Age features of the respiratory system. Age features of the respiratory system
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SMOLENSK STATE ACADEMY
PHYSICAL CULTURE OF SPORTS AND TOURISM
Topic: Age-related features of breathing
Fulfilled
student group 1-2-07
Darevsky P.I
Smolensk 2012
THE SIGNIFICANCE OF BREATHING
Breathing is a vital process of constant exchange of gases between the body and its external environment.
Almost all complex reactions the transformation of substances in the body are with the obligatory participation of oxygen. Without oxygen, metabolism is impossible, and a constant supply of oxygen is necessary to preserve life.
During oxidative processes, decay products are formed, including carbon dioxide, which are removed from the body.
When breathing, gases are exchanged between the body and the environment, which ensures a constant supply of oxygen to the body and removal from it. carbon dioxide. This process takes place in the lungs. The carrier of oxygen from the lungs to the tissues, and carbon dioxide from the tissues to the lungs is the blood.
STRUCTURE OF THE RESPIRATORY ORGANS
Nasal cavity. In the respiratory organs, airways are distinguished, through which the inhaled and exhaled air passes, and the lungs, where gas exchange takes place between air and blood. The respiratory tract begins with the nasal cavity, separated from the oral cavity by a septum: in front - the hard palate, and behind - the soft palate. Air in nasal cavity penetrates through the nasal openings - nostrils. At the outer edge of them are hairs that protect against dust from entering the nose. The nasal cavity is divided by a septum into the right and left halves, each of which is divided by the turbinates into the lower, middle and upper nasal passages.
In the first days of life, breathing in children through the nose is difficult. The nasal passages in children are narrower than in adults, and are finally formed by the age of 14-15.
The mucous membrane of the nasal cavity is abundantly supplied with blood vessels and covered with stratified ciliated epithelium. There are many glands in the epithelium that secrete mucus, which, together with dust particles that have penetrated with the inhaled air, is removed by the flickering movements of the cilia. In the nasal cavity, the inhaled air is warmed, partially cleaned of dust and moistened.
The nasal cavity behind through openings - choanas - communicates with the nasopharynx.
Nasopharynx. Nasopharynx -- top part throats. The pharynx is a muscular tube into which the nasal cavity, oral cavity and larynx open. In the nasopharynx, in addition to the choanae, the auditory tubes open, connecting the pharyngeal cavity with the cavity of the middle ear. From the nasopharynx, air passes into the oral part of the pharynx and further into the larynx.
The pharynx in children is wide and short, the auditory tube is low. Diseases of the upper respiratory tract are often complicated by inflammation of the middle ear, since the infection easily penetrates into the middle ear through a wide and short auditory tube.
Larynx. The skeleton of the larynx is formed by several cartilages interconnected by joints, ligaments and muscles. The largest of these is the thyroid cartilage. Above the entrance to the larynx is a cartilaginous plate - the epiglottis. It acts as a valve that closes the entrance to the larynx when swallowing.
The cavity of the larynx 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 covers the vocal cords. The space between the vocal cords is called the glottis. Thus, the larynx not only connects the pharynx with the trachea, but also participates in the speech function.
During normal breathing, the vocal cords are relaxed and the gap between them narrows. Exhaled air, passing through a narrow gap, causes the vocal cords to vibrate - a sound is produced. The pitch of the tone depends on the degree of tension of the vocal cords: with strained cords, the sound is higher, with relaxed ones, lower. The movements of the tongue, lips and cheeks, the contraction of the muscles of the larynx itself contribute to the trembling of the vocal cords and the formation of sounds.
The larynx in children is shorter, narrower and higher than in adults. The larynx grows most intensively in the 1-3 years of life and during puberty.
At the age of 12-14, in boys, at the junction of the plates of the thyroid cartilage, the Adam's apple begins to grow, the vocal cords lengthen, the entire larynx becomes wider and longer than in girls. In boys, during this period, there is a breaking of the voice.
Trachea and bronchi. The trachea departs from the lower edge of the larynx. This is a hollow, non-collapsing tube (in an adult) about 10–13 cm long. Inside, the trachea is lined with a mucous membrane. The epithelium here is multi-row, ciliated. Behind the trachea is the esophagus. At the level of IV-V thoracic vertebrae, the trachea divides into the right and left primary bronchi.
The bronchi are similar in structure to the trachea. The right bronchus is shorter than the left. The primary bronchus, having entered the gates of the lungs, is divided into bronchi of the second, third and other orders, which form the bronchial tree. The thinnest branches are called bronchioles.
In newborns, the trachea is narrow and short, its length is 4 cm; by the age of 14-15, the length of the trachea is 7 cm.
Lungs. Thin bronchioles enter the lung lobules and within them divide into terminal bronchioles. Bronchioles branch into alveolar passages with sacs, the walls of which are formed by many pulmonary vesicles - alveoli. The alveoli are the final part of the airway. 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. Through the walls of the alveoli and capillaries there is an exchange of gases -? oxygen passes from the air into the blood, and carbon dioxide and water vapor enter the alveoli from the blood.
In the lungs, there are up to 350 million alveoli, and their surface reaches 150 m2. The large surface of the alveoli contributes to better gas exchange. On one side of this surface is alveolar air, constantly renewing in its composition, on the other - blood continuously flowing through the vessels. Diffusion of oxygen and carbon dioxide occurs through the vast surface of the alveoli. During physical work when the alveoli are significantly stretched with deep breaths, the size of the respiratory surface increases. The larger the total surface of the alveoli, the more intense the diffusion of gases occurs.
Each lung is covered with a serous membrane called the pleura. The pleura has two leaves. One is tightly fused with the lung, the other is attached to the chest. Between the two sheets is a small pleural cavity filled with serous fluid(about 1-2 ml), which facilitates the sliding of the pleura during respiratory movements.
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 three years old enhanced growth lungs and differentiation of their individual elements. The number of alveoli by the age of eight reaches the number of them in an adult. Between the ages of 3 and 7 years, the growth rate of the lungs decreases. Alveoli grow especially vigorously after 12 years. The volume of the lungs by the age of 12 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).
RESPIRATORY MOVEMENTS
Acts of inhalation and exhalation. Due to the rhythmically performed acts of inhalation and exhalation, gases are exchanged between atmospheric and alveolar air located in the pulmonary vesicles.
There is no muscle tissue in the lungs, and therefore they cannot actively contract. An active role in the act of inhalation and exhalation belongs to the respiratory muscles. With paralysis of the respiratory muscles, breathing becomes impossible, although the respiratory organs are not affected.
When inhaling, the external intercostal muscles and the diaphragm contract. The intercostal muscles lift the ribs and take them somewhat to the side. This increases the volume of the chest. When the diaphragm contracts, its dome flattens, which also leads to an increase in the volume of the chest. With deep breathing, other muscles of the chest and neck also take part. The lungs, being in a hermetically sealed chest, passively follow its moving walls during inhalation and exhalation, since they are attached to the chest with the help of the pleura. This is facilitated by the negative pressure in chest cavity. Negative pressure is pressure below atmospheric pressure.
During inhalation, it is lower than atmospheric by 9-12 mm Hg, and during exhalation - by 2-6 mm Hg.
During development, the chest grows faster than the lungs, which is why the lungs are constantly (even when exhaling) stretched. The stretched elastic lung tissue tends to shrink. The force with which lung tissue tends to shrink due to elasticity counteracts atmospheric pressure. Around the lungs, in the pleural cavity, pressure is created equal to atmospheric pressure minus the elastic recoil of the lungs. This creates negative pressure around the lungs. Due to the negative pressure in the pleural cavity, the lungs follow the expanded chest. The lungs are stretched. Atmosphere pressure acts on the lungs from the inside through the airways, stretches them, presses them against the chest wall.
In a distended lung, the pressure becomes lower than atmospheric pressure, and due to the pressure difference, atmospheric air rushes into the lungs through the respiratory tract. The more the volume of the chest increases during inhalation, the more the lungs are stretched, the deeper the inhalation.
When the respiratory muscles relax, the ribs descend to their original position, the dome of the diaphragm rises, the volume of the chest, and, consequently, the lungs, decreases, and air is exhaled outward. In a deep, exhalation, the abdominal muscles, internal intercostal and other muscles take part.
Breath types. In young children, the ribs have a slight bend and occupy an almost horizontal position. The upper ribs and the entire shoulder girdle are high, the intercostal muscles are weak. In connection with such features, newborns are dominated by diaphragmatic breathing with little involvement of the intercostal muscles. The diaphragmatic type of breathing persists until the second half of the first year of life. As the intercostal muscles develop and the child grows, the difficult cage descends and the ribs take on an oblique position. The breathing of infants now becomes thoracoabdominal, with a predominance of the diaphragmatic, and in the upper chest there is still little mobility.
At the age of 3 to 7 years, in connection with the development of the shoulder girdle, more and more begins to predominate chest type breathing and by the age of seven it becomes pronounced.
At the age of 7-8, gender differences in the type of breathing begin: in boys, the abdominal type of breathing becomes predominant, in girls - chest. Sexual differentiation of respiration ends at 14-17 years of age. It should be noted that the type of breathing in boys and girls may vary depending on sports, work activities.
Due to the peculiarity of the structure of the chest and the low endurance of the respiratory muscles, the respiratory movements in children are less deep and frequent.
Depth and frequency of breathing. An adult makes an average of 15-17 respiratory movements per minute; in one breath with calm breathing inhales 500 ml of air. During muscular work, breathing quickens by 2-3 times. For some types sports exercises the respiratory rate reaches 40-45 times per minute.
In trained people, with the same work, the volume of pulmonary ventilation gradually increases, as breathing becomes rarer, but deeper. With deep breathing, alveolar air is ventilated by 80-90%, which ensures greater diffusion of gases through the alveoli. With shallow and frequent breathing ventilation of the alveolar air is much less and a relatively large part of the inhaled air remains in the so-called dead space - in the nasopharynx, oral cavity, trachea, bronchi. Thus, in trained people, the blood is more saturated with oxygen than in untrained people.
The depth of breathing is characterized by the volume of air entering the lungs in one breath - respiratory air.
The breathing of a newborn baby is frequent and shallow. The frequency is subject to significant fluctuations - 48-63 respiratory cycles per minute during sleep.
In children of the first year of life, the frequency of respiratory movements per minute during wakefulness is 50--60, and during sleep - 35--40. In children 1-2 years old during wakefulness, the respiratory rate is 35-40, in 2-4-year-olds - 25-35 and in 4-6-year-olds 23-26 cycles per minute. In school-age children there is a further decrease in breathing (18-20 times per minute).
The high frequency of respiratory movements in the child provides high pulmonary ventilation.
The volume of respiratory air in a child at 1 month is 30 ml, at 1 year old - 70 ml, at 6 years old - 156 ml, at 10 years old - 230 ml, at 14 years old - 300 ml.
Due to the high respiratory rate in children, the minute volume of breathing (in terms of 1 kg of weight) is much higher than in adults. Minute respiratory volume is the amount of air that a person inhales in 1 minute; it is determined by the product of the value of respiratory air by the number of respiratory movements in 1 min. In a newborn, the minute volume of breathing is 650-700 ml of air, by the end of the first year of life - 2600-2700 ml, by the age of six - 3500 ml, in a 10-year-old child - 4300 ml, in a 14-year-old - 4900 ml, in an adult - 5000-6000 ml.
Vital capacity of the lungs. At rest, an adult can inhale and exhale a relatively constant volume of air (about 500 ml). But with increased breathing, you can inhale about 1500 ml of air. Similarly, after a normal exhalation, a person can still exhale 1500 ml of air. The largest amount of air a person can exhale after deep breath, called vital capacity lung,
The vital capacity of the lungs changes with age, it also depends on gender, the degree of development of the chest, and respiratory muscles. It is usually greater in men than in women; athletes have more than untrained people. For weightlifters, for example, it is about 4000 ml, for football players - 4200 ml, for gymnasts - 4300, for swimmers - 4900, for rowers - 5500 ml or more.
Since the measurement of the vital capacity of the lungs requires the active and conscious participation of the child himself, it can be determined only after 4-5 years.
By the age of 16-17 vital capacity lung reaches values characteristic of an adult.
GAS EXCHANGE IN THE LUNGS
Composition of inhaled, exhaled and alveolar air.
By alternately inhaling and exhaling, a person ventilates the lungs, maintaining a relatively constant gas composition in the alveoli. A person breathes atmospheric air with a high oxygen content (20.9%) and a low carbon dioxide content (0.03%), and exhales air in which oxygen is 16.3% and carbon dioxide is 4%.
In the alveolar air, oxygen is 14.2%, and carbon dioxide is 5.2%.
Why is there more oxygen in exhaled air than in alveolar air? This is explained by the fact that during exhalation, the air that is in the respiratory organs, in the airways, is mixed with the alveolar air.
The lower efficiency of pulmonary ventilation in children is expressed in a different gas composition of both exhaled and alveolar air. The younger the children, the lower the percentage of carbon dioxide and the greater the percentage of oxygen in exhaled and alveolar air. Accordingly, they have a lower percentage of oxygen use. Therefore, to consume the same volume of oxygen and release the same volume of carbon dioxide, children need to ventilate their lungs more than adults.
Gas exchange in the lungs. In the lungs, oxygen from the alveolar air passes into the blood, and carbon dioxide from the blood enters the lungs. The movement of gases occurs according to the laws of diffusion, according to which a gas propagates from an environment with a high partial pressure to an environment with a lower pressure.
Partial pressure is the part of the total pressure that falls on the proportion of a given gas in a gas mixture. The higher the percentage of gas in the mixture, the correspondingly higher its partial pressure.
For gases dissolved in a liquid, the term "voltage" is used, which corresponds to the term "partial pressure" used for free gases.
Gas exchange in the lungs takes place between alveolar air and blood. The alveoli of the lungs are surrounded by a dense network of capillaries. The walls of the alveoli and the walls of the capillaries are very thin, which facilitates the penetration of gases from the lungs into the blood and vice versa. Gas exchange depends on the surface through which the diffusion of gases is carried out, and the difference in the partial pressure (voltage) of the diffusing gases. Such conditions exist in the lungs. With a deep breath, the alveoli are stretched and their surface reaches 100-150 m2. The surface of the capillaries in the lungs is also large. There is also a sufficient difference in the partial pressure of the gases of the alveolar air and the tension of these gases in the venous blood.
From Table 15 it follows that the difference between the tension of gases in the venous blood and their partial pressure in the alveolar air is 110-40=70 mm Hg for oxygen, and 47-40=7 mm Hg for carbon dioxide. This pressure difference is sufficient to provide the body with oxygen and remove carbon dioxide from it.
The binding of oxygen to the blood. In the blood, oxygen combines with hemoglobin, forming an unstable compound - oxyhemoglobin. 1 g of hemoglobin is able to bind 1.34 cm3 of oxygen. The higher the partial pressure of oxygen, the more more oxyhemoglobin is formed. In the alveolar air, the partial pressure of oxygen is 100 - PO mm Hg. Art. Under these conditions, 97% of blood hemoglobin binds to oxygen.
In the form of oxyhemoglobin, oxygen is transported from the lungs by the blood to the tissues. Here, the partial pressure of oxygen is low and oxyhemoglobin dissociates, releasing oxygen. This ensures the supply of tissues with oxygen.
The presence of carbon dioxide in the air or tissues reduces the ability of hemoglobin to bind oxygen.
The binding of carbon dioxide to the blood. Carbon dioxide is carried in the blood in a chemically bound form - in the form of sodium bicarbonate and potassium bicarbonate. Part of it is transported by hemoglobin.
The binding of carbon dioxide and its release by the blood depend on its tension in the tissues and blood. An important role in this belongs to the enzyme carbonic anhydrase contained in erythrocytes. Carbonic anhydrase, depending on the content of carbon dioxide, accelerates the reaction many times over, the equation of which is: CO2 + H2O = H2CO3.
In tissue capillaries, where the tension of carbon dioxide is high, carbonic acid is formed. In the lungs, carbonic anhydrase promotes dehydration, which leads to the expulsion of carbon dioxide from the blood.
Gas exchange in the lungs in children is closely related to the peculiarities of regulation in them. acid-base balance. In children, the respiratory center is very sensitive to the slightest changes in the reaction of the blood. Even with a slight shift in balance towards acidification, shortness of breath occurs easily in children.
The diffusion capacity of the lungs in children increases with age. This is due to an increase in the total surface of the alveoli of the lungs.
The body's need for oxygen and the release of carbon dioxide are determined by the level of oxidative processes occurring in the body. With age, this level decreases, respectively, and the amount of gas exchange per 1 kg of weight decreases as the child grows.
REGULATION OF BREATH
Respiratory center. A person's breathing changes depending on the state of his body. It is calm, rare during sleep, frequent and deep during physical exertion, intermittent, uneven during emotions. When immersed in cold water a person’s breathing stops for a while, “it captures the spirit.” Russian physiologist N. A. Mislavsky in 1919 established that in the medulla oblongata there is a group of cells, the destruction of which leads to respiratory arrest. This was the beginning of the study respiratory center. The respiratory center is a complex formation and consists of an inhalation center and an exhalation center. Later it was possible to show that the respiratory center has a more complex structure and the overlying parts of the central nervous system also take part in the processes of regulation of breathing, which provide adaptive changes in the respiratory system to various activities of the body. An important role in the regulation of respiration belongs to the cerebral cortex.
The respiratory center is in a state of constant activity: impulses of excitation rhythmically arise in it. These impulses arise automatically. Even after the complete shutdown of the centripetal pathways leading to the respiratory center, rhythmic activity can be registered in it. The automatism of the respiratory center is associated with the process of metabolism in it. Rhythmic impulses are transmitted from the respiratory center along the centrifugal neurons to the respiratory muscles and diaphragm, providing an alternation of inhalation and exhalation.
reflex regulation. With pain irritation, with irritation of the abdominal organs, receptors of blood vessels, skin, respiratory tract receptors, a change in breathing occurs reflexively.
When ammonia vapor is inhaled, for example, the receptors of the mucous membrane of the nasopharynx are irritated, which leads to a reflex breath holding. This is an important protective device that prevents toxic and irritating substances from entering the lungs.
Of particular importance in the regulation of respiration are impulses coming from the receptors of the respiratory muscles and from the receptors of the lungs themselves. The depth of inhalation and exhalation depends on them to a greater extent. It happens like this. When you inhale, when the lungs are stretched, the receptors in their walls are irritated. Impulses from the lung receptors along the centripetal fibers of the vagus nerve reach the respiratory center, inhibit the inhalation center and excite the exhalation center. As a result, the respiratory muscles relax, the chest descends, the diaphragm takes the form of a dome, the volume of the chest decreases and exhalation occurs. Exhalation, in turn, reflexively stimulates inspiration.
The cerebral cortex takes part in the regulation of respiration, which provides the finest adaptation of respiration to the needs of the body in connection with changes in environmental conditions and the life of the body.
Here are examples of the influence of the cerebral cortex on breathing. A person can hold his breath for a while, at will change the rhythm and depth of respiratory movements. The influence of the cerebral cortex explains the pre-start changes in breathing in athletes - a significant deepening and quickening of breathing before the start of the competition. It is possible to develop conditioned respiratory reflexes. If 5-7% of carbon dioxide is added to the inhaled air, which in such a concentration speeds up breathing, and the breath is accompanied by the beat of a metronome or a bell, then after several combinations, only a bell or a beat of a metronome will cause an increase in breathing.
Humoral effects on the respiratory center. It has a great influence on the state of the respiratory center chemical composition blood, in particular its gas composition. The accumulation of carbon dioxide in the blood causes irritation of the receptors in the blood vessels that carry blood to the head, and reflexively excites the respiratory center. Other acidic products that enter the blood act in a similar way, such as lactic acid, the content of which in the blood increases during muscular work.
The first breath of a newborn. During intrauterine development, the fetus receives oxygen and gives off carbon dioxide through the placenta to the mother's body. However, the fetus makes respiratory movements in the form of a slight expansion of the chest. In this case, the lungs do not straighten out, but only a slight negative pressure arises in the pleural space.
According to I. A. Arshavsky, this kind of fetal respiratory movements contribute to better blood flow and improve blood supply to the fetus, and are also a kind of training for lung function. During childbirth, after the umbilical cord is tied, the baby's body is separated from the mother's body. At the same time, carbon dioxide accumulates in the blood of the newborn and the oxygen content decreases. A change in the gas composition of the blood leads to an increase in the excitability of the respiratory center both humorally and reflexively through irritation of receptors in the walls of blood vessels. The cells of the respiratory center are irritated, and the first breath occurs in response. And then inhalation reflexively causes exhalation.
In the emergence of the first breath, an important role belongs to the change in the conditions of the newborn's existence in comparison with its intrauterine existence. Mechanical irritation of the skin when the obstetrician's hands touch the child's body, lower temperature environment compared with intrauterine, the drying of the body of a newborn in the air - all this also contributes to the reflex excitation of the respiratory center and the emergence of the first breath.
I. A. Arshavsky in the appearance of the first breath assigns the main role to the excitation of the spinal respiratory motor neurons, cells of the reticular formation of the medulla oblongata; the stimulating factor in this case is a decrease in the partial pressure of oxygen in the blood.
During the first breath, the lungs are straightened, which the fetus was in a collapsed state, the lung tissue of the fetus is very elastic, slightly stretchable. It takes a certain amount of force to stretch and expand the lungs. Therefore, the first breath is difficult and requires a lot of energy.
Features of the excitability of the respiratory center in children. By the time a child is born, his respiratory center is able to provide 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 by the time of birth the functional formation of the respiratory center has not yet ended. This is evidenced by the large variability in the frequency, depth, rhythm of breathing in young children. The excitability of the respiratory center in newborns and infants is low.
Children of the first years of life are more resistant to lack of oxygen (hypoxia) than older children.
The formation of the functional activity of the respiratory center occurs with age. By the age of 11, the ability to adapt breathing to different conditions vital activity.
The sensitivity of the respiratory center to the content of carbon dioxide increases with age and at school age reaches approximately the level of adults. It should be noted that during puberty there are temporary violations of the regulation of breathing and the body of adolescents is less resistant to oxygen deficiency than the body of an adult.
O functional state the respiratory apparatus is also evidenced by the ability to arbitrarily change breathing (suppress respiratory movements or produce maximum ventilation). Voluntary regulation of breathing involves the cerebral cortex, centers associated with the perception of speech stimuli and responses to these stimuli.
Voluntary regulation of breathing is associated with the second signaling system and appears only with the development of speech.
Voluntary changes in breathing play an important role in the execution of a series breathing exercises and help to correctly combine certain movements with the phase of breathing (inhalation and exhalation).
Breathing during physical work. In an adult, during muscular work, pulmonary ventilation increases due to the increase and deepening of breathing. Activities such as running, swimming, skating, skiing, and cycling dramatically increase pulmonary ventilation. In trained people, the increase in pulmonary gas exchange occurs mainly due to an increase in the depth of breathing. Children, due to the peculiarities of their respiratory apparatus, cannot significantly change the depth of breathing during physical exertion, but increase their breathing. The already frequent and shallow breathing in children during physical exertion becomes even more frequent and superficial. This results in lower ventilation efficiency, especially in young children.
Adolescents, in contrast to adults, reach the maximum level of oxygen consumption faster, but also stop work faster due to the inability to maintain high oxygen consumption for a long time.
Proper breathing. Have you noticed that a person holds his breath for a short time when he listens to something? And why do rowers and hammerers have the moment of greatest gain coincides with a sharp exhalation (“wow”)?
In normal breathing, inhalation is shorter than exhalation. This breathing rhythm facilitates physical and mental activity. It can be explained like this. During inhalation, the respiratory center is excited, while, according to the law of induction, the excitability of other parts of the brain decreases, and during exhalation, the opposite occurs. Therefore, the strength of muscle contraction decreases during inhalation and increases during exhalation. Therefore, performance decreases and fatigue sets in sooner if the inhalation is lengthened and the exhalation is shortened.
Teaching children to breathe correctly when walking, running and other activities is one of the tasks of the teacher. One of the conditions correct breathing This is the development of the chest. For this, the correct position of the body is important, especially while sitting at a desk, breathing exercises and other physical exercises that develop the muscles that move the chest. Especially useful in this regard are sports such as swimming, rowing, skating, skiing.
Usually a person with a well-developed chest will breathe evenly and correctly. It is necessary to teach children to walk and stand in a straight posture, as this contributes to the expansion of the chest, facilitates the activity of the lungs and provides 1 deeper breathing. When the body is bent, less air enters the body.
Adaptation of the body to physical activity
From a biological point of view, physical training is a process of directed adaptation of the body to training effects. The loads used in the process of physical training act as an irritant that stimulates adaptive changes in the body. The training effect is determined by the direction and magnitude of physiological and biochemical changes occurring under the applied loads. The depth of the shifts taking place in the body depends on the main characteristics physical activity:
* the intensity and duration of the exercises performed;
* the number of repetitions of exercises;
* the duration and nature of the rest intervals between repetitions of exercises.
A certain combination of the listed parameters of physical activity leads to the necessary changes in the body, to the restructuring of metabolism and, ultimately, to an increase in fitness.
The process of adaptation of the body to the effects of physical activity has a phase character. Therefore, two stages of adaptation are distinguished: urgent and long-term (chronic).
The stage of urgent adaptation is reduced mainly to changes in energy metabolism and the related functions of vegetative support based on the already formed mechanisms for their implementation, and is a direct response of the body to single effects of physical activity.
With repeated repetition of physical impacts and the summation of many traces of loads, long-term adaptation gradually develops. This stage is associated with the formation of functional and structural changes in the body that occur as a result of stimulation of the genetic apparatus of cells loaded during work. In the process of long-term adaptation to physical activity, the synthesis of nucleic acids and specific proteins is activated, resulting in an increase in the capabilities of the musculoskeletal system, and its energy supply is improved.
The phase nature of the processes of adaptation to physical loads allows us to distinguish three types of effects in response to the work performed.
An urgent training effect that occurs directly during exercise and during an urgent recovery period within 0.5 - 1.0 hours after the end of work. At this time, the oxygen debt formed during work is eliminated.
Delayed training effect, the essence of which is the activation of plastic processes by physical activity for excessive synthesis of those destroyed during work cell structures and replenishment energy resources organism. This effect is observed on later phases recovery (usually within 48 hours after the end of the load).
The cumulative training effect is the result of the sequential summation of the urgent and delayed effects of repetitive loads. As a result of the cumulation of trace processes of physical influences over long periods of training (more than one month), there is an increase in performance indicators and an improvement in sports results.
Small physical loads do not stimulate the development of the trained function and are considered ineffective. To achieve a pronounced cumulative training effect, it is necessary to perform an amount of work that exceeds the value of ineffective loads.
A further increase in the volume of work performed is accompanied, to a certain limit, by a proportional increase in the trained function. If the load exceeds the maximum allowable level, then a state of overtraining develops, and adaptation fails.
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Respiration is a necessary physiological process of constant exchange of gases between the body and the external environment. As a result of respiration, oxygen enters the body, which is used by each cell of the body in oxidation reactions, which is the basis for the exchange of speech and energy. During these reactions, carbon dioxide is released, the excess of which must be constantly excreted from the body. Without access to oxygen and removal of carbon dioxide, life can last only a few minutes. The breathing process includes five stages:
Exchange of gases between the external environment and the lungs (pulmonary ventilation);
The exchange of gases in the lungs between the air of the lungs and the blood of the capillaries, densely permeate the alveoli of the lungs (pulmonary respiration)
Transportation of gases by the blood (transfer of oxygen from the lungs to the tissues, and carbon dioxide from the tissues to the lungs)
The exchange of gases in tissues;
The use of oxygen by tissues (internal respiration at the level of cell mitochondria).
The first four stages relate to external respiration, and the fifth stage - to interstitial respiration, which occurs at the biochemical level.
The human respiratory system consists of the following organs:
Airways, which include the nasal cavity, nasopharynx, larynx, trachea and bronchi of different diameters;
Lungs, consisting of the smallest air channels (bronchioles), air bubbles - alveoli, tightly braided blood capillaries pulmonary circulation
Bone - muscular system chest, which provides respiratory movement and includes the ribs, intercostal muscles and the diaphragm (the membrane between the chest cavity and the abdominal cavity). The structure and performance of the organs of the respiratory system change with age, which determines certain features of the breathing of people of different ages.
The airways start from the nasal cavity, which consists of three passages: upper, middle and lower and is covered with a mucous membrane, hairs and permeated with blood vessels
(capillaries). Among the cells of the mucous membrane of the upper nasal passages, there are olfactory receptors surrounded by the olfactory epithelium. The corresponding nasolacrimal ducts open into the lower nasal passage of the right and left halves of the nose. The upper nasal passage is connected to the sphenoid cavities of the sphenoid and partially ethmoid bones, and the middle nasal passage - with cavities upper jaw(maxillary sinus) and frontal bones. In the nasal cavity, the air inhaled is normalized by temperature (heated or cooled), moistened or dehydrated and partially cleared of dust. The cilia of the mucosal epithelium are constantly moving rapidly (flickering), due to which the mucus from the dust particles stuck on it is pushed outward at a speed of up to 1 cm per minute and most often towards the pharynx where it is periodically coughed up or swallowed. The inhaled air can also enter the throat through the oral cavity, but in this case it will not normalize due to temperature, humidity and the level of dust removal. Thus, mouth breathing will not be physiological and should be avoided.
Children under 8-11 years of age have an underdeveloped nasal cavity, swollen mucous membrane and narrowed nasal passages. This makes it difficult to breathe through the nose and therefore children often breathe with their mouth open, which can contribute to colds, inflammation of the pharynx and larynx. In addition, constant mouth breathing can lead to frequent otitis media, inflammation of the middle ear, bronchitis, dry mouth, abnormal development of the hard palate, disruption of the normal position of the nasal septum, etc. Cold and infectious diseases of the nasal mucosa (rhinitis) almost always contribute to it. additional edema and an even greater reduction in the narrowed nasal passages in children, additionally contributes to the complication of their breathing through the nose. Therefore, colds in children require quick and effective treatment, especially since the infection can enter the air cavities of the skull bones (in the maxillary cavity of the upper jaw, or in the frontal cavity of the frontal bone), causing appropriate inflammation of the mucous membrane of these cavities and development chronic rhinitis(see below for details).
From the nasal cavity, air enters through the choanae into the pharynx, where the oral cavity (calling), auditory (Eustachian canals) tubes also open, and the larynx and esophagus originate. In children under 10-12 years old, the pharynx is very short, which leads to the fact that infectious diseases of the upper respiratory tract are often complicated by inflammation of the middle ear, since the infection easily gets there through a short and wide auditory tube. This should be kept in mind when treating colds children, as well as in organizing physical education classes, especially on the basis of water pools, in winter sports, and the like.
Around the openings of the mouth, nose and eustachian tubes in the pharynx are lymphoepithelial nodes designed to protect the body from pathogens that can enter the mouth and pharynx along with air, inhaled or with food or water measures. These formations are called adenoids or tonsils (tonsils). The composition of the tonsils includes pharyngeal tubal, tonsils of the pharynx (palatine and lingual) and December lymph nodes, which form a lympho-epithelial ring of immune defense.
Among all respiratory diseases, including children from the first days of life, acute respiratory infections are the most common. viral infections(ARVI) group of which, according to A. A. Drobinsky (2003), includes influenza, parainfluenza, adenovirus, rhinovirus and other diseases of the upper respiratory tract. Children over 3 years of age are most sensitive to influenza pathogens, while in other acute respiratory viral infections they gradually acquire relative immunity. The most common clinical forms of ARVI diseases are rhinitis (inflammation of the nasal mucosa), pharyngitis (general burning of the tonsils of the pharynx), tonsillitis (inflammation of the pharyngeal tonsils), laryngitis (inflammation of the larynx), tracheitis, bronchitis (inflammation of the airways), pneumonia (pneumonia). Tonsillitis can be complicated in the form of follicular or lacunar tonsillitis and lymphadenitis. When the infection involves epithelial connective tissues and the vascular system, edema and hyperemia of the mucosa (airway catarrh) may occur. Viruses can also spread through the blood throughout the body, affecting the liver, gastrointestinal tract, heart, blood vessels, central nervous system, kidneys and other organs. ARVI diseases are promoted by crowding of people, unsatisfactory hygienic condition of premises (including classrooms, gyms), hypothermia of the body (colds), therefore, appropriate preventive measures should be implemented, and quarantine days should be introduced during SARS epidemics, including stopping the work of sports training sections.
Among other dangerous infectious diseases of the respiratory organs, measles, whooping cough, diphtheria, and tuberculosis should be singled out, the main reasons for the spread of which are contact with the patient, unsatisfactory hygienic and social conditions.
One of the most common forms of complications of frequent rhinitis in children can be inflammation paranasal sinuses nose, that is, the development of sinusitis or frontal sinusitis. Sinusitis is an inflammation that covers the mucous membrane of the air cavities of the upper jaw. The disease develops as a complication after infectious diseases (bark, flu, tonsillitis) with their careless treatment, as well as from frequent inflammation of the nasal mucosa (runny nose), which happens, for example, in children involved in water sports. Inflammation of the maxillary cavity of the upper jaw can also spread to the cavity of the frontal bone, leading to inflammation of the frontal sinus - frontal sinusitis. With this disease, children experience headaches, lacrimation, purulent discharge from the nose. Sinusitis and frontal sinusitis are dangerous by transition to chronic forms and therefore require careful and timely treatment.
From the nasopharynx, air enters the larynx, which consists of cartilage, ligaments and muscles. The cavity of the larynx from the side of the pharynx when swallowing food is covered with elastic cartilage - the epiglottis, which counteracts the ingress of food into the airways.
The vocal cords are also located in the upper part of the larynx.
In general, the larynx in children is shorter than in adults. This organ grows most intensively in the first 3 years of a child's life, and during puberty. In the latter case, gender differences are formed in the structure of the larynx: in boys it becomes wider (especially at the level of the thyroid cartilage), the Adam's apple appears and the vocal cords become longer, which leads to a breakdown of the voice with the final formation of a lower voice in men.
The trachea departs from the lower edge of the larynx, which further branches into two bronchi, which supply air in accordance with the left and right lungs. The mucous membrane of the airways of children (up to 15-16 years old) is very vulnerable to infections due to the fact that it contains fewer mucous glands and is very tender.
The main gas exchange organs of the respiratory system are the lungs. With age, the structure of the lungs changes significantly: the length of the airways increases, and at the age of 8-10 years, the number of pulmonary vesicles - alveoli, which are the final part of the respiratory tract, also increases. The wall of the alveoli has one layer of epithelial cells (Alveocytes), 2-3 millimicrons (µm) thick and is braided with a dense retina of capillaries. Through such an insignificant membrane, gases are exchanged: oxygen passes from the air into the blood, and carbon dioxide and water pass in the opposite direction. In adults, there are up to 350 million alveoli in the lungs, with a total surface area of up to 150 m ~.
Each lung is covered with a serous membrane (pleura), which consists of two sheets, one of which adheres to inner surface chest, the second - to the tissue of the lungs. A small cavity is formed between the sheets, filled with serous fluid (1-2 ml), which helps to reduce friction when the lungs slide during breathing. The lungs in children up to 8-10 years old grow by increasing the number of alveoli, and after 8 years by increasing the volume of each alveoli, which can increase 20 or more times over the entire period of development, relative to the volume of a newborn. Helps increase lung capacity physical training, especially running and swimming, and this process can continue up to 28-30 years.
The state of external respiration is characterized by functional and volume indicators.
The functional indicators include primarily the type of breathing. Children under 3 years of age have a diaphragmatic type of breathing. From 3 to 7 years, all children develop a chest type of breathing. From the age of 8, sexual characteristics of the type of breathing begin to appear: in boys, the belly-diaphragmatic type of breathing gradually develops, and in girls, the thoracic type of breathing improves. The consolidation of such differentiation is completed at the age of 14-17. It should be noted that the type of breathing may vary depending on physical activity. With intensive breathing, not only the diaphragm, but also the chest begins to work actively in the guys, and in the girls, the diaphragm is activated along with the chest.
The second functional indicator of respiration is the respiratory rate (the number of breaths or exhalations per minute), which decreases significantly with age (Table 15).
Table 15
Age dynamics of the main indicators of the state of respiration (S. I. Galperin, 1965; V. I. Bobritskaya, 2004)
With age, all volume indicators of respiration increase significantly. In table. 15 shows the age dynamics of changes in the main volumetric indicators of respiration in children, depending on gender.
Volumetric respiration also depends on the length of the body, on the state of development of the chest and on physical fitness. So, for example, in rowers and runners, VC can reach 5500-8000 ml, and minute respiratory volume up to 9000-12000 ml.
The regulation of breathing is carried out primarily by the respiratory center located in the medulla oblongata. The central nervous system provides automatic alternation of inhalation and exhalation due to the supply of periodic impulses through descending pathways spinal cord to the external intercostal muscles and the muscles of the diaphragm of the chest, which carry out the rise of the chest (lowering the diaphragm), which determines the act of inhaling air. In a calm state, exhalation occurs when the internal intercostal muscles and diaphragm muscles relax and the chest lowers (diaphragm leveling) under its own weight. With a deep exhalation, the internal intercostal muscles tighten, and the diaphragm rises.
The activity of the respiratory center is regulated by reflex or humoral. Reflexes are switched on from receptors located in the lungs (mechanoreceptors of lung tissue stretching), as well as from chemoreceptors (sensitive to the content of oxygen or carbon dioxide in human blood) and from pressoreceptors (sensitive to blood pressure in the veins). There are also chains of conditioned reflex regulation of breathing (for example, from pre-start excitement in athletes), and conscious regulation from centers in the cerebral cortex.
According to A. G. Khripkov et al. (1990) Infants in their first years of life have a higher resistance to lack of oxygen (hypoxia) than older children. The formation of the functional maturity of the respiratory center continues during the first 11-12 years, and at the age of 14-15 it becomes adequate for such regulation in adults. With the maturation of the cerebral cortex (15-16 years), the ability to consciously change the parameters of breathing is improved: hold your breath, make maximum ventilation, etc.
During puberty, some children may experience temporary violation regulation of respiration (resistance to oxygen deficiency decreases, respiratory rate increases, etc.), which should be taken into account when organizing physical education classes.
Sports training significantly increases breathing parameters. In trained adults, an increase in pulmonary gas exchange during physical exertion occurs mainly due to the depth of breathing, while in children, especially of primary school age, due to an increase in respiratory rate, which is less effective.
Children also achieve maximum oxygen supply more quickly, but this does not last long, reducing endurance in work.
It is very important from early childhood to teach children to breathe correctly when walking, running, swimming, etc. This is facilitated by normal posture in all types of work, breathing through the nose, as well as special breathing exercises. With the correct breathing stereotype, the duration of the exhalation should be 2 times the duration of the inhalation.
In the process of physical education, especially for children of preschool and primary school age (4-9 years old), special attention should be paid to educating proper breathing through the nose, both in a state of relative rest and during work or sports. Breathing exercises, as well as swimming, rowing, skating, skiing, especially contribute to the improvement of breathing.
Breathing exercises are best done in full breathing mode (deep breathing with a combination of thoracic and abdominal rear breathing). Such gymnastics is recommended to be done 2-3 times a day 1-2 hours after eating. In this case, you should stand or sit upright in a relaxed state. It is necessary to take a quick (2-3 s) deep breath and a slow (15-30 s) exhalation with full tension of the diaphragm and "compression" of the chest. At the end of the exhalation, it is advisable to hold your breath for 5-10 seconds, and then forcefully inhale again. Such breaths can be 2-4 per minute. Duration of one session breathing exercises should be in 5-7 minutes.
Breathing exercises are of great health importance. Taking a deep breath lowers the pressure in the chest cavity (by lowering the diaphragm). This leads to an increase in venous blood flow to the right atrium, which facilitates the work of the heart. The diaphragm, descending towards the abdomen, massages the liver and the second organs of the abdominal cavity, helps to remove metabolic products from them, and from the liver - venous stagnant blood and bile.
During deep exhalation, the diaphragm rises, which promotes the outflow of blood from lower parts body, from the organs of the small pelvis and abdomen. There is also a slight massage of the heart and improved blood supply to the myocardium. These effects of breathing exercises produce the stereotypes of correct breathing in the best way, and also contribute to general health improvement, increase in protective forces, and optimization of the work of internal organs.
breathing age hygienic air
Fetal respiration. 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 respiratory movements of the fetus consist of a slight expansion of the chest, which is replaced by a longer fall, and then an even longer pause. When inhaling, the lungs do not expand, but only a slight negative pressure arises in the pleural space, which is absent at the time of the collapse of the chest. The significance of fetal respiratory movements lies in the fact that they contribute to an increase in the speed of blood movement through the vessels and its flow to the heart. And this leads to an improvement in the blood supply to the fetus and the supply of tissues with oxygen. In addition, fetal breathing movements are considered as a form of lung function training.
Breath of a newborn. The occurrence of the first breath of a newborn is due to a number of reasons. After the umbilical cord is ligated, the placental exchange of gases between the blood of the fetus and the mother stops in the newborn. This leads to an increase in the content of carbon dioxide in the blood, which irritates the cells of the respiratory center and causing the occurrence rhythmic breathing.
The reason for the first breath of a newborn is a change in the conditions of its existence. The action of various environmental factors on all receptors on the surface of the body becomes the stimulus that reflexively contributes to the occurrence of inspiration. A particularly powerful factor is the irritation of skin receptors.
The first breath of a newborn is especially difficult. When it is implemented, 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. After the appearance of the first 1 - 3 respiratory movements, the lungs are completely straightened and evenly filled with air.
The chest grows faster than the lungs, therefore, negative pressure arises in the pleural cavity, and conditions are created for the constant stretching of the lungs. The creation of negative pressure in the pleural cavity and maintaining it at a constant level also depends on the properties of the pleural tissue. It has a high absorption capacity. Therefore, the 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 the act of breathing in a newborn. Features of the child's breathing are associated with 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 is almost the same as in an adult. Newborns have an elastic diaphragm, its tendon part occupies a small area, and the muscular part occupies a large one. As it develops, the muscular part of the diaphragm increases even more. It begins to atrophy from the age of 60, and instead of it, the tendon part increases. Since infants have mainly diaphragmatic breathing, during inspiration, the resistance of the internal organs located in the abdominal cavity must be overcome. In addition, when breathing, one has to overcome the elasticity of the lung tissue, which in newborns is still large and decreases with age. It is also necessary to overcome bronchial resistance, which in children is much greater than in adults. Therefore, the work expended on breathing is much greater in children than in adults.
Change with age in the type of breathing. Diaphragmatic breathing persists until the second half of the first year of life. As the child grows, the chest descends and the ribs take on an oblique position. At the same time, mixed breathing (chest-abdominal) occurs in infants, and stronger mobility of the chest is observed in its lower sections. In connection with the development of the shoulder girdle (3-7 years), chest breathing begins to predominate. From the age of 8-10, there are gender differences in the type of breathing: in boys, a predominantly diaphragmatic type of breathing is established, and in girls - chest.
Change with age in the rhythm and frequency of breathing. In newborns and infants, breathing is irregular. Arrhythmia is expressed in the fact that deep breathing is replaced by shallow breathing, 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). Already from the moment of birth, the same ratio 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, the respiratory rate (RR) in boys is higher than in girls. By the time of puberty, BH in girls becomes larger, and this ratio is maintained throughout life. By the age of 14 - 15, the respiratory rate approaches the value of an adult.
The respiratory rate in children is much greater than in adults, it changes under the influence of various influences. It increases with mental arousal, small physical exercises, a slight increase in body temperature and the environment.
Change with age in the respiratory and minute volumes of the lungs, their vital capacity. In a newborn child, the lungs are malelastic and relatively large. During inspiration, their volume increases slightly, by only 10 - 15 mm. Providing the child's body with oxygen occurs by increasing the frequency of breathing. The tidal volume of the lungs increases with age, along with a decrease in the respiratory rate.
With age, the absolute value of MOD increases, but the relative MOD (ratio of MOD to body weight) decreases. In newborns and children of the first year of life, it is twice as large as in adults. This is due to the fact that in children with the same relative tidal volume, the respiratory rate is several times greater than in adults. In this regard, pulmonary ventilation per 1 kg of body weight in children is greater (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 - 13-year-olds - 130 - 145, 14-year-olds - 125, and 15 - 17-year-olds - 110). Due to this, a large need for a growing organism in O 2 is provided.
The value of VC increases with age due to the growth of the chest and lungs. In a child of 5-6 years old, it is 710-800 ml, in 14-16 years old - 2500-2600 ml. From 18 to 25 years, the vital capacity of the lungs is maximum, and after 35 - 40 years it decreases. The value of the vital capacity of the lungs varies depending on age, height, type of breathing, sex (girls are 100-200 ml less than boys).
In children, during physical work, breathing changes in a peculiar way. During the load, the RR increases and the TO almost does not change. Such breathing is uneconomical and cannot ensure long-term performance of work. Pulmonary ventilation in children during physical work increases by 2-7 times, and when heavy loads(mid-distance running) almost 20 times. In girls, when performing maximum work, oxygen consumption is less than in boys, especially at 8-9 years old and at 16-18. All this should be taken into account when doing physical labor and sports with children of different ages.
Age features of the respiratory system. Children under 8-11 years of age have an underdeveloped nasal cavity, swollen mucous membrane and narrowed nasal passages. This makes it difficult to breathe through the nose and therefore children often breathe with their mouth open, which can contribute to colds, inflammation of the pharynx and larynx. In addition, constant mouth breathing can lead to frequent otitis media, bronchitis, dry mouth, abnormal development of the hard palate, disruption of the normal position of the nasal septum, etc. and to the narrowed nasal passages in children, further complicates their breathing through the nose. Therefore, colds in children require quick and effective treatment, especially since the infection can enter the cavities of the bones of the skull, causing corresponding inflammation of the mucous membrane of these cavities and the development of chronic rhinitis. From the nasal cavity, air enters through the choanae into the pharynx, where the oral cavity (calling), auditory (Eustachian canals) tubes also open, and the larynx and esophagus originate. In children under 10-12 years old, the pharynx is very short, which leads to the fact that infectious diseases of the upper respiratory tract are often complicated by inflammation of the middle ear, since the infection easily gets there through a short and wide auditory tube. This should be remembered in the treatment of colds in children, as well as in the organization of physical education classes, especially on the basis of water pools, in winter sports, and the like. Around the openings of the mouth, nose, and eustachian tubes in the pharynx are knots designed to protect the body from pathogens that can enter the mouth and pharynx with the air that is inhaled, or with food or water consumed. These formations are called adenoids or tonsils (tonsils).
From the nasopharynx, air enters the larynx, which consists of cartilage, ligaments and muscles. The cavity of the larynx from the side of the pharynx when swallowing food is covered with elastic cartilage - the epiglottis, which counteracts the ingress of food into the windy path. The vocal cords are also located in the upper part of the larynx. In general, the larynx in children is shorter than in adults. This organ grows most intensively in the first 3 years of a child's life, and during puberty. In the latter case, gender differences are formed in the structure of the larynx: in boys, it becomes wider (especially at the level of the thyroid cartilage), the Adam's apple appears and the vocal cords become longer, which causes the final voice to be brittle and form a lower voice in men.
The trachea departs from the lower edge of the larynx, which further branches into two bronchi, which supply air in accordance with the left and right lung. The mucous membrane of the tracts of children (up to 15-16 years old) is very vulnerable to infections due to the fact that it contains fewer mucous glands and is very tender.
The state of external respiration is characterized by functional and volume indicators. The functional indicators include primarily the type of breathing. Children under 3 years of age have a diaphragmatic type of breathing. From 3 to 7 years, all children develop a chest type of breathing. From the age of 8, sexual characteristics of the type of breathing begin to appear: in boys, the belly-diaphragmatic type of breathing gradually develops, and in girls, the thoracic type of breathing improves. The consolidation of such differentiation is completed at the age of 14-17. It should be noted that the type of breathing may vary depending on physical activity. With intensive breathing, not only the diaphragm, but also the chest begins to work actively in the guys, and in the girls, the diaphragm is activated along with the chest.
The second functional indicator of respiration is the respiratory rate (the number of breaths or exhalations per minute), which decreases significantly with age.
The human respiratory organs are very important for the life of the body, as they supply oxygen to tissues and remove carbon dioxide from them. The upper respiratory tract includes the nasal openings reaching the vocal cords, and the lower respiratory tract includes the bronchi, trachea and larynx. At the time of the birth of a child, the structure of the respiratory organs is not yet fully developed, which makes up the features of the respiratory system in infants.
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 branching of the bronchi).
By the time of birth, the respiratory organs in children are not only absolutely smaller, but, in addition, they also differ in some incompleteness of the anatomical and histological structure, which is also associated with the functional features of breathing.
Intensive growth and differentiation of the respiratory organs continue during the first months and years of life. The formation of the respiratory organs ends on average by the age of 7, and then only their sizes increase (Fig. 1).
Fig.1. The structure of the respiratory system in children
Features of the morphological structure of OD in children of the first years of life:
1) thin, tender, easily damaged dry mucosa with insufficient development of the glands, reduced production of 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 suppleness of the cartilaginous framework of the lower respiratory tract, the absence of elastic tissue in them and in the lungs.
These features reduce the barrier function of the mucous membrane, facilitate easier penetration of the infectious agent into the bloodstream, and also create preconditions for narrowing of the airways due to rapidly occurring edema or compression of the compliant breathing tubes from the outside (thymus gland, abnormally located vessels, enlarged tracheobronchial lymph nodes).
Nose and nasopharyngeal space in young children of small size, 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 tender, rich in blood vessels. Even slight hyperemia and swelling of the mucous membrane with a runny nose make the nasal passages impassable, cause shortness of breath, and make sucking the breast difficult. The submucosa in the first years of life is poor in cavernous tissue, which develops by the age of 8-9, so nosebleeds in young children are rare and are caused by pathological conditions. They are more common during puberty.
Accessory cavities of the nose in young children, they are very poorly developed or even completely absent.
By the birth of a child, only the maxillary (maxillary) sinuses are formed; frontal and ethmoid are open protrusions of the mucous membrane, which are formed in the form of cavities only after 2 years, the main sinus is absent. Completely all the paranasal sinuses develop by the age of 12-15, however, sinusitis can also develop in children of the first two years of life.
Nasolacrimal canal 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. auditory trumpet, connecting the pharyngeal cavity with the middle ear in young children is wide and short, located low, which often leads to a complication 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 because of the well-developed arches. Their crypts and vessels are poorly developed, which to some extent explains the rare diseases of angina 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), is often hyperplastic, especially in children with exudative and lymphatic diathesis. Their barrier function at this age is low, like that of the lymph nodes.
In the pubertal period, the pharyngeal and nasopharyngeal tonsils begin to undergo reverse development, and after puberty it is relatively very rare to see their hypertrophy.
With hyperplasia of the tonsils and their colonization 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 can be observed, adenoiditis develops. Thus, foci of infection are formed in the child's body.
Larynx in children of the earliest age, it has a funnel-shaped shape, with a distinct narrowing in the region 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. A narrow lumen, an abundance of blood vessels and nerve receptors in the subglottic space, easily occurring edema of the submucosal layer can cause severe violations breathing even with small manifestations of a respiratory infection (croup syndrome).
The larynx in children is shorter, narrower and higher than in adults, 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 below ).
The most vigorous growth of the transverse and anterior-posterior dimensions of the larynx is noted in the 1st year of life and at the age of 14-16 years; with age, the funnel-shaped form of the larynx gradually approaches the cylindrical. The larynx in young children is relatively longer than in adults.
The cartilages of the larynx in children are tender, very pliable, the epiglottis up to 12-13 years old is relatively narrow and in infants it can be easily seen even during 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. False vocal cords and mucous membrane are tender, rich in blood vessels and lymphoid tissue.
Sexual differences in the larynx in boys and girls begin to be revealed only after 3 years, when the angle between the plates of the thyroid cartilage in boys becomes more acute. From the age of 10, the features characteristic of the male larynx are already quite clearly identified in boys.
Trachea in newborns has a length of about 4 cm , 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 an older age, cylindrical and conical shapes predominate. In newborns upper end 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 children 5 years old - 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 of the first months of life resembles an ellipse, in subsequent ages it is a circle.
The framework of the trachea consists of 14-16 cartilaginous half-rings connected behind 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, tender, vulnerable and relatively dry due to the smaller number and insufficient secretion of the mucous glands that protect it from damage. These features of the mucous membrane lining the airways, in childhood in combination with a narrower lumen of the larynx and trachea, children are more susceptible to inflammatory diseases of the respiratory system. The muscular layer of the membranous part of the tracheal wall is well developed even in newborns, the elastic tissue is in a relatively small amount.
Children's trachea is soft, easily squeezed. With the development 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 child is born, the bronchial tree is formed. With the growth of the child, the number of branches and their distribution in the lung tissue do not change. The dimensions of the bronchi increase intensively in the first year of life and in the pubertal period. The bronchi are narrow, their basis is also made up of cartilaginous semicircles, 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 are observed, its inflammatory swelling significantly narrows the lumen of the bronchi, up to their complete obstruction (the movement of air along the bronchial tree to the lungs is difficult). Active motility of the bronchi 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 small child, which leads to the accumulation of infected mucus in the bronchial tree, which clogs the lumens of the small bronchi, contributes to 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 the lung tissue. Thus, the main functional feature of the bronchial tree of a small child is the insufficient performance of the drainage, cleansing function.
Lungs a newborn weighs about 50 g, by 6 months their weight doubles, by a year it triples, 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, also changes significantly. The primary bronchus, having entered the gates of the lungs, is divided into smaller bronchi, which form the bronchial tree. The thinnest twigs call it bronchioles. Thin bronchioles enter the lung lobules and within them divide 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 airway. 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. Through the walls of the alveoli and capillaries, gases are exchanged - oxygen passes from the air into the blood, and carbon dioxide and water vapor enter the alveoli from the blood.
In the lungs, there are up to 350 million alveoli, and their surface reaches 150 m 2. The large surface of the alveoli contributes to better gas exchange. On one side of this surface is alveolar air, constantly renewing in its composition, on the other - blood continuously flowing through the vessels. Diffusion of oxygen and carbon dioxide occurs through the vast surface of the alveoli. During physical work, when the alveoli are significantly stretched at deep entrances, the size of the respiratory surface increases. The larger the total surface of the alveoli, the more intense the diffusion of gases occurs. In a child, as in adults, the lungs have a segmental structure.
Fig.2. Segmental structure of the lung
The segments are separated from each other by narrow grooves and layers of connective tissue (lobular lung). The main structural unit is the acinus, 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 is 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 alveolus also increases (0.05 mm in a newborn, 0.12 mm at 4-5 years, 0.17 mm by 15 years). At the same time, the vital capacity of the lungs increases (this maximum amount air that can be taken into the lungs after maximum exhalation. The vital capacity of the lungs in children is more labile than in adults.
Vital capacity of the lungs, the norm in children
Vital capacity (VC)- this is the maximum amount of air exhaled after the deepest breath (Table 1).
For girls aged 4 to 17 years, whose height is in the range from 1 to 1.75 meters, the normal vital capacity of the lungs is calculated by the formula: 3.75 x height - 3.15.
For boys aged 4 to 17 and up to 1.65 meters tall, the JEL is calculated using the formula: 4.53 X height − 3.9
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 lung capacity in children depending on age
The volume of the lungs 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 is relatively larger in children than in adults; the contact surface of the alveolar air with the system of vascular pulmonary capillaries 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 in them.
Atelectasis occurs especially often in the posterior parts of the lungs, where hypoventilation and blood stasis are constantly observed due to forced horizontal position a small child (mainly on the back).
The tendency to atelectasis is increased due to a deficiency of surfactant - this is a film that regulates the surface alveolar tension.
Surfactant is produced by alveolar macrophages. It is this deficiency that leads to insufficient expansion of the lungs in preterm infants after birth (physiological atelectasis).
Pleural cavity
. The child is easily extensible due to the weak attachment of the parietal sheets. Visceral pleura, especially in newborns, relatively thick, loose, folded, contains villi, outgrowths, most pronounced in the sinuses, interlobar grooves. In these areas, there are conditions for a more rapid emergence of infectious foci.
Mediastinum relatively more in children than in adults. In its upper part it contains the trachea, large bronchi, thymus and lymph nodes, arteries and large nerve trunks, in its lower part are the heart, blood vessels and nerves.
The mediastinum is an integral part of the lung root, which is characterized by easy displacement and is often the site of the development of inflammatory foci, from where the infectious process spreads to the bronchi and lungs.
The right lung is usually slightly larger than the left. In young children, pulmonary fissures are often weakly expressed, only in the form of shallow furrows on the surface of the lungs. Especially often, the middle lobe of the right lung almost merges with the upper one. A large, or main, oblique fissure separates the lower lobe from the upper and middle lobes to the right, and the small horizontal one runs between the upper and middle lobes. There is only one gap on the left.
Therefore, differentiation children's lung, is characterized by quantitative and qualitative changes: a decrease in respiratory bronchioles, the development of alveoli from the alveolar passages, 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 predetermine some of its features. The chest is always in a state of inhalation, the thin intercostal spaces are smoothed out, and the ribs are quite strongly pressed into the lungs.
The ribs in very young children are almost perpendicular to the spine, and it is almost impossible to increase the capacity of the chest by raising the ribs. This explains the diaphragmatic nature of breathing at this age. In newborns and children in the first months of life, the anterior-posterior and lateral diameters of the chest are almost equal, and the epigastric angle is obtuse.
As the child ages, the cross-section of the chest becomes oval or barrel-shaped.
The frontal diameter increases, the sagittal diameter relatively decreases, 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 falls to the level of the II-III thoracic vertebrae. Diaphragm dome reaching in infants top edge IV ribs, with age falls slightly lower.
From the foregoing, it can be seen that the chest in children gradually passes from the inspiratory position to the expiratory one, 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 past illnesses(rickets, pleurisy) and various negative environmental influences.
First breath of a newborn. During intrauterine development in the fetus, gas exchange takes place exclusively due to the placental circulation. At the end of this period, the fetus develops correct intrauterine respiratory movements, indicating the ability of the respiratory center to respond to irritation. From the moment the child 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 since the 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 along the birth canal mother. However, in those cases when a child is born with a sufficient supply of oxygen in the blood or there is a slightly reduced excitability of the respiratory center, it takes several seconds, and sometimes even minutes, until the first breath appears. This brief breath holding is called neonatal apnea.
After the first deep breath in healthy children, the correct and for the most part fairly even breathing. The unevenness of the respiratory rhythm noted in some cases during the first hours and even days of a child's life usually quickly levels off.
Similar information.
The respiratory organs in children are not only absolutely smaller, but, in addition, they also differ in some incompleteness of the anatomical and histological structure.
The child's nose is relatively small, its cavities are underdeveloped, the nasal passages are narrow; the lower nasal passage in the first months of life is completely absent or rudimentary developed. The mucous membrane is tender, rich in blood vessels, the submucosa is poor in cavernous tissue in the first years of life; at 8-9 years old, the cavernous tissue is already quite developed, and it is especially abundant during puberty.
The paranasal cavities in young children are very poorly developed or even completely absent. The frontal sinus appears only in the 2nd year of life, by the age of 6 it reaches the size of a pea and is finally formed only by the age of 15. The maxillary cavity, although already present in newborns, is very small and only from the age of 2 begins to noticeably increase in volume; approximately the same must be said of sinus ethmoidalis. Sinus sphenoidalis in young children is very small; up to 3 years of age, its contents are easily emptied into the nasal cavity; from the age of 6, this cavity begins to increase rapidly. Due to the poor development of the accessory nasal cavities in young children, inflammatory processes with the nasal mucosa very rarely spread to these cavities.
The nasolacrimal canal is short, its outer opening is located close to the corner of the eyelids, the valves are underdeveloped, which greatly facilitates the infection from the nose into the conjunctival sac.
The pharynx in children is relatively narrow and has a more vertical direction. Waldeyer's ring in newborns is poorly developed; pharyngeal tonsils are invisible when examining the pharynx and become visible only by the end of the 1st year of life; in the following years, on the contrary, accumulations of lymphoid tissue and tonsils are somewhat hypertrophied, reaching maximum expansion most often between 5 and 10 years. In puberty, the tonsils begin to undergo reverse development, and after puberty it is relatively very rare to see their hypertrophy. Adenoid expansions are most pronounced in children with exudative and lymphatic diathesis; they especially often have to observe nasal breathing disorders, chronic catarrhal conditions of the nasopharynx, sleep disturbances.
The larynx in children of the earliest age has a funnel-shaped shape, later - cylindrical; it is located slightly higher than in adults; its lower end in newborns is at the level of the IV cervical vertebra (in adults it is 1-1.5 vertebrae lower). The most vigorous growth of the transverse and anterior-posterior dimensions of the larynx is noted in the 1st year of life and at the age of 14-16 years; with age, the funnel-shaped form of the larynx gradually approaches the cylindrical. The larynx in young children is relatively longer than in adults.
The cartilages of the larynx in children are tender, very pliable, the epiglottis up to 12-13 years old is relatively narrow, and in infants it can be easily seen even with a normal examination of the pharynx.
Sexual differences in the larynx in boys and girls begin to be revealed only after 3 years, when the angle between the plates of the thyroid cartilage in boys becomes more acute. From the age of 10, the features characteristic of the male larynx are already quite clearly identified in boys.
These anatomical and histological features of the larynx explain the mild onset of stenotic phenomena in children, even with relatively mild inflammation. The hoarseness of the voice, often noted in young children after a cry, usually does not depend on inflammatory phenomena, but from the lethargy of easily fatigued muscles of the glottis.
The trachea in newborns is about 4 cm long, by the age of 14-15 it reaches approximately 7 cm, and in adults it is 12 cm. It has a somewhat funnel-shaped shape in children of the first months of life and is located higher than in adults; 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 III-IV thoracic vertebrae, in children 5 years old - IV-V and 12-year-olds - V - VI vertebrae.
The growth of the trachea is approximately parallel to the growth of the trunk; between the width of the trachea and the circumference of the chest at all ages, almost constant relationships remain. The cross section of the trachea in children of the first months of life resembles an ellipse, in subsequent ages it is a circle.
The mucous membrane of the trachea is tender, rich in blood vessels, and comparatively dry, owing to insufficient secretion of the mucous glands. The muscular layer of the membranous part of the tracheal wall is well developed even in very young children; elastic tissue is in a relatively small amount.
Children's trachea is soft, easily squeezed; under the influence of inflammatory processes, stenotic phenomena easily occur. The trachea is mobile to some extent and can move under the influence of unilateral pressure (exudate, tumors).
Bronchi. The right bronchus is, as it were, a continuation of the trachea, the left bronchus departs at a large angle; this explains the more frequent entry of foreign bodies into the right bronchus. The bronchi are narrow, their cartilage is soft, the muscle and elastic fibers are relatively poorly developed, the mucosa is rich in blood vessels, but relatively dry.
The lungs of a newborn weigh about 50 g, by 6 months their weight doubles, by a year it triples, by 12 years it reaches 10 times its original weight; in adults, the lungs weigh almost 20 times more than at birth. The right lung is usually slightly larger than the left. In young children, pulmonary fissures are often weakly expressed, only in the form of shallow furrows on the surface of the lungs; especially often, the middle lobe of the right lung almost merges with the upper one. A large, or main, oblique fissure separates the lower lobe from the upper and middle lobes to the right, and the small horizontal one runs between the upper and middle lobes. There is only one gap on the left.
From the growth of the mass of the lungs, it is necessary to distinguish the differentiation of individual cellular elements. The main anatomical and histological unit of the lung is the acinus, which, however, has a relatively primitive character in children under 2 years of age. From 2 to 3 years, cartilaginous muscular bronchi develop vigorously; from the age of 6-7 years, the histostructure of the acinus basically coincides with that of an adult; the sacculuses that sometimes come across do not already have a muscular layer. Interstitial (connective) tissue in children is loose, rich in lymphatic and blood vessels. Children's lung is poor in elastic tissue, especially in the circumference of the alveoli.
The epithelium of the alveoli in non-breathing stillborns is cuboidal, in breathing newborns and in older children it is flat.
Differentiation of the children's lung, thus, is characterized by quantitative and qualitative changes: a decrease in respiratory bronchioles, the development of alveoli from the alveolar passages, an increase in the capacity of the alveoli themselves, a gradual reverse development of intrapulmonary connective tissue layers and an increase in elastic elements.
The volume of the lungs of already breathing newborns is about 67 cm 3; by the age of 15, their volume increases 10 times and in adults - 20 times. The overall growth of the lungs is mainly due to an increase in the volume of the alveoli, while the number of the latter remains more or less constant.
The breathing surface of the lungs is relatively larger in children than in adults; the contact surface of the alveolar air with the system of vascular pulmonary capillaries 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 in them.
Children, especially young children, are prone to pulmonary atelectasis and hypostasis, the occurrence of which is favored by the abundance of blood in the lungs and the insufficient development of elastic tissue.
The mediastinum in children is relatively larger than in adults; in its upper part it contains the trachea, large bronchi, thymus and lymph nodes, arteries and large nerve trunks, in its lower part are the heart, blood vessels and nerves.
The lymph nodes. The following groups of lymph nodes in the lungs are distinguished: 1) tracheal, 2) bifurcation, 3) bronchopulmonary (at the entry of the bronchi into the lungs) and 4) nodes of large vessels. These groups of lymph nodes are connected by lymphatic routes with the lungs, mediastinal and supraclavicular nodes (Fig. 48).
Rice. 48. Topography of mediastinal lymph nodes (according to Sukennikov).
1 - lower tracheobronchial;
2 - upper tracheobronchial;
3 - paratracheal;
4 - bronchopulmonary nodes.
Rib cage. Relatively large lungs, heart and mediastinum occupy relatively more space in the child's chest and predetermine some of its features. The chest is always in a state of inhalation, the thin intercostal spaces are smoothed out, and the ribs are quite strongly pressed into the lungs.
The ribs in very young children are almost perpendicular to the spine, and it is almost impossible to increase the capacity of the chest by raising the ribs. This explains the diaphragmatic nature of breathing at this age. In newborns and infants in the first months of life, the anterior-posterior and lateral diameters of the chest are almost equal, and the epigastric angle is very obtuse.
With the age of the child, the cross section of the chest takes an oval or kidney-shaped shape. The frontal diameter increases, the sagittal diameter relatively decreases, and the curvature of the ribs increases significantly; the epigastric angle becomes more acute.
These ratios are characterized by a chest indicator (the percentage ratio between the anterior-posterior and transverse diameters of the chest): in the fetus of the early embryonic period it is 185, in the newborn 90, by the end of the year - 80, by 8 years - 70, after the pubertal period it is again somewhat increases and fluctuates around 72-75.
The angle between the costal arch and the medial section of the chest in a newborn is approximately 60 °, by the end of the 1st year of life - 45 °, at the age of 5 years - 30 °, at 15 years - 20 ° and after the end of puberty - about 15 °.
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 falls to the level of the II-III thoracic vertebrae. The dome of the diaphragm, reaching the upper edge of the IV rib in infants, falls slightly lower with age.
From the foregoing, it can be seen that the chest in children gradually passes from the inspiratory position to the expiratory one, 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 impacts environment. The age-related anatomical features of the chest also determine some physiological features of the breathing of children in different periods childhood.
First breath of a newborn. During intrauterine development in the fetus, gas exchange takes place exclusively due to the placental circulation. At the end of this period, the fetus develops correct intrauterine respiratory movements, indicating the ability of the respiratory center to respond to irritation. From the moment the child is born, gas exchange stops due to the placental circulation and pulmonary respiration begins.
The physiological causative agent of the respiratory center is carbon dioxide, the increased accumulation of which since the termination 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 an excess of carbon dioxide in the blood of a newborn, but 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 those cases when a child is born with a sufficient supply of oxygen in the blood or there is a slightly reduced excitability of the respiratory center, it takes several seconds, and sometimes even minutes, until the first breath appears. This brief breath holding is called neonatal apnea.
After the first deep breath, normal and mostly fairly regular breathing is established in healthy children; the unevenness of the respiratory rhythm noted in some cases during the first hours and even days of a child's life usually quickly levels off.
Respiratory rate in newborns, about 40-60 per minute; with age, breathing becomes more rare, gradually approaching the rhythm of an adult. According to our observations, the respiratory rate in children is as follows.
Up to 8 years, boys breathe more often than girls; in the prepubertal period, girls overtake boys in respiratory rate, and in all subsequent years their breathing remains more frequent.
Children are characterized by mild excitability of the respiratory center: lungs physical stress and mental excitement, slight increases in body temperature and ambient air almost always cause a significant increase in breathing, and sometimes some violation of the correctness of the respiratory rhythm.
For one respiratory movement in newborns, on average, there are 272-3 pulse beats, in children at the end of the 1st year of life and older - 3-4 beats, and, finally, in adults - 4-5 heartbeats. These ratios usually persist with increased heart rate and respiration under the influence of physical and mental stress.
Breathing volume. To assess the functional ability of the respiratory system, the volume of one respiratory movement, the minute volume of respiration and the vital capacity of the lungs are usually taken into account.
The volume of each respiratory movement in a newborn in a state of restful sleep is equal to an average of 20 cm 3, in a month-old child it rises to approximately 25 cm 3, by the end of the year it reaches 80 cm 3, by 5 years - about 150 cm 3, by 12 years - an average of about 250 cm 3 and by 14-16 for years it rises to 300-400 cm 3; however, this value, apparently, can fluctuate within fairly wide individual limits, since the data of various authors differ greatly. When crying, the volume of breathing increases sharply - by 2-3 and even 5 times.
The minute volume of respiration (the volume of one breath multiplied by the respiratory rate) increases rapidly with age and approximately equals 800-900 cm 3 in a newborn, 1400 cm 3 in a child aged 1 month, and about 2600 cm 3 by the end of the 1st year , at the age of 5 years - about 3200 cm 3 and at 12-15 years old - about 5000 cm 3.
The vital capacity of the lungs, i.e., the amount of air exhaled as much as possible after a maximum breath, can only be indicated for children from 5-6 years old, since the research methodology itself requires the active participation of the child; at 5-6 years old, the vital capacity fluctuates around 1150 cm 3, at 9-10 years old - about 1600 cm 3 and at 14-16 years old - 3200 cm 3. Boys have greater lung capacity than girls; The greatest lung capacity occurs with thoraco-abdominal breathing, the smallest - with purely chest.
The type of breathing varies depending on the age and sex of the child; in children of the neonatal period, diaphragmatic breathing predominates with little participation of the costal muscles. In infants, the so-called thoraco-abdominal breathing with a predominance of diaphragmatic is detected; chest excursions are weakly expressed in its upper parts and, conversely, much stronger in the lower parts. With the transition of the child from a constant horizontal position to a vertical position, the type of breathing also changes; it at this age (the beginning of the 2nd year of life) is characterized by a combination of diaphragmatic and chest breathing, and in some cases one prevails, in others the other. At the age of 3-7 years, in connection with the development of the muscles of the shoulder girdle, chest breathing becomes more and more distinct, beginning to definitely dominate diaphragmatic breathing.
The first differences in the type of breathing depending on sex begin to clearly affect at the age of 7-14 years; in the prepubertal and pubertal periods, boys develop mainly the abdominal type, and girls develop the chest type of breathing. Age-related changes in the type of breathing are predetermined by the above anatomical features of the chest of children in different periods of life.
Increasing chest capacity by raising the ribs in infants is almost impossible due to the horizontal position of the ribs; it becomes possible in later periods, when the ribs descend somewhat downward and anteriorly, and when they are raised, an increase in the anterior-posterior and lateral dimensions of the chest occurs.
