The tracheal framework consists of 14-16 cartilaginous half-rings connected posteriorly by a fibrous membrane (instead of an elastic end plate in adults). The membrane contains many muscle fibers, the contraction or relaxation of which changes the lumen of the organ.
The mucous membrane of the airways in children is more abundantly supplied with blood vessels, is tender, vulnerable and relatively dry due to the smaller number and insufficient secretion of mucous glands that protect it from damage. These features of the mucous membrane lining the airways in childhood, combined with the narrower lumen of the larynx and trachea, make children susceptible to inflammatory diseases respiratory organs. The muscle layer of the membranous part of the tracheal wall is well developed even in newborns; elastic tissue is found in relatively small quantities.
A child's trachea is soft and easily compressed. With the development of inflammatory processes, stenotic phenomena easily occur (this is a condition in which a narrowing of the airways occurs.). The trachea is mobile, which, along with the changing lumen and softness of the cartilage, sometimes leads to its slit-like collapse.
Bronchi. By the time the baby is born, the bronchial tree is formed. As the child grows, the number of branches and their distribution in the lung tissue do not change. The size of the bronchi increases rapidly in the first year of life and during puberty. The bronchi are narrow, their basis is also made up of cartilaginous semirings, which in early childhood do not have a closing elastic plate, connected by a fibrous membrane containing muscle fibers. The cartilage of the bronchi is very elastic, soft, springy and easily displaced; the mucous membrane is rich in blood vessels, but relatively dry.
The right bronchus is, as it were, a continuation of the trachea, the left one departs at a large angle, this anatomical feature explains the more frequent entry of foreign bodies into the right bronchus.
With the development of the inflammatory process, hyperemia and swelling of the bronchial mucosa is observed, its inflammatory swelling significantly narrows the lumen of the bronchi, up to their complete obstruction (the movement of air along the bronchial tree into the lungs is hampered). Active bronchial motility is insufficient due to poor development of muscles and ciliated epithelium.
Incomplete myelination of the vagus nerve and underdevelopment of the respiratory muscles contribute to the weakness of the cough impulse in a small child, which leads to the accumulation of infected mucus in the bronchial tree, which clogs the lumens of the small bronchi, promotes atelectasis (this is a decrease or complete disappearance of the airiness of the lung due to partial or complete collapse of the alveoli.) and infection of lung tissue. Thus, the main functional feature of the bronchial tree of a small child is the insufficient performance of the drainage and cleansing function.
Lungs in a newborn they weigh about 50 g, by 6 months their weight doubles, by one year it triples, and by 12 years it reaches 10 times its original weight. In adults, the lungs weigh almost 20 times more than at birth.
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. The thinnest branches are called bronchioles. Thin bronchioles enter the pulmonary lobules and within them are divided into terminal bronchioles.
Bronchioles branch into alveolar ducts with sacs, the walls of which are formed by many pulmonary vesicles - alveoli The alveoli are the final part of the respiratory tract. 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 and capillaries - oxygen passes from the air into the blood, and carbon dioxide and water vapor enter the alveoli from the blood.
There are up to 350 million alveoli in the lungs, and their surface reaches 150 m2. The large surface area of the alveoli promotes better gas exchange. On one side of this surface there is alveolar air, constantly renewed in its composition, on the other - blood continuously flowing through the vessels. Diffusion of oxygen and carbon dioxide occurs through the extensive surface of the alveoli. During physical work, when the alveoli stretch significantly during deep entrances, the size of the respiratory surface increases. The larger the total surface of the alveoli, the more intense the diffusion of gases. In children, as in adults, the lungs have a segmental structure
Fig.2. Segmental lung structure
The segments are separated from each other by narrow grooves and layers of connective tissue (lobular lung). The main structural unit is the acini, but its terminal bronchioles end not in a cluster of alveoli, as in an adult, but in a sac (sacculus). The overall growth of the lungs occurs mainly due to an increase in the volume of the alveoli, while the number of the latter remains more or less constant.
The diameter of each alveoli also increases (0.05 mm in a newborn, 0.12 mm at 4-5 years, 0.17 mm at 15 years). At the same time, the vital capacity of the lungs increases (this is the maximum amount of air that can be taken into the lungs after maximum exhalation. The vital capacity of the lungs in children is a more labile value than in adults.
Vital capacity of the lungs, normal in children
Vital capacity of the lungs (VC)– this is the maximum amount of air exhaled after the deepest inhalation (Table 1).
For girls aged 4 to 17 years, whose height ranges from 1 to 1.75 meters, normal vital capacity is calculated by the formula: 3.75 x height - 3.15.
For boys aged 4 to 17 years and height up to 1.65 meters, JEL is calculated by the formula: 4.53 X height - 3.9
The normal vital capacity for boys of the same age, but whose height exceeds 1.65 meters can be calculated as follows: 10 x height - 12.85.
Table 1. Indicators of vital capacity of the lungs in children depending on age
The lung volume of already breathing newborns is 70 ml. To At the age of 15 their volume increases 10 times and in adults - 20 times.
The breathing surface of the lungs in children is relatively larger than in adults; The contact surface of the alveolar air with the vascular pulmonary capillary system decreases relatively with age. The amount of blood flowing through the lungs per unit time is greater in children than in adults, which creates the most favorable conditions for gas exchange.
Atelectasis occurs especially often in the posterior lower parts lungs, where hypoventilation and blood stagnation are constantly observed due to forced horizontal position small child (mostly on the back).
The tendency to atelectasis increases due to a deficiency of surfactant - this is a film that regulates surface alveolar tension.
Surfactant is produced by alveolar macrophages. It is this deficiency that leads to insufficient expansion of the lungs in premature infants after birth (physiological atelectasis).
Pleural cavity. In a child, it is easily extensible due to weak attachment of the parietal layers. The visceral pleura, especially in newborns, is relatively thick, loose, folded, contains villi and outgrowths, most pronounced in the sinuses and interlobar grooves. In these areas there are conditions for faster emergence of infectious foci.
Mediastinum children have relatively more than adults. In its upper part it contains the trachea, large bronchi, thymus gland and lymph nodes, arteries and large nerve trunks; in its lower part there is the heart, blood vessels and nerves.
The mediastinum is integral part lung root, which is characterized by easy displacement and is often the site of development of inflammatory foci, from where infectious process spreads to the bronchi and lungs.
The right lung is usually slightly larger than the left. In young children, the pulmonary fissures are often weakly expressed, only in the form of shallow grooves on the surface of the lungs. Especially often, the middle lobe of the right lung almost merges with the upper one. The large, or main, oblique fissure separates the lower lobe on the right from the upper and middle lobes, and the small horizontal fissure runs between the upper and middle lobes. There is only one slot on the left.
Consequently, the differentiation of the children's lung is characterized by quantitative and qualitative changes: a decrease in respiratory bronchioles, the development of alveoli from the alveolar ducts, an increase in the capacity of the alveoli themselves, a gradual reverse development of intrapulmonary connective tissue layers and an increase in elastic elements.
Rib cage. Relatively large lungs, heart and mediastinum occupy relatively more space in the child's chest and determine some of its features. The chest is always in a state of inhalation, the thin intercostal spaces are smoothed out, and the ribs are pressed quite strongly into the lungs.
In very young children, the ribs are almost perpendicular to the spine, and increasing the capacity of the chest by raising the ribs is almost impossible. This explains the diaphragmatic nature of breathing at this age. In newborns and children in the first months of life, the anteroposterior and lateral diameters of the chest are almost equal, and the epigastric angle is obtuse.
As the child ages cross section The chest takes on an oval or barrel-shaped shape.
The frontal diameter increases, the sagittal diameter decreases relatively, and the curvature of the ribs increases significantly. The epigastric angle becomes more acute.
The position of the sternum also changes with age: its upper edge, lying in a newborn at the level of the VII cervical vertebra, by the age of 6-7 years falls to the level of the II-III thoracic vertebrae. The dome of the diaphragm, which reaches the upper edge of the fourth rib in infants, drops somewhat lower with age.
From the above it is clear that the chest in children gradually moves from the inspiratory position to the expiratory position, which is the anatomical prerequisite for the development of the thoracic (costal) type of breathing.
The structure and shape of the chest can vary significantly depending on the individual characteristics of the child. The shape of the chest in children is especially easily affected by past diseases (rickets, pleurisy) and various negative environmental influences.
Newborn's first breath. During the period of intrauterine development in the fetus, gas exchange occurs exclusively due to the placental circulation. At the end of this period, the fetus develops regular intrauterine respiratory movements, indicating the ability of the respiratory center to respond to irritation. From the moment the baby is born, gas exchange stops due to the placental circulation and pulmonary respiration begins.
The physiological causative agent of the respiratory center is a lack of oxygen and carbon dioxide, the increased accumulation of which from the moment of cessation of placental circulation is the cause of the first deep breath of the newborn. It is possible that the cause of the first breath should be considered not so much an excess of carbon dioxide in the blood of a newborn, but mainly a lack of oxygen in it.
The first breath, accompanied by the first cry, in most cases appears in the newborn immediately - as soon as the passage of the fetus through the mother’s birth canal ends. However, in cases where a child is born with a sufficient supply of oxygen in the blood or there is a slightly reduced excitability of the respiratory center, several seconds, and sometimes even minutes, pass until the first breath appears. This short-term holding of breath is called neonatal apnea.
After the first deep breath healthy children Correct and mostly fairly uniform breathing is established. The uneven breathing rhythm observed in some cases during the first hours and even days of a child’s life usually quickly levels out.
Related information.
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 only a few minutes. Oxidative processes produce carbon dioxide, which must be removed from the body.
Nasal cavity. When you breathe with your mouth closed, air enters the nasal cavity, and when you breathe open, it enters the oral cavity. The formation of the nasal cavity involves bones and cartilage, which also make up the nasal skeleton. Most of the mucous membrane of the nasal cavity is covered with multirow ciliated columnar epithelium, which contains mucous glands, and its smaller part contains olfactory cells. Thanks to the movement of the cilia of the ciliated epithelium, dust that enters with inhaled air is expelled out. The nasal cavity is divided in half by the nasal septum. Each half has three nasal conchas - superior, middle and inferior. They form three nasal passages: the upper - under the superior concha, the middle - under the middle concha and the lower - between the inferior concha and the bottom of the nasal cavity. The inhaled air enters through the nostrils and, after passing through the nasal passages of each half of the nasal cavity, exits it into the nasopharynx through two posterior openings - choanae. The nasolacrimal duct opens into the nasal cavity, through which excess tears are removed.
Adjacent to the nasal cavity are the accessory cavities, or sinuses, connected to it by openings: the maxillary, or maxillary (located in the body upper jaw), sphenoid (in the sphenoid bone), frontal (in the frontal bone) and ethmoidal labyrinth (in ethmoid bone). The inhaled air, in contact with the mucous membrane of the nasal cavity and accessory cavities, in which there are numerous capillaries, is warmed and moistened.
Larynx. The nasopharynx is the upper part of the pharynx that conducts air from the nasal cavity to the larynx, which is attached to the hyoid bone. The larynx forms the initial part of the respiratory tube itself, which continues into the trachea, and at the same time functions as a voice apparatus. It consists of three unpaired and three paired cartilages, connected by ligaments. The unpaired cartilages include the thyroid, cricoid and epiglottis cartilages, and the paired cartilages include the arytenoid, corniculate and sphenoid. The main cartilage is the cricoid. Its narrow part faces anteriorly, and its wide part faces the esophagus. Posteriorly on the cricoid cartilage they are located symmetrically on the right and left sides, movably articulated with it back two arytenoid cartilages triangular shape. When the muscles contracting, pulling back the outer ends of the arytenoid cartilages, and the intercartilaginous muscles relax, these cartilages rotate around their axis and the glottis opens wide, necessary for inhalation. With contraction of the muscles between the arytenoid cartilages and tension of the ligaments, the glottis looks like two tightly stretched parallel muscle ridges, preventing the flow of air from the lungs.
Vocal cords. The true vocal cords are located in the sagittal direction from the internal angle of the junction of the plates of the thyroid cartilage to the vocal processes of the arytenoid cartilages. The true vocal cords include the internal thyroarytenoid muscles. A certain relationship is established between the degree of tension of the vocal cords and the pressure of air from the lungs: the stronger the ligaments are closed, the more pressure the air escaping from the lungs puts on them. This regulation is carried out by the muscles of the larynx and is important for the formation of sounds. When swallowing, the entrance to the larynx is closed by the epiglottis. The mucous membrane of the larynx is covered with stratified ciliated epithelium, and the vocal cords are covered with stratified squamous epithelium. The mucous membrane of the larynx contains a variety of receptors that perceive tactile, temperature, chemical and pain stimuli; they form two reflexogenic zones. Some of the receptors in the larynx are located superficially, where the mucous membrane covers the cartilage, and the other part is located deep in the perichondrium, in the places of muscle attachment, in the pointed parts of the vocal processes. Both groups of receptors are located on the path of inhaled air and are involved in the reflex regulation of breathing and in protective reflex closing the glottis. These receptors, signaling changes in the position of cartilage and contractions of the muscles involved in voice formation, reflexively regulate it.
Trachea. The larynx goes into windpipe, or the trachea, which in an adult is 11–13 cm long and consists of 15–20 half-rings of hyaline cartilage connected by membranes of connective tissue. The cartilages are not closed at the back, so the esophagus, located behind the trachea, can enter its lumen when swallowing. The mucous membrane of the trachea is covered with multirow ciliated epithelium, the cilia of which create a flow of fluid secreted by the glands towards the pharynx; it removes dust particles settled from the air. The powerful development of elastic fibers prevents the formation of folds of the mucous membrane, which reduce the access of air. In the fibrous membrane, located outward from the cartilaginous half-rings, there are blood vessels and nerves.
Bronchi. The trachea branches into two main bronchi; each of them enters the gate of one of the lungs and divides into three branches in the right lung, consisting of three lobes, and two branches in the left lung, consisting of two lobes. These branches split into smaller ones. The wall of the large bronchi has the same structure as the trachea, but it contains closed cartilaginous rings; There are smooth muscle fibers in the wall of the small bronchi. The inner lining of the bronchi consists of ciliated epithelium. The smallest bronchi - up to 1 mm in diameter - are called bronchioles. Each bronchiole is part of a lung lobe (lung lobes are made up of hundreds of lobes). The bronchioles in the lobule are divided into 12–18 terminal bronchioles, which in turn are divided into alveolar bronchioles. The alveolar bronchioles branch into the alveolar ducts, which consist of alveoli. The thickness of the epithelial layer of the alveoli is 0.004 mm. Capillaries are adjacent to the alveoli. Gas exchange occurs through the walls of the alveoli and capillaries. The number of alveoli is approximately 700 million. The total surface of all alveoli in a man is up to 130 square meters. m, for a woman – up to 103.5 sq. m. On the outside, the lungs are covered with an airtight serous membrane, or visceral pleura, which passes into the pleura that covers the inside of the chest cavity - the parietal, or parietal, pleura.
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 approximately 2.5 times with age. The structural features of the nasal cavity of young children make nasal breathing difficult; children often breathe with their mouths open, which leads to susceptibility to colds. The baby's pharynx is shorter, wider and lower in position auditory tube. 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. 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 airways, in childhood, in combination with a narrower lumen of the larynx and trachea, make children susceptible to inflammatory diseases of the respiratory system. The lungs in children grow mainly due to an increase in the volume of the alveoli (in a newborn, the diameter of the alveoli is 0.07 mm, in an adult it already reaches 0.2 mm). Up to 3 years of age, increased growth of the lungs and differentiation of their individual elements occurs. The number of alveoli by the age of 8 reaches the number in an adult. Between the ages of 3 and 7 years, the rate of lung growth decreases. Alveoli grow especially vigorously after 12 years of age. By the age of 12, the volume of the lungs increases 10 times compared to the volume of the lungs of a newborn, and by the end of puberty - 20 times (mainly due to an increase in the volume of the alveoli). 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.
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 arises in the pleural fissure, which is absent at the moment the chest collapses. The significance of the fetal breathing movements 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 the content of carbon dioxide in the blood, which irritates the cells of the 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 in order to stretch the lungs, a certain change in the shape of the chest with age is necessary, matching the force of contraction of the respiratory muscles and the extensibility of the 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 mainly breathe diaphragmatically, during inhalation the resistance of the internal organs located in the 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 take on an oblique position. In this case, mixed breathing (thoraco-abdominal) occurs in infants, 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 gives way to superficial, 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 respiratory and minute volumes lungs, their vital capacity. 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, the absolute value of MOR increases, but the relative MOR (the 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 of age, the vital capacity of the lungs is maximum, and after 35 to 40 years of age 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, when performing physical work, it increases by 2–7 times, and with heavy loads (middle distance running) by almost 20 times. 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 different ages.
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