Anatomical and physiological features of the respiratory organs
The respiratory system consists of airways and a gas exchange apparatus. The upper respiratory tract includes the nasal cavity, pharynx and larynx, and the lower respiratory tract includes the trachea and bronchi. Gas exchange between atmospheric air and carried out by blood in the lungs. The respiratory organs are morphologically imperfect at the time of the child. During the first years of life, they grow and differentiate rapidly. By the age of 7, the formation of the respiratory organs ends and in the future there is only an increase in their size. Features of the morphological structure of the respiratory organs are: 1) thin, easily wounded mucosa; 2) underdeveloped glands; 3) reduced production of immunoglobulin A and surfactant; 4) a submucosal layer rich in capillaries, consisting mainly of loose fiber; 5) soft, pliable cartilaginous frame lower sections respiratory tract; 6) insufficient amount of elastic tissue in the respiratory tract and lungs. Nasal cavity. The nose in children of the first three years of life is small, its cavities are underdeveloped, the nasal passages are narrow, and the shells are thick. The lower nasal meatus is absent. It is formed by the age of 4. When young children have a runny nose, swelling of the mucous membrane easily occurs, which leads to obstruction of the nasal passages, makes it difficult to suck the breast, and causes shortness of breath. The cavernous tissue of the nasal submucosa is underdeveloped, which explains rare nosebleeds. The paranasal sinuses are not formed at the time of birth. The nasolacrimal duct is wide, which allows infection to penetrate from the nose into the conjunctival sac. Pharynx. In children early age relatively narrow and small. Eustachian tube. Short and wide, located more horizontally than in older children, its opening is closer to the choanae. This predisposes to easier infection of the tympanic cavity with rhinitis. Epiglottis. In a newborn, it is soft and bends easily, losing the ability to hermetically cover the entrance to the trachea. This partly explains great danger aspiration of stomach contents into the respiratory tract during vomiting and regurgitation. Incorrect position and softness of the epiglottis cartilage can cause functional narrowing of the entrance to the larynx and the appearance of noisy (stridorous) breathing. Larynx. It is located higher than in adults, so the child, lying on his back, can swallow liquid food. The larynx has a funnel shape. In the area of the subglottic space there is a clearly pronounced narrowing. The diameter of the larynx in this place in a newborn is only 4 mm and increases slowly with age; by the age of 14 it is 1 cm. The narrow lumen of the larynx, easily occurring swelling of the submucosal layer, spasm of smooth muscles due to the abundance of nerve receptors in the subglottic space can lead to respiratory infection to stenosis (narrowing) of the larynx. Trachea. In a newborn baby, it is relatively wide, supported by open cartilaginous rings and a wide muscle membrane. Contraction and relaxation of muscle fibers change its lumen. The trachea is very mobile, which, along with the changing lumen and softness of the cartilage, leads to its collapse at the exit and is the cause of expiratory shortness of breath or rough wheezing breathing (congenital stridor). Symptoms of stridor disappear by age two, when the cartilage becomes denser. Bronchial tree. By the time the child is born, it is formed. The bronchi are narrow, their cartilage is soft and pliable, since the basis of the bronchi, like the trachea, is made up of half rings connected by a fibrous film. In young children, the angle of departure of both bronchi from the trachea is the same and foreign bodies can enter both the right and left bronchus. With age, the angle changes; foreign bodies are more often found in the right bronchus, since it is like a continuation of the trachea. At an early age, the bronchial tree does not perform its cleansing function sufficiently. Self-cleaning mechanisms - wave-like movements of the ciliated epithelium of the bronchial mucosa, peristalsis of bronchioles, cough reflex - are much less developed than in adults. Hyperemia and swelling of the mucous membrane, accumulation of infected mucus significantly narrow the lumen of the bronchi until they are completely blocked, which contributes to the development of atelectasis and infection of the lung tissue. Spasm easily develops in the small bronchi, which explains the frequency bronchial asthma and the asthmatic component in bronchitis and pneumonia in childhood. Lungs. In a newborn baby, the lungs are not fully formed. The terminal bronchioles do not end in a cluster of alveoli, as in an adult, but in a sac, from the edges of which new alveoli are formed. The number of alveoli and their diameter increase with age. The vital capacity of the lungs also increases. The interstitial tissue in the lung is loose, contains very little connective tissue and elastic fibers, and is rich in fiber and blood vessels. In this regard, the lungs of a young child are more full-blooded and less airy than those of an adult. The poverty of elastic fibers contributes to the ease of emphysema and atelectasis of lung tissue. The tendency to atelectasis increases due to surfactant deficiency. A surfactant is a surfactant that coats thin film inner surface of the alveoli. It prevents them from collapsing as you exhale. With surfactant deficiency, the alveoli do not expand sufficiently and respiratory failure develops. Atelectasis most often occurs in the posterior regions of the lungs due to their poor ventilation. The development of atelectasis and ease of infection of the lung tissue is facilitated by blood stagnation as a result of the forced horizontal position of the child infancy. The lung parenchyma in young children can rupture with a relatively small increase in air pressure in the respiratory tract. This can occur if the technique of artificial ventilation is violated. K o r e n l e g k o g consists of large bronchi, vessels and lymph nodes. Lymph nodes react to the introduction of infection. Pleura well supplied with blood and lymphatic vessels, relatively thick, easily extensible. The parietal layer of the pleura is weakly fixed. The accumulation of fluid in the pleural cavity causes displacement of the mediastinal organs. Thorax, diaphragm and mediastinum. The diaphragm is located high. Its contractions increase the vertical size of the thoracic cavity. Ventilation of the lungs is worsened by conditions that impede the movement of the diaphragm (flatulence, increase in the size of parenchymal organs). The pliability of a child's chest can lead to paradoxical retraction of the intercostal spaces during breathing. At different periods of life, breathing has its own characteristics: 1) shallow and frequent breathing. The respiratory rate is higher, the more younger child. The greatest number of respirations is observed after birth - 40-60 per 1 minute, which is sometimes called “physiological shortness of breath” of a newborn. In children 1-2 years old, the respiratory rate is 30-35, in 5-6 years old it is about 25, in 10 years old it is 18-20, in adults it is 15-16. The ratio of respiratory rate to pulse rate in newborns is 1: 2.5-3; in children of other ages 1: 3.5-4; in adults 1: 4; 2) respiratory arrhythmia in the first 2-3 weeks of a newborn’s life. It manifests itself as an incorrect alternation of pauses between inhalation and exhalation. The inhalation is much shorter than the exhalation. Sometimes breathing is intermittent. This is due to the imperfection of the function of the respiratory center; 3) the type of breathing depends on age and gender. At an early age, the abdominal (diaphragmatic) type of breathing is noted; at 3-4 years, chest breathing begins to predominate over diaphragmatic breathing. Differences in breathing depending on gender are detected from 7-14 years. During puberty, boys develop abdominal, girls - infant type of breathing. To study respiratory function, the respiratory rate is determined at rest and during physical activity; measure the size of the chest and its mobility (at rest, during inhalation and exhalation), determine the gas composition and acid-base state of the blood. Children over 5 years of age undergo spirometry. Anatomical and physiological features respiratory system, imperfect immunity, the presence of concomitant diseases, and the influence of environmental factors explain the frequency and severity of respiratory diseases in children.
The development of the respiratory organs begins in the 3rd week of embryonic development and continues for a long time after the birth of the child. At the 3rd week of embryogenesis from cervical region a protrusion appears in the endodermal tube, which grows rapidly, and a flask-shaped expansion appears on its caudal section. At the 4th week, it is divided into right and left parts - the future right and left lungs - each of which branches like a tree. The resulting protrusions grow into the surrounding mesenchyme, continuing to divide, and at their ends spherical extensions appear - the rudiments of the bronchi - of an increasingly smaller caliber. At the 6th week they form lobar bronchi, on the 8th--10th - segmental. The typical number of airways for an adult is formed by the end of the 16th week of fetal development. From this endodermal rudiment the epithelium of the lungs and respiratory tract is formed. Smooth muscle fibers and bronchial cartilage are formed from mesodermal mesenchyme (the formation of the cartilaginous framework of the trachea and bronchi begins from the 10th week of fetal development). This is the so-called pseudoglandular stage of lung development. A greater number of bronchi approach the lower lobes of the lungs, the airways of which are longer than those of the upper lobes.
The canalicular phase (recanalization) - weeks 16-26 - is characterized by the formation of a lumen in the bronchi, continued development and vascularization of the future respiratory parts of the lung. The final phase (alveolar) - the period of formation of alveoli - begins from the 24th week, does not end at birth, the formation of alveoli continues in the postnatal period. By the time of birth, there are about 70 million primary alveoli in the fetal lungs.
The respiratory organs in children are relatively smaller in size and are characterized by incomplete anatomical and histological development. The nose of a young child is relatively small, the nasal passages are narrow, and the lower nasal passage is absent. The nasal mucosa is delicate, relatively dry, rich in blood vessels. Due to the narrowness of the nasal passages and the abundant blood supply to their mucous membrane, even minor inflammation causes difficulty breathing through the nose in young children. Breathing through the mouth is impossible in children in the first six months of life, since the large tongue pushes the epiglottis backward. The exit from the nose - the choanae - is especially narrow in young children, which is often the cause of long-term disruption of nasal breathing in them.
The paranasal sinuses in young children are very poorly developed or completely absent. As the facial bones increase in size ( upper jaw) and teeth erupt, the length and width of the nasal passages and the volume of the paranasal sinuses increase. By the age of 2 years, the frontal sinus appears, and the maxillary cavity increases in volume. By the age of 4, the lower nasal passage appears. These features explain the rarity of diseases such as sinusitis, frontal sinusitis, ethmoiditis in early childhood. Due to the insufficient development of cavernous tissue in young children, the inhaled air is poorly warmed up; therefore, children cannot be taken outside at temperatures below -10° C. Cavernous tissue develops well by the age of 8-9 years, this explains the relative rarity of nosebleeds in children 1 year of life. A wide nasolacrimal duct with underdeveloped valves contributes to the transfer of inflammation from the nose to the mucous membrane of the eyes. Passing through the nose, atmospheric air is warmed, moistened and purified. 0.5-1 liters of mucus per day are secreted into the nasal cavity. Every 10 minutes, a new layer of mucus passes through the nasopharynx, which contains bactericidal substances (lysozyme, complement, etc.), secretory immunoglobulin A.
The pharynx in children is relatively narrow and has a more vertical direction than in adults. The lymphopharyngeal ring in newborns is poorly developed. Pharyngeal tonsils become visible only at the end of the 1st year of life. Therefore, tonsillitis in children under 1 year of age occurs less frequently than in older children. By the age of 4-10 years, the tonsils are already well developed, and their hypertrophy can easily occur. During puberty, the tonsils begin to undergo reverse development. The tonsils are like a filter for microbes, but with frequent inflammatory processes, a focus of chronic infection can form in them, causing general intoxication and sensitization of the body.
The proliferation of adenoids (nasopharyngeal tonsil) is most pronounced in children with constitutional abnormalities, in particular with lymphatic-hypoplastic diathesis. If the adenoids are significantly enlarged - degree 1.5-2 - they are removed, since nasal breathing is impaired in children (children breathe open mouth- the air is not purified and warmed by the nose, and therefore they often get sick colds), the shape of the face changes (adenoid face), children become distracted (mouth breathing distracts attention), and their academic performance deteriorates. When breathing through the mouth, posture is also disturbed; adenoids contribute to the formation of malocclusion.
The Eustachian tubes in young children are wide, and when the child is in a horizontal position, the pathological process from the nasopharynx easily spreads to the middle ear, causing the development of otitis media.
The larynx in young children has a funnel-shaped shape (later - cylindrical) and is located slightly higher than in adults (at the level of the 4th cervical vertebra in a child and the 6th cervical vertebra in an adult). The larynx is relatively longer and narrower than in adults; its cartilages are very pliable. False vocal cords and mucous membrane are tender, rich in blood and lymphatic vessels, elastic tissue is poorly developed. The glottis in children is narrow. Young children's vocal cords are shorter than older children's, which is why they have a high-pitched voice. From the age of 12, boys' vocal cords become longer than girls'. These features of the larynx explain easy development in children, stenotic phenomena even with moderate inflammatory changes in the laryngeal mucosa. The increased neuromuscular excitability of a small child is also of great importance. Hoarseness, often observed in young children after a cry, often depends not on inflammatory phenomena, but on the weakness of the easily fatigued muscles of the vocal cords.
The trachea in newborns is funnel-shaped, its lumen is narrow, the posterior wall has a wider fibrous part, the walls are more pliable, the cartilage is soft and easily compressed. Its mucous membrane is delicate, rich in blood vessels and dry due to the insufficient development of the mucous glands, elastic tissue is poorly developed. The secretion of the glands provides a layer of mucus on the surface of the trachea 5 microns thick, the speed of which is 10-15 mm/min (provided by cilia - 10-30 cilia per 1 micron 2). The growth of the trachea occurs in parallel with the growth of the body, most intensively in the 1st year of life and during puberty. The structural features of the trachea in children lead to inflammatory processes easy occurrence stenotic phenomena are determined by frequent isolated (tracheitis), combined with damage to the larynx (laryngotracheitis) or bronchi (tracheobronchitis). In addition, due to the mobility of the trachea, its displacement may occur during a unilateral process (exudate, tumor).
The bronchi are quite well formed at birth. The growth of the bronchi is intense in the 1st year of life and during puberty. Their mucous membrane is richly vascularized, covered with a layer of mucus, which moves at a speed of 3-10 mm/min, in the bronchioles it is slower - 2-3 mm/min. The right bronchus is like a continuation of the trachea; it is shorter and wider than the left. This explains the frequent entry of a foreign body into the right main bronchus. The bronchi are narrow, their cartilage is soft. Muscle and elastic fibers in children of the 1st year of life are not yet sufficiently developed. The tenderness of the bronchial mucosa and the narrowness of their lumen explain frequent occurrence in young children, bronchiolitis with complete or partial obstruction syndrome.
The lungs of newborns weigh about 50 g, by 6 months their weight doubles, by one year it triples, by 12 years it increases 10 times, by 20 years it increases 20 times. The pulmonary fissures are poorly expressed. In newborns, the lung tissue is less airy, with abundant development of blood vessels and connective tissue in the septa of the acini and an insufficient amount of elastic tissue. The latter circumstance explains the relatively easy occurrence of emphysema in various pulmonary diseases. The weak development of elastic tissue partly explains the tendency of young children to atelectasis, which is also facilitated by insufficient excursion of the chest and narrowness of the bronchi. This is also facilitated by insufficient production of surfactant, especially in premature infants. Atelectasis occurs especially easily in the posterior lower sections of the lungs, since these sections are especially poorly ventilated due to the fact that the child lies on his back almost all the time, and blood stagnation easily occurs. The acini are not sufficiently differentiated. During postnatal development, alveolar ducts with typical alveoli are formed. Their number increases rapidly during the 1st year and continues to increase up to 8 years. This leads to an increase in the respiratory surface. The number of alveoli in newborns (24 million) is 10-12 times, and their diameter (0.05 mm) is 3-4 times less than in adults (0.2-0.25 mm). 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.
The formation of the lung structure occurs depending on the development of the bronchi. After the trachea divides into the right and left main bronchi, each of them is divided into lobar bronchi, which approach each lobe of the lung. Then the lobar bronchi are divided into segmental bronchi. Each segment has independent ventilation, a terminal artery and intersegmental septa made of elastic connective tissue. The segmental structure of the lungs is already well expressed in newborns. There are 10 segments in the right lung, 9 in the left. The upper left and right lobes are divided into three segments - 1, 2 and 3, the middle right lobe - into two segments - the 4th and 5th. In the left light medium The lobe corresponds to the lingular lobe, also consisting of two segments - the 4th and 5th. The lower lobe of the right lung is divided into five segments - 6, 7, 8, 9 and 10th, the left lung - into four segments - 6, 8, 9 and 10th. In children, the pneumonic process is most often localized in certain segments (6, 2, 10, 4, 5), which is associated with the characteristics of aeration, the drainage function of the bronchi, the evacuation of secretions from them and possible infection.
External respiration, that is, the exchange of gases between atmospheric air and the blood of the capillaries of the lungs, is carried out through simple diffusion of gases through the alveolar-capillary membrane due to the difference in the partial pressure of oxygen in the inhaled air and venous blood flowing through the pulmonary artery into the lungs from the right ventricle. Compared to adults, young children have marked differences external respiration due to the development of acini, numerous anastomoses between the bronchial and pulmonary arteries, capillaries.
The depth of breathing in children is much less than in adults. This is explained by the small mass of the lungs and the structural features of the chest. The chest in children of the 1st year of life seems to be in a state of inhalation due to the fact that its anteroposterior size is approximately equal to the lateral size, the ribs extend from the spine almost at a right angle. This determines the diaphragmatic nature of breathing at this age. A full stomach and bloated intestines limit the mobility of the chest. With age, it gradually moves from the inspiratory position to the normal one, which is a prerequisite for the development of thoracic breathing.
The oxygen requirement in children is much higher than in adults. Thus, in children of the 1st year of life, the need for oxygen per 1 kg of body weight is about 8 ml/min, in adults - 4.5 ml/min. The shallow nature of breathing in children is compensated by a high breathing frequency (in a newborn - 40--60 breaths per minute, at the age of 1 year - 30--35, 5 years - 25, 10 years - 20, in adults - 16--18 breaths in 1 min), with the participation of most of the lungs in breathing. Due to the higher frequency, the minute volume of breathing per 1 kg of body weight is twice as high in young children as in adults. The vital capacity of the lungs (VC), that is, the amount of air (in milliliters) maximally exhaled after a maximum inhalation, is significantly lower in children compared to adults. Vital capacity increases in parallel with the increase in alveolar volume.
Thus, the anatomical and functional features respiratory systems in children create the preconditions for milder breathing problems than in adults.
ANATOMICAL AND PHYSIOLOGICAL FEATURES OF THE RESPIRATORY SYSTEM
The formation of the tracheopulmonary system begins at the 3-4th week of embryonic development. Already by the 5-6th week of embryo development, second-order branches appear and the formation of three lobes of the right lung and two lobes of the left lung is predetermined. During this period, the trunk of the pulmonary artery is formed, growing into the lungs along the primary bronchi.
In the embryo, at the 6-8th week of development, the main arterial and venous collectors of the lungs are formed. Within 3 months, the bronchial tree grows, segmental and subsegmental bronchi appear.
During the 11-12th week of development, areas of lung tissue are already present. They, together with the segmental bronchi, arteries and veins, form the embryonic segments of the lungs.
Between the 4th and 6th months there is fast growth pulmonary vascular system.
In fetuses at 7 months, the lung tissue acquires the features of a porous canal structure; the future air spaces are filled with fluid, which is secreted by the cells lining the bronchi.
At 8–9 months of the intrauterine period, further development of the functional units of the lungs occurs.
The birth of a child requires the immediate functioning of the lungs; during this period, with the onset of breathing, significant changes occur in the airways, especially the respiratory part of the lungs. The formation of the respiratory surface in individual parts of the lungs occurs unevenly. For the expansion of the respiratory apparatus of the lungs, the condition and readiness of the surfactant film lining the lung surface are of great importance. Violation of the surface tension of the surfactant system leads to serious illnesses young child.
In the first months of life, the child maintains the ratio of the length and width of the airways, like a fetus, when the trachea and bronchi are shorter and wider than in adults, and the small bronchi are narrower.
The pleura covering the lungs in a newborn baby is thicker, looser, contains villi and outgrowths, especially in the interlobar grooves. Pathological foci appear in these areas. Before the birth of a child, the lungs are prepared to perform the respiratory function, but individual components are at the stage of development, the formation and maturation of the alveoli is rapidly proceeding, the small lumen of the muscular arteries is being reconstructed and the barrier function is being eliminated.
After three months of age, period II is distinguished.
I – period of intensive growth of the pulmonary lobes (from 3 months to 3 years).
II – final differentiation of the entire bronchopulmonary system (from 3 to 7 years).
Intensive growth of the trachea and bronchi occurs in the 1st-2nd year of life, which slows down in subsequent years, and small bronchi grow intensively, and the branching angles of the bronchi also increase. The diameter of the alveoli increases, and the respiratory surface of the lungs doubles with age. In children under 8 months, the diameter of the alveoli is 0.06 mm, in 2 years – 0.12 mm, in 6 years – 0.2 mm, in 12 years – 0.25 mm.
In the first years of life, growth and differentiation of lung tissue elements and blood vessels occur. The ratio of share volumes of individual segments is equalized. Already at 6–7 years of age, the lungs are a mature organ and are indistinguishable from the lungs of adults.
FEATURES OF THE RESPIRATORY TRACT
The respiratory tract is divided into the upper, which includes the nose, paranasal sinuses, pharynx, and Eustachian tubes, and the lower, which includes the larynx, trachea, and bronchi.
The main function of breathing is to conduct air into the lungs, cleanse it of dust particles, protect the lungs from harmful effects bacteria, viruses, foreign particles. In addition, the airways warm and humidify the inhaled air.
The lungs are represented by small sacs that contain air. They connect with each other. The main function of the lungs is to absorb oxygen from the atmospheric air and release gases, primarily carbon dioxide, into the atmosphere.
Breathing mechanism. When you inhale, the diaphragm and chest muscles contract. Exhalation in older age occurs passively under the influence of elastic traction of the lungs. With bronchial obstruction, emphysema, and also in newborns, active inhalation occurs.
Normally, breathing is established at a frequency at which the volume of breathing is performed due to the minimum energy expenditure of the respiratory muscles. In newborn children, the respiratory rate is 30–40, in adults – 16–20 per minute.
The main carrier of oxygen is hemoglobin. In the pulmonary capillaries, oxygen binds to hemoglobin to form oxyhemoglobin. In newborns, fetal hemoglobin predominates. On the first day of life, it is contained in the body about 70%, by the end of the 2nd week - 50%. Fetal hemoglobin has the ability to easily bind oxygen and difficult to release it to tissues. This helps the child in the presence of oxygen starvation.
Transport of carbon dioxide occurs in dissolved form; blood oxygen saturation affects the carbon dioxide content.
The respiratory function is closely related to pulmonary circulation. This is a complex process.
During breathing, autoregulation is noted. When the lung is stretched during inhalation, the inhalation center is inhibited, while exhalation is stimulated during exhalation. Deep breathing or forced inflation of the lungs leads to a reflex expansion of the bronchi and increases the tone of the respiratory muscles. When the lungs collapse and are compressed, the bronchi become narrowed.
IN medulla oblongata The respiratory center is located, from where commands to the respiratory muscles come. The bronchi lengthen when you inhale, and shorten and narrow when you exhale.
The relationship between the functions of breathing and blood circulation manifests itself from the moment the lungs expand during the first breath of a newborn, when both the alveoli and blood vessels expand.
With respiratory diseases in children, respiratory dysfunction and respiratory failure may occur.
STRUCTURE FEATURES OF THE NOSE
In young children, the nasal passages are short, the nose is flattened due to an underdeveloped facial skeleton. The nasal passages are narrower, the conchae are thickened. The nasal passages are finally formed only by the age of 4 years. The nasal cavity is relatively small in size. The mucous membrane is very loose and well supplied with blood vessels. The inflammatory process leads to the development of edema and, as a result, a reduction in the lumen of the nasal passages. Mucus often stagnates in the nasal passages. It can dry out, forming crusts.
When the nasal passages close, shortness of breath may occur; during this period, the child cannot suckle, becomes anxious, abandons the breast, and remains hungry. Children, due to difficulty in nasal breathing, begin to breathe through their mouths, their warming of incoming air is disrupted and their susceptibility to colds increases.
If nasal breathing is impaired, there is a lack of discrimination of odors. This leads to a disturbance in appetite, as well as a disturbance in the understanding of the external environment. Breathing through the nose is physiological, breathing through the mouth is a sign of nasal disease.
Accessory nasal cavities. The paranasal cavities, or sinuses as they are called, are confined spaces filled with air. The maxillary (maxillary) sinuses are formed by the age of 7. Ethmoidal - by the age of 12, the frontal is fully formed by the age of 19.
Features of the nasolacrimal canal. The nasolacrimal duct is shorter than in adults, its valves are not sufficiently developed, and the outlet is located close to the corner of the eyelids. Due to these features, the infection quickly spreads from the nose to the conjunctival sac.
FEATURES OF THE PHARYN
The pharynx in young children is relatively wide, the palatine tonsils are poorly developed, which explains rare diseases sore throat in the first year of life. The tonsils are fully developed by the age of 4–5 years. By the end of the first year of life, almond tissue hyperplasias. But its barrier function at this age is very low. Overgrown almond tissue can be susceptible to infection, which is why diseases such as tonsillitis and adenoiditis occur.
The Eustachian tubes open into the nasopharynx and connect it to the middle ear. If an infection enters the middle ear from the nasopharynx, middle ear inflammation occurs.
FEATURES OF THE LARYNX
The larynx in children is funnel-shaped and is a continuation of the pharynx. In children, it is located higher than in adults, and has a narrowing in the area of the cricoid cartilage, where the subglottic space is located. The glottis is formed by the vocal cords. They are short and thin, which is responsible for the child’s high, sonorous voice. The diameter of the larynx in a newborn in the subglottic space is 4 mm, at 5–7 years old – 6–7 mm, by 14 years old – 1 cm. Features of the larynx in children are: its narrow lumen, many nerve receptors, easily occurring swelling of the submucosal layer, which can lead to severe breathing problems.
The thyroid cartilages form a more acute angle in boys over 3 years of age; from the age of 10, a typical male larynx is formed.
FEATURES OF THE TRACHEA
The trachea is a continuation of the larynx. It is wide and short, and the tracheal frame consists of 14–16 cartilaginous rings, which are connected by a fibrous membrane instead of an elastic end plate in adults. The presence of a large number of muscle fibers in the membrane contributes to changes in its lumen.
Anatomically, the trachea of a newborn is located at the level of the IV cervical vertebra, and in an adult – at the level of the VI–VII cervical vertebra. In children, it gradually descends, as does its bifurcation, which is located in a newborn at the level of the third thoracic vertebra, in children 12 years old - at the level of the V-VI thoracic vertebra.
During physiological breathing, the lumen of the trachea changes. During coughing, it decreases by 1/3 of its transverse and longitudinal dimensions. The mucous membrane of the trachea is rich in glands that secrete a secretion that covers the surface of the trachea with a layer 5 microns thick.
The ciliated epithelium promotes the movement of mucus at a speed of 10–15 mm/min from the inside to the outside.
The characteristics of the trachea in children contribute to the development of its inflammation - tracheitis, which is accompanied by a rough, low-pitched cough, reminiscent of a cough “like in a barrel”.
FEATURES OF THE BRONCHIAL TREE
The bronchi in children are formed at birth. Their mucous membrane is richly supplied with blood vessels, covered with a layer of mucus, which moves at a speed of 0.25-1 cm/min. A feature of the bronchi in children is that elastic and muscle fibers are poorly developed.
The bronchial tree branches to bronchi of the 21st order. With age, the number of branches and their distribution remain constant. The size of the bronchi changes rapidly in the first year of life and during puberty. They are based on cartilaginous semirings in early childhood. Bronchial cartilage is very elastic, pliable, soft and easily displaced. The right bronchus is wider than the left and is a continuation of the trachea, so foreign bodies are more often found in it.
After the birth of a child, a cylindrical epithelium with a ciliated apparatus is formed in the bronchi. With hyperemia of the bronchi and their swelling, their lumen sharply decreases (up to its complete closure).
Underdevelopment of the respiratory muscles contributes to a weak cough impulse in a small child, which can lead to blockage of small bronchi with mucus, and this, in turn, leads to infection of the lung tissue and disruption of the cleansing drainage function of the bronchi.
With age, as the bronchi grow, wide lumens of the bronchi appear, and the bronchial glands produce less viscous secretions, acute diseases of the bronchopulmonary system are less common compared to younger children.
FEATURES OF THE LUNG
The lungs in children, as in adults, are divided into lobes, and lobes into segments. The lungs have a lobular structure, the segments in the lungs are separated from each other by narrow grooves and partitions of connective tissue. The main structural unit is the alveoli. Their number in a newborn is 3 times less than in an adult. Alveoli begin to develop from 4-6 weeks of age, their formation occurs up to 8 years. After 8 years, the lungs in children increase due to their linear size, and the respiratory surface of the lungs increases in parallel.
The following periods can be distinguished in the development of the lungs:
1) from birth to 2 years, when intensive growth of the alveoli occurs;
2) from 2 to 5 years, when elastic tissue intensively develops, bronchi with peribronchial inclusions of lung tissue are formed;
3) from 5 to 7 years the functional abilities of the lungs are finally formed;
4) from 7 to 12 years, when a further increase in lung mass occurs due to the maturation of lung tissue.
Anatomically right lung consists of three lobes (upper, middle and lower). By 2 years, the sizes of the individual lobes correspond to each other, like in an adult.
In addition to the lobar division, segmental division is distinguished in the lungs: in the right lung there are 10 segments, in the left - 9.
The main function of the lungs is breathing. It is believed that 10,000 liters of air pass through the lungs daily. Oxygen absorbed from the inhaled air ensures the functioning of many organs and systems; the lungs take part in all types of metabolism.
The respiratory function of the lungs is carried out with the help of a biologically active substance - surfactant, which also has a bactericidal effect, preventing fluid from entering the pulmonary alveoli.
The lungs remove waste gases from the body.
A feature of the lungs in children is the immaturity of the alveoli; they have a small volume. This is compensated by increased breathing: than younger child, the more shallow his breathing. The respiratory rate in a newborn is 60, in a teenager it is already 16–18 respiratory movements per minute. Lung development is completed by age 20.
A variety of diseases can disrupt the vital respiratory function of children. Due to the characteristics of aeration, drainage function and evacuation of secretions from the lungs, the inflammatory process is often localized in the lower lobe. This occurs when infants are lying down due to insufficient drainage function. Paravisceral pneumonia most often occurs in the second segment of the upper lobe, as well as in the basal-posterior segment of the lower lobe. The middle lobe of the right lung may often be affected.
The following studies are of greatest diagnostic importance: X-ray, bronchological, determination of blood gas composition, blood pH, study of external respiration function, study of bronchial secretions, computed tomography.
By the frequency of breathing and its relationship with the pulse, the presence or absence of respiratory failure is judged (see Table 14).
Table 14 Age dynamics of respiratory rate (Fomin V.F., 2003)
source: Directory of Children's Diseases.
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477 rub
Pediatric dermatology
This book is a practical, well-illustrated tool for recognizing and treating all dermatological diseases and conditions encountered in pediatric practice. It includes over 900 color drawings to help you interpret the full spectrum clinical manifestations skin diseases in newborns, children and adolescents.
The guide is intended for dermatologists, pediatricians, neonatologists, students and graduate students of medical universities and faculties.
2399 rub
Posture. Cultivating correct posture. Treatment of postural disorders
The book is devoted to the problems of education of correct posture, prevention and treatment of its disorders in children of preschool and primary school age. Sets of gymnastic exercises are given that contribute to the formation of the correct skills necessary in Everyday life, as well as the development of agility, strength, endurance.
For a wide range of readers working with children, and especially for parents.
257 rub
Current issues of herbal medicine in pediatrics
Interest in herbal medicine has increased in recent years, as evidenced by big number publications in medical and popular science literature, as well as the growing attention of practitioners and parents of sick children to herbal medicine. The return to herbal medicine at the end of the twentieth century, the century of omnipotent chemistry, is paradoxical, but not an accident. A number of circumstances have emerged that confirm the feasibility of the ancient method of treatment along with other methods traditional medicine who have received citizenship rights in recent years. Let's name just a few problems: drug diseases, prevention and treatment of allergic diseases, possibilities for widespread use medicinal plants for the prevention of exacerbations of chronic diseases, as well as great prospects for their use in the clinic...
749 rub
Work in progress. Additional materials. Manual 1. “Cool” / “Not cool” (+ DVD-ROM)
In addition to the popular Work in Progress guide and curriculum, the Autism Partnership is offering this long-awaited series. It contains the most comprehensive information on various teaching strategies and shows videos of training sessions.
The goal of the Autism Partnership has always been to combine friendly informality and strict systematic teaching in the learning process. This series provides a unique opportunity to see how this approach is implemented in practice during educational process.
Manual 1 is devoted to the strategy of distinguishing between “Cool” and “Not Cool”. This is one of the most commonly used strategies for teaching both basic and more complex social skills. It is designed primarily to teach students the difference between socially acceptable (“cool”) behavior and socially unacceptable (“uncool”) behavior. In subsequent stages, students begin to master the target behavior and receive feedback for their efforts. Results scientific research confirm clinical experience: the “Cool” / “Not Cool” strategy is effective in teaching social skills and the ability to control one’s own behavior.
The manual comes with a DVD with examples of using this program in training center Autism Partnership in the USA.
334 rub
The book describes the most common diseases of periodontal and oral mucosa in children. The issues of the structure of the periodontium and oral mucosa in childhood, the classification and prevalence of these diseases in children at different age periods are considered. When describing the structure of diseases, modern international terminological additions were taken into account. Modern diagnostic methods available for use in pediatric dentistry practice are given. Treatment methods are outlined that aim the doctor not only at eliminating the symptoms of diseases, but also at identifying causal and pathogenetic relationships in the development of pathology in the oral cavity and other organs and systems. child's body. The organization and criteria for the effectiveness of treatment of children with periodontal diseases and oral mucosa are described.
182 rub
The modern guide outlines general issues, fundamentals and indications for the clinical use of ultrasound in the diagnosis of diseases of various organs and systems in children. The first chapter is devoted to the use of various techniques ultrasound examination in the diagnosis of anomalies and diseases of newborns. Subsequent chapters examine the ultrasound semiotics of infectious diseases and neoplasms of the chest, gastrointestinal tract and parenchymal organs. Clinical observations with detailed description ultrasonic semiotics various diseases in children. The manual is intended for students receiving postgraduate professional additional education, including in the system of continuing medical education, as well as radiology specialists, doctors working in ultrasound diagnostics offices and departments.
1724 rub
Physical and rehabilitation medicine in pediatrics
Currently, a relevant area of domestic healthcare is the development of physical and rehabilitation medicine, studying the influence physical methods treatment on the body, including children. This book is devoted to the theoretical, organizational and methodological foundations of physical and rehabilitation medicine in pediatrics, non-drug technologies of medical rehabilitation (physiotherapy, physical therapy, manual therapy, reflexology, medical psychology, etc.).
The publication is addressed to doctors in medical rehabilitation and physical therapy, physiotherapists, reflexologists, and will also be of interest to a wide range of specialists. The chapters on newborns (L. Salomonsen) and premature babies (A. Ilppö), on metabolism in children and its disorders (G. Fanconi, B. Wahlqvist, S. van Creveld), on diseases of the endocrine glands (G. Fanconi) are presented in great detail ), the doctrine of vitamins and avitaminosis (E. Glanzmann), about diseases of the blood and hematopoietic organs (L. Salomonsen), about heart and circulatory diseases (G. Fanconi and M. Grob) and a number of others.
Particularly valuable is the description of some rare diseases, as well as some issues of regional pathology (G. Zellweger) in the chapter on diseases of children in hot countries.
Special chapters are devoted surgical diseases in children, diseases of the musculoskeletal system, diseases of the skin, eyes, teeth, etc., which are usually not described in general guidelines for pediatricians.
Thus, this book represents a kind of encyclopedia of childhood diseases in one volume, presented at the level modern achievements medical science.
689 rub
The book is devoted to topical issues of modern pedagogy and pediatrics - issues of the formation of a teenager’s personality, the role of the family in his upbringing, ensuring the unity of ideological, political, moral, labor, mental, aesthetic and physical development teenage children.
The book also talks about preventing diseases, psychological characteristics raising difficult teenagers, about choosing a profession, some articles from the Civil and Criminal Codes of the RSFSR on the rights, duties and responsibilities of minors are given.
The publication is intended for parents.
150 rub
The respiratory system is a collection of organs consisting of the respiratory tract (nose, pharynx, trachea, bronchi), lungs (bronchial tree, acini), as well as muscle groups that promote contraction and relaxation of the chest. Breathing provides the body's cells with oxygen, which in turn convert it into carbon dioxide. This process occurs in the pulmonary circulation.
The formation and development of the child’s respiratory system begins during the 3rd week of a woman’s pregnancy. Formed from three primordia:
- Splanchnotome.
- Mesenchyme.
- Epithelium of the foregut.
The pleural mesothelium develops from the visceral and parietal layers of the splanchnotome. It is represented by a single-layer squamous epithelium (polygonal cells), lining the entire surface of the pulmonary system, separating it from other organs. External surface The leaf is covered with microcilia that produce serous fluid. It is necessary for the two layers of pleura to slide between each other during inhalation and exhalation.
From the mesenchyme, namely the germ layer of the mesoderm, cartilage, muscle and connective tissue structures, and blood vessels are formed. The bronchial tree, lungs, and alveoli develop from the epithelium of the foregut.
During the prenatal period, the respiratory tract and lungs are filled with fluid, which is removed during childbirth with the first breath, and is also absorbed by the lymph system and partially into the blood vessels. Breathing is carried out by maternal blood enriched with oxygen through the umbilical cord.
By the eighth month of gestation, pneumocytes produce a surfactant - surfactant. It lines the inner surface of the alveoli, prevents them from collapsing and sticking together, and is located at the air-liquid interface. Protects against harmful agents with the help of immunoglobulins and macrophages. Insufficient secretion or absence of surfactant threatens the development of respiratory distress syndrome.
A feature of the respiratory system in children is its imperfection. The formation and differentiation of tissues and cellular structures is carried out in the first years of life and up to seven years.
Structure
Over time, the child’s organs adapt to the environment in which he will live, and the necessary immune and glandular cells are formed. In a newborn, the respiratory tract, unlike an adult body, has:
- Narrower clearance.
- Short stroke lengths.
- Many vascular vessels in a limited area of the mucosa.
- The delicate, easily traumatized architectonics of the lining membranes.
- Loose structure of lymphoid tissue.
Upper paths
The baby's nose is small, its passages are narrow and short, so the slightest swelling can lead to obstruction, which will complicate the sucking process.
Structure upper paths The child has:
- Two nasal sinuses are developed - the upper and middle, the lower one will be formed by the age of four. The cartilage frame is soft and pliable. The mucous membrane has an abundance of blood vessels and lymphatic vessels, and therefore minor manipulation can lead to injury. Nosebleeds are rarely observed - this is due to undeveloped cavernous tissue (it will form by the age of 9). All other cases of bleeding from the nose are considered pathological.
- The maxillary sinuses, frontal and ethmoid sinuses are not closed, protrude the mucous membrane, are formed by 2 years of age, cases of inflammatory lesions are rare. Thus, the shell is more adapted to cleansing and humidifying the inhaled air. Full development of all sinuses occurs by age 15.
- The nasolacrimal duct is short, exits in the corner of the eye, close to the nose, which ensures rapid upward spread of inflammation from the nose to the lacrimal sac and the development of polyetiological conjunctivitis.
- The pharynx is short and narrow, which allows it to quickly become infected through the nose. At the level between the oral cavity and the pharynx there is a nasopharyngeal ring-shaped Pirogov-Waldeyer formation, consisting of seven structures. The concentration of lymphoid tissue protects the entrance to the respiratory and digestive organs from infectious agents, dust, and allergens. Features of the structure of the ring: poorly formed tonsils, adenoids, they are loose, susceptible to colonization of inflammatory agents in their crypts. Chronic foci of infection, frequent respiratory diseases, sore throats, and difficulty in nasal breathing occur. Such children develop neurological disorders, they usually walk with their mouths open and are less able to learn at school.
- The epiglottis is scapula-shaped, relatively wide and short. During breathing, it rests on the root of the tongue - it opens the entrance to lower paths, during the period of eating - prevents foreign bodies from entering the respiratory tract.
Lower Paths
The larynx of a newborn is located higher than that of an adult and is very mobile due to the muscular frame. It looks like a funnel with a diameter of 0.4 cm, the narrowing is directed towards the vocal cords. The chords are short, which explains the high timbre of the voice. With slight swelling, during acute respiratory diseases, symptoms of croup and stenosis occur, which are characterized by heavy, wheezing breathing with the inability to take a full breath. As a result, hypoxia develops. The laryngeal cartilages are rounded, their sharpening in boys occurs by the age of 10–12 years.
At the time of birth, the trachea is already formed, located at the level of the 4th cervical vertebra, mobile, funnel-shaped, then acquires a cylindrical appearance. The lumen is significantly narrowed, unlike in an adult; there are few glandular areas in it. When coughing, it can shrink by a third. Considering anatomical features, during inflammatory processes, narrowing and the appearance of a barking cough and symptoms of hypoxia (cyanosis, shortness of breath) are inevitable. The tracheal framework consists of cartilaginous half-rings, muscle structures, and a connective tissue membrane. The bifurcation at birth is higher than in older children.
The bronchial tree is a continuation of the tracheal bifurcation and is divided into the right and left bronchus. The right one is wider and shorter, the left one is narrower and longer. The ciliated epithelium is well developed, producing physiological mucus that cleanses the bronchial lumen. Mucus moves outward with cilia at a speed of up to 0.9 cm per minute.
A feature of the respiratory system in children is a weak cough impulse, due to poorly developed torso muscles, incomplete myelin coating of the nerve fibers of the tenth pair of cranial nerves. As a result, infected sputum does not pass away, accumulates in the lumen of bronchi of different sizes and becomes clogged with thick secretions. The structure of the bronchus contains cartilaginous rings, with the exception of the terminal sections, which consist only of smooth muscle. When they are irritated, a sharp narrowing of the passage may occur - an asthmatic picture appears.
The lungs are an air tissue, their differentiation continues until the age of 9, they consist of:
- Lobes (right of three, left of two).
- Segments (right – 10, left – 9).
- Dolek.
The bronchioles end in a sac in the baby. As the child grows, lung tissue grows, the sacs turn into alveolar clusters, and vital capacity indicators increase. Active development from the 5th week of life. Birth weight paired organ is 60–70 grams, well supplied with blood and vascularized with lymph. Thus, it is full-blooded, and not airy as in older people. The important point is that the lungs are not innervated, inflammatory reactions are painless, and in this case, a serious illness can be missed.
Due to the anatomical and physiological structure, pathological processes develop in the basal regions, cases of atelectasis and emphysema are common.
Functional Features
The first breath is carried out due to a decrease in oxygen in the blood of the fetus and an increase in the level of carbon dioxide, after clamping the umbilical cord, as well as a change in living conditions - from warm and humid to cold and dry. Signals travel along nerve endings to the central nervous system and then to the respiratory center.
Features of respiratory function in children:
- Conducting air.
- Cleaning, warming, moisturizing.
- Saturation with oxygen and purification from carbon dioxide.
- Protective immune function, synthesis of immunoglobulins.
- Metabolism – synthesis of enzymes.
- Filtration – dust, blood clots.
- Lipid and water metabolism.
- Shallow breaths.
- Tachypnea.
In the first year of life, respiratory arrhythmia occurs, which is considered normal, but its persistence and the occurrence of apnea after one year of age is fraught with respiratory arrest and death.
The frequency of breathing movements directly depends on the age of the baby - the younger, the more often the breath is taken.
NPV norm:
- Newborn 39–60/minute.
- 1–2 years – 29–35/min.
- 3–4 years – 23–28/min.
- 5–6 years – 19–25/min.
- 10 years – 19–21/min.
- Adult – 16–21/min.
Taking into account the characteristics of the respiratory system in children, the attentiveness and awareness of parents, timely examination, therapy reduces the risk of transition to the chronic stage of the disease and severe complications.
The airways and respiratory tract begin nasal cavity . In the nasal cavity, the inhaled air is warmed, partially cleared of dust and moistened. By the time of birth nasal cavity the child is underdeveloped, it is characterized by narrow nasal openings and the virtual absence of paranasal sinuses, the final formation of which occurs in adolescence. The volume of the nasal cavity increases approximately 2.5 times with age. The structural features of the nasal cavity of young children make nasal breathing difficult; children often breathe with their mouths open, which leads to susceptibility to colds.B paranasal sinuses Children's nasal cavities may develop inflammatory processes- sinusitis and frontal sinusitis.
Air enters from the nasal cavity into nasopharynx - upper part of the pharynx. The baby's pharynx is shorter, wider and lower in position auditory tube. The structural features of the nasopharynx lead to the fact that diseases of the upper respiratory tract in children are often complicated by inflammation of the middle ear.
The next link of the airways is larynx. The larynx in children is shorter, narrower and located higher than in adults. The larynx grows most intensively in the 1st-3rd years of life and during puberty. During puberty, gender differences appear in the structure of the larynx. In boys, an Adam's apple forms, the vocal cords lengthen, the larynx becomes wider and longer than in girls, and the voice breaks.
Extends from the lower edge of the larynx trachea. Its length increases in accordance with the growth of the body; the maximum acceleration of tracheal growth is noted at the age of 14-16 years. The circumference of the trachea increases according to the increase in the volume of the chest. The trachea branches into two bronchus , the right one is shorter and wider. The greatest growth of the bronchi occurs in the first year of life and during puberty.
The mucous membrane of the airways in children is more abundantly supplied with blood vessels, is tender and vulnerable, it contains fewer mucous glands that protect it from damage. These features of the mucous membrane lining the airways in childhood, combined with the narrower lumen of the larynx and trachea, make children susceptible to inflammatory diseases respiratory organs.
Lungs. With age, the structure of the main respiratory organ - the lungs - changes significantly.
The lungs in children grow mainly due to an increase in the volume of the alveoli (in a newborn, the diameter of the alveoli is 0.07 mm, in an adult it already reaches 0.2 mm). Up to 3 years of age, increased growth of the lungs and differentiation of their individual elements occurs. The number of alveoli by the age of 8 reaches the number in an adult. Between the ages of 3 and 7 years, the rate of lung growth decreases. Alveoli grow especially vigorously after 12 years of age. By the age of 12, the volume of the lungs increases 10 times compared to the volume of the lungs of a newborn, and by the end of puberty - 20 times (mainly due to an increase in the volume of the alveoli). Accordingly, gas exchange in the lungs changes, an increase in the total surface of the alveoli leads to an increase in the diffusion capabilities of the lungs.
An important characteristic of the functioning of the respiratory system is vital capacity lungs- the greatest amount of air that a person can exhale after take a deep breath. The vital air capacity of the lungs changes with age and depends on body length, the degree of development of the chest and respiratory muscles, and gender. Since measuring 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 years, the vital capacity of the lungs reaches values characteristic of an adult. A spirometer is used to determine the vital capacity of the lungs. Vital capacity is an important indicator of physical development.
The gradual maturation of the musculoskeletal apparatus of the respiratory system and the characteristics of its development in boys and girls determine age and gender differences in breathing types. In newborns it predominates diaphragmatic breathing
with minor involvement of the intercostal muscles. The diaphragmatic type of breathing persists until the second half of the first year of life. Gradually, the breathing of infants becomes thoraco-abdominal
, with a predominance of the diaphragmatic. At the age of 3 to 7 years, due to the development of the shoulder girdle, the chest breathing
,
and by the age of 7 it becomes pronounced.
At 7-8 years old, gender differences in the type of breathing are revealed: in boys it becomes predominant abdominal type of breathing, for girls - chest Sexual differentiation of breathing ends by the age of 14-17 years.
Age characteristics The structure of the chest and muscles determine the characteristics of the depth and frequency of breathing in childhood. 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-year olds - 23-26 cycles per minute. In school-age children, breathing decreases further (18-20 times per minute).