Features of the structure and development of the respiratory system in children. Respiratory system of children. Respiratory failure

Basic vital important function The respiratory system is to provide tissues with oxygen and remove carbon dioxide.

From this article you will learn how the child’s respiratory system develops, as well as what features of the respiratory system exist in children.

Respiratory system of children

Development of the child's respiratory system

The respiratory organs consist of the airways (respiratory) tracts and the respiratory section itself (lungs). The respiratory tract is divided into upper (from the opening of the nose to the vocal cords) and lower (larynx, trachea, bronchi). By the time the child is born, their morphological structure is still imperfect, which is also associated with the functional characteristics of breathing. Intensive growth and differentiation respiratory organs continue during the first months and years of life. The formation of the organs of the respiratory system ends on average by the age of 7, and only their sizes subsequently increase.

Structure of the respiratory tract of a newborn:

All airways in a child are significantly smaller and have narrower openings than in an adult. The features of their morphological structure in children of the first years of life are:

Thin, tender, easily wounded dry mucous membrane with insufficient development of glands, with reduced production of secretory immunoglobulin A (SIgA) and surfactant deficiency;

Rich vascularization of the submucosal layer, represented predominantly by loose fiber and containing few elastic and connective tissue elements;

The softness and pliability of the cartilaginous frame of the lower respiratory tract, the absence of elastic tissue in them and in the lungs.

This reduces the barrier function of the mucous membrane, facilitates easier penetration of the infectious agent into the bloodstream, and also creates the preconditions for narrowing of the airways due to rapidly occurring swelling or compression of the pliable respiratory tubes from the outside (the thymus gland, abnormally located vessels, enlarged tracheobronchial lymph nodes).

Upper respiratory tract of the newborn

Nose and nasopharyngeal space

In children early age the nose and nasopharyngeal space are small, short, flattened 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. Even slight hyperemia and swelling of the mucous membrane during a runny nose makes the nasal passages obstructed, causes shortness of breath, and makes breastfeeding difficult. Cavernous tissue develops by 8–9 years of age, so nosebleeds in young children are rare and are caused by pathological conditions. During puberty they are observed more often.

Accessory nasal cavities

By the birth of the child, only the maxillary (maxillary) sinuses are formed; The frontal and ethmoid are open protrusions of the mucous membrane, taking shape in the form of cavities only after 2 years; the main sinus is absent. Everything completely accessory cavities The nose develops by the age of 12-15, but sinusitis can also develop in children in the first two years of life.

Nasolacrimal duct

It is 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 conjunctival sac.

Throat of a newborn

In young children, the pharynx is relatively wide, tonsils at birth they are clearly visible, but do not protrude due to well-developed arches. Their crypts and vessels are poorly developed, which to some extent explains rare diseases sore throat in the first year of life. By the end of the first year, the lymphoid tissue of the tonsils, including the nasopharyngeal (adenoids), often hyperplasias, especially in children with diathesis. Their barrier function at this age is low, like lymph nodes. The overgrown lymphoid tissue is populated by viruses and microbes, and foci of infection are formed - adenoiditis and chronic tonsillitis. In this case, frequent sore throats, acute respiratory viral infections are observed, and the nasal breathing, the facial skeleton changes and an “adenoid face” is formed.

Epiglottis of the newborn

Closely related to the root of the tongue. In newborns it is relatively short and wide. Incorrect position and softness of its cartilage can cause narrowing of the entrance to the larynx and the appearance of noisy (stridor) breathing.

Lower respiratory tract of the newborn

Newborn's larynx

This organ of the respiratory system of a newborn is located higher than in adults, lowers with age, and is very mobile. Its position is not constant even in the same patient. It has a funnel-shaped shape with a distinct narrowing in the area of ​​the subglottic space, limited by the rigid cricoid cartilage. The diameter of the larynx in this place in a newborn is only 4 mm and increases slowly (6 - 7 mm at 5 -7 years, 1 cm by 14 years), its expansion is impossible. A narrow lumen, an abundance of nerve receptors in the subglottic space, and easily occurring swelling of the submucosal layer can cause severe breathing problems even with minor manifestations respiratory infection(croup syndrome).

Thyroid cartilages In young children they form a blunt rounded angle, which becomes sharper in boys after 3 years. From the age of 10, the characteristic male larynx is formed. True vocal cords in children it is shorter than in adults, which explains the height and timbre of the child’s voice.

Trachea of ​​a newborn

In children in the first months of life, the larynx is often funnel-shaped; at older ages, cylindrical and conical shapes predominate. Its upper end is located in newborns much higher than in adults (at the level of the IV and VI cervical vertebrae, respectively), and gradually descends, like the level of the tracheal bifurcation (from the III thoracic vertebra in a newborn to V-VI at 12-14 years). The tracheal framework consists of 14-16 cartilaginous half-rings connected posteriorly by a fibrous membrane (instead of an elastic end plate in adults). The membrane contains many muscle fibers, the contraction or relaxation of which changes the lumen of the organ. The child’s trachea is very mobile, which, along with the changing lumen and softness of the cartilage, sometimes leads to a slit-like collapse during exhalation (collapse) and is the cause of expiratory shortness of breath or rough snoring breathing (congenital stridor). Symptoms of stridor usually disappear by age 2 as the cartilage becomes denser.

Bronchial tree

By the time of birth, the bronchial tree is formed. As the child grows, the number of branches and their distribution in the lung tissue do not change. The size of the bronchi increases rapidly in the first year of life and in puberty. They are also based on cartilaginous semirings in early childhood, which do not have a closing elastic plate and are connected by a fibrous membrane containing muscle fibers. The cartilage of the bronchi is very elastic, soft, springy and easily displaced. The right main bronchus is usually an almost direct continuation of the trachea, so it is in it that foreign bodies are most often found. The bronchi, like the trachea, are lined with multirow cylindrical epithelium, the ciliated apparatus of which is formed after the birth of the child. Hyperemia and swelling of the bronchial mucosa, its inflammatory swelling significantly narrow the lumen of the bronchi, up to their complete obstruction. Due to an increase in the thickness of the submucosal layer and mucous membrane by 1 mm, the total area of ​​the bronchial lumen of a newborn decreases by 75% (in an adult - by 19%). Active bronchial motility is insufficient due to poor development of muscles and ciliated epithelium.

Incomplete myelination vagus nerve and underdevelopment of the respiratory muscles contribute to the weakness of the cough impulse in small child; Infected mucus accumulating in the bronchial tree clogs the lumens of the small bronchi, promotes atelectasis and infection of the lung tissue. As follows from the above, the main functional feature bronchial tree of a small child is insufficient performance of the drainage and cleansing function.

Lungs of a newborn

In children, as in adults, the lungs have a segmental structure. Segments are separated from each other by narrow grooves and layers connective tissue(lobular lung). The main structural unit is the acini, but its terminal bronchioles end not in a cluster of alveoli, as in an adult, but in a sac (sacculus). New alveoli are gradually formed from the “lace” edges of the latter, the number of which in a newborn is 3 times less than in an adult. The diameter of each alveoli increases (0.05 mm in a newborn, 0.12 mm at 4-5 years, 0.17 mm at 15 years). At the same time, the vital capacity of the lungs increases. Intermediate tissue in child's lung loose, rich in blood vessels, fiber, contains very little connective tissue and elastic fibers. In this regard, the lungs of a child in the first years of life are more full-blooded and less airy than those of an adult. Underdevelopment of the elastic framework of the lungs contributes to both the occurrence of emphysema and atelectasis of the lung tissue. Atelectasis occurs especially often in the posterior regions of the lungs, where hypoventilation and blood stagnation are constantly observed due to the forced horizontal position of a small child (mainly on the back). The tendency to atelectasis is enhanced by a deficiency of surfactant, a film that regulates alveolar surface tension and is produced by alveolar macrophages. It is this deficiency that causes insufficient expansion of the lungs in premature infants after birth (physiological atelectasis).

Pleural cavity

In a child, it is easily extensible due to the weak attachment of the parietal layers. The visceral pleura, especially in newborns, is relatively thick, loose, folded, contains villi and outgrowths, most pronounced in the sinuses and interlobar grooves. In these areas there are conditions for more rapid occurrence infectious foci.

Lung root

Comprises large bronchi, vessels and lymph nodes (tracheobronchial, bifurcation, bronchopulmonary and around large vessels). Their structure and function are similar to peripheral lymph nodes. They easily respond to the introduction of infection, creating a picture of both nonspecific and specific (tuberculous) bronchoadenitis. The root of the lung is integral part mediastinum. The latter is characterized by easy displacement and is often the site of development of inflammatory foci, from where infectious process spreads to the bronchi and lungs. The mediastinum also contains thymus(thymus), which at birth has big sizes and normally decreases gradually during the first two years of life. An enlarged thymus gland can cause compression of the trachea and large vessels, impair breathing and blood circulation.

Diaphragm

Due to the peculiarities chest The diaphragm plays a large role in the breathing mechanism of a small child, providing depth of inspiration. The weakness of its contractions partly explains the extremely shallow breathing of a newborn. Any processes that impede the movement of the diaphragm (formation of a gas bubble in the stomach, flatulence, intestinal paresis, enlargement of parenchymal organs of intoxication, etc.) reduce ventilation of the lungs (restrictive respiratory failure).

Physiological characteristics of the respiratory system in children

Main functional physiological characteristics respiratory system of a newborn are:

• shallow breathing;
• physiological shortness of breath (tachypnea);
• often irregular breathing rhythm;
• intensity of gas exchange processes;
• mild respiratory failure.

The depth of breathing, the absolute and relative volumes of one respiratory act in a child are significantly less than in an adult. With age, these figures gradually increase. When screaming, the volume of breathing increases 2-5 times. The absolute value of the minute volume of respiration is less than that of an adult, and the relative value (per 1 kg of body weight) is much greater.

The younger the child, the higher the breathing rate, it compensates for the small volume of each respiratory act and provides the child’s body with oxygen. Rhythm instability and short (3-5 min) pauses in breathing (apnea) in newborns and premature infants are associated with incomplete differentiation respiratory center and its hypoxia. Oxygen inhalation usually eliminates respiratory arrhythmia in these children.

Gas exchange in children is carried out more vigorously than in adults, due to the rich vascularization of the lungs, blood flow speed, and high diffusion capacity. At the same time, the function of external respiration in a small child is disrupted very quickly due to insufficient excursion of the lungs and straightening of the alveoli.

Swelling of the epithelium of the alveoli or interstitium of the lungs, exclusion of even a small area of ​​lung tissue from the act of breathing (atelectasis, congestion in the posterior parts of the lungs, focal pneumonia, restrictive changes) reduce pulmonary ventilation, cause hypoxemia and the accumulation of carbon dioxide in the blood, i.e. the development of respiratory failure, as well as respiratory acidosis. Tissue respiration occurs in a child at higher energy costs than in adults, and is easily disrupted with the formation metabolic acidosis due to the instability of enzyme systems characteristic of early childhood.

Research of the respiratory system of children

Methods for studying the respiratory system of a newborn

Assessing respiratory health involves questioning (usually the mother) and objective methods: inspection and counting the number of respiratory movements, palpation, percussion, auscultation, as well as laboratory and instrumental research.

Questioning. The mother is asked how the perinatal period and childbirth proceeded, what the child was sick with, including shortly before the present illness, what symptoms were observed at the onset of the illness. Pay attention Special attention for nasal discharge and difficulty in nasal breathing, the nature of cough (periodic, paroxysmal, barking, etc.) and breathing (hoarse, whistling, audible at a distance, etc.), as well as contact with patients with respiratory or other acute or chronic infection.

Visual inspection. Examination of the face, neck, chest, and limbs provides more information the younger the child. Pay attention to such features of the respiratory system in children as screaming, voice and coughing. The examination helps to identify, first of all, signs of hypoxemia and respiratory failure - cyanosis and shortness of breath.

Cyanosis can be expressed in certain areas (nasolabial triangle, fingers) and be widespread. With advanced microcirculation disorders, a rough cyanotic (marble) pattern on the skin is observed. Cyanosis may appear during crying, swaddling, feeding, or be constant.

Expansion of the surface capillary network in zone VII cervical vertebra(Frank's sign) may indicate enlargement of the tracheobronchial lymph nodes. Pronounced vasculature on the breast skin is sometimes additional symptom hypertension in the pulmonary artery system.

Dyspnea often accompanied by the participation of auxiliary muscles and retraction of the compliant areas of the chest.

Inspiratory dyspnea with difficult, sonorous, sometimes whistling inhalation is observed with croup syndrome and any obstruction of the upper respiratory tract.

Expiratory shortness of breath with difficulty and prolongation of exhalation is characteristic of obstructive bronchitis, bronchial asthma, bronchiolitis, viral respiratory syncytial infection, significant enlargement of tracheobronchial lymph nodes.

Mixed shortness of breath is observed with pneumonia, pleurisy, circulatory disorders, restrictive respiratory failure ( severe flatulence, ascites). Puffing shortness of breath of a mixed nature is observed in severe rickets.

The child's voice allows us to judge the condition of the upper respiratory tract. A hoarse, low-pitched voice or complete aphonia is characteristic of laryngitis and croup syndrome. A rough, low voice is characteristic of hypothyroidism. The voice acquires a nasal, nasal tone when chronic runny nose, adenoids, paresis velum(for birth trauma, polio, diphtheria), tumors and abscesses of the pharynx, congenital defects of the upper jaw.

The cry of a healthy full-term baby is loud, sonorous, promotes the straightening of lung tissue and the disappearance of atelectasis. A premature and weakened baby has a weak cry. Crying after feeding, before defecation, during urination requires, accordingly, the exclusion of hypolactia, fissures anus, phimosis, vulvitis and urethritis. A periodic loud cry is often observed with otitis media, meningitis, abdominal pain, a monotonous inexpressive “brain” cry - with organic damage CNS.

Cough. This is a very valuable diagnostic sign. To artificially induce a cough, you can press on the cartilage of the trachea, the root of the tongue, or irritate the pharynx. A barking, rough cough that gradually loses sonority is characteristic of croup syndrome. A paroxysmal, prolonged cough consisting of successive cough shocks, accompanied by a loud, difficult inhalation (reprise) and ending with vomiting, is observed with whooping cough. Bitonal cough is characteristic of enlarged tracheobronchial and bifurcation intrathoracic lymph nodes. Short painful cough with groaning exhalation often occurs with pleuropneumonia; dry, painful - with pharyngitis, tracheitis, pleurisy; wet - for bronchitis, bronchiolitis. It must be remembered that swelling of the mucous membrane of the nasopharynx, enlarged adenoids, and excessive mucus formation can cause a persistent cough, especially when changing position, without affecting the underlying respiratory tract.

Breath. The number of respiratory movements should be counted at the beginning of the examination at rest (or sleep), since the child easily experiences tachypnea under any influence, including emotional. Bradypnea is rare in children (with meningitis and other brain lesions, uremia). In cases of severe intoxication, the breathing of a driven animal is sometimes observed - frequent and deep. Breath counting is carried out within a minute, better in sleeping children and by breathing sounds, through a phonendoscope brought to the nose. In older children, counting is done with a hand placed on the chest and stomach at the same time (on the costal arch), since children are characterized by abdominal or mixed breathing. The respiratory rate of a newborn child is 40 - 60 per minute, one year old - 30 - 35, 5 - 6 years old - 20 - 25, 10 years old - 18 - 20, adult - 15 - 16 per minute.

Palpation. Palpation reveals deformities of the chest (congenital, associated with rickets or other disorders of bone formation). In addition, the thickness of the skin fold is determined symmetrically on both sides of the chest and the bulging or retraction of the intercostal spaces, the lag of one half of the chest during breathing. Swelling of the tissue, a thicker fold on one side, and bulging of the intercostal spaces are characteristic of exudative pleurisy. Retraction of the intercostal spaces can be observed with atelectasis and adhesive processes in the cavity of the pleura and pericardium.

Percussion. In children, percussion has a number of features:

The position of the child's body should ensure maximum symmetry of both halves of the chest. Therefore, the back is percussed with the child standing or sitting with legs crossed or extended, the lateral surfaces of the chest - in a standing or sitting position with the hands on the back of the head or extended forward, and the chest - lying down;

Percussion should be quiet - finger on finger or direct, since the chest of a child resonates much more than that of an adult;

The pessimeter finger is positioned perpendicular to the ribs, which creates conditions for a more uniform formation of percussion tone.

Percussion tone healthy child the first years of life, as a rule, tall, clear, with a slightly boxy tint. When screaming, it can change - up to distinct tympanitis at maximum inspiration and shortening during exhalation.

Any stable change in the nature of the percussion tone should alert the doctor. For bronchitis, bronchiolitis, asthmatic syndrome and asthma, and often with bronchopneumonia with small-sized foci of compaction of lung tissue and vicarious emphysema, a box or high-pitched tympanic sound may occur. With pneumonia, especially prolonged and chronic ones, a “variegated” sound is possible - alternating areas of shortening of the tone and percussion tympanic sound. Significant local or total shortening of tone indicates massive (lobar, segmental) pneumonia or pleurisy. Enlargement of the tracheobronchial lymph nodes is detected by direct percussion along the spinous processes of the vertebrae, starting from the lower ones thoracic regions. Shortening of the sound below the IV thoracic vertebra indicates possible bronchoadenitis (Koranyi's symptom).

The boundaries of the lungs are determined along the same lines as in adults, on average 1 cm higher due to the higher position of the diaphragm (in children of early age and up to school age). The mobility of the pulmonary edge is determined by free breathing child.

Auscultation. Features of the technique:

During percussion, the strictly symmetrical position of both halves of the chest is similar;

The use of a special children's stethoscope - with long tubes and a small diameter, since the membrane can distort the sound.

The normal respiratory sounds heard depend on age: up to one year in a healthy child, breathing is weakened vesicular due to its superficial nature; at the age of 2 - 7 years, puerile (children's) breathing is heard, more distinct, with a relatively louder and longer exhalation from inhalation. In school-age children and adolescents, breathing is the same as in adults - vesicular (the ratio of the duration of inhalation and exhalation is 3:1). When a child is crying, auscultation is no less valuable than at rest. When screaming, the depth of inspiration increases and bronchophony, intensifying over areas of compaction of the lung tissue, and various wheezing are well defined.

Pathological breathing sounds include:

Bronchial breathing (the ratio of the duration of inhalation and exhalation is 1:1) with infiltration of the lung tissue and over the area of ​​​​the lung pressed with liquid or air; prolonged exhalation indicates bronchospasm;

Weakened vesicular respiration in children older than one year with pleurisy, tuberculous infiltration of lung tissue, painful inhalation (with a rib fracture, myositis, appendicitis, peritonitis), severe bronchial obstruction, foreign body;

Amphoric breathing heard over bullous (with destructive pneumonia) and other cavities in the lungs.

Wheezing is heard during various pathological processes in the bronchi and lungs, most often at the depth of inspiration. Dry wheezing of a conductive nature (rough, sonorous, whistling) is heard with laryngitis, pharyngitis, tracheitis, asthmatic bronchitis, foreign body, attack of bronchial asthma. IN the latter case they can be heard at a distance. Moist rales - large and medium bubbly - indicate damage to the bronchi: small, sonorous ones are formed in the bronchioles, crepitants - in the alveoli. The prevalence and stability of auscultation of wheezes are of diagnostic importance: small and crepitating wheezes detected locally over a long period of time are more likely to indicate a pneumonic focus. Diffuse, intermittent, variable-caliber moist rales are more typical of bronchitis or bronchiolitis.

Bronchoadenitis is characterized by Despina's symptom - clear auscultation of whispered speech over the spinous processes in the area of ​​the VII cervical - V thoracic vertebrae. Pleural friction noise is detected in pleurisy and is characterized in children by its instability and transient nature.

The oropharynx is the last place to be examined in a child. The patient’s head and hands are securely fixed by the mother or a nurse; first, the mucous membrane of the cheeks, gums, teeth, tongue, hard and soft palate are examined using a spatula. Then use a spatula to press down on the root of the tongue and examine the palatine tonsils, arches, back wall throats. In young children, the epiglottis can often be examined.

Laboratory and instrumental examination of the respiratory system in children

Greatest diagnostic value have the following studies:

• X-ray;
• bronchological;
• definition gas composition, blood pH, balance of acids and bases;
• study of external respiration function;
• analysis of bronchial secretions.

Features of instrumental and laboratory research in pediatric practice are:

Technical difficulties of bronchological examination associated with the small size of the airways;

Usage general anesthesia, especially in young children, for bronchoscopy and bronchography;

Mandatory participation in the bronchological examination of specialists - pediatrician, pediatric bronchopulmonologist, anesthesiologist;

The impossibility of using the most common spirographic determination of external respiration function in children under 5 - 6 years of age and the use of pneumography and general plethysmography in this group of patients;

Difficulties in conducting gas analytical studies in newborns and children under 3 years of age due to rapid breathing and a negative attitude towards the methods used.

There are several stages in the development of the respiratory system:

Stage 1 – before the 16th week of intrauterine development, the formation of bronchial glands occurs.

From the 16th week - the recanalization stage - cellular elements begin to produce mucus and fluid and, as a result, the cells are completely displaced, the bronchi acquire lumen, and the lungs become hollow.

Stage 3 - alveolar - begins from 22 - 24 weeks and continues until the birth of the child. During this period, the formation of the acini, alveoli, and the synthesis of surfactant occurs.

By the time of birth, there are about 70 million alveoli in the fetal lungs. From 22-24 weeks, differentiation of alveolocytes begins - the cells lining inner surface alveoli

There are 2 types of alveolocytes: type 1 (95%), type 2 – 5%.

Surfactant is a substance that prevents the alveoli from collapsing due to changes in surface tension.

It lines the alveoli from the inside with a thin layer; during inhalation, the volume of the alveoli increases, surface tension increases, which leads to breathing resistance.

During exhalation, the volume of the alveoli decreases (more than 20-50 times), surfactant prevents their collapse. Since 2 enzymes are involved in the production of surfactant, they are activated by different dates gestation (at the latest from 35-36 weeks), it is clear that the shorter the child’s gestational age, the more pronounced the surfactant deficiency and the higher the likelihood of developing bronchopulmonary pathology.

Surfactant deficiency also develops in mothers with preeclampsia, during complicated pregnancy, caesarean section. The immaturity of the surfactant system is manifested by the development of respiratory distress syndrome.

Surfactant deficiency leads to collapse of the alveoli and the formation of atelectasis, as a result of which the function of gas exchange is disrupted, the pressure in the pulmonary circulation increases, which leads to the persistence of the fetal circulation and the functioning of the open ductus arteriosus and oval window.

As a result, hypoxia and acidosis develop, vascular permeability increases and the liquid part of the blood with proteins sweats into the alveoli. Proteins are deposited on the wall of the alveoli in the form of half rings - hyaline membranes. This leads to impaired diffusion of gases and the development of severe respiratory failure, which is manifested by shortness of breath, cyanosis, tachycardia, and the participation of auxiliary muscles in the act of breathing.

The clinical picture develops within 3 hours from the moment of birth and changes increase within 2-3 days.

AFO of the respiratory organs

By the time a child is born, the respiratory system reaches morphological maturity and can perform the function of breathing.
In a newborn, the respiratory tract is filled with a liquid that has low viscosity and a small amount of protein, which ensures its rapid absorption after the birth of the child through the lymphatic and blood vessels. In the early neonatal period, the child adapts to extrauterine existence.
After 1 inhalation, a short inspiratory pause occurs, lasting 1-2 seconds, after which exhalation occurs, accompanied by a loud cry of the child. In this case, the first respiratory movement in a newborn is carried out according to the type of gasping (inspiratory “flash”) - this is deep breath with difficulty breathing. Such breathing persists in healthy full-term infants until the first 3 hours of life. U healthy newborn With the child's first exhalation, most of the alveoli expand, and at the same time, vasodilation occurs. Complete expansion of the alveoli occurs within the first 2-4 days after birth.
The mechanism of the first breath. The main trigger point is hypoxia, which occurs as a result of clamping of the umbilical cord. After ligation of the umbilical cord, oxygen tension in the blood drops, carbon dioxide pressure increases and pH decreases. In addition, for a newborn child big influence renders temperature environment, which is lower than in the womb. Contraction of the diaphragm creates negative pressure in the chest cavity, which allows air to enter the airways more easily.

A newborn baby has well-expressed protective reflexes - coughing and sneezing. Already in the first days after the birth of a child, the Hering-Breuer reflex functions, which, at threshold stretching of the pulmonary alveoli, leads to the transition of inhalation to exhalation. In an adult, this reflex occurs only with very strong stretching of the lungs.

Anatomically, the upper, middle and lower respiratory tract are distinguished. The nose is relatively small at birth, the nasal passages are narrow, there is no lower nasal passage, turbinate, which are formed by the age of 4. Submucosal tissue is poorly developed (matures by 8-9 years), cavernous or cavernous tissue is underdeveloped up to 2 years (as a result, young children do not experience nosebleeds). The nasal mucosa is delicate, relatively dry, rich in. 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 in children in the first six months of life is impossible, since big tongue pushes the epiglottis posteriorly. 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. These features explain the rarity of diseases such as sinusitis, frontal sinusitis, ethmoiditis in early childhood. A wide nasolacrimal duct with underdeveloped valves contributes to the transfer of inflammation from the nose to the mucous membrane of the eyes.

The pharynx is narrow and small. The lymphopharyngeal ring (Waldeyer-Pirogov) is poorly developed. It consists of 6 tonsils:

• 2 palatines (between the anterior and posterior palatines)

  2 tubes (near the Eustachian tubes)

  1 throat (in the upper part of the nasopharynx)

  1 lingual (in the area of ​​the root of the tongue).

The palatine tonsils are not visible in newborns; by the end of the 1st year of life they begin to protrude from behind the palatine arches. By the age of 4-10 years, the tonsils are well developed and their hypertrophy can easily occur. During puberty, the tonsils begin to undergo reverse development. Eustachian tubes in young children they are wide, short, straight, located horizontally and with horizontal position child, the pathological process from the nasopharynx easily spreads to the middle ear, causing the development of otitis media. With age they become narrow, long, and tortuous.

The larynx has a funnel shape. The glottis is narrow and located high (at the level of the 4th cervical vertebra, and in adults - at the level of the 7th cervical vertebra). Elastic tissue is poorly developed. The larynx is relatively longer and narrower than in adults; its cartilages are very pliable. With age, the larynx acquires a cylindrical shape, becomes wide and descends 1-2 vertebrae lower. The false vocal cords and mucous membrane are delicate, rich in blood vessels and lymphatic vessels, elastic tissue is poorly developed. The glottis in children is narrow. Young children's vocal cords are shorter than those of older children, which is why they have a high-pitched voice.

The bifurcation of the trachea lies higher than in an adult. The cartilaginous frame of the trachea is soft and easily narrows the lumen. Elastic tissue is poorly developed, the mucous membrane of the trachea is tender and richly supplied with blood vessels. 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 bronchi are richly supplied with blood, muscle and elastic fibers in young children are underdeveloped, and the lumen of the bronchi is narrow. Their mucous membrane is richly vascularized.
The right bronchus is like a continuation of the trachea; it is shorter and wider than the left. This explains the frequent occurrence foreign body into the right main bronchus.
The bronchial tree is poorly developed.
There are bronchi of the 1st order - main, 2nd order - lobar (3 on the right, 2 on the left), 3rd order - segmental (10 on the right, 9 on the left). 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 blood supply is good. The bronchial mucosa is lined with ciliated epithelium, which provides mucociliary clearance, which plays a major role in protecting the lungs from various pathogens from the upper respiratory tract and has an immune function (secretory immunoglobulin A). The tenderness of the bronchial mucosa and the narrowness of their lumen explain the frequent occurrence of bronchiolitis with the syndrome of complete or partial obstruction and pulmonary atelectasis in young children.

Lung tissue is less airy, elastic tissue is underdeveloped. In the right lung there are 3 lobes, in the left 2. Then the lobar bronchi are divided into segmental ones. A segment is an independently functioning unit of the lung, directed with its apex towards root of the lung, has an independent artery and nerve. 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, and 9 in the left lung. The upper left and right lobes are divided into three segments - 1, 2 and 3rd, the middle right lobe - into two segments - 4th and 5th. In the left light medium The lobe corresponds to the lingual 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, 7, 8 and 9th. The acini are underdeveloped, the alveoli begin to form from 4 to 6 weeks of life and their number quickly increases within 1 year, increasing up to 8 years.

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, the participation of most of the lungs in breathing

In the fetus and newborn, hemoglobin F predominates, which has an increased affinity for oxygen, and therefore the dissociation curve of oxyhemoglobin is shifted to the left and up. Meanwhile, in a newborn, like in a fetus, red blood cells contain extremely little 2,3-diphosphoglycerate (2,3-DPG), which also causes less saturation of hemoglobin with oxygen than in an adult. At the same time, in the fetus and newborn, oxygen is more easily transferred to the tissues.

In healthy children, depending on age, different breathing patterns are determined:

a) vesicular - exhalation is one third of inhalation.

b) puerile breathing - enhanced vesicular

c) hard breathing - exhalation is more than half of the inhalation or equal to it.

d) bronchial breathing - exhalation is longer than inhalation.

It is also necessary to note the sonority of breathing (normal, increased, weakened). In children of the first 6 months. breathing is weakened. After 6 months up to 6 years of age, breathing is puerile, and from 6 years of age - vesicular or intensely vesicular (one third of inhalation and two thirds of exhalation are heard), it is heard evenly over the entire surface.

Respiratory rate (RR)

	Frequency per minute
Premature
Newborn

Stange test - holding your breath while inhaling (6-16 years old - from 16 to 35 seconds).

Gench's test - holding your breath while exhaling (N - 21-39 seconds).

By the time the child is born, the morphological structure is still imperfect. Intensive growth and differentiation of the respiratory organs continues during the first months and years of life. The formation of the respiratory organs ends on average by 7 years, and subsequently only their size increases. All airways in a child are significantly smaller and have narrower openings than in an adult. Features of their morphol. structures in children of the first years of life are:

1) thin, delicate, easily wounded dry mucous membrane with insufficient development of glands, with reduced production of secretory immunoglobulin A (SIgA) and surfactant deficiency;

2) rich vascularization of the submucosal layer, represented mainly by loose fiber and containing few elastic and connective tissue elements;

3) softness and pliability of the cartilaginous frame of the lower respiratory tract, the absence of elastic tissue in them and in the lungs.

Nose and nasopharyngeal space . In young children, the nose and nasopharyngeal space are small, short, flattened 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. Cavernous tissue develops by 8-9 years.

Accessory nasal cavities . By the birth of a child, only maxillary sinuses; The frontal and ethmoid are open protrusions of the mucous membrane, taking shape in the form of cavities only after 2 years; the main sinus is absent. All nasal cavities develop completely by the age of 12-15 years.

Nasolacrimal duct . It is 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 young children, they are relatively wide; the palatine tonsils are clearly visible at birth, but do not protrude due to well-developed arches. Their crypts and blood vessels are poorly developed, which to some extent explains the rare diseases of sore throat in the first year of life. By the end of the first year, the lymphoid tissue of the tonsils, including the nasopharyngeal (adenoids), often hyperplasias, especially in children with diathesis. Their barrier function at this age is low, like that of lymph nodes. The overgrown lymphoid tissue is populated by viruses and microbes, and foci of infection are formed - adenoiditis and chronic tonsillitis.

Thyroid cartilages In young children they form a blunt rounded angle, which becomes sharper in boys after 3 years. From the age of 10, the characteristic male larynx is formed. The true vocal cords of children are shorter than those of adults, which explains the pitch and timbre of a child's voice.

Trachea. In children in the first months of life, it is often funnel-shaped; at older ages, cylindrical and conical shapes predominate. Its upper end is located in newborns much higher than in adults (at the level of the IV cervical vertebrae), and gradually lowers, like the level of the tracheal bifurcation (from the III thoracic vertebra in a newborn to V -VI at 12-14 years). The tracheal framework consists of 14-16 cartilaginous half-rings connected posteriorly by a fibrous membrane (instead of an elastic end plate in adults). The membrane contains many muscle fibers, the contraction or relaxation of which changes the lumen of the organ. The child’s trachea is very mobile, which, along with the changing lumen and softness of the cartilage, sometimes leads to a slit-like collapse during exhalation (collapse) and is the cause of expiratory shortness of breath or rough snoring breathing (congenital stridor). Symptoms of stridor usually disappear by age 2 as the cartilage becomes denser.

Bronchial tree . By the time of birth, the bronchial tree is formed. The size of the bronchi increases rapidly in the first year of life and during puberty. They are based on cartilaginous semirings in early childhood, which do not have a closing elastic plate and are connected by a fibrous membrane containing muscle fibers. The cartilage of the bronchi is very elastic, soft, springy and easily displaced. The right main bronchus is usually an almost direct continuation of the trachea, so it is in it that foreign bodies are most often found. The bronchi, like the trachea, are lined with multirow cylindrical epithelium, the ciliated apparatus of which is formed after the birth of the child.

Due to an increase in the thickness of the submucosal layer and mucous membrane by 1 mm, the total area of ​​the bronchial lumen of a newborn decreases by 75% (in an adult - by 19%). Active bronchial motility is insufficient due to poor development of muscles and ciliated epithelium. Incomplete myelination of the vagus nerve and underdevelopment of the respiratory muscles contribute to the weakness of the cough impulse in a small child; Infected mucus accumulating in the bronchial tree clogs the lumens of the small bronchi, promotes atelectasis and infection of the lung tissue. A functional feature of the bronchial tree of a small child is the insufficient performance of the drainage and cleansing function.

Lungs. In children, as in adults, the lungs have a segmental structure. The segments are separated from each other by narrow grooves and layers of connective tissue (lobular lung). The main structural unit is the acini, but its terminal bronchioles end not in a cluster of alveoli, as in an adult, but in a sac (sacculus). New alveoli are gradually formed from the “lace” edges of the latter, the number of which in a newborn is 3 times less than in an adult. The diameter of each alveoli increases (0.05 mm in a newborn, 0.12 mm at 4-5 years, 0.17 mm at 15 years). At the same time, the vital capacity of the lungs increases. The interstitial tissue in a child's lung is loose, rich in blood vessels, fiber, and contains very little connective tissue and elastic fibers. In this regard, the lungs of a child in the first years of life are more full-blooded and less airy than those of an adult. Underdevelopment of the elastic framework of the lungs contributes to both the occurrence of emphysema and atelectasis of the lung tissue.

The tendency to atelectasis is enhanced by a deficiency of surfactant, a film that regulates alveolar surface tension and is produced by alveolar macrophages. It is this deficiency that causes insufficient expansion of the lungs in premature infants after birth (physiological atelectasis).

Pleural cavity . In a child, it is easily extensible due to the weak attachment of the parietal layers. The visceral pleura, especially in newborns, is relatively thick, loose, folded, contains villi and outgrowths, most pronounced in the sinuses and interlobar grooves.

Lung root . Consists of large bronchi, vessels and lymph nodes (tracheobronchial, bifurcation, bronchopulmonary and around large vessels). Their structure and function are similar to peripheral lymph nodes. They easily respond to infection. The mediastinum also contains the thymus gland (thymus), which is large at birth and normally gradually decreases during the first two years of life.

Diaphragm. Due to the characteristics of the chest, the diaphragm plays a large role in the breathing mechanism of a small child, providing depth of inspiration. The weakness of its contractions partly explains the extremely shallow breathing of a newborn. Main functions physiological features respiratory organs are: shallow breathing; physiological shortness of breath (tachypnea), often irregular breathing rhythm; tension of gas exchange processes and easy occurrence of respiratory failure.

1. The depth of breathing, the absolute and relative volumes of one respiratory act in a child are significantly less than in an adult. When screaming, the volume of breathing increases 2-5 times. The absolute value of the minute volume of respiration is less than that of an adult, and the relative value (per 1 kg of body weight) is much greater.

2. The younger the child, the higher the breathing rate, it compensates for the small volume of each respiratory act and provides the child’s body with oxygen. Rhythm instability and short (3-5 min) pauses in breathing (apnea) in newborns and premature infants are associated with incomplete differentiation of the respiratory center and its hypoxia. Oxygen inhalation usually eliminates respiratory arrhythmia in these children.

3. Gas exchange in children is carried out more vigorously than in adults, due to the rich vascularization of the lungs, blood flow speed, and high diffusion capacity. At the same time, the function of external respiration in a small child is disrupted very quickly due to insufficient excursion of the lungs and straightening of the alveoli.

The respiratory rate of a newborn child is 40 - 60 per minute, a one-year-old child is 30 -35, 5 - 6 years old is 20 -25, 10 years old is 18 - 20, an adult is 15 - 16 per minute.

The percussion tone in a healthy child of the first years of life is usually high, clear, with a slightly boxy tint. When screaming, it can change - up to distinct tympanitis at maximum inspiration and shortening during exhalation.

The normal respiratory sounds heard depend on age: up to one year in a healthy child, breathing is weakened vesicular due to its superficial nature; at the age of 2 - 7 years, puerile (children's) breathing is heard, more distinct, with a relatively louder and longer (1/2 of the inhalation) exhalation. In school-age children and adolescents, breathing is the same as in adults - vesicular.

The leading role in the origin of this syndrome is played by a deficiency of surfactant - a surfactant that lines the inside of the alveoli and prevents their collapse. Surfactant synthesis changes in prematurely born children, and various adverse effects on the fetus also occur, leading to hypoxia and hemodynamic disorder in the lungs. There is evidence of the participation of prostaglandins E in the pathogenesis of respiratory distress syndrome. These biologically active substances indirectly reduce the synthesis of surfactant, have a vasopressor effect on the vessels of the lungs, prevent the closure of the ductus arteriosus and normalize blood circulation in the lungs.

About 70% of childhood diseases are caused by disorders normal operation respiratory organs. They are involved in passing air through the lungs, while preventing pathogenic microorganisms from entering them and further development. inflammatory process. At the slightest disruption in the full functioning of the respiratory organs, the entire body suffers.

Photo: Respiratory organs

Features of the respiratory system in childhood

Respiratory diseases in children occur with some peculiarities. This is due to a number of factors:

• narrowness of the nasal passages and glottis;
• insufficient depth and increased frequency of breathing;
• low airiness and increased density lungs;
• poor development of respiratory muscles;
• unstable breathing rhythm;
• tenderness of the nasal mucosa (rich in blood vessels and easily swells).

Photo: Respiratory muscles

The respiratory system becomes mature no earlier than 14 years of age. Until this moment, the pathologies attributed to it need to be given increased attention. Respiratory system diseases should be detected in a timely manner, which increases the chances of a speedy cure, avoiding complications.

Causes of diseases

The child's respiratory organs are often exposed. More often pathological processes develop under the influence of activation of staphylococci and streptococci. Allergies often lead to disturbances in the functioning of the respiratory system.

Among the predisposing factors are not only the anatomical features of the respiratory system in childhood, but also an unfavorable external environment and hypovitaminosis. Modern children with noticeable regularity do not follow a daily routine and do not eat properly, which affects the body’s defenses and subsequently leads to diseases.

The situation may be aggravated by the lack of hardening procedures.

Photo: Activation of staphylococci is the cause of the disease

Symptoms Despite the existence of characteristics characteristic of each separate disease

• signs of the child's respiratory system, doctors identify common ones:
• (obligatory symptom, a kind of protective reaction of the body); dyspnea
• (signals a lack of oxygen); sputum
• (special mucus produced in response to the presence of irritants); nasal discharge (can be different color
• and consistency);
• labored breathing; temperature increase

(this also includes general intoxication of the body, which is a combination of the body’s biological reactions to infection).

Diseases of the respiratory system are divided into two groups. The former affect the upper respiratory tract (URT), the latter - lower sections(NDP). In general, it is not difficult to determine the onset of one of the respiratory diseases in a child, especially if a doctor takes over the work. Using a special device, the doctor will listen to the child and perform an examination. If clinical picture

turns out to be blurred, a detailed examination will be needed.

Photo: Examination of a child by a doctor

Upper respiratory tract diseases Viruses and bacteria can lead to pathologies. It is known that

This group of diseases is one of the common reasons why parents of a child turn to a pediatrician.

According to static data, a child of preschool and primary school age can experience from 6 to 10 episodes of disruption of the upper respiratory tract per year. Inflammation of the nasal mucosa that occurs due to a viral infection

. The impetus for the development of rhinitis can be banal hypothermia, which as a result reduces the body's defenses.

Photo: Rhinitis Acute rhinitis may be a symptom of acute infectious disease

or manifest as an independent pathology.

Photo: Lower respiratory tract

Tracheitis occurs extremely rarely as an independent disease.

Photo: Breathing exercises

Is it possible to prevent trouble? Any respiratory disease can be prevented

. For this purpose, you need to strengthen the child’s body, regularly take him for walks in the fresh air, and always dress according to the weather. It is very important to avoid hypothermia and wet feet. In the off-season, the child’s health should be supported with vitamin complexes.

At the first signs of discomfort, you should contact a specialist.