Age features of the child's body

Natalia Krutikova
Features of the physiological development of preschool children

Age 3-7 years old applies to preschool, which is very important in child development, as it is characterized by qualitative and functional improvement of the brain, all organs and systems of the body.

Dynamics physical development of a child in preschool age is uneven. At the 4th and 5th years of life, the growth of the child slows down somewhat, the child grows by 4-6 cm per year, and during the subsequent period of life (v age 6-7 years) increase in growth reaches 8-10 cm per year. Rapid increase in growth children at this age is called"first pull period". It is associated with functional changes in the endocrine system. (increased function of the pituitary gland). Over the years, the proportions of the child's body have changed significantly. By the age of 7, his upper and lower limbs noticeably lengthen, and the chest circumference increases. If the growth of the child is behind the norm by 10%, it is necessary to pay attention to the following factors:

Is your child eating rationally?

Is the psychological climate in the family good?

If growth is delayed by 20%, an endocrinologist should be consulted.

Weight gain children by the age of 4, as well as growth increases, somewhat slow down and average 1.2-1.3 kg per year, and then again a more intensive increase in weight is noted body: for the 5th year of life, the child adds an average of 2 kg, for the 6th -2.5 kg, for the 7th about 3.5 kg. By 6-7 years of age, a child's body weight doubles compared to its weight in a one-year-old. age. If body weight exceeds the norm by 10%, taking into account the deviation, this is considered obese and requires correction by specialists. If body weight is below normal in this age, it indicates poor physical development and requires consultation with a pediatrician, rationalization of the diet.

At preschool children further development musculoskeletal system. Bone tissue becomes denser, body weight increases.

By the age of 5, her strength increases significantly and performance. The contractile muscle ability increasing their strength. Development and differentiation of the central nervous system in preschoolers expressed in the improvement of motor functions, development coordination of movements, decreased muscle tone, develops a sense of balance. Much muscles develop, especially on the legs. More developed children can take off both legs from the ground, it’s good to jump from a running start, but they still don’t know how to use the wave of their hands correctly; able to stand on one leg, walk on heels and on toes. In that age especially gymnastics is easy. A child can be taught to ski and skate, on a two-wheeled bicycle. Majority children at this age dance with pleasure and carefully perform various movements to the music.

After 4 years, maximum visual acuity is reached, and the child physically ready for initial reading. The brain by the age of five in size and mass (90%) almost equal to the brain of an adult. The process is very intense development convolutions and furrows of the brain. However, it should be noted that the child is dominated by the right hemisphere, "responsible" for figurative perception, the emotional sphere, while the left "responsible" for speech, logical thinking, not yet formed. The child is in the grip of emotions, the main nervous processes: excitation predominates, inhibition is usually achieved with difficulty. This is manifested in the immediacy and sincerity of the child and in a pronounced imbalance and distractibility. Characterizing features of the development of children 4-5 years old, you should pay attention to the signs of psychomotor dysfunction in external manifestations child:

Hunchback, humiliation, depression, tension (head drawn into the shoulders, hands pressed to the body, fingers tense or clenched into fists);

Gait - on tiptoe, unsteady, sluggish, stumbling or like a mannequin;

Poses - frozen, constrained and monotonous;

Movements - aimless, unproductive at high intensity or psychomotor retardation;

Gesticulation and facial expressions - sluggish, poor, inexpressive, perhaps grimacing or facial mobility;

Speech is slurred, inexpressive, monotonous, stuttering is possible.

Be careful if the child has at least half of the described symptoms.

Play more games with your child, give him care, attention and love - he expects them from you, it's hard for him. Build your child's self-confidence and desire to actively interact with the outside world.

Children preschool age compared to early childhood age are more resistant to physical activity. They are good developed speech, the children of this age have certain skills in self-service, work, prepared for schooling. Their resistance to diseases is much higher.

The activity of the digestive tract children by the end of preschool» period reaches the level of an adult. By the age of 7, the child's molars erupt. From 6-7 years old, the change of all milk teeth begins. The volume of the stomach by the age of 5-7 reaches 400-500 ml, its muscular layer increases, the amount of digestive juices increases significantly and their enzymatic activity increases. At children of this age much less often there are disorders of the gastrointestinal tract. Acute childhood infections are common promotes wide communication of preschoolers with others. They flow more easily than young children, and rarely lead to serious consequences. Due to the ever-increasing sensitization of the body in preschool children already there are allergic and infectious-allergic diseases, such as bronchial asthma, rheumatism, and others.

Children preschool age often suffer from acute respiratory diseases, which is associated with relatively low immunity in this aging and growing contacts with adults and peers. This is especially noticeable among children. visiting children's preschool institutions, in which it is necessary to distinguish groups of frequently and long-term ill (bdb) children. This group children requires great attention and assistance in the process of adaptation to new conditions, as well as in strengthening and hardening their body.

At preschool age, all internal organs (lungs, heart, liver, kidneys) increase and their functions improve. The nervous system is actively developing. The musculoskeletal system is strengthened: cartilage tissue is gradually replaced by bone tissue, muscle mass and strength increase significantly. The formation of bone and muscle systems creates the prerequisites for the successful assimilation of various movements.

Skeletal system

Ligaments, joints provide the position of the body and the possibility of movement of its parts, performing a protective function. The bone tissue of a child contains water and only 13% of mineral salts, i.e. the elasticity of the bones prevents fractures. The joints in children are very mobile, the ligamentous apparatus is easily stretched, the tendons are shorter and weaker.

Excessive physical activity adversely affects the development of the skeleton, delays the growth of bones. Moderate exercise, on the contrary, stimulates the growth of bones, contributes to their strengthening.

Physiological curves of the spine are formed up to 6-7 years. The structure of the bone tissue of the vertebrae is not yet complete, the vertebral column is very elastic, consisting mainly of cartilage tissue. Due to unfavorable conditions, posture disorders may occur (the head is lowered, the back is bent, the shoulders are brought forward, etc.) Conditioned reflex connections reinforce the wrong position of the body, the skill of correct posture is lost, which can lead to spinal curvature.

The formation of posture is significantly influenced by the static-dynamic function of the foot. A change in the shape of the foot can cause a displacement of the pelvis, curvature of the spine, and posture disorders in different planes. The diagnosis of flat feet is confirmed by plantography - a foot print using coloring solutions.

Muscular system

Muscles in children are poorly developed and make up 20-22% of body weight. They contain more water than proteins and fats. The flexor muscles are more developed than the extensor muscles. Children 3-4 years old often take the wrong posture - the head is lowered, the shoulders are brought forward, the back is stooped.

By the age of 5, muscle mass (especially of the lower extremities) increases significantly, muscle strength and performance increase, but children are not yet capable of prolonged physical activity.

Working with alternating tension and muscle relaxation is less tiring for the child than holding the muscles in a fixed position. Dynamic work promotes active blood flow to muscles and bones, which ensures their intensive growth.

The cardiovascular system

The blood vessels are wider than in adults. Blood pressure is weaker, heart rate is higher. Junior preschooler - 85-105 beats / min. Less during sleep, more during emotional arousal. In older preschoolers, it is more stable - 78-99 beats / min. Girls have 5-7 strokes more than boys.

The optimal load is 150-180% compared to the original data.

Arterial pressure almost does not change: 3-4 g. - 96/58 mm Hg. Art., 5-6 years old - 98/60 mm Hg. Art.

Prolonged physical and mental stress can adversely affect the activity of the heart.

Respiratory system

The upper respiratory tract is relatively narrow, the mucous membrane is rich in lymphatic and blood vessels. Under adverse conditions, it swells, breathing is disturbed.

Shallow breathing prevails. The development of the lungs is not yet fully completed: the nasal passages, trachea and bronchi are relatively narrow, which makes it difficult for air to enter the lungs, the chest is raised and the ribs on exhalation cannot fall as low as in an adult. Children cannot take deep breaths in and out. The respiratory rate is greater than in adults: infants - 40-35 breaths per minute, at 7 years old - 24-22 breaths.

Much more blood flows through the lungs than in adults. These meet the need for oxygen for intensive metabolism.

It is necessary to teach to breathe through the nose (cleansing and warming the air).

Internal organs

Not developed enough. The stomach has weak muscular walls, the muscular layer and elastic fibers in the intestinal wall are poorly developed. The activity of the intestines is easily disturbed.

Leather

Protects internal organs and tissues from damage and penetration of microorganisms, is an organ of excretion, thermoregulation and respiration. In children, tender, easily injured. It is necessary to protect, protect from damage, promote the development of thermoregulatory and protective functions.

Nervous system

The main differentiation of nerve cells occurs before the age of 3 and almost ends by the end of preschool age.

A feature is the ability to preserve traces of the processes that took place in it. Children quickly and easily memorize the movements shown to them. For consolidation and improvement, multiple repetitions are necessary.

High excitability, reactivity, high plasticity of the nervous system contribute to faster and better mastery of motor skills - skiing, skating, swimming. It is necessary to form motor skills correctly, it is difficult to correct them.

Features of the mental development of children:

Predominance of excitation over inhibition;

Instability of attention;

Impulsivity in behavior;

Great emotionality;

Concreteness of perception and thinking.

Knowledge of the age characteristics of the development of the child will help to choose physical exercises, tempering procedures, monitor the physical and mental development of children.

The body of a preschooler is developing rapidly. During the first seven years of his life, not only all the internal organs increase, but their functions also improve. The main indicators of the physical development of the child are height, body weight and chest circumference. Knowing these indicators, it is possible to compare the data on the physical development of children of a particular child in a group with the average developmental indicators of children of the corresponding age (see Table 1)

Table 1.

Average indicators of physical development of children aged 3-6 years (according to Shebeko V.N. et al., 1996)

Indicators of physical development	Age, years
Body weight, kg
Body length, cm
boys
Body weight, kg
Body length, cm
Chest circumference, cm

To ensure the normal physical development of the child, to give him the necessary load in physical education, it is necessary to take into account the anatomical features of the child's body. Peculiarities of children's movements, their coordination abilities change significantly from age to age, which significantly affects the organization of physical education classes.

Muscular system in children it is formed on the basis of the development of the nervous system and an increase in the mass of skeletal muscles, and this process occurs unevenly. In young years bones the child is rich in blood vessels, contain a small amount of salts. They are elastic, flexible, easily deformed and bent, since the osseous system of 2-3 year old children has significant areas of cartilage tissue, weak, soft joints and ligaments. Toddlers do not yet have stable curves of the spine, which appear only by the age of four. All this must be taken into account when conducting physical education classes.

Particular attention should be paid to the development arch of the foot, since in the second and partially in the third year of life it is flattened. Therefore, it is useful to exercise babies in lifting, walking on an inclined plane and a ribbed board.

Small children breathe shallowly, often, unevenly, as respiratory the musculature is not yet fully formed. The development of the body of a child who masters walking leads to a restructuring of the breathing process and a gradual strengthening of the corresponding organs. The frequency normalizes, chest-abdominal, and then chest type of breathing appears, the lung capacity increases. Breathing quickens only with excitement or physical exertion. Taking into account the peculiarities of the respiratory system of preschoolers, care should be taken that they are as much as possible in the fresh air (A.P. Chabovskaya, 1971).

Prolonged physical and mental stress can adversely affect the activity of the heart and lead to violations of its function. Therefore, it is necessary with great care to dose the physical load on the child's body. The work of the heart is closely related to muscle development. Regular exercise trains the heart muscle, leading to a gradual decrease in heart rate.

Early and preschool age is characterized by significant changes not only in physical, but also in motor development (Zh.K. Kholodov, V.S. Kuznetsov, 2004) (see Table 2).

According to Yu.A. Ermolaev preschool age covers the period of life from 3 to 6 - 7 years. At this time, there is an intensive biological development of the child's body. The child's body is always in the process of growth and development, which take place continuously in a certain regular sequence.

A child in different periods of life is characterized by certain anatomical and physiological features, the totality of which leaves an imprint on the educational and educational process (1985).

Physiological features of preschool children

The first 7 years of a child's life are characterized by the intensive development of all organs and systems. A child is born with certain inherited biological properties that form the basis for further physical and mental development, and the determining factor from the first months of life is the environment and upbringing of the child.

A feature of the central nervous system of a child in the first years of life is the incompleteness of the morphological structure and functional development of the cerebral cortex. The completion of these processes occurs in subsequent years under the influence of external and internal stimuli.

The nervous system in preschool children is characterized by high excitability and weakness of inhibitory processes, which leads to a wide irradiation of excitation through the cortex and insufficient coordination of movements. But long-term maintenance of the process of excitation is not yet possible, and children quickly get tired.

The first years of children's life are characterized by a lack of intersystem relationships in the body. With the weakness of cortical processes in children, subcortical processes of excitation predominate. Children at this age are easily distracted by any external stimulus. Arbitrary attention is very short-term from 3 to 20 minutes, therefore, the use of imitative reflexes, the emotionality of classes, and game activity are of great importance for the formation of motor skills.

Of particular importance in the behavior of the child is the development of speech. Until the age of 6, reactions to direct signals predominate in children, and from the age of 6, speech signals begin to dominate (A.S. Solodkov, 2005).

The development of sensory systems mainly occurs during preschool and primary school age. The visual sensory system develops especially rapidly during the first 3 years of life, and then continues to improve. As the child grows and the relationship between visual information and motor experience improves, the estimation of the depth of space improves. The field of view increases sharply from the age of 6.

The child's auditory sensory system is of paramount importance for the development of speech, providing not only the perception of the speech of strangers, but also playing the formative role of the feedback system in their own pronunciation of words. Her excitability to verbal signals especially noticeably increases at the age of 4 years and continues to increase by 6-7 years. Hearing acuity and the ability to differentiate sounds increase (N.I. Obreimova, 2000).

The motor sensory system is one of the first to mature in humans. The formation of proprioceptors - muscle spindles and tendon receptors begins as early as 2-4 months of intrauterine development and continues after birth until 4-6 years. This dramatically improves the ability to regulate motor activity and develop new skills.

Many children show high vestibular resistance to rotations and twists. The earlier appearance of contacts of the vestibular sensory system with the motor system and with other sensory systems allows the child to master the basic fund of movements by the age of 2-3 years and begin physical exercises from the first years of life (A.S. Solodkov, 2005).

At preschool age, there is an intensive formation of the musculoskeletal system. By the age of 5-6, the shape of the spine is similar to that of an adult, but the fixation of the spine is still imperfect (N.I. Obreimova, 2000). The calcium content in the skeleton increases, so the skeleton is ossified, but still there is still a lot of cartilage tissue in it. The intensity of metabolism in the bone tissue decreases. In the bones and skeletal muscles of children, there are a lot of organic substances and water, but few minerals, therefore the bones are flexible, therefore during this period incorrect postures, overwork, excessive overloads during physical exercises can cause severe posture disorders due to improper redistribution of muscle-ligamentous tone. apparatus (Z.V. Lyubimova, 2003).

In the first years of life in children, the tone of the flexor muscles exceeds the tone of the extensor muscles. It is difficult for children to maintain an upright posture for a long time. The muscles of the limbs are relatively weaker than the muscles of the trunk. Insufficient development of the muscular-ligamentous apparatus of the abdominal press can cause the formation of a sagging abdomen and the appearance of hernias when lifting weights. The strength of the muscles of boys of preschool age is equal to the strength of the muscles of girls (A.S. Solodkov, 2005).

Gradually increases the mass of muscle tissue. In the period from 4 to 7 years, there is a significant increase in muscle mass and, accordingly, the contractility, strength and performance of muscles increase, therefore, according to the recommendations of L. Kechedzhieva (1985) and others, exercises for the muscles of the shoulder girdle and hip joints, the child is 5-7- summer age can be performed daily from 20 to 30 times, and for the muscles of the body - from 40 to 60 times, in separate series of 6-8 or 12-16 times. A large amount of work performed causes noticeable changes in metabolism, in the work of the functional systems of the body, expanding the mechanisms of adaptation not only to physical activity, but also to the action of various environmental factors, and contributes to an increase in overall performance.

The cardiorespiratory apparatus is of great importance in ensuring human life. Children of preschool age are distinguished by the small size of the heart and weakness of the heart muscle, which in turn determine a small SOC, and in combination with high elasticity and a wide lumen of the vessels, a low level of blood pressure. With age, the cardiovascular system becomes more efficient. The mass of the heart and the strength of heart contractions increase, the heart rate decreases: at 3 years old it is 105 beats per 1 minute, at 5 years old - 100 beats per 1 minute, at 7 years old - 85-90 beats per 1 minute. The value of heart rate is very labile, easily changes with any external stimulation (Z.V. Lyubimova, 2003).

The lung tissue of the child is not very extensible, the bronchial tree is not sufficiently formed. The chest is cone-shaped and has a small excursion, the respiratory muscles are weak. All this complicates external breathing, increases energy consumption for inhalation and reduces the depth of breathing. Breathing in children is often superficial. Due to the high excitability of children, the respiratory rate increases extremely easily during stress and emotional outbursts. At the end of preschool age, the formation of the chest is completed, the abdominal type of breathing appears.

Energy metabolism in preschool children significantly exceeds the level of metabolism in adults, decreasing most sharply in the first 5 years and less noticeably throughout the rest of life. Daily energy expenditure increases with age.

At the age of 6-7 years, there is some acceleration of growth, the so-called. the first physiological traction, at the same time, differences in the behavior of boys and girls appear. Glands such as the thyroid, adrenal glands, and pituitary gland take an active part in these processes. The "preparation" of the gonads for the period of puberty begins (N.I. Obreimova, 2000).

Thus, over a period of 3 to 7 years, the third, fifth and seventh years of life are distinguished, when not only quantitative growth occurs, but also a significant restructuring of functions, while the restructuring of the activity of the main energy supply systems precedes that in the motor function, which creates prerequisites for purposeful influence during these critical periods of means of physical education. At the same time, it was proved that the age from 4 to 5 years is characterized by the greatest intensity and harmony of development.

SKIN AND SUBCUTANEOUS FIBRE

Newborn children: the skin is tender, velvety, elastic, pink; rich in blood vessels and capillaries. The sweat glands are poorly developed, the sebaceous glands are active, which leads to rapid overheating or hypothermia of the child. Newborns have easily vulnerable skin. The subcutaneous fat is well developed and denser than it will become in the future.

Babies: the skin is still very delicate, easily hurt. Thermoregulation is imperfect (overheating or hypothermia of the body).

Older toddlers: the skin is thin, delicate, its suction capacity is very high. One must be very careful with medicines in the form of ointments.

Preschool children: there is a gradual thickening of the skin, but it is still easy to become cold or overheated.

Children of primary school age: the sweat glands are finally formed, the child is less susceptible to hypothermia and overheating. There are large accumulations of fat cells in the chest and abdomen, which, with improper nutrition, is aggravated by general obesity.

Children of senior school age: skin like an adult.

MUSCULAR SYSTEM

Newborns: increased tone - arms bent at the elbows, legs pressed to the stomach. The neck muscles are not strong - they do not hold the head.

Thoracic: if the posture of a newborn child at rest persists for 2.5 months, a consultation with a neurologist is necessary.

1-3 years: the mass of the muscular system increases, but subtle movements (of the fingers) are still difficult.

3-11 years: muscle strength increases, performance improves. Fingers can do finer work (writing, modeling).

11-17 years: the muscular system becomes like that of an adult.

BONE SYSTEM

Newborns: fragile. Bones are easily distorted by improper care of the child. In the skull there are non-ossified areas - fontanelles. The head is 1-2 cm larger than the circumference of the chest, the arms are much longer than the legs. The chest is barrel-shaped, the ribs are horizontal and consist mainly of cartilage, as is the spine, which does not yet have physiological curves.

Thoracic: by 1-2 months, a small fontanel closes, and by a year - a large one. By 6-8 months, teething begins. Their appearance is accompanied by a slight appearance of temperature, anxiety, insomnia and malaise.

1-3 years: by 2.5 years, milk teeth are fully erupted. The shape of the chest changes, the ribs are more oblique, and the curves of the spine are formed. The growth of the pelvic bones continues.

3-7 years: the spine already corresponds in shape to an adult, but so far the child's skeleton is not strong. Strict control over the posture of the child is necessary. Scoliosis - curvature of the spine - begins at this age. The formation of the chest is completed.

7-11 years: chest volume increases. By the age of 11, differences in the shape of the pelvis appear - in girls it is wider.

12-17 years: the shape of the chest and pelvis approaches their structure in adults. Bones are stronger and less elastic. Something harder to fix.

RESPIRATORY SYSTEM

Newborns: the lungs are underdeveloped, breathing is shallow and carried out mainly by the diaphragm. Therefore, breathing is easily disturbed by the accumulation of gases, constipation and tight swaddling. Breathing is frequent: 40-60 breaths per minute. The mucous membranes of the respiratory tract are delicate, contain a large number of blood vessels. The nasal passages are narrow, as are the trachea and bronchi. The auditory tube is wider and shorter, so newborns often develop otitis media. There are no frontal and maxillary sinuses, so newborns do not have frontal sinusitis and sinusitis.

Thoracic: lungs are more developed. Up to 3 months, the respiratory rate is 40-45 breaths per minute, at 4-6 months - 35-40, at 7-12 months - 30-35. The respiratory organs of a small child are very different from the respiratory organs of an adult. The mucous membrane of the nasopharynx and oral cavity is rich in blood and lymphatic vessels, which creates favorable conditions for the development of swelling and various kinds of inflammation.

A child of the first year of life does not know how to breathe through his mouth, so when he has a cold, he suffocates while sucking.

1-3 years: the trachea and bronchi are still narrow, there is a danger of a sharp narrowing of their lumen and respiratory disorders with bronchitis, tracheitis, acute respiratory infections, influenza. Respiratory frequency by 3 years - 25-30 breaths per minute.

3-7 years: breathing is deeper and rarer. By the age of 7, it reaches 23-25 ​​breaths per minute.

7-11 years: the structure of the lung tissue is finally formed. The diameter of the trachea and bronchi increases, and in diseases of the respiratory system, swelling of the mucosa no longer poses a serious danger. Respiratory rate - up to 20 breaths per minute.

12-17 years old: Respiratory system almost like that of an adult.

THE CARDIOVASCULAR SYSTEM

Newborns: With the birth of a child, changes in the circulatory system occur. The umbilical vessels and vein cease their activity, the intrauterine blood flow channels are closed. With the first breath, the pulmonary circulation begins to work. The pulse rate is 120-140 beats per minute, when feeding or crying it increases to 160-200 beats. Blood pressure at the beginning of the first month - 66/36, and by the end of the month - 80/45.

Thoracic: up to 1 year, the mass of the heart increases. The pulse rate gradually decreases to 125 beats per minute. Blood pressure increases to 90/63.

1-3 years: 1 year - pulse 120, at 3 years - 105 beats per minute. Arterial pressure by 3 years - 95/60.

3-7 years: pulse by 7 years - 85-90, blood pressure - 104/67.

7-11 years: pulse decreases to 80 beats per minute. The blood pressure of an 11-year-old child is on average 110/70.

11-17 years old: pulse rate - 60-80 beats per minute, i.e. like an adult. Blood pressure by the age of 17 is 120/70. Again, just like an adult.

Considering even this limited information, it becomes obvious that even the mere fact of the difference in the hydration of the tissues of the child and adult organisms gives reason to assume that the distribution of medicinal substances in them, especially soluble or easily solubilized in the presence of natural co-solvents, is not the same.

DIGESTIVE SYSTEM

Newborns: functionally immature. The metabolism is increased, so minor errors in the diet of a breastfeeding mother and the child's diet can cause indigestion (dyspepsia). The digestive glands have not yet developed. The muscles of the intestine are still little trained and the movement of food through it is slowed down. In the first 10-20 hours of life, the intestines of the child are almost sterile, then it begins to be populated with the bacterial flora necessary for digestion of food. The liver is relatively large.

Nursing: up to 6 months, the child feeds mainly on breast milk, boiled water is given. Then they gradually begin to give juices, cereals. New foods should be introduced into the diet very carefully.

1-3 years: more complex food is digested, the frequency of defecation is 1-2 times a day.

3-11 years: The digestive system approaches that of adults, and by 11 years is no different from it.

THE IMMUNE SYSTEM

Newborns and infants: a child receives part of the immune substances from the mother and with breast milk. But in general, the immune system is imperfect; the child is poorly protected from infections.

1-3 years: the formation of immune cells increases, which dramatically increases the body's resistance.

3-7 years: The child's body produces enough immune cells, so many illnesses are more mild.

7-11 years: the body's defenses are well developed. Laboratory indicators are almost the same as adults.

URINARY ORGANS

Newborns: By the time of birth, the kidneys, ureters and bladder are well formed. However, the severe stress experienced by the child during childbirth disrupts the metabolism for a short time. The child urinates only 5-6 times a day. From the second week, the metabolism gradually stabilizes, the number of urination increases up to 20-25 times a day.

Thoracic: the volume of the bladder increases, the walls become more elastic. By the end of the first year, the number of urination decreases to 15-16 times a day.

1-3 years: the structure of the kidneys improves, and the number of urination decreases up to 10 times a day. A healthy child regulates the act of urination independently. Most drugs and/or their metabolites are excreted by the kidneys. Kidney function in newborns is reduced, so the excretion of many substances in the urine is less intensive than in adults.

Renal blood flow increases with age as a result of an increase in cardiac output and a decrease in total peripheral vascular resistance. Renal blood flow in newborns is 5-6% of the cardiac output, while in adults it reaches 15-25%. At birth, renal blood flow is 12 ml / min (0.72 l / h), and by the 1st year it increases to 140 ml / min (8.4 l / h).

At birth, glomerular filtration rate is directly proportional to gestational age. The glomerular filtration rate in all full-term newborns at the time of birth is 2-4 ml / min, in preterm infants - 1 ml / min. In the first 2-3 days after birth, it rises to 8-20 ml/min and 2-3 ml/min, respectively. Glomerular filtration reaches the level of adults by 2.5-5 months. An increase in glomerular filtration rate after birth is due to a number of reasons: an increase in cardiac output and blood pressure, a decrease in total peripheral vascular resistance, an increase in the surface area capable of filtering, and the size of membrane pores.

The function of the tubules of the kidneys in newborns is also reduced (small tubules and the number of functioning cells, low blood flow in the outer part of the cortex, immaturity of energy-providing processes). The tubular apparatus matures later than the glomerular apparatus. The excretion of paraaminohippuran, which is secreted by the proximal tubules during the first year of life, increases 10 times, reaching the level in adults by 8 months. Drugs that are excreted from the body by tubular secretion include aminoglycosides, cephalosporins, penicillin, digoxin, furosemide. They should be used with particular caution in the presence of impaired renal function.

7-11 years: the structure of the kidneys as in adults. The daily amount of urine gradually increases.

NERVOUS SYSTEM

Neonates and infants: immature nervous system.

1-3 years: the little man begins to realize himself and the world around him.

3-7 years: the foundations of intelligence are laid.

7-11 years old: Analytical capabilities expand.

12-17 years: analytical and abstract thinking develops.

Biotransformation of drugs occurs mainly in the liver, as well as in the adrenal glands, kidneys, intestines, and skin. As a result of biotransformation, more polar molecules are formed, which are quickly excreted from the body with urine or bile. However, in the process of metabolism, some drugs are converted into pharmacologically active substances.

In the body of a child with medicinal substances, the same biochemical changes occur as in adults, however, the intensity of metabolic processes can differ significantly. In particular, in newborns, the rate of oxidative reactions involving cytochrome P450 and NADP-cytochrome-C reductase is halved, so the biotransformation of drugs based on these reactions slows down. Due to the relatively low rate and biotransformation of medicinal substances, their excretion in unchanged form increases.

The state of other metabolic enzyme systems (besides oxidative ones) in children is less studied. Conjugation reactions with sulfates and glycine proceed in the same way as in adults. At the same time, the activity of glucuronyl transferase, alcohol dehydrogenase, and esterase in newborns is reduced. The excretion of drugs, in the biotransformation of which the listed enzymes are involved, slows down in the newborn, and their half-life increases. Such preparations may be affected by other enzymes, the activity of which is higher. So, in 2-3-day-old full-term children, the conjugation of paracetamol with glucuronic acid is reduced, but the drug is actively conjugated with sulfates.

In children in the first years of life, the glucuronidization of salicylamide, chloramphenicol is also impaired. Phenobarbital can induce glucuronyl transferase activity in neonates.

The biotransformation of some drugs in newborns differs from that in adults. Thus, the methylation reaction in the fetus and newborn is of great functional importance, so theophylline is not demethylated as in adults, but is methylated into caffeine.

If attention is always paid to the anatomical and physiological characteristics of the child when studying the pathogenesis of diseases and their clinical manifestations in different periods of childhood when substantiating differential diagnostic criteria, then the functional characteristics of the child's body, taking into account the pharmacokinetics of drugs, often remain out of focus or are ignored. The pediatrician loses sight of the direction and nature of the metabolic processes in the body of a sick child and does not take into account the peculiarities of the biotransformation of the prescribed remedy. The situation is aggravated by the fact that when prescribing several drugs to a child at the same time, their compatibility, potentiation, or vice versa, the leveling of the pharmacological effect is not always taken into account. But, unfortunately, polypharmacy in real life is the rule, not the exception.

Polypharmacy itself causes considerable difficulties, since drug interactions in children are little studied, although the pediatrician is focused on the possible manifestations of both antagonism and synergism of drugs. Some drugs affect the absorption and metabolism of vitamins, especially fat-soluble ones, which is not always corrected in a timely manner in sick children. For example, laxatives, cholestyramine and similar lipid-lowering drugs disrupt the absorption of vitamins A, D, E. Anticonvulsants, antibiotics used to treat H. pylori infection significantly alter the metabolism of vitamin K, while the absorption and metabolism of water-soluble vitamins are disrupted.

The transformation of drugs in a child's body is different than in adults. Many detoxification enzyme systems mature gradually during a child's development. These include, in particular, the system of microsomal oxidation of cytochrome P-450 oxidase in the liver, as well as the enzyme systems of glutathione reductase, glutathione transferase, UDP (uridine diphosphate glucose) glucuronyl transferase, and others. With age, the sensitivity of tissue receptors to hormones, hormone-like and other drugs with a pronounced biologically active effect changes.

What factors influence the kinetics and metabolism of drugs? With age, the relative volume of distribution of fluids in children changes, extracellular fluid predominates, which determines the peculiarities of the distribution in the child's body of both water-soluble and fat-soluble drugs. The rate of maturation of liver enzyme systems that convert drugs into inactive and water-soluble forms slows down. In childhood, low renal glomerular filtration, which limits the excretion of drugs and their metabolites in the urine, the ability of liver proteins (ligandins) and blood plasma to bind drugs and xenobiotics is reduced, the permeability of the membrane structures of capillaries and the blood-brain barrier is increased. When prescribing treatment, it is also necessary to take into account the state of the endocrine glands in children, which are known to play an important role in the metabolism of drugs. With a decrease in the functional ability of the thyroid gland, especially congenital hypothyroidism, the metabolism of drugs also changes to one degree or another.

Pharmacogenetics is one of the poorly studied aspects of pediatrics, although it is the genetic factors that determine the processes of metabolism, reception, immune response, etc., that largely determine the tolerability of drugs, their safety and effectiveness.

An effective drug, the cost of which can be quite high, is often not safe for a child. For example, the regimens used in adults for the treatment of gastroduodenal diseases associated with the notorious H. pylori cannot always be extrapolated to children, since they can use tetracycline antibiotics. The side effects of these drugs on the child's body are well known. In pediatric gastroenterology, the safety aspect of pharmacotherapy is given sufficient attention. At the same time, these aspects, unfortunately, are not always known to pediatricians. Using the example of cimetidine, a first-generation histamine H2-receptor blocker, I would like to recall that in addition to effectively lowering the concentration of hydrochloric (or hydrochloric) acid, the drug caused numerous undesirable effects in the vast majority of children. In addition to violations of the liver and kidneys, hematological and immunological abnormalities, pronounced neurovegetative and psycho-emotional changes were noted in children. The drug had a negative effect on the endocrine glands. It was the risk of a negative impact on the formation of gonadotropic function in children in the pre- and pubertal periods that kept pediatric gastroenterologists from the widespread use of cimetidine in the treatment of patients with gastroduodenal diseases. The reason for the various adverse reactions of this drug was that related receptors are widely distributed in liver cells, endocrine organs, nervous tissue and even lymphocytes. New generations of the same group of drugs, such as ranitidine, famotidine, have exceptional selectivity for H2 receptors and, with the exception of individual intolerance, are safe and effective in childhood. In connection with the foregoing, I would like to once again draw attention to the fact that the issue of prescribing drugs should be decided by a specialist.

Rule 1

Treatment of a child should be carried out at the most optimal level using the most effective and safe medicines in childhood. Therefore, most often, children should be prescribed medicines that have been proven over the years: infusions and decoctions from medicinal plant materials, aromatic waters, activated charcoal - inside, furatsilin, lycopodium - externally, and similar preparations.

The most convenient dosage forms for young children are in the form of syrups, drops or suspensions. Once in the intestine, liquid drugs spread over a larger area of ​​the mucous membrane and are better absorbed. Suspensions and medicinal syrups, however, are fraught with considerable danger. Since they are quite tasty, kids tend to drink more of them. It happens that a child, imperceptibly for parents, swallows a whole

vial of the medicine he liked. This can lead to dire consequences.

Rule 2

All medicines, and especially medicines for children, should be kept out of reach of them.

Candles are also quite convenient to use for small children. However, it is more natural for the body when drugs enter it through the mouth, and not through the rectum. Candles are best used only in cases where the child cannot swallow the medicine and when you need it to work immediately. Then they are introduced to the baby in the anus, laying him on his side or on his back and pressing his bent legs to his stomach. In this position, you need to hold it for half a minute so that the candle does not slip out.