Currently, the following classification is used in pediatrics.

A. Intrauterine stage:

a) the phase of embryonic development (2-3 months);

b) the phase of placental development (from 3 months to birth).

B. Extrauterine stage:

a) the neonatal period (up to 1 month of life);

b) infancy (up to 1 year);

c) preschool (senior nursery) period - from 1 year to 3 years;

d) preschool period (from 3 to 6 years);

e) school age: junior (from 7 to 10 years old), middle (from 11 to 14 years old), senior - adolescent (from 14 to 18 years old).

Preschool educational institutions (preschool educational institutions) are organized for children from the age of 2 months. up to 7 years old; the groups are completed taking into account the age of the children (Table 1).

Table 2.1

Distribution of children into groups depending on age

The neonatal period begins with a cry that marks the baby's first breath. From this moment, the child begins to adapt to the conditions of the external environment. At this stage, an objective determination of the condition of the newborn is carried out on the scale

Table 2.1.1

Criteria for assessing a newborn on the Apgar scale

Apgar (Table 2.1), depending on how he adapts to new environmental conditions (outside the womb). Evaluated in points for five clinical signs at the 1st and 5th minutes after birth, heart rate, depth and adequacy of breathing, reflex excitability, muscle tone, color skin... A well-expressed sign is estimated at 2 points, an insufficiently pronounced one - 1 point, the absence of a sign - 0 points. When scoring 7 points or more, newborns are considered to be practically healthy, with a good prognosis in terms of vitality and neuropsychic development. IA Arshavsky considers it necessary to take into account the time of attachment to the mother's breast when assessing the state of the child after birth.

Children with an assessment of 5-6 points are regarded as born in a state of mild asphyxia, 1-4 points - severe. These children are considered to be at risk, as they may experience delay or delay in mental and physical development, which may be persistent.

Premature babies experience quite great difficulties in growth and development. These include babies born between weeks 28 and 38 intrauterine development... There are 4 degrees of prematurity:Idegree - body weight 2001 - 2500 g ; II degree - 1051-2000 g;IIIdegree - 1001-1500 g;IVdegree - less 1000 g ... Most frequent reasons prematurity are previous artificial terminations of pregnancy, multiple pregnancy, toxicosis of pregnant women, physical and mental trauma, etc. The main signs of prematurity include body weight less 2500 g , insufficient development of the subcutaneous fat layer, wrinkled skin covered with fluff, thin nails, not always covering the nail beds.

In healthy newborns, congenital reflexes are determined: sucking, blinking, pain, temperature, grasping, tonic (defensive), seeking, walking, Moro's reflex, plantar. During the first year of life, these reflexes undergo certain changes.

For the first time 2-4 days, newborns experience such phenomena as a decrease in body weight (by 6-10% of the indicator at birth), icteric staining associated with temporary failure of the liver and increased breakdown of red blood cells, hyperemia (reddening of the skin, sometimes accompanied by peeling ), insufficient thermoregulation (body temperature changes depending on the ambient temperature), as a result of which the child may overheat or overcool. By the end of the 1st - the beginning of the 2nd week, under normal conditions of nutrition and care, most disorders almost completely disappear.

Diseases of children of this period can be associated with impaired intrauterine development (prematurity, congenital deformities, heart defects), the consequences of birth trauma (intracranial hemorrhage, birth tumors, bone fractures) or with a burdened heredity. Breast milk in this period is the main and only complete food that ensures the correct development of the child.

At the end of the neonatal period in a child infancy there is an intensive rate of growth and development, which at no other age is so significant. This pattern is especially pronounced when considering changes in the length and weight of the child's body. So, if at birth in a full-term baby in 95% of cases, the body length on average is 45-50 cm, and the body weight is 2.5-4.6 kg, then by the end of the first year of life these parameters increase accordingly to 75 cm and 11- 12 Kg ... To provide enhanced growth and development for children first year of life more food is needed (for 1 kg body weight) than older children or adults. At the same time, the digestive tract at this age is underdeveloped, and at the slightest violation of the diet, a change in the quality or quantity of food, children may experience both acute and chronic disorders of digestion and nutrition, vitamin deficiencies, constitutional anomalies (an incorrect reaction of the body to normal living conditions and nutrition), manifested most often in the form of atopic dermatitis. In the first 4-5 months. breast milk remains the main food of the child.

Tissues in infants are thin and tender, insufficient development of elastic (elastic) fibers, as a result of which they are easily injured. At the same time, due to the presence of a large number of young cellular elements and blood vessels in the tissues, which provide them with good nutrition, any damage in children heals much faster than in adults. The inflammatory (protective) reaction to the penetration of pathogens in infants is weak, there is almost no defense reaction from the regional (peripheral) lymph nodes, therefore, the child's body often responds to any local disease with a general reaction. children at this age are prone to pustular skin lesions, which, with poor child care, can give serious complications up to sepsis.

With a lack of vitamins in food, primarily vitaminD, as well as a number of mineral salts, insufficient solar insolation in a child of this age, rickets may occur.

In infants, vigorous growth and ossification of the skeleton occurs, the muscles of the trunk and legs develop. By the end of the first year, the largest anterior fontanelle is overgrown, located at the junction of the coronal and longitudinal sutures. The spine of the newborn is almost straight (Fig. 2.1). From the 2nd month of life, physiological bends of the spinal column are formed (Fig. 2.2-2.4 ).

Cervical lordosis appears immediately after the child begins to hold the head. Then the formation of thoracic kyphosis occurs - at 6-7 months, when the child begins to sit on his own. Lumbar lordosis becomes noticeable by the time the child is standing steadily, and by the end of the year begins to walk. By the end of the year of life, a healthy child is sitting well, standing firmly on his legs, walking, but his movements are not yet coordinated enough.

It should be emphasized that the final formation of the spinal column ends in school years. Failure to comply with hygienic requirements for the formation of correct posture, starting from an early age, can lead to pathological changes in the shape of the spinal column.

Infectious diseases in infants, especially in the first months of their life, are rare.

Measles, rubella, scarlet fever are almost never found; diphtheria, chickenpox, dysentery, etc. proceed in a peculiar way, often without characteristic symptoms.

It depends, on the one hand, on the immunity acquired by the child during his uterine life through the placenta and received with mother's milk, on the other, on the incompleteness of the structure of many organs and systems, especially the central and peripheral nervous systems.

Children, especially in the first months of life, cannot stay awake for a long time. The increased activity of the nervous system quickly leads to inhibition, which, spreading through the cortex and other parts of the brain, causes sleep.

Already in the first year of life, speech begins to form in the child. Undifferentiated sounds - humming - are gradually replaced by syllables. By the end of the year, a healthy child understands quite well the speech of the adults around him, he himself pronounces 5-10 simple words.

Preschool age - from 1 to 3 years. During this period, the rate of growth and development of the child slows down somewhat. The increase in height is 8-10 cm, body weight is 4-6 kg per year. The proportions of the body change, the dimensions of the head are relatively reduced: from 1/4 of the body length in a newborn to 1/5 in a 3-year-old child. The presence of teeth (by the end of the year there should be 8 of them), an increase in the amount of digestive juices and an increase in their concentration serve as the basis for transferring a child from breastfeeding on a common table.

Children of the second year of life experience intensive growth and formation of the musculoskeletal system. The nervous system and sense organs develop rapidly, coordination of movements improves, children begin to walk and run on their own, which allows them to communicate more widely with the world around them. The child masters speech (the vocabulary reaches 200-300), he pronounces not only individual words, but also whole phrases.

Broader communication with the outside world also creates a greater opportunity for healthy children to come into contact with children who have fallen ill with infectious diseases. In addition, with age, the passive immunity transmitted to the child by the mother weakens. As a result, the threat of infectious diseases (measles, whooping cough, chickenpox, dysentery, etc.) increases significantly.

Preschool age (from 3 to 7 years) differs from the previous one more in quantitative than qualitative features. There is a slower growth rate of the child. For 1 year, growth increases by an average of 5-8 cm, body weight - by about 2 Kg ... Body proportions change markedly. By the age of 6-7 years, the head is only 1/6 of the body length. As a result of uneven growth of the head, trunk and limbs, the midpoint of the body length moves. In a full-term newborn, this point is located almost on the navel, in a 6-year-old child - in the middle between the navel and the symphysis (pubis), in an adult - on the pubis.

Due to the further development of muscle tissue and the formation of the innervation apparatus of muscles, children are able to perform a variety of physical exercises that require good coordination of movements; they master the ability to run and jump quickly, walk freely on steps, play musical instruments, draw, sculpt, cut out various rather complex ornaments from paper.

At this age, the ability of nerve cells to be in an active state increases, the processes of negative induction in the cerebral cortex are somewhat enhanced, so children can concentrate on any activity for a longer time.

In the third year of life, the number of words used by children in speech increases significantly; speech signals begin to play a major role in organizing the child's behavior. The development of speech is facilitated by games and activities, learning poems and songs, communication between children and adults. Lack of attention on the part of adults, acute and chronic diseases can slow down the development of speech in a child.

Children 3-5 years old still have little command of speech motor skills, therefore they are characterized by physiological defects in sound pronunciation (incorrect pronunciation of hissing, whistling sounds, as well as sounds R and l). At correct teaching sound culture of speech, these disorders usually disappear with age ( see Attachment 7 ).

Among acute diseases, the first place is occupied by diseases of the respiratory system, especially acute respiratory viral infections and influenza, which account for almost 70% in the structure of diseases of children of this age. Pneumonia is more common in the first 2 years of life, its frequency decreases by 7 years. Due to the greater stability of enzymatic processes, diseases of the gastrointestinal tract recede into the background. Due to the high efficiency of vaccinations and preventive measures, the number of childhood infectious diseases is gradually decreasing, however, in children over 2-3 years old, they still occupy the second place in the structure of acute diseases. By the age of 6, the number of allergic diseases and reactions is gradually increasing. At the age of 6-7 years, cases of injuries begin to be registered more often.

There are certain peculiarities in the spread of chronic diseases among preschoolers. With age, diseases of the digestive system become more frequent, primarily due to dental caries, which ranks first in the structure of the incidence of children aged 5-7 years; on the second - diseases of the nervous system and sensory organs (neurotic reactions, enuresis, otitis media); in third place - diseases of the respiratory system, mainly chronic diseases of the pharynx and nasopharynx; on the fourth - diseases of the musculoskeletal system and connective tissue (flat feet, poor posture); on the fifth - skin disease (atopic dermatitis).

The timely detection of disorders of the musculoskeletal system requires special attention. It should be borne in mind that at the age of 4 to 7 years, the number of children with poor posture increases, and with flat feet decreases, which is associated with the process of foot formation at this age. The prevalence of eye diseases is also increasing. First of all, this applies to myopia., which occurs in children aged 7 years 2 times more often than in 3-year-olds. With age, the number of children with atopic dermatitis (exudative diathesis) decreases significantly.

A direct reflection of the functional state of the central nervous system (CIS) is the child's behavior, determined by many parameters. The majority of preschool children (77-84%) have no behavioral deviations. Arising deviations: disturbance of daytime or night sleep, lack of physical activity, loss of appetite up to anorexia, the appearance of inadequate reactions (tearfulness, increased irritability, pugnaciousness), rapid fatigue and great distraction during exercise, unstable, often low, depressed mood - indicate functional disorders of the central nervous system.

Such phenomena can be observed during adaptation to a preschool institution, during the period of convalescence after acute illnesses. Deviations in behavior are often combined with other functional disorders in the state of the body, such as frequent acute diseases, allergic predisposition, the initial stage of rickets, a decrease in hemoglobin levels to the lower limit of the norm, malnutrition, obesity, refractive errors, etc. Scarlet fever, tonsillitis, catarrh upper respiratory tract create a prerequisite for the occurrence of rheumatoid diseases in children.

V school age(from 6-7 to 17 years old) all organs and systems of children and adolescents continue to develop. Milk teeth are completely replaced with permanent ones, further skeletal ossification and muscle growth occur.

Thanks to enhanced intellectual development during this period, the child becomes more independent. Compulsory schooling begins at the age of 6-7.

Currently, using empirical formulas, it is possible to determine the body length (height) in preschool children. So,body length ( L) in children over 1 year old, it is calculated by the formula:L= L1 + (5 xn) , whereL1 - body length of a one-year-old child, equal to 75 cm ; 5 cm - average annual increase in body length;n - the number of years of life. Some authors offer to acceptL1 = 77 cm , and the average annual increase in body length is 6 cm .

Body mass M can be determined in children of the first year of life by the following formula:M = (9 + n) : 2 , wheren - the number of months of life. In children over a year old the approximate body weight can be calculated as follows:M = M1 + ( 2 Kg NSn) , where M1- the body weight of a one-year-old child, equal to approximately 10.5 - 11 Kg ; 2 Kg - annual weight gain;n - number of years. The body weight of children from 1 to 6 years old can be determined in another way:M = nx 2 + 8 , and children from 7 to 12 years old according to the following formula:M = ( nx 7 - 5): 2 , wheren - the number of years of life. Head circumference at a particular period of development in children of the first year of life is determined by the formula:( L+ 19) : 2 .

The child is constantly growing, and his development proceeds in a certain, regular sequence. Identifying the stages and periods of the child's development, which have their own anatomical and physiological features, allows a differentiated approach to the child. Its development is influenced by both genetic factors and various environmental factors, including teratogenic and infectious. Traditionally, intrauterine (prenatal) and extrauterine (postnatal) stages of development are distinguished.

INTERNAL STAGE OF DEVELOPMENT

The intrauterine stage of development lasts an average of 280 days (40 weeks) from the moment of conception to birth (Table 1-1).

Table 1-1.Periods of prenatal development

Initial period (concept)

Fertilization occurs within 1 day after ovulation. The fertilized egg moves along the fallopian tube; in this case, the process of crushing occurs (the outer layer of cells is trophoblast, the inner layer is embryoblast) and the implantation of the formed blastocyst into the endometrium. Gastrulation - the formation of primary germ layers - begins at the end of the 2nd week of development and is characterized by the appearance of the cells' ability to move.

The embryonic period

This period is distinguished by a high rate of tissue differentiation, and by the end of it (at a period of 8 weeks), rudiments of all the main organs and systems are formed. During the first 7 weeks, the embryo does not show motor activity, with the exception of palpitations, determined from the 4th week. At the 8th week of development, a localized muscle reaction in response to stimulation can be detected, by the 9th week, the surfaces of the palms and soles become reflexogenic, and spontaneous intestinal motility is also noted. The weight of the embryo at this time is 9 g, and the body length is 5 cm. Various diseases and bad habits of the pregnant woman, genetic and chromosomal abnormalities of the fetus can lead to its death or spontaneous abortion. Unfavorable conditions of intrauterine life, exposure to infectious agents (rubella virus, cytomegalovirus, mycoplasma, etc.) can disrupt the differentiation of fetal tissues, which leads to the formation of congenital malformations.

Fetal (fetal) period

From the 9th week, the number and size of cells increase, the fetus grows rapidly, there is a structural reorganization of organs and systems with intensive maturation of tissues. The fetal circulatory system reaches its final development between the 8th and 12th weeks of pregnancy. Blood from the placenta through the umbilical vein and the ductus venosus enters the liver and the inferior vena cava. Having reached the right atrium, blood through the open oval window enters the left atrium, then into the left ventricle, ascending aorta and cerebral arteries. Through the superior vena cava, blood returns to the right atrium and ventricle, and from the pulmonary artery through the ductus arteriosus it enters the descending aorta, from where it returns through the umbilical arteries to the placenta. By the 12th week, the weight of the fetus is 14 g, the length is 7.5 cm, the signs of sex become distinct, the cerebral cortex is determined. By the 27-28th week of gestation, the brain resembles the brain of a newborn, but the cortex is not yet functioning, the brain stem and spinal cord, which perform vital functions, are actively growing and myelinating. By the 13-14th week, smooth movements appear in response to stimulation of all zones, at this time, fetal movements can be first noticed by the mother; they are clearly felt by the 20th week. The grasp reflex appears by the 17th week. Respiratory movements are noted at the 18th week; these movements create a current amniotic fluid in and out of the developing lungs. With prolonged pregnancy (more than 42 weeks), when meco-

aspiration amniotic fluid can lead to the entry of meconium into the alveoli, which subsequently causes respiratory disturbances. By the 12th week, the megaloblastic type of hematopoiesis is completely replaced by normoblastic, leukocytes appear in the peripheral blood. From the 20th to the 28th week, bone marrow hematopoiesis is established (instead of hepatic). Fetal hemoglobin (Hb), mainly fetal (HbF), has a higher affinity for oxygen than adult Hb (HbA) synthesized in the late fetal period. At the 14th week of development, the fetus begins to swallow, and from 28-29 weeks it can actively suckle. Bile begins to separate around 12 weeks, and digestive enzymes appear soon after. Meconium begins to form by the 16th week; it consists of desquamated intestinal epithelial cells, intestinal juices and squamous epithelial cells, swallowed with amniotic fluid. The immune system is formed from the 6th week in the form of a response to mitogens. At the 10th week, the activity of T-killers is determined. At the 8-9th week of intrauterine development, the infiltration of the thymus gland with lymphoid cells begins; by the 12th week, the iron outwardly resembles a mature organ. Circulating B-lymphocytes are found at the 13th week of gestation; A 20-week-old fetus has the ability to synthesize all major classes of immunoglobulins (Ig). IgM appears first, and their elevated content is considered a sign of IUI. The transfer of IgG from a pregnant woman to a fetus until the 32nd week is insignificant, therefore, their content is low in premature babies.

By the end of the second trimester of pregnancy, the weight of the fetus is approximately 1000 g, the body length is about 35 cm. The last trimester is characterized by a significant increase in the weight of the fetus, subcutaneous tissue and muscles.

The development of the fetus largely depends on the condition of the placenta. With various injuries, it becomes permeable to bacteria, viruses and other infectious agents that can cause fetal disease and / or premature birth. These and other pathogenic factors lead to a delay in the intrauterine development of the fetus, a lag in the differentiation of tissues and the maturation of their functions, dystrophic and inflammatory changes in organs.

Intranatal period

The intranatal period is calculated from the time of the appearance of regular labor pains until the time of the ligation of the umbilical cord. Usually it lasts from 6 to 18 hours.After the ligation of the umbilical cord begins

extrauterine stage, or childhood itself. Given the direct dependence of the level of infant mortality, the development and health of the fetus and newborn on the course of pregnancy and childbirth, as well as on the adaptive capabilities of the child to new living conditions, it is customary to combine the late fetal (fetal), intrapartum and early neonatal periods in the perinatal - from the end of 27 1st week of intrauterine development until the 7th day of extrauterine life.

EXTRA UTERINE STAGE OF DEVELOPMENT

Neonatal period

The neonatal period (neonatal) begins from the moment the baby is born and lasts 4 weeks.

The early neonatal period - the main period in the process of a child's adaptation to new living conditions - lasts from the moment of cord ligation to the end of the 7th day of life. The passage of the fetus through the natural birth canal causes birth stress with a consistent tension of the functional activity of the hormonal systems involved in adaptation processes. In the first hours of life, the release of catecholamines and glucocorticoids increases, followed by switching to "long-term protective measures" - an increase in the secretion of thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH) and thyroxine (T 4). A high concentration of catecholamines in the umbilical cord blood at birth contributes to the initiation of respiration, the formation of pulmonary function, and the cessation of fluid secretion by the lungs. With the first breath of the newborn, the respiratory organs begin to function. Balancing the pressure in the aorta and pulmonary artery leads to the cessation of blood flow through the ductus arteriosus and blood flow from the right atrium through the foramen ovale to the left. There is a complete "inclusion" of the small circle of blood circulation; adequate breathing with effective gas exchange is established; the umbilical vessels become desolate, and the baby's nutrition becomes enteral (the preferred option is breastfeeding). During the first few days of life, a decrease in the initial body weight by 5-6% is noted, which is considered a physiological phenomenon. Immediately after birth, the kidneys take on homeostatic functions, blood flow in them increases dramatically due to a decrease in resistance in the renal vessels.

Physiological catarrh of the skin, conjugational jaundice, etc. are also referred to the conditions reflecting the adaptation of the child to the new conditions of life (see the chapter “Borderline states”). The body temperature of a newborn is unstable, the energy requirement for its maintenance and physical activity is 55 kcal / kg / day.

Birth stress, restructuring of respiratory and circulatory functions, immaturity of the child's adaptive mechanisms are reflected in the metabolism. Metabolic processes in newborns follow the anaerobic, or glycolytic, pathway. If adequate oxygenation is not established, metabolic acidosis and hypoproteinemia may develop. Gas exchange in a newborn becomes the same as in an adult, the catabolic phase of exchange is replaced by an anabolic one, an intensive increase in body weight and length begins, analyzers (primarily visual) develop; conditioned reflexes and coordination of movements begin to form.

Due to the predominance of inhibition processes in the central nervous system (CNS), the newborn sleeps most of the day. The child reacts to sound and auditory stimuli with a set reaction. From the moment you open your eyes, i.e. from the first hours of a child's life, the visual channel of information transmission begins to function. An indicator of the perception of an object by newborns is the movement of the eyeballs - tracking and fixation of the gaze, which are established by the month of life.

Breathing, blood circulation, digestion and excretion occur with maximum intensity: respiratory rate (RR) 40 per minute, heart rate (HR) 140-160 per minute, number of urinations 20-25 times a day. The first act of bowel movement occurs within 24 hours after birth. A newborn's stool changes color from black-green (meconium) to yellow-brownish. The frequency of bowel movements during the neonatal period corresponds to the frequency of feeding and the amount of food received and on average is 3-5 times a day.

The presence of circulating mother's hormones in the newborn's blood may be accompanied by a sexual crisis (see the chapter "Borderline states"): girls have a reaction from the uterus - bloody menstrual discharge appears. Both girls and boys may have a reaction of the mammary glands (up to the secretion of colostrum).

By the 3-4th week of a child's life, the skin is cleansed and becomes pink, the umbilical wound heals. Protection against many viral and some bacterial infections is provided by IgG transmitted to the child from the mother. The function of own T-lymphocytes is somewhat reduced.

Diseases of the neonatal period are primarily due to unfavorable factors acting in utero or during childbirth. In this period, developmental defects, hereditary diseases, diseases caused by antigenic incompatibility of erythrocytes of the mother and the fetus are revealed [hemolytic disease of the newborn -

(HDN) for Rh (Rh) - or group (AB0) incompatibility], perinatal CNS damage of hypoxic, traumatic or infectious genesis, the consequences of intrauterine infection or infection during childbirth. In the first days of life, purulent-septic diseases (for example, pyoderma), bacterial and viral lesions of the respiratory tract and intestines may occur. The ease of infection is due to the absence of secretory IgA in newborns and the low content of antibodies (AT) belonging to the class

IgM.

Breast period

The breast period lasts from the 29th-30th day to the end of the 1st year of life. The main processes of adaptation to extrauterine life are completed, a violent physical, motor and mental development... At the same time, the intensity of metabolic processes is very high with persisting immaturity of anatomical structures, functional limitations of the respiratory system and gastrointestinal tract. Passive immunity to many childhood infectious diseases (measles, rubella, diphtheria, etc.), acquired intrauterinely through the placenta and maintained extrauterinely by mother's milk, persists for 3-4 months.

During the breastfeeding period, the length of the child's body increases by 50%, and the weight more than threefold. The relative energy requirement of children of this age is 3 times higher than that of an adult, and is covered by a significant amount of food per 1 kg of body weight. Therefore, rational feeding is so important.

The most significant processes of tissue differentiation occur in the nervous system. During the first year of life, motor functions are improved. At 1-1.5 months, the child begins to hold his head, at 6-7 months - to sit, by the age of one - to walk independently. At the age of 6 months, milk teeth erupt; by the end of the first year of life, there are usually eight of them. The child's psyche develops just as intensively. Starting from the first month of life, the child fixes his gaze on bright objects, by the end of the 2nd month he follows the movement of the object, smiles. An important milestone in the functional maturation of the cerebral cortex is 3 months. By this time, a state of calm wakefulness is formed with the main α-rhythm characteristic of this state on the electroencephalogram (EEG), the transmission of information to the cerebral cortex and its processing are accelerated. After 2-3 months, there is a differentiated perception of objects, memorization, and behavioral reactions are formed. One of the most important acquisitions by 6 months is speech function, which is formed on the basis of developing mechanisms of perception, attention and emotional sphere.

child. The first sound reaction is a cry, signaling the functional state of the child (hunger, discomfort). From about 3 months, the child utters sounds, "hums", begins to recognize loved ones. By the 4th-6th month, humming turns into babbling. At 6 months, the child repeats individual syllables ("pa", "yes", etc.), laughs loudly. By the end of the year, he utters the first words (his active vocabulary can contain 10-15 words), fulfills simple requirements, understands the prohibition. For normal physical and psychomotor development of an infant, his body's resistance to infections and other unfavorable environmental factors requires proper nutrition, a rational regimen, hardening, attentive care, and affectionate communication. To protect against infectious diseases, natural feeding and timely preventive vaccinations are especially important.

Intensive growth, differentiation of organs and high tension of metabolic processes become the background on which diseases such as malnutrition, paratrophy, anemia, rickets, acute digestive disorders, dyspepsia, easily develop (especially with insufficient, one-sided, excess nutrition and care errors) atopic dermatitis, recurrent obstructive syndrome. The passive immunity caused by the antibodies received from the mother is gradually weakening, and in the second half of the first year of life, children can get sick with measles, chickenpox and other childhood infectious diseases.

Preschool period

The preschool period (from 1 year to 3 years) is characterized by a gradual slowdown in the rate of weight gain and body length, continuing maturation of the nervous system, expansion of conditioned reflex connections, the formation of a second signaling system, the formation of nasopharyngeal lymphoid tissue, and an increase in muscle mass. By the age of 2, the eruption of 20 deciduous teeth is completed. During this period, children actively come into contact with the world around them, are mobile, inquisitive, and when communicating with adults and older children, their speech improves. Vocabulary by 2 years is up to 300, by 3 years - up to 1500 words. By the end of the 3rd year, children speak in long phrases, reason, their speech is characterized by pronounced word-creation (the use of changed sound forms of the word, inventing their own). Movement capabilities are rapidly expanding - from walking to running, climbing and jumping. Starting from one and a half years, children sleep about 3 hours during the day and 11 hours at night. During this period, through the game and observing the actions of adults, labor and household skills are taught. The child clearly shows individual

dual character traits, so education becomes the main element of childcare. At this time, it is important to properly organize the child's regimen, so as not to overload him with impressions and protect him from the negative influences of the environment. The main physiological systems have a greater degree of maturity: NPV becomes less and is 25-35 per minute, heart rate 100-120 per minute, urination is voluntary, stool 1-2 times a day. Acute digestive disorders, pneumonia, bronchitis, anemia often develop, but they are easier than in infants. Against the background of physiological hyperplasia of lymphoid tissue, tonsillitis, adenoids, and lymphadenitis often develop. In connection with the expansion of the child's contacts with other children, acute respiratory viral infections (ARVI), acute intestinal infections (AEI), whooping cough, rubella, chickenpox, measles, scarlet fever, etc. become frequent pathologies.

Preschool period

The preschool period (from 3 to 7 years) is characterized by the expansion of the child's contacts with the outside world. The increase in body weight slows down, the first physiological extension in length occurs, the length of the limbs increases markedly. At 5-6 years old, the change of milk teeth to permanent ones begins, the child switches to the diet of an adult. The immune defense reaches a certain degree of maturity. At 3-4 years of age, a close interaction of visual perception and movements remains. Practical manipulations (grasping, feeling) are a necessary factor in visual recognition. From 4 to 7 years old, there is a rapid increase in the volume of attention. During this time, children usually begin to attend Kindergarten, their intellect is intensively developing, motor and work skills become more complicated, subtle coordinated movements appear. By the age of 5, children speak their native language correctly, memorize poems, retell fairy tales. Differences appear in behavior, hobbies and games of boys and girls. Emotional manifestations become much more restrained. By the end of this period, the child is preparing to enter school.

Various links of the endocrine system are sequentially activated. The leading role during this period is assigned to thyroid hormones and growth hormone (STH) of the pituitary gland. The maximum activity of the thyroid gland was detected at the age of 5 years.

The incidence of acute respiratory viral infections and other infectious diseases remains high. In connection with the increasing sensitization of the body, the proportion of chronic diseases such as bronchial asthma, rheumatism, hemorrhagic vasculitis, nephritis, etc. is increasing. Lack of proper behavior skills with increased mobility often leads to injuries.

Junior school age

Junior school age includes the period from 7 to 11 years old. The structural differentiation of tissues is completed, a further increase in body weight occurs and internal organs, sex differences appear: boys differ from girls in height, maturation rate, physique. There is a complete replacement of milk teeth with permanent ones. Such motor skills as dexterity, speed, endurance are developed; subtle differentiated skills are successfully mastered - writing, needlework. By the age of 12, the formation of the nervous system ends, the cerebral cortex is similar in structure to that of an adult. The physiological parameters of the respiratory and cardiovascular systems are also close to those in adults. The development of higher nervous activity continues, metabolic processes in the brain are significantly enhanced, memory improves, intelligence increases, and volitional qualities are developed. During this period, social conditions change (the beginning and transition to subject teaching at school), the requirements for adolescents increase, and self-esteem increases. By the end of primary school age (prepubertal period), with the structural and functional maturation of the brain, the neurophysiological mechanisms underlying higher mental processes are improving, the functional and adaptive capabilities of the child increase. After 8 years, a pronounced growth of the ovaries is noted, from the age of 10, the growth of the uterus, prostate and testicles increases, and qualitative changes in their structure and functions also occur. The gradual development of the reproductive sphere begins. The frequency of infectious, gastrointestinal and allergic diseases remains high. Classes at school significantly limit the movement of schoolchildren, there are problems of impaired posture and visual impairment. Often, foci of chronic infection (caries, tonsillitis, cholecystitis) are found.

Senior school age

Senior school, or adolescent, age - the period from 12 to 17-18 years. It coincides with puberty. In a fairly short period of time, the reproductive system matures in boys and girls, its morphological and functional state reaches that in adults by the age of 17-18. In puberty, intense sexual differentiation occurs, due to the activity of the endocrine glands. The activity of the pituitary-gonadal and pituitary-adrenal relationships, which regulate the development and formation of the genital area, increases. On

the organization of the activity of the brain is influenced not only by the maturation of its own structures, but also by endocrine changes. This period is characterized by a rapid increase in body size, a sharp change in the function of the endocrine glands. Before the onset of puberty, the content of gonadotropins in the blood of girls and boys is low. The period from 1 year to the appearance of the first signs of puberty is regarded as a stage of sexual infantilism. However, a slight and gradual increase in the secretion of hormones from the pituitary gland and gonads is indirect evidence of the maturation of diencephalic structures. The concentration of testosterone in the blood of boys aged 7-13 is not high, but it increases significantly from 15 years of age, with the stabilization of the hormone concentration by 20 years. In parallel with the pubertal development of the larynx, a mutation of the voice occurs - an important sign indicating the degree of puberty of a young man. In the ovaries, sex cells mature and many hormones (estrogens, androgens, progesterone) are synthesized. Already at the age of 10-12, against the background of a low content of estrogen, on some days, its increase by 2-3 times is noted. The closer to menarche, the more often such a short-term increase in estrogen excretion is observed. Average age the onset of menarche - 12-13 years. At the age of 16-17, most girls have a regular menstrual-ovarian cycle. The increase in body length is especially pronounced during puberty, therefore, at the age of 12-14, girls often overtake boys in physical development. During the "sprout leap", at about the age of 12, girls grow by about 8 cm per year. In boys, such a "leap" occurs later - about 14 years old, when they grow on average by 10 cm per year. Muscle strength and performance are significantly increased. The increasing motor and neuropsychic activity, the intensive increase in body weight and length require intense work of the endocrine glands, the nervous system and metabolic processes, which dictates the need for additional introduction of nutrients. Accelerated physical and puberty does not always go parallel with intellectual development, physical maturation occurs faster and ends earlier.

In adolescence, they often choose a profession; this is the time for self-determination and personality development, the time for the affirmation of gender and the development of a sense of sexual conformity. Thinking becomes more independent, active, creative. The ability for self-sacrifice, devotion, trust appears.

Particular attention should be paid to the heart with a variety of morphological variants of its development, lability of the heart rate, imperfection of neurovegetative control. In that

period often meet functional disorders of the cardiovascular and autonomic nervous system ("youthful heart", "juvenile hypertension", dyscirculatory disorders). Eating disorders (obesity, dystrophy) and gastrointestinal diseases (gastritis, duodenitis, peptic ulcer) are also widespread. With the onset of puberty, defects in the development of the reproductive apparatus are revealed (dysmenorrhea, amenorrhea, etc.), infectious-allergic diseases, tuberculosis can worsen. Due to hormonal changes, deviations in the functioning of the endocrine apparatus (hypo or hyperthyroidism, etc.) are possible. The imbalance of hormonal influences, a temporary decrease in the immune properties of the skin, the enhanced function of the sebaceous glands in both boys and girls are often accompanied by pustular skin diseases, especially on the face. This is a difficult period of psychological development, striving for self-affirmation, often with a dramatic revision of the entire system of life values, attitudes towards oneself, parents and peers.

To determine biological age, signs are used that reflect the process of biological maturation. In all periods of childhood, there are distinctive features of body proportions and characteristics of physical and psychomotor development. In infants and toddlers, the biological age can be judged by the disappearance of congenital unconditioned and the appearance of conditioned reflexes, the eruption of milk teeth and the formation of ossification nuclei, the development of motor skills and speech. V preschool age an important sign of maturity is the appearance of permanent teeth, and in children of primary and senior school age - the development of secondary sexual characteristics, intelligence, physical performance.

During this period, dependence on an adult is pervasive.

By the age of one, the child pronounces the first words, at this time the foundations of speech skills are laid. Children themselves lay these foundations, seeking to establish contact with adults through crying, humming, cooing, babbling, gestures, and then the first words.

In the development of objective activity, toys are of great importance. Knowledge about people and the surrounding objects is formed in children on the basis of information received from their own senses and random movements.

The need for age is the need for safety, security. This is the main function of an adult. If a child feels safe, then he is open to the world around him, they will trust him and master it more boldly. If not, it restricts interaction with the world to a closed situation. V younger age a person develops a feeling of trust or distrust in the world around him (people, things, phenomena), which the person will carry through his whole life. A sense of alienation occurs with a lack of attention, love, affection, and child abuse.

At the same age, a feeling of attachment is formed.

Development of movements and actions. During the first year of life, the child achieves great success, mastering movement in space and the simplest actions with objects. He learns to hold his head, sit down, crawl, move on all fours, take an upright position and take several steps; begins to reach for objects, grab and hold them, finally, manipulate (act with objects) them - swing, throw, knock on the bed, etc.

Cooperative activity an adult and a child consists in the fact that the adult guides the actions of the infant, and also in the fact that the infant, being unable to perform any action himself, turns to the help and assistance of an adult. Development of orientation in the surrounding world. As new types of movement are mastered and improved, the child's orientation is formed in the properties and relationships of objects, in the surrounding space.

The actions that the child masters under the guidance of an adult create the basis for mental development. The dependence of the infant on adults leads to the fact that the child's attitude to reality and to himself is always refracted through the prism of relations with another person. In other words, the child's relation to reality turns out from the very beginning to be a social, social relation.

There is a formation of prerequisites for mastering speech. The need for communication creates the basis for the emergence of imitation of the sounds of human speech.

It is good for every mother to know about age, anatomical and physiological characteristics of the child's body and the associated disease potential. Why have infants most often there is indigestion, and do schoolchildren have acute infectious diseases? The nature of childhood painful depends largely on age characteristics of the body and from the child's environment.

Intrauterine development of the child

Human development goes through two stages: intrauterine and extrauterine. The intrauterine period lasts about 9 months (270 days). The correct development of the fetus depends mainly on the state of health of the mother, the conditions of her work and life. Some diseases of the mother (especially a viral infection), unhealthy diet, improper lifestyle can lead to stillbirth, developmental defects, deformities and diseases during the neonatal period and in the subsequent life of the baby.

Newborn period

The first period of prenatal development - the neonatal period - lasts 3-4 weeks from the moment of birth. The newborn finds himself in completely new living conditions: from a sterile, that is, microbial-free, uterine period of development, the child moves on to life in an external environment inhabited by microbes and rich in various stimuli. He must adapt to the new conditions of life, but the immaturity of organs in the systems of the newborn's body, including the central nervous system, makes this adaptation rather difficult, therefore the body of the newborn is especially unstable and vulnerable.

Of the diseases in this period, in addition to congenital malformations and congenital infections (malaria, syphilis, less often tuberculosis, etc.), various injuries, diseases of the navel and umbilical wound are noted. At this age, there are often inflammatory processes of the skin, pustular rashes. A high susceptibility to some microbes with the structural features of the skin of newborns often leads, under the influence of a minor infection, to severe general blood poisoning - sepsis.

Infant physiology

The next period - infancy - lasts mainly 1 year. (Some consider it big - up to 1.5 years.) At this age, the metabolism increases, the child grows and develops rapidly. In the first half of his life, he doubles his weight, by the year he triples. The body length increases by 20-25 cm. Such an increased growth also requires increased nutrition. However, the child's digestive organs are not yet sufficiently adapted to the digestion of food, since during the period of uterine development, nutrition took place through the mother's body. Minor errors in feeding a child (for example, overfeeding) easily disable the digestive tract, cause indigestion, indigestion - dyspepsia (diarrhea). That is why, at this age, the so-called "acute disorders of digestion and nutrition" are especially often noted, which have a difficult effect on the general condition of children.

Improper feeding, deficiencies in care, regimen and upbringing, infectious diseases lead to chronic eating disorders (malnutrition). At the same time, the correct development of the child is disrupted: he lags behind in weight and height, higher nervous activity, the function of the most important organs and systems of the body are disrupted, and the resistance to infection decreases.

Among the diseases of infants, rickets is especially common. Rickets is a disease of the whole organism associated with a violation of phosphorus-calcium metabolism. It occurs as a result of a lack of vitamins in food, mainly vitamin D, unfavorable environmental conditions - inadequate exposure to air, sun, poor childcare. With rickets, the nervous system is affected (excitability, anxiety, sweating, poor sleep appears), the skeletal system (softening of the skull bones, curvature of long tubular bones, in severe cases - their fractures), the muscular system, the function of other organs and systems of the body is disrupted. Rickets is also dangerous because it retards the mental development of children; such children begin to sit, stand, walk much later than healthy ones.

Sometimes in the first months of life, manifestations of exudative diathesis are also observed. Inflammatory lesions of the skin and mucous membranes (seborrhea, eczema, pruritus, urticaria, diaper rash), frequent rhinitis, bronchitis appear.

Protect infants from acute respiratory infections, including pneumonia (pneumonia). Pulmonary diseases in young children are very difficult and cause complications in the form of suppurative processes (pleurisy, etc.). Complications often lead to inflammation of the middle and inner ear and are accompanied by diarrhea.

Measles, scarlet fever, diphtheria up to six months of age are relatively rare, especially up to three months. This is due to innate immunity - the body's immunity to disease. After birth, the baby receives valuable substances in the mother's milk that increase his resistance to infection.

The highest morbidity and mortality in children is observed during the period of newborn and infancy. Therefore, parents should be especially careful to follow all the instructions of the doctor and nurse for the care, regimen and nutrition of the child.

Preschool and preschool developmental periods

The third period - preschool (from 1 year to 3 years) and the fourth - preschool (from 3 to 7 years) are characterized by further growth and development of the child, but the growth rate compared to infancy is much lower. The child's living conditions change dramatically - he begins to walk, to get acquainted with the objects around him, with the external environment. The shift from breastfeeding to a varied diet increases the risk of infection. Therefore, during these periods, especially in preschool, worm diseases are often observed. Congenital immunity and the resistance to diseases that a child receives with mother's milk weaken after a year. Children at this age suffer from measles, whooping cough, scarlet fever, chickenpox. The danger of the disease increases even more if children are not given timely vaccinations, thanks to which immunity is artificially produced in the body. Repeated vaccinations are also very important - they strengthen the body's immunity to the disease.

In the preschool and preschool periods, the child's entire body is further developed and strengthened. The digestive organs adapt to the new diet, therefore, gastrointestinal diseases, exudative diathesis in preschool age are less common. Respiratory organs are also strengthened, respiratory diseases are less severe, especially in preschool age, complications such as ear diseases are less common. Tuberculosis gives a better outcome than infants. The mortality rate of children is much lower.

Age periods of child development: Younger school age

The fifth period is primary school age (from 7 to 12 years old). At this age, communication of children with the environment expands. The guys go to school, are in a team. Infectious diseases are especially dangerous for this age. Very often, the disease spreads through the air - a capillary infection. Therefore, it is important in schools to carefully monitor the cleanliness of the premises, to regularly ventilate classes.

Rheumatism is also recognized as a disease of school age. V last years some scientists talk about the rejuvenation of this disease, that is, that rheumatism began to appear more often in preschool age and even in preschool age, but still it is mainly a disease of school age, and the disease is serious, leading to deep lesions of the cardiovascular system, to early disability of children. The causes of the disease and its causative agent have not yet been established. However, it is indisputable that the general strengthening of the body by hardening, proper nutrition, a mode of exercise and rest contributes to the development of resistance to this disease. Curvature of the spine and myopia are recognized as school diseases, which are largely associated with non correct position torso during class at school and at home. With the wrong regimen, insufficient physical education and stay in the fresh air, children develop anemia, diseases of the nervous system.

Adolescent period of child development

The sixth period is puberty, or adolescence (12 to 18 years). Rapid growth at this age leads to diseases associated with a discrepancy, a disproportion between the growth and size of some organs (for example, the heart - this is the so-called "youthful heart"), as well as some functional disorders of the endocrine glands, especially the thyroid, disorders of the nervous system - neuropathy, etc. During adolescence, the period of rapid growth and transition to maturity, diseases are of an acute character of outbreaks. In this respect, tuberculosis is especially dangerous.

Thus, the nature of the disease in children is closely related to the characteristics of their body at different age periods and with the conditions surrounding the child. In different periods of childhood, the nature of diseases and their course change.

The main task of health care is not only to treat diseases, but also to prevent their occurrence. And the task of parents is to provide daily assistance in this: to monitor the timely implementation of protective vaccinations, systematic physical education, sports, the correct position of the child's body when doing homework, and the right approach to children, taking into account their age and individual characteristics.

The joint care of parents and health workers will help to raise our young generation to be healthy, resilient, well resistant to infection.

Tags: age periods of child development, physiology of development, diseases of children of different ages, the physiological development of the child at different periods of life.

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While still in the womb, the first stages of the child's development are laid, after birth, the little man begins to learn the world through the sense of smell and touch, every month he acquires new skills. It is believed that up to 3 years of age, a baby develops a psyche, character, skills - this is facilitated by the environment, conditions and parental care. The child is like a blank sheet - absorbs all the information received from the outside - the task of adults is to bring up a full-fledged personality from him, to teach

For each age, there are developmental games and activities in the formation of a mental and physical baby that are fundamentally different from other stages and require special attention and approach. During this main period of life, the newborn is mastering motor skills, which closely interacts with mental and motor functions. Most pediatricians, psychologists and neuropathologists adhere to the theory that a person goes through several stages to reach maturity. mental development.

Each stage prepares the foundation for the development of the next. The stages of a child's development from birth to 2 years are fundamental, it is during this period that the baby learns to listen, beat, push, move, look. Also, a significant role is played by the hereditary mechanism, which links the first acquired abilities with each other and encourages the achievement of new goals. Thus, the sensory stage is subdivided into six main stages:

1. The first month of life - these are innate reflexes, which over time become more effective and pronounced.

2. From 2 to 4 months - conditional skills: grasping and sucking movements.

3. From 5 to 8 months - circular reactions, formed on the basis of motor functions and coordination.

4. From 9 to 12 months - all the baby's actions become more conscious, he already knows how to get an object of interest, a toy.

5. From one to 1.5 years - inadvertently discovers new abilities. For example, opening the cabinet doors, the child can get the item lying there.

6. From 1.5 to 2 years old - on the basis of the acquired skills, the baby is able to explore the world in new colors, moving independently and looking for solutions to eliminate any obstacles.

The subsequent stages of development of children from 2 to 11 years old are aimed at studying specific situations and actions. The child discovers that having built a tower, it can be easily destroyed and recreated again, such a game is a motor function, mental activity. The attention of the baby at this age is very scattered, everything is interesting to him and he wants to try and touch new objects on his own.

After two years, the baby has favorite toys, activities (drawing, music, cars, dolls) with the right approach to the child, you can develop certain abilities in him. But in no case should the baby be forced to engage in the same activity for a long time, because you can forever push him away from this hobby. Due to the narrow range of thinking and egocentric disposition, the baby is inconsistent in actions and deeds, he is quickly bored with toys, similar activities - this aspect should be taken into account by young parents. The early stages of a child's development are a kind of preparation for adulthood.

Growing up, the baby begins to imitate his parents in everything, copy their actions, take on the role of an adult. For example, the stages of a child's development three years of age the most difficult ones, requiring patience from the parents. His consciousness becomes more complicated, his needs increase - the little man needs the attention and support of his parents even more. The kid is overly inquisitive, tries to climb everywhere, shows independence in some moments, is inconsistent in actions - during this period, the kid should be under the constant supervision of adults.