Newborn period (neonatal period) - first 4 weeks

Breast period - 1 month - 1 year

Early childhood - 1-3 years

First childhood - 4-7 years

Second childhood

• boys 8-12 years old

  girls 8-11 years old

Adolescence

• boys 13-16 years old

  girls 12-15 years old

Youth period

• boys 17-23 years old

  girls 16-21 years old

Mature age (1st period)

• men 24-35 years old

  women 22-35 years old

Mature age (2nd period)

• men 36-60 years old

  women 36-55 years old

Old age

• men 61-74 years old

  women 56-74 years old

Senile age- 75-90 years

Centenarians- 90 years or more

Development - this is a process of quantitative and qualitative changes, incl. includes 3 main factors:

The growth process is continuous and wavy in nature.

Changes in body proportions are an external indicator of development.

Factors influencing growth and development:

Nutrition

Muscle activity

Time of year

Psychological stress

Socio-economic status, etc.

3.Higher nervous activity, its age-related characteristics. Types of VND in children, their significance in the process of education and upbringing.

The cortex and the subcortical structures closest to it are the highest department of the central nervous system - the substrate for the implementation of complex reflex reactions that underlie higher nervous activity. The idea of ​​the reflex nature of the activity of the higher parts of the central nervous system was first put forward by I. M. Sechenov. Before I.M. Sechenov, the idea of ​​the separation of body and “soul” prevailed, and the question of the possibility of an objective study of mental activity was not even raised.

The brilliant ideas of I.M. Sechenov were confirmed experimentally by I.P. Pavlov. I.M. Sechenov and I.P. Pavlov are the founders of the reflex theory, which materialistically explains the principles of human reflection of the surrounding material world. I. P. Pavlov developed the reflex theory and created the doctrine of higher nervous activity. He managed to discover a nervous mechanism that provides complex forms of response in humans and higher animals to the influence of the external environment. This mechanism is a conditioned reflex.

The set of complex forms of activity of the cerebral cortex and the subcortical formations closest to it, ensuring the interaction of the whole organism with the external environment, is called higher nervous activity.

The doctrine of higher nervous activity reveals the physiological mechanisms of the most complex processes of man's reflection of the external objective world, which provided a brilliant natural scientific justification for Lenin's theory of reflection.

A reflex is the body’s response to irritation of receptors, carried out with the participation nervous system.

Let's give some idea about conditioned and unconditioned reflexes. Features of unconditioned and conditioned reflexes. The main form of activity of the nervous system is reflex. All reflexes are usually divided into unconditioned and conditioned. Unconditioned reflexes are innate, genetically programmed reactions of the body, characteristic of all animals and humans. The reflex arcs of these reflexes are formed during the process of prenatal development, and in some cases during the process of postnatal development. For example, innate sexual reflexes are finally formed in a person only at the time of puberty in adolescence. Unconditioned reflexes have conservative, little changing reflex arcs passing mainly through the subcortical sections of the central nervous system. Participation of the cortex in the course of many unconditioned reflexes optional.

Conditioned reflexes are adaptive reactions individually acquired during life or special training, arising on the basis of the formation of a temporary connection between a conditioned stimulus (signal) and an unconditioned reflex act. Conditioned reflexes are always individually unique.

Reflex arcs of conditioned reflexes are formed in the process of postnatal ontogenesis. They are characterized by high mobility and the ability to change under the influence of environmental factors. Reflex arcs of conditioned reflexes pass through the higher part of the brain of the CGM.

For the formation of a conditioned reflex, the following most important conditions are necessary: ​​the presence of a conditioned stimulus, the presence of unconditional reinforcement. The conditioned stimulus must always somewhat precede the unconditional reinforcement, i.e., serve as a biologically significant signal; the conditioned stimulus, in terms of the strength of its effect, must be weaker than the unconditioned stimulus; finally, for the formation of a conditioned reflex, a normal (active) functional state of the nervous system, primarily its leading part of the brain, is necessary. Any change can be a conditioned stimulus! Powerful factors contributing to the formation of conditioned reflex activity are reward and punishment. At the same time, we understand the words “reward” and “punishment” in a broader sense than just “satisfying hunger” or “painful influence.”

Thus, educational work, in its essence, is always associated with the development in children and adolescents of various conditioned reflex reactions or their complex interconnected systems.

Age characteristics of GNI

A child is born with a set of unconditioned reflexes, reflex arcs of which begin to form in the 3rd month of prenatal development. Thus, the first sucking and breathing movements appear in the fetus precisely at this stage of ontogenesis, and active movement of the fetus is observed in the 4-5th month of intrauterine development.

Simple food conditioned reactions, despite the morphological and functional immaturity of the brain, arise already on the first or second day, and by the end of the first month of development, conditioned reflexes from the motor analyzer and vestibular apparatus are formed: motor and temporary. All these reflexes form very slowly, they are extremely gentle and are easily inhibited. From the second month of life, auditory, visual and tactile reflexes are formed, and by the 5th month of development, the child develops all the main types of conditioned inhibition.

By the end of the first year of development, the child can distinguish relatively well the taste of food and smells, the shape and color of objects, and distinguishes voices and faces. Movements improve significantly, and some children begin to walk. The child tries to pronounce individual words (“mom”, “dad”, “grandfather”, “aunt”, “uncle”, etc.), and he develops conditioned reflexes to verbal stimuli. Consequently, already at the end of the first year, the development of the second signaling system is in full swing and its joint activities are being formed.

In the second year of child development, all types of conditioned reflex activity are improved and the formation of the second signaling system continues, the vocabulary increases significantly (250-300 words); immediate stimuli or their complexes begin to cause verbal reactions. If in a one-year-old child conditioned reflexes to direct stimuli are formed 8-12 times faster than to a word, then at two years old words acquire signal meaning.

Of decisive importance in the formation of the child’s speech and the entire second signaling system as a whole is the child’s communication with adults, that is, the surrounding social environment and learning processes. Children deprived of a linguistic environment and communication with people do not speak; moreover, their intellectual abilities remain at a primitive animal level. The ages from two to five are “critical” in mastering speech! There are cases where children abducted by wolves in early childhood and returned to human society after five years are able to learn to speak only to a limited extent, and those returned only after 10 years are no longer able to utter a single word.

The second and third years of life are distinguished by lively orientation and research activities. The child reaches out to every object, touches it, feels it, pushes it, tries to lift it, etc. This feature is largely associated with the morphological maturation of the brain, since many motor cortical zones and zones of musculoskeletal sensitivity reach sufficiently high functional usefulness. The main factor stimulating the maturation of these cortical zones is muscle contractions and high motor activity of the child. Limiting his mobility at this stage of ontogenesis significantly slows down mental and physical development.

The period up to three years is also characterized by the extraordinary ease of formation of conditioned reflexes to a wide variety of stimuli, including the size, heaviness, distance and color of objects. A special feature of a two- to three-year-old child is also the ease of developing dynamic stereotypes. Conditional connections and dynamic stereotypes in children under three years of age are extremely strong, so changing them is always an unpleasant event for a child.

The age from three to five years is characterized by further development of speech and improvement of nervous processes (their strength, mobility and balance increase), the processes of internal inhibition acquire dominant importance, but delayed inhibition and conditioned inhibition are developed with difficulty. Dynamic stereotypes are still developed just as easily. Their number increases every day, but their alteration no longer causes disturbances in higher nervous activity.

By the age of five to seven years, the role of the signal system of words increases even more and children begin to speak freely. This is due to the fact that only by the seven years of postnatal development does the material substrate of the second signaling system functionally mature.

From 7 to 12 years (junior school age) is a period of relatively “quiet” development of higher nervous activity. The strength of the processes of inhibition and excitation, their mobility, balance and mutual induction, as well as a decrease in the strength of external inhibition, provide opportunities for extensive learning of the child. This is a transition “from reflexive emotionality to intellectualization of emotions.” However, only on the basis of learning to write and read does the word become an object of the child’s consciousness, moving further away from the images of objects and actions associated with it. A slight deterioration in the processes of higher nervous activity is observed only in the 1st grade in connection with the processes of adaptation to school.

Of particular importance for teachers and educators is the following age period - adolescence (from II - 12 to 15-17 years). This is a time of major endocrine transformations in the body of adolescents and the formation of secondary sexual characteristics in them, which in turn affects the properties of higher nervous activity. The balance of nervous processes is disrupted, excitation becomes more powerful, the increase in the mobility of nervous processes slows down, and the differentiation of conditioned stimuli deteriorates significantly. The activity of the cortex is weakened, and at the same time the second signaling system. All functional changes lead to mental instability of the teenager (hot temper, “explosive” response to even minor irritations) and frequent conflicts with parents and teachers. The situation of a teenager, as a rule, is aggravated by increasingly complex demands on him from adults and, above all, from the school.

Only the right healthy regimen, a calm environment, a solid program of classes, physical education and sports, interesting extracurricular activities, goodwill and understanding on the part of adults are the main conditions for the transition period to pass without the development of functional disorders and associated complications in the child’s life.

Senior school age (15-18 years) coincides with the final morphofunctional maturation of all physiological systems of the human body. The role of cortical processes in the regulation of mental activity and physiological functions of the body is increasing; cortical processes that ensure the functioning of the second signaling system are given leading importance. All properties of basic nervous processes reach the level of an adult.

4. General patterns of skeletal development: functions of the musculoskeletal system. Chemical composition and growth of children's bones. Flat feet. Prevention.

Movement, movement in space is one of the most important functions of living beings, including humans. The function of movement in humans is performed by musculoskeletal system, uniting bones, their joints and skeletal muscles. The musculoskeletal system is divided into passive and active parts. TO passive part include bones and their connections, on which the nature of the movements of body parts depends, but they themselves cannot perform the movements. Active part constitute skeletal muscles, which have the ability to contract and move the bones of the skeleton (bone levers).

The specificity of the human support apparatus and movements is associated with the vertical position of his body, upright posture and labor activity. Adaptations for the vertical position of the body are present in the structure of all parts of the skeleton: the spine, skull and limbs. The closer to the sacrum, the more massive the vertebrae (lumbar), which is caused by the heavy load on them. In the place where the spine, which bears the weight of the head, the entire torso and upper limbs, rests on the pelvic bones, the vertebrae (sacral) are fused into one massive bone - the sacrum. Curves create the most favorable conditions for maintaining a vertical body position, as well as for performing springing functions when walking and running.

The lower limbs of a person can withstand heavy loads and completely take over the functions of movement. They have a more massive skeleton, large and stable joints and arched feet. Only humans have developed longitudinal and transverse arches of the foot. The fulcrum points of the foot are the heads of the metatarsal bones in front and the calcaneal tubercle in the back. Springy arches of the feet distribute the weight on the foot, reduce shocks and jolts when walking, and impart a smooth gait. The muscles of the lower limb have greater strength, but at the same time less variety in their structure than the muscles of the upper limb.

Freeing the upper limbs from support functions and adapting them to work activities led to a lighter skeleton, the presence of more muscles and joint mobility. The human hand has acquired special mobility, which is ensured by long collarbones, the position of the shoulder blades, the shape of the chest, the structure of the shoulder and other joints of the upper limbs. Thanks to the collarbone, the upper limb is moved away from the chest, as a result of which the arm has acquired significant freedom in its movements.

The shoulder blades are located on the posterior surface of the chest, which is flattened in the anteroposterior (sagittal) direction. The articular surfaces of the scapula and humerus provide greater freedom and variety of movements of the upper limbs, their large range.

Due to the adaptation of the upper limbs to labor operations, their muscles are functionally more developed. The movable hand of a person acquires special importance for labor functions. A big role in this belongs to the first finger of the hand due to its great mobility and ability to oppose the rest of the fingers. The functions of the first finger are so great that if it is lost, the hand almost loses the ability to grasp and hold objects.

Significant changes in the structure of the skull are also associated with the vertical position of the body, work activity and speech functions. Brain department the skull clearly prevails over the facial. The facial section is less developed and is located under the brain. The reduction in the size of the facial skull is associated with the relatively small size of the lower jaw and its other bones.

In humans, the functions of the musculoskeletal system are associated with something that provides him with an advantage over other representatives of the organic world: purely human qualities - work and speech, which were the most important driving forces anthropogenesis.

Improving polytechnic education, physical education and military-patriotic training of students requires teachers to know the anatomical and physiological characteristics of the musculoskeletal system of children and adolescents, the physiological foundations physical exercise and physical labor. The reasons for such close attention to the development of a child’s physical abilities are quite understandable. The human body at any age is a single whole. All of its physiological systems: nervous, musculoskeletal, cardiovascular, etc. are closely interconnected, functional changes in one physiological system lead to changes in the activity of another.

Muscle activity is of particular importance for the developing child’s body. Limitation of mobility or muscle overload disrupts the harmony of development and is an important pathogenetic factor in the development of many diseases. That is why training and education involve not only the development of the mental abilities of schoolchildren, but also their physical improvement. It is quite natural that this task falls not only on the shoulders of physical education and labor teachers, but is also a primary task for every teacher and educator.

Chemical composition of bone tissue and its age-related changes

Bone is made up of two types of chemicals: inorganic and organic. Inorganic substances include water and salts (mainly calcium salts). organic matter bones is called ossein. Fresh bone contains about 50% water, 22% salts, 12% ossein and 16% fat. Dehydrated, defatted and bleached bone contains approximately 1/3 ossein and 2/3 inorganic matter.

A special specific physicochemical combination of organic and inorganic substances in bones determines their basic properties - elasticity, elasticity, strength and hardness. This is easy to verify. If a bone is placed in hydrochloric acid, the salts will dissolve, ossein will remain, the bone will retain its shape, but will become very soft (it can be tied into a knot). If the bone is burned, the organic substances will burn, and the salts will remain (ash), the bone will also retain its shape, but will be very fragile. Thus, the elasticity of bone is associated with organic substances, and hardness and strength are associated with inorganic substances. Human bone can withstand pressure of 1 mm 2 15 kg, and a brick only 0.5 kg.

The chemical composition of bones is not constant; it changes with age and depends on functional loads, nutrition and other factors. The bones of children contain relatively more ossein than the bones of adults, they are more elastic, less susceptible to fractures, but under the influence of excessive loads they are more easily deformed. Bones that can withstand heavy loads are richer in lime than bones that are less loaded. Eating only plant foods or only animal foods can also cause changes in bone chemistry. If there is a lack of vitamin D in the food, lime salts are poorly deposited in the child’s bones, the timing of ossification is disrupted, and there is a lack of vitamin. And it can lead to thickening of the bones, neglect of the channels in the bone tissue.

In old age, the amount of ossein decreases, and the amount of inorganic salts, on the contrary, increases, which reduces its strength properties, creating the preconditions for more frequent bone fractures. With old age, growths of bone tissue in the form of spines and outgrowths may appear in the area of ​​​​the edges of the articular surfaces of bones, which can limit mobility in the joints and cause pain when moving. The mechanical properties of bone can be judged on the basis of their strength in compression, tension, rupture, fracture, etc. In compression, bone is ten times stronger than cartilage, five times stronger than reinforced concrete, twice as strong as lead. In tension, the compact bone substance can withstand a load of up to 10-12 kg per 1 mm 2, and in compression - 12-16 kg. In terms of tensile strength, bone in the longitudinal direction exceeds the resistance of oak and is equal to the resistance of cast iron. So, for example, to crush a femur with pressure, you need approximately 3 thousand kg, to crush a tibia, at least 4 thousand kg. The organic substance of bone - ossein - can withstand a tensile load of 1.5 kg per 1 mm 2, a compressive load - 2.5 kg, and the strength of the tendons is 7 kg per 1 mm 2. Despite its significant strength and strength, bone is a very plastic organ and can be rebuilt throughout a person's life.

Just like body weight, the increase in body height is uneven. The average height of newborns is 50 centimeters. Over the course of a year of life, a child’s height increases by 25 centimeters. During the second and third years, he adds 8 cm annually, and from 4 to 7 years, the annual increase in height is 5–7 cm. Height increases sharply during puberty, when the annual increase can be 7–8 centimeters. To roughly determine height, add 5 cm to the height of a one-year-old child, multiplied by the number of years. Thus, the height of a five-year-old child should be 100 cm, according to the formula 75 cm + 5´5 cm = 100 cm.

With age, body proportions also change. In newborns, for example, the length of the head is ¼ of the total height, in a two-year-old child - 1/5, in a six-year-old - 1/6, and in an adult - 1/8.

The head circumference also changes. At birth, the head circumference is greater than the chest circumference. The head circumference of a newborn baby is 34 cm, and the chest circumference is 33 centimeters. By the end of the first year of life, the chest and head circumferences change places, and then this trend continues.

Over the entire period of development, the length of the legs increases five times, the arms – 4 times, and the torso – 3 times.

4. Age-related changes in indicators of physical development of boys and girls.

Changes in indicators of physical development that occur during the period of growth of the body are not the same in intensity. As already emphasized above, the greatest increase in all indicators of physical development occurs in the first year of a child’s life. Another period when indicators of physical development change very intensively is puberty or puberty. However, the time frame for this period is different for girls and boys.

For girls, the greatest increase in height occurs from 10 to 13 years, and for boys from 12 to 15 years. Body growth in girls ends by the age of 17–18 (although it is possible up to 25 years), and in boys, growth ends mainly by the age of 19. The greatest increase in weight in girls occurs at the age of 11-14 years, and in boys - 13-15 years. At the same time, the greatest increase in chest circumference occurs. After 11 years of age, girls begin to overtake boys in their development, and after 15 years of age, boys begin to overtake girls.

Uneven development between boys and girls poses challenges for teachers physical culture. One way to overcome these difficulties is to introduce separate physical education lessons in schools, starting in the 6th grade. However, such a solution to the problem sometimes encounters difficulties associated with a lack of premises and equipment in schools, as well as a shortage of personnel.

Rice. 5Changes in body proportions with age.

The second growth spurt is associated with the onset of puberty. Over the course of a year, body length increases by 7-8 and even 10 cm. Moreover, from the age of 11-12, girls are slightly ahead of boys in growth due to the earlier onset of puberty. At the age of 13-14, girls and boys grow almost equally, and from the age of 14-15, boys and young men outstrip girls in height, and this excess of height in men over women persists throughout life.

Body proportions also change greatly with age (Fig. 4). From the newborn period to adulthood, body length increases by 3.5 times, body length by 3 times, arm length by 4 times, leg length by 5 times.

Three periods of differences in the proportions between the length and width of the body can be noted: from 4 to 6 years, from 6 to 15 years, and from 15 years to adulthood. If in the prepubertal period general height increases due to the growth of the legs, then in the puberty period it increases due to the growth of the torso.

The growth curves of individual parts of the body, as well as many organs, basically coincide with the growth curve of body length. However, some organs and parts of the body have a different type of growth. For example, the growth of the genital organs occurs intensively during puberty, and the growth of lymphatic tissue ends by this period. The size of the head in children 4 years old reaches 75-90% of the size of the head of an adult. Other parts of the skeleton continue to grow rapidly even after 4 years.

Uneven growth is an adaptation developed by evolution. Rapid growth of the body in length in the first year of life is associated with an increase in body weight, and a slowdown in growth in subsequent years is due to the manifestation active processes differentiation of organs, tissues, cells.

We have already noted that development leads to morphological and functional changes, and growth leads to an increase in the mass of tissues, organs and the entire body. During the normal development of a child, both of these processes are closely interrelated. However, periods of intense growth may not coincide with periods of differentiation.

Along with the typical characteristics for each age period, there are individual developmental characteristics. They vary and depend on the state of health, living conditions, and the degree of development of the nervous system.

ChapterII. Research materials

2.1. Research objectives

1. Study the methodological basis of adaptation of children and adolescents to physical activity.

2. Determine students’ adaptation to physical activity.

3. Assess the health and physical development of students.

4. Compare the levels of adaptation and health status of urban and rural schoolchildren.

2.2. Methodology for organizing research.

We conducted research by testing urban and rural school students using the Ruffier index. Observation of students, measurement to determine physical development, as well as determination of physical fitness.

During the research process, the following methods were used: 1. Analysis of scientific and methodological literature;

2. Statistical processing of research results;

3. Comparative analysis test results.

The study was conducted in the Tattinsky ulus in Ytyk-Kyuelskaya high school No. 1 and at school No. 14 in Yakutsk. A total of 40 students took part in the testing (of which 20 were urban and 20 were rural students). The study was conducted among high school male students.

1. To assess the effect of physical education classes on adaptation to stress, testing using the Ruffier index was used.

After a five-minute rest, heart rate or at rest is noted for 15 seconds (P1), then in 45 seconds, perform 30 squats and immediately measured in 15 seconds (P2) and after the first minute of recovery, we also measure the pulse in 15 seconds (P3), then the result is assessed according to the given formula:

Index = (4x(P1+P2+P3)-200)/10

Ruffier Index: less than 0 = “athletic heart”

0.1-5= “excellent”

5.1-10= “good”

10.1-15= “satisfactory”

15.1-20= “bad”

(see Appendix No.)

2. To assess the health and physical development of students, the “physiological curve” method was used. For this purpose, 10 students were selected from both schools (Y-KSSH No. 1 and school No. 14 in Yakutsk) who passed the heart rate test. Then we derived the arithmetic average results (for each school separately) and compiled a physiological curve. (See Appendix No.)

3. To check the physical activity of students in addition to the physical education lesson (exercises in the morning, outdoor games, haymaking, etc.), a survey consisting of 10 questions was conducted.

2.3. Research results.

40 students took part in the study using the Ruffier index. Of these, 20 are students of secondary school No. 14 in Yakutsk; 20 students of YKSSH No. 1 of the Tattinsky ulus.

Based on the results of testing in Yakutsk, the following indicators were revealed:

The human body, like any living organism, is characterized by growth and development.
Height- This is a quantitative increase in the biomass of an organism due to an increase in the geometric dimensions and mass of its individual cells or an increase in the number of cells due to their division.
Development- these are qualitative transformations in a multicellular organism that occur due to differentiation processes(increasing the diversity of cellular structures) and lead to qualitative and quantitative changes in the functions of the body.
The relationship between growth and development is manifested, in particular, in the fact that certain stages of development can occur only when certain body sizes are reached. Thus, puberty in girls can occur only when body weight reaches a certain value (for representatives of the European race this is about 48 kg). Active growth processes also cannot continue at the same stage of development indefinitely.
Differentiation processes or differentiation, - this is the emergence of specialized structures of a new quality from poorly specialized precursor cells. The least specialized can be considered the zygote - the germ cell formed as a result of the fusion of the mother's egg with the father's sperm. The first stages of zygote development are a simple increase in the number of cells indistinguishable from each other - first the zygote is divided into 2, then each of them is divided into 2 more, i.e. 4 cells are formed, then 8, 16, 32, etc. These embryonic cells are called blastomeres, they are like two peas in a pod. However, already at the stage of 32 blastomeres, some features of individual cells associated with their location begin to emerge.

In recent decades, it has been convincingly shown that differentiation processes do not end in the prenatal period: many tissues of the body continue to develop, including through differentiation processes, until the completion of puberty. The period of maturation of excitable tissues - nervous and muscle - is especially long.
Growth processes lead, as a rule, to quantitative, proportional changes. Differentiation processes can lead to the appearance of qualitative, disproportionate changes in the activity of the physiological systems of the body.
Energy costs in the process of growth and development. Even during the period of the most intensive growth, no more than 4-5% of daily energy consumption is spent on growth processes. Visible to the eye Changing the size and proportions of the body is actually a fairly easy process (from the point of view of the body’s energy) to implement. The situation is completely different with differentiation processes that determine the dynamics of the qualitative development of the organism. The number of syntheses that occur during the process of differentiation may not be so great, but their energy “price” is much higher. This is due to the fact that in the process of growth synthesis, ready-made, proven metabolic pathways are used, while differentiation processes require the organization of new metabolic pathways.
Quantitative
and qualitative changes in the activities of fi
physiological systems. All physiological functions are somehow related to body size. But at the same time, some of them change in ontogenesis in proportion to changes in body mass, while others change in proportion to changes in body surface area. If, during development, one or another function demonstrates a change disproportionate to mass or surface area, then this is indicates a qualitative transformation of the implementation mechanisms this function.
Alternating periods of growth and differentiation serves as a natural biological marker of stages of age-related development, at each of which the body has specific characteristics. In other words, the stages of ontogenesis are not an abstraction, but a completely real sequence of events that invariably repeats itself in the development process of each individual.
Growth and development proceed more intensively the younger the child: growth at birth doubles by 4.5-5 years; triples by 14-15 years; in junior school age Body length increases by an average of 4-5 cm. During puberty, the annual increase in length is 6-8 cm.
The basis is a pattern spasmodic development when the gradual accumulation of quantitative changes at a certain moment transforms into a new qualitative state (the appearance of perfect coordination of movements, increased attention, interest in the environment).
The concept of a “growth spurt”.
In those cases when growth processes are simultaneously observed in many different tissues of the body, the phenomena of so-called “growth spurts” are noted. First of all, this is manifested in a sharp increase in the longitudinal dimensions of the body due to an increase in the length of the torso and limbs.
In postnatal human ontogenesis such “jumps” are most pronounced
in the first year of life(1.5-fold increase in length and 3-4-fold increase in body weight per year, growth mainly due to lengthening of the body),
at the age of 5-6 years(the so-called “half-height leap”, as a result of which the child reaches approximately 70% of the adult’s body length, growth mainly due to lengthening of the limbs), and also
at 13-15 years old(pubertal growth spurt due to both lengthening of the body and lengthening of the limbs).
For the first time, the growth spurt became known from the studies of Count F. de Montbailard, who in 1759-1777. monitored his son's development, weighing him every six months.
As a result of each growth spurt, the proportions of the body change significantly, becoming closer and closer to adults. In addition, quantitative changes, expressed in an increase in body length and a change in its proportions, are necessary accompanied by qualitative changes in the functioning of the most important physiological systems, who must “tune in” to work in a new morphological situation.

Heterochrony
(from the Greek - other, - time) - the growth and development of all organs and physiological systems of the body of children and adolescents occurs heterochronically (that is, not simultaneously and unevenly). The order of development and improvement of organs depends on their “need” and “usefulness” for the child’s body. For example, the heart begins to work in the 3rd week of prenatal development, and the kidneys form much later and come into effect only in the newborn child.
P.K. Anokhin: “Heterochrony is a special pattern consisting in the uneven deployment of hereditary information. Thanks to this hereditarily fixed feature of maturation, the basic requirement for the survival of the newborn is ensured-a harmonious relationship between the structure and function of a given newborn organism with the sudden impact of environmental factors on it.”
Features of human development
■ in humans, periods of accelerated growth alternate with their slowdown;
■ in the first year of life and during puberty, the most intensive growth and development of the body occurs;
■ During growth, the ratio of head to body length changes. In a newborn it is 1:4, in an adult - 1:8;
■ for the development of thinking and motor activity The period from 2 to 4 years is very important. "Mowgli" - returned to society before this period - develops to normal person, and after this period they cannot become full-fledged people.
In the growth and development of children there are:
■ the first period of extension - the first year of life, the child’s body length increases by 25 cm, and its weight increases by 6-7 kg;
■ the first rounding period is 1-3 years, the pace of development is decreasing;
■ the second period of extension - 5-7 years - a new increase in growth rates, body growth of 7-10 cm;
■ second rounding period - 7-10 years - growth slowdown;
■ the third period of extension - from 11-12 to 15-16 years - an increase in the rate of physical development during puberty;
■ in subsequent years the rate of physical development decreases. Growth in women stops at 18-22 years, in men - at 20-25 years.
Rate of sexual development and biologically determined life expectancy. Some representatives species Homo sapiens live up to 130-140 years in certain conditions, maintaining clarity of thought and relative ability to work. According to a number of enthusiasts, a person, if he were not susceptible to some diseases and vices, could live up to 200 years or more. It must be recognized that, no matter how attractive these concepts are, they are not based on modern scientific knowledge. For mammals, which includes humans, the following pattern is typical: the average life expectancy is approximately 5 times longer than the age of puberty. Apparently, this relationship was established in the process natural selection as most adequate to the tasks of population reproduction. It follows that the natural limit of human lifespan is approximately 16 x 5 = 80 years. Anyone who lives longer than this period can rightfully be considered a long-liver.
Life expectancy is determined by the genome. At the ends of the chromosome there are sections - telomeres, the length of which is shortened with each division. Each cell has its own number of divisions.
It should be emphasized that all the above arguments make sense only at the population level and have nothing to do with individual characteristics rates of biological maturation. Special studies have not revealed significant correlations between the rate of puberty and life time in individuals. Residents southern countries usually reach sexual maturity 1-2 years earlier than northerners, but this does not mean that they live 5-10 years less.
Only 15% of Russians live to biological old age. 85% of Russians do not live to biological old age. This data is provided by experts from the Center for Strategic Studies of the Ministry of Emergency Situations. According to statistics, more than 56 percent of deaths are due to socio-economic causes, 20% due to environmental causes. Five percent premature deaths associated with natural and man-made causes. For example, up to 35 thousand people die annually in road accidents and up to 20 thousand in fires.
In recent decades, in all developed countries Life expectancy is progressively increasing. Along with this, a decrease in life expectancy has been noted in countries in Africa and the former Soviet Union.
Individual differences in the process of growth and development can vary widely. The existence of individual fluctuations in the processes of growth and development served as the basis for the introduction of such a concept as biological age or developmental age(unlike passport age).
Main biological age criteria are considered:
1) “external” criterion (skin);
2) “skeletal maturity” (the order and timing of skeletal ossification);
3) “dental maturity” (timing of eruption of baby and permanent teeth);
4) the degree of development of secondary sexual characteristics. For everyone
From these criteria of biological age - “external”, “dental” and “bone” - rating scales and normative tables have been developed that make it possible to determine the chronological (passport) age based on morphological features.
The simplest, but also the crudest way to estimate biological age is by body proportions- the ratio of the lengths of the limbs and the torso. Such an assessment can only give a very rough, approximate result, since the factor of biological diversity intervenes here, i.e. constitutional affiliation of the individual. Potential dolichomorphs, already in childhood, may have relatively longer legs than their brachymorph peers, although the rate of morphofunctional development of brachymorphs is often higher in many respects. Therefore, judging by the proportions of the body, one can confidently attribute the child only to one or another age group, and quite a wide one at that.
Bone age. A much more accurate result is obtained by studying bone (skeletal) age. Ossification of each bone begins from the primary center and passes through a series of successive stages of increase and formation of the ossification area. In practice, the hand and wrist (usually the left hand) are most often used for these purposes. Comparing the resulting radiograph with standards and scoring the degree of development of many bones makes it possible to express the result obtained quantitatively (in years and months).
Dental age. If you count the number of teeth that have erupted (or replaced) and compare this value with standards, you can estimate the so-called dental age. However, the age periods when such a determination is possible are limited: baby teeth appear in the range from 6 months to 2 years, and their replacement with permanent teeth occurs from 6 to 13 years. In the period from 2 to 6 years and after 13 years, determining dental age loses its meaning.
External sexual characteristics. Man and woman are distinguished sexual characteristics. This absolute signs of sex (presence or absence of a y chromosome), primary(genitals) and secondary(for example, the development of pubic hair, the development of mammary glands, voice changes, body features, proportions of body parts, etc.). Hermaphroditism– the presence of male sex glands on one side of the body, and female sex glands on the other.
During puberty, biological age can be assessed by external sexual characteristics. There are different - quantitative and qualitative - methods for taking into account these signs, but they all operate on the same set of indicators: for young men, this is the size of the scrotum, testicles and penis, hair growth on the pubis, in the armpits, on the chest and abdomen, the appearance of wet dreams , swelling of the nipples; in girls, this is the shape and size of the mammary glands and nipples, pubic and armpit hair, the time of the first appearance and establishment of regular menstruation.
The sequence of appearance and dynamics of the severity of the listed signs are well known, which provides grounds for fairly accurate dating of biological age in the period from 11-12 to 15-17 years.
Factors influencing individual development (ontogenesis), are divided into hereditary and environmental (influence external environment).
The degree of hereditary (genetic) influence varies different stages growth and development. The impact of hereditary factors on total body size increases from the neonatal period to the second childhood, with subsequent weakening by 12-15 years.

The influence of environmental factors on the processes of morphofunctional maturation of the body can be clearly seen in the example of the timing of menarche (menstruation). Studies of growth processes in children and adolescents in various geographical zones have shown that climatic factors have almost no effect on growth and development if living conditions are not extreme. Adaptation to extreme conditions causes such a profound restructuring of the functioning of the entire organism that it cannot but affect the growth processes.

"I affirm"

head Department of Pediatrics,

Doctor of Medical Sciences, Professor A.I. Kuselman

_____________________

"_____" _____________2006

“METHODOLOGY FOR ASSESSING THE PHYSICAL DEVELOPMENT OF CHILDREN AND ADOLESCENTS. ANTHROPOMETRY TECHNIQUE. METHOD FOR ASSESSING BIOLOGICAL AGE. SEMIOTICS OF PHYSICAL DEVELOPMENT DISORDERS IN CHILDREN AND ADOLESCENTS.”

TYPE OF CLASS: practical

DURATION OF CLASS: 2 hours

OBJECTIVE OF THE LESSON: Master the methodology for assessing the physical development of children and adolescents. To study the semiotics of physical development disorders in children and adolescents"

The student must know:

Physical development of children. Definition. Factors that determine the growth of children (genetic, environmental, the role of the endocrine and nervous systems, etc.).

The concept of acceleration and retardation of children's development.

Changes in body length and weight during the growth and development of children, changes in body proportions, body type during growth:

intrauterine development of the fetus;

growth after birth;

body weight after birth;

correspondence of length and body weight indicators (determined by formulas)

the rate of development and change in the circumference of the head and chest;

5. Determination of body surface

Methods of anthropometric measurements and calculation of various indicators of physical development (PD) in children of different ages (body length, weight, chest circumference, head circumference, abdominal circumference, limb circumference).

Combined assessment of various anthropometric characteristics (parametric or sigma method; nonparametric or centile method).

Semiotics of the most common deviations in the physical development of children: impaired growth, insufficient or excess body weight, disproportionate development of individual parts of the body and their causes.

The concept of hypo- and paratrophy, hypostature, nanism, gigantism.

Questions for students’ independent work:

Diagnosis of short stature.

Growth retardation in children with endocrine pathology.

Somatotypes.

The student must be able to:

- Assess the physical development of children and adolescents.

Be able to conduct anthropometric studies.

Be able to evaluate physical development using formulas and tables.

Calculate indices of children's physical development.

Determine the somatotype of children and adolescents.

Be able to calculate the surface of a body.

Find out information about the child’s physical development.

Identify the most common deviations in physical development in children and adolescents.

PHYSICAL DEVELOPMENT OF CHILDREN

Physical development in clinical pediatrics it is understood as a dynamic process of growth (increase in body length and weight, development of individual parts of the body, etc.) and biological maturation of the child in one or another period of childhood.

The rate of growth, increase in body weight, the sequence in the increase of various parts of the body, and therefore proportions, as well as the maturation of various organs and systems at each age stage, are mainly programmed by hereditary mechanisms and, under optimal living conditions, follow a certain plan. Factors determining the physical development of children can be divided into genetic, exogenous and difficult to classify.

1. Genetic factors are by far the most significant. It is believed that there are more than 100 genes that regulate the rate and limit of human growth, but direct evidence of their role is difficult to obtain. The influence of heredity generally affects the physical development, especially the growth, of a child after 2 years of life. There are two periods when the correlation between the heights of parents and children is most significant. This is the age from 2 to 9 years, when the action of one group of genes is affected (the first family factor), and the age from 14 to 18 years, when the regulation of growth depends on other genes (the second family factor). Hereditary factors determine the rate and possible limit of a child’s growth under optimal living and upbringing conditions.

2. The influence of exogenous factors on the speed and growth limit of children has been better studied. The most important is the influence of nutrition.

Moderate nutritional deficiencies delay weight gain and increase the time of growth and maturation, but the child's height may not decrease. Large degrees of nutritional deficiency are not compensated by prolongation of development and lead to short stature with changes in body proportions. Deficiency of certain nutritional components (vitamin A, zinc, iodine, etc.) selectively disrupts the growth processes of children. Excess nutrition, especially in early age, also adversely affects the development process, especially in early childhood. In this case, biological maturation can be accelerated.

The lifestyle for a child’s development is also important. We can name two of the most important regime factors influencing physical development: the first is adequate physical mobility, which creates that degree of vertical and intermittent mechanical load on the bone skeleton, which is a stimulator of osteogenesis and cartilage growth, as well as muscle development. Excessive vertical load, for example, when carrying heavy objects, has the opposite effect - it inhibits growth. Therefore, it is necessary to constantly monitor the child’s lifestyle, avoiding hypokinesia or engaging in sports or work that could have a harmful effect on his development. The second important factor is lack of sleep. It is during sleep that all the main metabolic and cellular rearrangements that determine the growth of the child’s skeleton take place.

The emotional state of a child - mental tension, depression, mental trauma - always leads to growth inhibition, which is associated with the activation of neuroendocrine mechanisms that block growth processes and accelerate catabolism.

Acute and especially chronic diseases of a child can cause growth retardation, as they disrupt anabolic processes for a long time, cause microcirculation disorders and hypoxemia.

Environmental factors may also influence growth. The category of environmental factors also includes the influence of various climatic and geographical conditions. Hot climates and high mountain conditions have a retarding effect on growth, but at the same time they can significantly accelerate the maturation of children. Fluctuations in growth rates due to the seasons of the year are widely known (acceleration in the spring and deceleration in the autumn-winter months). The seasonality of growth makes it necessary to estimate the growth rate of children based on annual dynamics.

3. The influence on a child’s growth of factors that are included in the unclassified group has been least studied. These include such as the serial number of pregnancy and childbirth, the date of birth, the body weight of the fetus (newborn) at the time of its birth, the age of the mother and, to a lesser extent, the father, the season of birth of the child. The degree of influence is relatively small.

4.The growth of a child is controlled by many endocrine glands: thyroid, pituitary, thymus, reproductive and adrenal glands. Their influence varies depending on the age of the child.

Somatotropic hormone (GH) secreted by the pituitary gland has an important influence on the growth process. HGH stimulates somatic growth (bone age, organ enlargement), it affects the differentiation of bone structure, affects protein, fat and carbohydrate metabolism. GH is the main stimulator of growth at the tissue level. The synthesis of GH is under the control of hypothalamic neurosecretory factors - somatoliberin and somatostatin. This process is also influenced by triiodothyronine, glucocorticosteroids, opioid peptides, dopamine and some amino acids. Alpha-adrenergic and serotonergic stimulation of the hypothalamus causes the secretion of GH, and beta-adrenergic stimulation inhibits it. Starting from puberty, growth hormone does not play a significant role in growth processes. The function of growth regulation passes to androgens.

Other hormones also influence growth processes. Thus, thyroid hormones promote protein synthesis and energy supply for synthetic processes. Throughout life, they stimulate the release of growth hormones. Before puberty, bone growth is accelerated by hormones of the thymus gland, which subsequently transfers this function to the gonads. Sex hormones accelerate the growth and differentiation of bone tissue. At the same time, they promote the fusion of epiphyseal clefts, limiting growth. Androgens are produced not only by the male gonads, but also by the female ones, as well as by the adrenal cortex. Androgens also ensure growth of the body. If the male body at a certain stage of development grows due to the androgens of the testes and partly the adrenal glands, then the female body grows only due to the androgens of the adrenal glands.

Mineralocorticoids normalize metabolism, glucocorticosteroids have a catabolic effect, their excess negatively affects growth. Calcitonin and parathyroid hormone influence the completion of calcification processes. Intrauterine development of the fetus occurs under the influence of human chorionic somatotropin, thyroid hormones, and maternal sex hormones.

Since anthropometric measurements were introduced into the practice of medical examination of children in the 30s of the last century, they began to notice that children’s height increases from decade to decade, and puberty occurs at an earlier age. This phenomenon is called acceleration(from Latin acceleratio - acceleration). Not long ago, archaeological research that was carried out at the site of the famous Battle of Poltava showed that the height of soldiers from the time of Peter I was an average of 20 cm shorter than a modern adult. The body length of children aged 15 from 1882 to 1970 increased by 19 - 20 cm. The current height of a 7-year-old child corresponds to the height of a 9-year-old, and a 15-year-old teenager corresponds to a 17-year-old youth who lived at the beginning of the 20th century. This accelerated development also affected the prenatal period, which is confirmed by a steady increase in the average length and body weight of newborns. IN Western Europe In general, an increase in adult height of 1 cm per decade has been observed for 100 years. There is also more rapid development muscle strength, as evidenced by the constantly changing (increasing) world sports records, which are now increasingly set by young men rather than adult athletes.

The period of biological maturation has also accelerated. This is evidenced by earlier dates than several decades ago for the appearance of ossification nuclei, eruption of permanent teeth, cessation of growth, and puberty.

In recent years, there has often been a dissonance between the maturation times of different organs and systems - the accelerated development of some characteristics is accompanied by a disproportionate immaturity of others. This led to rejuvenation and an increase in the incidence of diseases in adolescence (hypertension, gastric ulcer, obesity, diabetes, etc.).

Accurate genetic factor biological acceleration has not been established.

Main reasons the action of which is often combined, according to various scientists the following:

significant migration (territorial movement) of the planet's population and marriages of people of different races;

more rational nutrition;

often overfeeding the child, especially with proteins and fats that increase growth through the endocrine system;

environmental factors:

influence of cosmic radiation;

action of magnetic field;

increased background radiation;

chemicals (medicines, preservatives, pesticides, carbon dioxide, etc.);

5) the influence of increased solar radiation, as well as taking vitamin D for the purpose of preventing and treating rickets (especially its overdose) - this accelerates the ossification process.

True acceleration is accompanied by an increase in life expectancy and reproductive period of the adult population.

It is necessary to distinguish true acceleration from the accelerated development of children caused by overfeeding (especially due to protein). Usually, in contrast to true acceleration, the accelerated development of children during overfeeding (protein) causes earlier maturation of biochemical systems (mainly enzymes), which actually reflects a disruption in the “biological clock” of maturation. This may be the reason for the rejuvenation of pathology in adults (for example, obesity, hypertension and coronary artery disease, diabetes mellitus, etc.). In connection with ongoing changes in the timing of development, the rate of increase in body weight and other indicators of physical development, the standards that we have should be periodically reviewed, and it is advisable to use regional standards to assess physical development. Retardation – delay in physical development and formation of functional systems of the body. In the group, there are 13-20% of both children. Retardation should be especially taken into account when determining school readiness. Psychophysiological maturation provides the conditions for the emergence and implementation of mental functions. Based on morphological and functional indicators, one can judge the processes of maturation and the degree of maturity of the structures and functions of the body at individual stages of development of each child. At the same time, we must not forget that everyone has an individual pace of development.

Changes in body length and weight during the growth and development of children, changes in body proportions, body type during growth: Intrauterine development

During the intrauterine (gestational) period of a child's development, the most intense increase in body length and weight occurs due to cellular reproduction (hyperplasia). During 40 weeks of intrauterine development, 44 consecutive cell divisions occur. The main factors regulating and determining fetal growth are uterine blood flow and placental perfusion. It is possible that the placenta, among many low-molecular peptides, also produces growth factors. Fetal thyroid hormones are also unlikely to be growth factors, but it has been proven that their influence is necessary for the formation of neurons and glial cells in the brain. The most likely growth influence is insulin and somatomedins. Towards the end of intrauterine development, the growth rate slows down. This is due to the occurrence at the end of pregnancy of the phenomena of “volumetric inhibition,” i.e., the inhibitory effect of the limited volume and elasticity of the uterus on the development of the fetus. Volumetric inhibition is the mechanism through which the formation of an approximate anatomical correspondence between the size of the fetus and the birth canal of the mother is carried out. To make an approximate judgment about body length depending on the period of intrauterine development, you can use the following empirical formulas:

1. Haase's formula: the length of the fetal body in the first 5 months of intrauterine development is equal to the square of the month of pregnancy; after 5 months, the length of the fetus is equal to the number of months multiplied by 5.

2. Fetal body length during pregnancy from 25 to 42 weeks equal to the gestational age in weeks + 10 cm.

To determine the body weight of the fetus, use the following formulas.

In the period of 25 - 42 weeks: the body weight of the fetus at 30 weeks is 1300 g, for each subsequent week you need to add 200 g, for each missing week you need to subtract 100 g.

Examples :

The fetus is 26 weeks old, its weight is approximately 1300 - 100 x 4= 900g;

at 35 weeks of age the weight is approximately 1300 + 200 x 5= 2300

The length of the fetal body, depending on gestational age, is calculated in the following ways:

aged 25-42 weeks body length is: gestational age in weeks+ 10 cm(example : fetal age is 32 weeks, its body length is 32+10= 42 cm);

fruit length in the first 5 months of pregnancy is equal to: month insidechild development squared(example : gestational age of the fetus 3 monthssize, its length is 3x3-9cm), and then, With6 months of pregnancy fetal growth is: number of months multiplied

by 5(example : cartThe fetus grows for 7 months, its length is 7x5 = 35 cm).

To determine whether the weight corresponds to the body length of the fetus: a fetus 40 cm long has a mass of 1300 g, for each additional centimeter of body length the weight increases by 200 g, for each missing centimeter 100 g are subtracted. Discrepancy between weight and body length reflects insufficiency of intrauterine nutrition or other adverse effects in the process of pregnancy. More accurate indicators of body weight depending on the duration of pregnancy are given in table. 1.

The fetal chest circumference at a gestational age of 25 to 42 weeks is equal to the gestational age (in weeks) -7 cm. The head circumference at a gestational age of 34 weeks is approximately equal to 32 cm. For each missing week, subtract 1 cm, for each subsequent week add 0.5 cm.

Based on these indicators, one can judge the actual age of the newborn. Often the task is to determine whether the length and weight of the fetus corresponds to the gestational age known from the anamnesis, which is important for diagnosis, detection increased risk diseases of children with this discrepancy.

Table 1. Birth weight depending on gestational age

There are cases when the size of the fetus corresponds to the expected gestational age; the size of the fetus is small relative to the gestational age; The size of the fetus is large for the duration of pregnancy. In addition, when comparing body weight and length, we can talk about relative insufficiency (intrauterine malnutrition) or excess weight for a given body length.