Age features of the child's body. Consultation on the topic: Consultation for educators "Functional features of the structure of the body of preschool children"
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. Bone formation and muscular 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 fix wrong position body, the skill of correct posture is lost, which can lead to a curvature of the spine.
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 wrong postures- 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 provides them 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. At adverse conditions 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 3 years and by the end preschool age almost ends.
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.
Great excitability, reactivity, high plasticity nervous system contribute to faster and better mastering of motor skills - skiing, skating, swimming. It is necessary to form motor skills correctly, it is difficult to correct them.
Peculiarities mental development children:
Predominance of excitation over inhibition;
Instability of attention;
Impulsivity in behavior;
Great emotionality;
Concreteness of perception and thinking.
Such activities will not bring any health benefits. Children often overestimate their abilities, try to become adults as soon as possible and take on a task that they are not yet capable of. System physical education of the younger generation in our country is built taking into account the peculiarities of the development of a growing organism.
The age of children, adolescents and young men is conditionally limited to the first 18 years of life and is divided into age periods: preschool (from birth to 7 years old), junior school (from 7 to 11 years old), teenage (from 11 to 15 years old, which corresponds approximately to the average school age) and youthful (from 15 to 18 years old). Growth and development child's body proceed continuously and in different age periods unevenly.
The most important stage of the physical and mental development the child is preschool age. At 7-11 years old, the child physically develops relatively calmly. Increase in height and weight, endurance, vital capacity lung goes quite evenly and proportionately. The skeletal system is in the stage of formation: ossification of the spine, chest, pelvis, limbs is not completed, and there is a lot of cartilage in the skeletal system. You need to know this and tirelessly take care of the correct posture, posture, gait of students. The process of ossification of the hand and fingers in younger age does not end, so small and precise movements of the fingers and hand are difficult and tiring. The muscles in children of this age are still weak, especially the muscles of the back, and cannot support the body for a long time. correct position which can lead to poor posture and curvature of the spine. Therefore, for younger students, daily systematic physical exercises are very important and necessary.
Primary school age is the period of formation of attitudes towards teaching as a labor, socially significant activity. It is very important to create in the child the habit of systematic work and the ability to overcome difficulties.
In the lives of children primary school age a large place is occupied by the game, the content of which is mainly actions and deeds, which make it possible to reveal such qualities as courage, courage, resourcefulness, etc. n. The children are occupied with outdoor games with rules and elements of competition. These games bring up such qualities as dexterity, strength, speed and coordination of movements, endurance, perseverance, courage. Differences between boys and girls at a younger age are not pronounced, so there are no fundamental features in the methodology and content of the exercises.
middle school age This is a period of rapid growth and development of the body. There is an intensive growth of the body, the muscular apparatus is being improved, the process of ossification of the skeleton is underway. The teenager looks awkward, angular. This is due to uneven physical development: while the bones of the spine and limbs grow intensively in length, the chest lags behind in development. At the same time, during this period, an intensive process of puberty occurs, muscle strength increases, which does not yet mean an increase in endurance. But the guys, experiencing a surge of strength and energy, take on hard, often overwhelming physical work, as a result of which the structure of the bones of the spine, pelvis and limbs can be disturbed. All this makes us treat the physical education of adolescents very carefully, select and dose exercises in accordance with the indicated characteristics of their age.
This requirement stems from the features cardiovascular systems s of a teenager: the heart at this age increases significantly in volume, it becomes stronger, and the diameter blood vessels lags behind in development. There are some temporary circulatory disorders, blood pressure rises. Some teenagers develop dizziness, palpitations, temporary weakness, headaches, etc.
At this time, the adolescent's nervous system is not always able to withstand prolonged monotonous stimuli (for example, sounds) and, under their influence, often goes into a state of inhibition or, conversely, into a state of strong excitement. Some adolescents under the influence of this quickly get tired, become lethargic, distracted; others - irritable, nervous, sometimes begin to commit acts unusual for them.
Adolescents are contraindicated in excessive strength exercises that require sudden strength movements. For this age, moderate-intensity physical exercises with relatively long-term muscular work are most suitable (for example, skating, swimming, cross-country skiing, etc.).
With properly organized training work and medical supervision, adolescents can even show outstanding results. An example is the performance of young gymnasts, figure skaters, swimmers.
by the most important fact physical development in adolescence is puberty, which in girls begins at primary school age, and in boys a little later. In adolescence, children often do not know how to evaluate, restrain and correctly direct instincts and aspirations that are new to them, often they do not know how to control their feelings and behavior, and how to properly build their relationships with people of the opposite sex. So that undesirable traits in the development of the personality of a teenager do not arise on this basis, educators must intelligently, tactfully help him figure out all the issues that concern him. The correct routine of a teenager's life will help, strict regime work, sleep, rest and nutrition, regular physical education and sports.
During this period, differences in the development of boys and girls begin to appear. Girls noticeably gain weight and height, but are inferior to boys in strength, speed and endurance. After 14-15 years, girls grow more slowly, and boys grow faster, and they again overtake girls in physical development and maintain this advantage over subsequent years.
Social activity of a teenager, participation in public affairs contribute to his creative activity, create a useful orientation and aspiration. IN close connection with the formation of beliefs and worldviews are formed moral ideals teenager. On the contrary, idleness, idleness, absence useful activities can lead to poor health and bad habits. The formation of a worldview, moral beliefs, principles, ideals in adolescence occupies an important place in common process development. Activity, energy, initiative, cheerfulness, cheerfulness, optimism, willpower - these are the most important character traits personalities that emerge during adolescence. Adolescents are very characterized by the development of a sense of camaraderie, the need for friendly communication with peers and adults, the desire for independence.
senior school age, or, as it is called, the period of early youth - the period of life and development of a person from about 15 to 18 years. By the end of this period, boys and girls usually reach physical maturity and their physical development is not much different from the physical development of an adult. Ends characteristic of adolescence period of rapid growth and development of the organism, a relatively calm period of physical development begins. At this age, height and weight are stable. The rate of growth in length slows down, muscle strength, mental and physical performance increase, the volume of the chest increases, ossification of the skeleton, tubular bones ends, the formation and functional development of tissues and organs. As a rule, at this age, the discrepancy in the growth of the heart and blood vessels, which is characteristic of adolescents, is leveled, blood pressure is balanced, and the rhythmic work of the endocrine glands is established. The development of the central nervous system is completed.
High school students have access to all types of strength and endurance exercises, they can participate in speed sports competitions without harm to themselves, achieving noticeable success.
At senior school age, puberty usually ends, secondary sexual characteristics develop, causing noticeable changes in the appearance of boys and girls. In some cases, the process of puberty is delayed (more often in boys than in girls), and then older students still have some physical traits characteristic of adolescents.
However, the completion of puberty and physical development does not yet mean civic maturity. And therefore only by the age of 18, according to the law, marriage is allowed. It should be borne in mind that early sex life harms the body, since the rest of the body's systems: cardiovascular, respiratory, endocrine - have not yet completed their formation.
At senior school age, the spiritual image is intensively formed, the traits of a person’s character are determined, the formation of a worldview and personality takes place. Boys and girls noticeably develop self-awareness, which arises from the requirements of life and activity. A new position in the team, new relationships with others make the student evaluate his capabilities, realize the characteristics of his personality in terms of compliance or inconsistency with the requirements placed on him. But it is always more difficult to evaluate oneself than to realize the assessment given from the outside. A senior student, being able to analyze his personal characteristics and behavior better than a teenager, evaluates himself in some cases less objectively. Therefore, some young men and women overestimate their personality, show arrogance, arrogance, vanity, and treat others with disdain; others, on the contrary, painfully underestimate themselves.
It is common for high school students developed sense partnerships, deep friendship, responsiveness, mutual trust, readiness for constant assistance, availability joint interests etc. Their conscious attitude to work and study is growing. cognitive interests become broader, more sustainable and more effective. More definitely and vividly, the ability to various types activities: mathematical, constructive-technical, literary, musical, sports, etc. At this time, the emotional sphere personality, there is an interest in their future.
FEATURES OF THE DEVELOPMENT OF THE CHILD'S ORGANISM
Source : Theoretical and methodological foundations physical education and development of children of early and preschool age / Ed. S.O. Filippova. – 4th ed., revised. M.: Publishing Center "Academy", 2012. - P.197-202.
The body of children is constantly evolving. The level and rate of its growth in different periods lives are not the same. During the first 7 years of a child's life, not only all internal organs (lungs, heart, liver, kidneys) intensively increase, but their functions also 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 all the prerequisites for the successful assimilation of various movements.
1. Skeletal system
Ligaments, joints provide both the position of the body and the possibility of moving its parts in different directions, performing, in addition, a protective function. The bone tissue of a child contains a significant amount of water and only 13% of mineral salts. It gives bone elasticity and protects them from fractures during frequent falls and bruises. joints children are very mobile, ligaments are easily stretched, tendons are shorter and weaker than in adults.
Excessive physical activity adversely affects the development of the skeleton, delays the growth of bones. Moderate in load and affordable for this age physical exercise, vice versa, stimulate bone growth contribute to their strengthening.
Physiological curves of the spine in children are formed up to 6-7 years. The structure of the bone tissue of the vertebrae is not yet complete, the spinal column is very elastic, it consists mainly of cartilage tissue. Due to adverse environmental conditions, various posture disorders may occur, which are characterized by such signs as: the head is lowered, the back is bent, the shoulders are brought forward, etc.
Postural problems are not a disease. They are associated with functional changes in the musculoskeletal system, in which vicious conditioned reflex connections are formed that reinforce the wrong position of the body, and the skill of correct posture is lost. In the future, these incorrect positions familiar to the child can lead to a curvature of the spine.
The formation of posture is significantly influenced by static-dynamic function of the foot. Even a slight change in its shape can cause displacement of the pelvis, curvature of the spine and, as a result, posture disorders in various planes. The deformity of the foot, which consists in a decrease in the height of its arches in combination with heel pronation and supination contracture of the forefoot, is called flat feet . The diagnosis of flat feet is confirmed by plantography - a foot print using coloring solutions.
2. Muscular system
Muscles in children are relatively poorly developed and make up only 20-22% of the total body weight. Muscles in children are richer saturated with water and poorer in proteins and fats.
First of all, preschoolers develop and begin to function large muscle groups. Moreover, the flexor muscles are developed somewhat more than the extensors. Therefore, children 3-4 years old quite often take the wrong postures - the head is lowered, the shoulders are brought forward, the back is stooped
By the age of 5, the child has significantly muscle mass increases(especially lower extremities), strength and performance of muscles increase. However, children are not yet capable of significant muscle tension and prolonged physical work.
Work with alternating voltage and relaxation of the muscles tire the child less than the one that requires static efforts (holding the body or its individual parts in a certain fixed position).
Dynamic work promotes active blood flow not only to the muscles, but also to the bones, which ensures their intensive growth.
3. The cardiovascular system
In preschoolers, it is well adapted to the requirements of a growing organism. The blood vessels in children are relatively wider than in adults. Due to this blood pressure is weaker, but it is offset by heart rate.
At younger preschool age, the heart rate ranges from 85-105 beats / min. The pulse changes depending on the physiological state of the body: during sleep it decreases, and during wakefulness (especially with emotional arousal) it becomes more frequent.
At the senior preschool age (6-7 years) the pulse becomes more stable and reaches 78-99 bpm. Moreover, girls have 5-7 strokes more than boys.
The load is considered optimal if the heart rate is 150-180% compared to the initial data. In the event that the heart rate is above the specified norm, physical activity should be reduced.
Blood pressure in children under 7 years of age almost does not change: at 3-4 years old it is 96/58 mm Hg, at 5-6 years old - 98/60 mm Hg. Art.
Prolonged physical and mental stress can adversely affect the activity of the heart and lead to a violation of cardiac activity. Therefore, great care must be taken when dosing physical activity on the child's body.
4. Respiratory system
The upper respiratory tract in children is relatively narrow, and their mucous membrane, rich in lymphatic and blood vessels, swells under adverse conditions, as a result of which breathing is severely disturbed.
A distinctive feature of children at this age is predominance of shallow breathing. 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 child’s chest is raised, as it were, and the ribs cannot fall as low as in an adult at the exit - therefore, children unable to take deep breaths. That is why the frequency of their breathing significantly exceeds the respiratory rate of adults (in infants - 40-35 breaths per minute, by the age of 7 - 24-22).
In preschool children, much more blood flows through the lungs than in adults. This allows you to satisfy the need of the child's body for oxygen, caused by intense metabolism.
WITH three years of age The child should be taught to breathe through the nose. With such breathing, the air, before entering the lungs, passes through narrow nasal passages, where it is cleaned of dust, microbes, and also warmed and moistened.
5. Internal organs
In children, especially at an early age, they are not yet sufficiently developed. The stomach is comparatively weak muscle walls. The muscular layer and elastic fibers in the intestinal wall are poorly developed, so the activity of the intestines is easily disturbed in children.
6. Leather
It protects internal organs and tissues from damage and penetration of microorganisms into them, is excretory organ, and also takes part in thermoregulation and respiration. In children, she tender and is easily injured. In this regard, it should protect, protect the skin children from injury and promote proper development its functions (thermoregulatory and protective).
7. Nervous system
The main differentiation of nerve cells occurs before the age of 3 and almost ends by the end of preschool age.
It is also important to take into account the essential feature of the central nervous system of the child - the ability to keep traces of those processes that happened to it. From this it becomes clear the ability of children to quickly and easily memorize the movements shown to them. However, in order to consolidate and improve what has been learned, it is necessary to multiple repetitions.
Big excitability, reactivity, and high plasticity the nervous system in children contributes to a better, and sometimes faster than in adults, mastering rather complex motor skills - skiing, figure skating skating, swimming, etc.
Correct motor skills formation preschoolers from the very beginning have great importance, because it is very difficult to fix them.
The most important features of the mental development of preschool children are:
· predominance of excitation over inhibition;
· instability of attention ;
· impulsive behavior;
· big emotionality;
· concreteness of perception and thinking.
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.
child in different periods 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, which 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 stimuli. 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 has essential for the development of speech, providing not only the perception of the speech of strangers, but also playing the formative role of the system feedback in their own pronunciation. 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 proprioreceptors - 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 developing 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 and start classes by the age of 2-3 years. exercise 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 when performing physical exercises can cause severe posture disorders due to improper redistribution of muscle-ligament 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's hard for children long time maintain an upright posture. The muscles of the limbs are relatively weaker than the muscles of the trunk. Underdevelopment 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 a child of 5-7 years of 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. Preschool children are distinguished by the small size of the heart and the weakness of the heart muscle, which in turn determine the small SOC, and in combination with high elasticity and a wide lumen of the vessels - low level HELL. With age, the cardiovascular system becomes more efficient. The mass of the heart and the strength of heart contractions increase, the heart rate is reduced: 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. Active participation in these processes, such glands as the thyroid, adrenal glands, pituitary gland take. 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 the prerequisites for targeted impact in these critical periods 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.
In this article:
Despite the outward resemblance of a child to an adult, the anatomical and physiological characteristics of children differ greatly, primarily in terms of qualitative and quantitative characteristics. Children are growing and developing organisms. And if by the age of 11 they are getting closer in terms of indicators to adults, then in more early age differ significantly.
Children are considered people before puberty. Every child has it at a certain age. Girls' bodies are rebuilt earlier. Sometimes as early as 11 years old they show the first signs of puberty. Boys begin to mature around the age of 13-14.
But on average, it is considered that the period of childhood in children is up to 14 years. Each period is characterized by certain age-related anatomical and physiological features, as evidenced by the constantly changing proportions of the body.
Qualitative and quantitative changes in the child's body
When a baby is just born, the length of his head is a quarter of the total body length. Over time, this ratio increases, and when a person becomes an adult, the length of the head will be equal to the eighth of the length of the body.
Especially 
noticeable changes in the first year after the birth of the baby into the world. The length and mass of his body is actively increasing. From about 5 to 7 years old and from 10 to 12 years old, children begin a period of so-called accelerated growth, and from 3 to 5 years and from 8 to 11 years - a period of increased weight gain. When the time of puberty comes, the child will again begin to grow rapidly and gain weight.
Age-related qualitative changes are directly related to quantitative ones. Parents need to take them into account when building the process of education and providing care for children. For example, weight gain and increased growth are invariably associated with the active development of two body systems at once - bone and muscle, in addition, at this time, some changes will also affect body functions - for example, motor.
Features of the skin of children
In the first years of life, the skin of children is thin, delicate, with an abundance of blood vessels and lymphatic capillaries. The horny layer of the skin is replaced quite often, especially in infants. Until about school age, the skin of children is different 
low scores elasticity, which increase only by 8 years.
If we compare the skin of children with the skin of adults, then in the former it is less resistant to external influences, but recovers faster in case of damage.
Functioning sweat glands starts at five months. Over the next years, they will continue to develop and are fully formed only in 5-7 years. It is with the imperfect work of the sweat glands that cases of frequent overheating or hypothermia in children are associated.
But the sebaceous skin glands begin to work already in the womb. They are responsible for the formation of a protective lubricant. A yellow crust on the head in infants, and subsequently acne during puberty, is associated with the production of a secret sebaceous glands in excess. Nails and hair in children appear before birth and continue to grow actively after they are born.
It is difficult to underestimate the role of the subcutaneous fat layer in a child's life. Given the softness and fragility of the still imperfect children's skeleton, it is this layer that prevents 
the appearance of injuries with bruises, softening the blow. In addition, subcutaneous fat for a child is a source of energy.
Compliance with the feeding regimen in the first year of life contributes to the active accumulation of subcutaneous fat. Up to 11 months in children, as a rule, the thickness of the fold on the abdomen slightly to the side in relation to the navel should be up to 2 cm. Excess fat on the child's body is undesirable, as this negatively affects the immunity of the crumbs and can cause early atherosclerosis. In young children, the fat layer is dense due to the numerous fatty acids that make up it.
Muscle mass: the process of change
In the first months after birth, children do not have a sufficiently developed muscle mass, which at that time is no more than one-fourth of the total body weight (for comparison, in an adult, muscle mass is at least 40%). Muscle fibers in children are not so long, 
like an adult, and noticeably thinner - this is how their age-related features appear during this period.
Gradually, as we grow older, the muscle fibers become longer. In the period from 3 to 7 years, the blood circulation process is established in the muscles, after which it is time to increase the mass of first the largest, and then the small muscles.
Muscles grow most actively during puberty - after 11-13 years. As for motor activity and its dependence on the state of the muscles, the degree of maturity of the mechanisms of nervous regulation of muscle activity also matters here.
Parents should understand that in order for the child's muscular system to develop and improve, as well as the skeletal system, as well as the entire musculoskeletal system, he needs to provide the right physical activity. The achievements of the child at an early age, associated with the development of the nervous and muscular systems, are as follows:
The development of coordination of movements during walking in babies reaches its peak only by two years. If you deal with the baby, then by the age of 2.5 he will be able to climb the board with an inclination of 45 degrees.
Features of the development of the skeletal system in children
In the first months after birth, the bone tissue of the child is characterized by a porous coarse-fibred mesh structure. It abounds in water, while there are few dense substances in it. It is with this factor that the excessive softness and elasticity of children's bones, which are simply amenable to deformation, are associated. However, if we compare the bones of a child with 
bones of an adult, then the first one is not so brittle.
Blood is actively supplied to children's bones, so they quickly increase in size. In the process, some changes in the fibrous mesh structure occur, instead of which a lamellar one appears. Cartilage is replaced by bone tissue.
Meanwhile, for a long time, between the ends and the middle of a long tubular bone, cartilage plates necessary for bone growth remain. Their cells actively multiply, due to this, the child's skeleton grows. Premature closure of growth zones will lead to violations of the growth of bones in length, and the growth of the child will stop. The bone substance located in the periosteum zone is responsible for the thickening of the bones. In terms of structure, the bones of a child begin to resemble adults only by the age of 11-12.
The cranial flat bones in infants after birth are characterized by increased softness, and between them sutures remain for up to about three months - fontanelles, which close over time. The largest fontanel (in the frontal and 
parietal bones) closes no earlier than 11 months.
How correctly the process of ossification of the child's skeleton proceeds can be quite simply judged by the time in which his teeth begin to erupt. In rare cases, the first two teeth can erupt while still in the womb, and the baby is born with them. This is not very good, because at such an early age, the teeth will interfere with the normal process of breastfeeding.
By 24 months, a baby should already have 20 teeth. Milk teeth begin to change no earlier than 5-6 years, and this process will continue until 11-13 years.
Respiratory Development
The active process of development of the respiratory organs during the period of growth of the child contributes to the full saturation of the child's body with oxygen. At the same time, up to a certain point, the respiratory organs in children are characterized by immaturity. Babies have too short noses, narrow nasal passages, and the lower nasal passage is in the active stage of development.
Getting into nasal cavity, the air is poorly filtered and almost does not heat up. In case of hypothermia, the nasal mucosa due to excess capillaries 
swells strongly, which leads to difficulties with breathing and, accordingly, with sucking.
The development of the paranasal sinuses occurs only in the second or third year of a child's life. And such respiratory organs as the bronchi, pharynx and larynx, in babies are characterized by small sizes, which, when the mucosa swells, are further reduced.
The shape of the child's chest resembles a cylinder, for the most part due to the location of the ribs at right angles to the spine, which in turn imposes some restrictions on the depth of breathing.
In order for the blood to receive enough oxygen, the child is forced to breathe frequently, which is why it is so important that at an early age he spends as much time as possible on the street and receives proper care that does not allow inflammation of the mucous membranes of the respiratory tract.
Features of the development of the cardiovascular system
To ensure sufficient blood supply to the body, the cardiovascular system in children is forced to work in an intensive mode. This is due to the increased mass baby heart.
In infants in the first months after birth, the atria are especially large, while the ventricles are not fully formed. As the baby grows older, the muscular wall of the left ventricle becomes thicker, despite the fact that immediately 
after birth, the wall thickness of both ventricles was the same. At about 5-6 years of age, the muscular wall of the left ventricle is twice as thick as the wall of the right ventricle.
Every year, the muscle fibers of the children's heart become more developed. The minimal risk of angina or heart attack at an early age is associated with an abundant blood supply to the heart muscle.
The main feature of the child's cardiovascular system is wide large vessels, as well as a sufficient number of capillaries and small vessels. It is more difficult for the heart muscle to work in such conditions, especially if the body is affected by an infection or virus.
You can train the heart muscle with moderate, age-appropriate exercise and hardening.
The digestive system of a child's body
The main organs of digestion are:
- oral cavity;
- pancreas;
- esophagus;
- liver.
The oral cavity is replenished with teeth, as already noted, gradually. By the age of two, children should have 20 teeth. The oral mucosa in childhood is distinguished by special tenderness, and in the first months after birth it is characterized 
excessive dryness due to lack of saliva. Over time, when the first teeth begin to erupt, salivation begins to improve, and it becomes so plentiful that the child does not always have time to swallow.
Up to a year, a child has a fairly large tongue with well-developed papillae on it, so children distinguish tastes well. Healthy babies born on time have a developed sucking reflex.
In young children, the stomach is relatively small - this explains the frequent regurgitation after eating and even vomiting. The mucous membrane is similar to the adult body digestive glands which are under development. As the child grows and matures, his stomach assumes a vertical position.
Food in the baby's stomach does not remain for more than 3.5 hours. Especially quickly removed from it breast milk while alternative blends and high-fat foods stay longer.
The intestines in children are much longer than in adults, and with a highly developed network of capillaries. The active work of parietal digestion contributes to the processing of enough a large number food, covering the needs of the body in the necessary for growth nutrients. It is important to feed your baby foods that are appropriate for their age. 
to avoid digestive problems that can threaten not only the health, but also the life of the child.
The liver in children is also noticeably larger than the liver of an adult. It makes up almost half of all abdominal cavity baby. The development of the liver lasts an average of 4-5 years. The older the child becomes, the more dense substances will be in the liver.
Urination system: features
Kidneys in children are lower than in adults, and twice as large as their mass. For for long years this organ remains immature and finally matures only by the age of 12.
The structure of the ureters is characterized by increased tortuosity. They are much wider than in adults, which sometimes leads to stagnation of urine. Immediately after birth bladder in children, it is located at the anterior abdominal wall and only by 24 months descends into the pelvic area. capacity of it 
increases with age and reaches 800-900 ml by the age of 11.
Age features of the urethra have some differences depending on gender. So, if in boys its length after birth is about 6 cm, then in girls it is up to 1 cm.
In the first days after birth, the child urinates no more than 6 times a day. Already in the middle of the month, the number increases to 20, and by the year it approaches 15 times a day. At 3 years old, the child feels the need to empty the bladder no more than 10 times a day, at 6-7 years old - 7 times. The daily amount of urine excreted increases as the child grows and reaches 1500 ml by the age of 11-13, while in the first six months it is no more than 600 ml.
Blood and changes associated with it
The quality of blood in a baby inside the womb differs markedly from the quality of the blood of a child after a year and an adult, largely due to the changing number of blood cells. 
In children's blood, red cells and hemoglobin are one and a half times more. At the same time, the hemoglobin of the child in the womb is several times more active than the hemoglobin of an adult due to the receipt of oxygen supplied through the mother's red blood cells approaching the placenta.
At 36-37 intrauterine week, and then in the first weeks after birth, there is an active change of erythrocytes with fetal hemoglobin content to erythrocytes with A-hemoglobin content. The number of erythrocytes at the same time decreases.
During this period - up to 5 months - it is very important to provide the baby with everything necessary for normal course hematopoietic process to prevent the development of anemia due to a lack of copper, iron, cobalt and a number of other vitamins and minerals. That is why in the first month of life, the baby is given vitamins and juices containing the necessary components. At an early age, anemia can develop in children due to chronic intoxication or frequent illnesses.
At 4-5 years old, the number and quality of leukocytes in a child differs from that of an adult. Neutrophils up to 5 years in children are almost two times less, and 
more lymphocytes. By the age of 5-6, this ratio becomes approximately the same as in adults.
The role of white blood cells can hardly be overestimated for the development of the child's body, because they stand guard, preventing harmful intrusions. The antibodies that are part of the blood serum make it possible to neutralize the toxins and microbes entering the body.
In the first months of a child's life, protective organisms remain immature, so vaccination is used to further protect them.
How do the endocrine and nervous systems develop?
The development of the endocrine and nervous systems in children ends only by the age of 18-20. The earliest in terms of development are the pituitary gland, the endocrine glands, as well as the thymus and thyroid gland, part of the pancreas. Their development ends at preschool age.
But the adrenal glands in children require more time to mature and form functionality. This process continues up to 10-11 years. On the growth of children during puberty and 
metabolism in the body is greatly influenced by the sex glands. During this period, the functions of the endocrine glands periodically decrease and increase.
The development of the nervous system of the child falls on the entire period of his childhood, that is, up to 14 years. After birth, the child has the same number of nerve cells as in the womb, while the brain and spinal cord continue to develop and increase in mass. If a baby immediately after birth, the brain weighs about 350-380 g, then by 11-12 months its mass doubles, and by three years - three times. At 10-11 years old, the child's brain weighs 1350 g, while in adulthood, a man's mass is 1400 g, and a woman's is 1270 g.
As children grow and mature, the processes of nerve cells become longer, the convolutions of the brain change. The brain develops and improves most actively in the period up to 8 years. It is from the schedule of maturation of the structures of the nervous system that the child's skills such as running, sitting, walking, speech and others will depend.
Immediately after birth, the child's autonomic nervous system is already working. It is responsible for the functioning of vascular tone and a number of internal organs, for reactions and a complex of processes playing important role in life 
child's body. When conditions worsen environment the functions of the autonomic nervous system stop working as they should.
The central nervous system develops from the bottom up. The first changes concern the spinal cord, followed by the lower parts of the brain, after which the subcortex and cortex change. This development meets the needs of the child's body. The process contributes to the provision of vital functions in children:
- breathing;
- sucking;
- swallowing;
- work of the cardiovascular systems, etc.
A healthy baby born on time has excellently expressed sucking, defensive and swallowing reflexes. They will form the basis for the development conditioned reflexes associated with sounds, images, body positions. Conditioned reflex activity allows the child to try his hand at performing purposeful actions, such as, for example, communication.
It is possible to talk about the normal development of the nervous system and the activity of the child only by providing him normal care, upbringing and education at school in accordance with the daily regimen necessary for his age, where the loads will be replaced by rest. Not less than an important factor For normal development the child will observe the rules of hygiene and active healthy lifestyle life.
