Age-related physiological changes in children. Maryana Bezrukikh - Age physiology: (Physiology of child development)

age physiology

1. The subject of age physiology. Communication of age physiology with other biological disciplines. The value of age physiology for pedagogy, psychology, medicine and physical education.

Age physiology is a science that studies the patterns of formation and features of the functioning of the body in the process of ontogenesis.

The structure and functions of any organ are inextricably linked. It is impossible to know the functions of the body, its organs, tissues and cells without knowing their structure. Therefore, physiology is closely related to the achievements of human anatomy, histology and cytology. The basic patterns of life are inherent in the entire world of animals. But in the process of evolution, the forms of manifestation of these regularities changed and became more complicated. To study the life of any organism, it is necessary to understand the history of its species development - phylogenesis ( historical development organism). Therefore, in age-related physiology, the data of evolutionary doctrine are widely used, and the main stages in the development of various organs of animals are traced. From this, the connection between age-related physiology and evolutionary physiology becomes clear.

The need for teachers and educators to know the age characteristics of the functioning of the child's body has been repeatedly emphasized by scientists.

The first thing a teacher should know is the structure and life of the human body and its development. Without this, it is impossible to be a good teacher, to properly raise a child.

The pedagogical effectiveness of upbringing and education is closely dependent on the extent to which the anatomical and physiological characteristics of children and adolescents are taken into account, periods of development that are characterized by the greatest susceptibility to the effects of certain factors, as well as periods of increased sensitivity and reduced body resistance. Knowledge of the physiology of the child is necessary in physical education to determine effective methods teaching motor actions in physical education lessons, to develop methods for the formation of motor skills, the development of motor qualities, to determine the content of physical education and health work at school.

1. Age features of the development of the stomach, pancreas, intestines.

Abdominal digestion is known to be carried out mainly by enzymes. pancreas , but in newborns it is poorly developed. The mass of the gland is 2-4 g, by the end of 1 year it reaches 10-12 g (in adults - 60-115 g).

Granulocytes of the pancreas of the newborn are slightly reactive to stimulants. The development of the secretion of various enzymes proceeds heterochronously. The transition to mixed and especially artificial feeding significantly increases the secretion and release of pancreatic enzymes. At the age of 2 years, the secretion of proteases, lipases and carbohydrases is well stimulated.

Regulation of pancreatic secretion is carried out by nervous and humoral mechanisms. In the regulation of the secretion of the duodenum, the importance of the nature of nutrition is especially great. This influence, which is formed with the transition to definitive nutrition, is heterochronous for the secretion of various enzymes. Big role in intestinal digestion belongs to bile.

A number of major metabolic pathways are common to most cells and organisms. These pathways, which result in the synthesis, destruction and interconversion of the most important metabolites, as well as the accumulation chemical energy, are called intermediate metabolism. Here is a highly simplified diagram of these processes.

Heterotrophs, such as animals and fungi, depend on obtaining organic matter from food. Since most of these nutrients (proteins, carbohydrates, nucleic acids, and lipids) cannot be utilized directly, they are first broken down into smaller fragments by the catabolic pathway (red arrows in the diagram). The resulting metabolites (collectively sometimes referred to as the "metabolite pool") are then catabolized to release free energy or used in anabolic pathways (blue arrows) to synthesize more complex molecules. Of the numerous metabolites, only the three most important representatives are represented here - pyruvate, acetyl-CoA and glycerol. These three compounds are the link between the metabolism of proteins, carbohydrates and lipids. The metabolic pool also includes intermediate metabolites of the citrate cycle (6). This cyclic pathway plays both a catabolic and anabolic role, that is, it is amphibolic (see p.). The end products of the breakdown of organic matter in animals are carbon dioxide (CO 2), water (H 2 O) and ammonia (NH 3). Ammonia is converted into urea and in this form is excreted from the body. The most important form of storage of chemical energy in cells is adenosine triphosphate (ATP, see p.). Energy must be expended on the formation of ATP, i.e., the reaction is endoergic. At the same time, when ATP is broken down into ADP and phosphate, free energy is released. Due to exoergic hydrolysis. Most 3. use this energy to synthesize new necessary compounds and do work.

Metabolism consists of two independent opposite processes:

Catabolism - the breakdown of incoming substances; directed downward, accompanied by the release of energy, which accumulates in the form of ATP;
anabolism - the synthesis of complex molecules from simpler ones; directed upwards, accompanied by the expenditure of energy.

At a young age, the predominance of anabolic processes (growth) over catabolic ones is characteristic. This is especially pronounced after birth and continues until about 18-19 years. During this period, the growth of organs and tissues ends, the full formation of the whole organism begins, and the processes of creation and decay come into balance.

With age, the processes of catabolism begin to predominate, which leads to a decrease (up to a complete cessation) in the production and content in the body of many of the most important substances for life. For example, the synthesis of coenzyme Q10 or levocarnitine stops, and so on. The result is the appearance of various age-related diseases, the loss of vital energy, a decrease in the capabilities of internal organs and muscle strength.

Compensation for the deficiency of such substances is currently possible with the correct use of high-quality biologically active additives (BA).

1. Factors that determine the age-related dynamics of energy metabolism.

In extreme old age (the phase of regressive development), there is a decrease in body weight, as well as a decrease in the linear dimensions of the human body, the main metabolism drops to low values. Moreover, the degree of decrease in basal metabolism at this age correlates, according to various researchers, with how old people show signs of decrepitude and lost working capacity.

As for sex differences in the level of basal metabolism, they are found in ontogeny already from 6-8 months. At the same time, the basal metabolism in boys is higher than in girls. Such relationships persist during puberty, and by old age they are smoothed out.

In ontogenesis, not only the average value of energy metabolism varies, but the possibilities of increasing this level under conditions of intense, for example, muscular activity also change significantly.

In early childhood, insufficient functional maturity of the musculoskeletal, cardiovascular and respiratory systems limits the adaptive possibilities of the reaction of energy metabolism during physical exertion. In adulthood, adaptive capacity, as well as muscle strength, reach a maximum. In old age, the possibilities of a compensatory increase in the level of respiration and energy exchange under stress are exhausted due to a decrease in VC, the coefficient of oxygen utilization by tissues, and a decrease in the functions of the cardiovascular system.

An increase in skeletal muscle tone with insufficient activity of the vagus nerve center during the first year of life contributes to an increase in energy metabolism. The role of age-related restructuring of the activity of skeletal muscles in the dynamics of energy metabolism is especially clearly distinguished in the study of gas exchange in people of different ages at rest and during physical activity. For progressive growth, an increase in metabolism at rest is characterized by a decrease in the level of basal metabolism and an improvement in energy adaptation to muscle activity. During the period of the stable phase, a high exchange of functional rest is maintained and the exchange during work increases significantly, reaching a stable, minimum level of basal metabolism. And in the regressive phase, the difference between the exchange of functional rest and the main exchange continuously decreases, the rest time lengthens. Changes in the nature of the central regulators of metabolism - the nervous and endocrine systems - are essential in the age-related dynamics of metabolism.

Many researchers believe that the decrease in the energy metabolism of the whole organism during ontogenesis is primarily due to quantitative and qualitative changes in metabolism in the tissues themselves, the magnitude of which is judged by the ratio between the main mechanisms of energy release - anaerobic and aerobic. This allows us to find out the potential capabilities of tissues to generate and use the energy of macroergic bonds. Tissue respiration is currently being studied using the polarographic method, by O 2 tension in tissues, or by oxygenometry, by the degree of blood oxygenation. Using these methods, Ivanov (1973) showed that the amount of oxygen exchange in the tissues of the subcutaneous tissue in people in extreme old age (90-106 years) is reduced compared to subjects aged 19-32 years, while the conditions for oxygen diffusion to tissues worsen. With age, a kind of restructuring of the bioenergetics of the heart muscle also occurs, it oxidizes energetically more efficient fatty acids less and less and retains the ability to oxidize energetically less valuable glucose at the same level. Thus, the bioenergetics of the heart in old age changes dramatically at the subcellular level. With age, parallel changes occur in the system of generation and use of macroergic compounds (ATP and creatine phosphate). For example, the concentration of ATP and CP in the muscles of white rats reaches a maximum value in adulthood and falls in old age; these shifts reflect the functional changes in skeletal muscles throughout life.

1. Age features of higher nervous activity.

Higher nervous activity represents the integrative ability of the higher parts of the brain to provide an individual behavioral adaptation of a person to changing conditions of the internal and external environment. The theory of higher nervous activity is built on the following basic basis:

1. on the concepts of reflex theory,

2. on the theory of reflection,

3. on the theory of systemic activity of the brain.

Development of conditioned reflexes. A child is born with a certain set of innate, unconditioned reflex reactions. From the second day of life, he begins to develop conditioned connections. For example, on the 2-5th day, a reaction to the position for feeding is formed, an orienting reflex occurs. From the 6th day, a leukocyte conditioned reflex reaction to food intake appears. On the 7-15th day of a child's life, conditioned reflexes to sound and vestibular stimuli appear. At 2 months, reflexes can be developed from any analyzer. In the second year of life, the child develops a large number of conditioned reflexes to the ratio of the size, severity, distance of objects. In the process of formation of a conditioned reflex, four stages are distinguished:

The stage of a non-specific reaction, which is characterized by the appearance of an orienting reaction to a stimulus;

the stage of inhibition, at which the child's activity is inhibited under the action of a conditioned signal;

The stage of an unstable conditioned reflex, when conditioned stimuli do not always cause a response;

stage of a stable conditioned reflex.

With age, the rate of development of conditioned reflexes increases. The systems of conditional connections developed in the early and before school age(up to 5 years), are especially durable and retain their value throughout life.

External unconditional braking. External unconditional inhibition appears in a child from the first days of life. At 6-7 years of age, the importance of external inhibition for higher nervous activity decreases and the role of internal inhibition increases.

Internal braking. Internal inhibition appears in a child approximately from the 20th day after birth in the form of a primitive form of differential inhibition. Fading inhibition appears at 2-2.5 months, conditioned inhibition is observed at 2.5-3 months, and delayed inhibition - from 5 months.

dynamic stereotype. In early childhood, stereotypes are of particular importance. They facilitate the adaptation of children to the environment, are the basis for the formation of habits and skills. In children under three years of age, stereotypes are easily developed and help the child develop the conditioned reflexes necessary for life with their help.

Speech development. Speech development is the process of development of the second signaling system. The terms of development of sensory and motor speech do not coincide. The development of sensory speech precedes the development of motor speech. Even before the child begins to speak, he already understands the meaning of the words. In the formation of speech, the following stages are distinguished:

1. Preparatory stage, or the stage of pronunciation of individual sounds and syllables (from 2-4 to 6 months);

2. The stage of the emergence of sensory speech, that is, the manifestation of the first signs of a conditioned reflex to the word, to its meaning (6-8 months);

3. The stage of the emergence of motor speech, that is, the pronunciation of meaningful words (10-12 months).

Up to 2 months, the child's vocabulary is 10-12 words, by 18 months - 30-40 words, by 24 months - 200-300 words, by 36 months - 500-700, in some cases - up to 1500 words. By the age of 6-7, the ability to internal (semantic) speech appears.

Development of thinking. Visual-effective thinking is formed in preschool and primary school age. Verbal-logical thinking manifests itself by the age of 8-9, reaching development by the age of 14-18.

Behavior Development. The behavioral act is carried out according to two principles:

on the principle of reflex, that is, from stimulus to action;

· according to the principle of self-regulation – when one or another physiological indicator deviates from the level that ensures normal life activity, a behavioral reaction is activated, which restores homeostasis.

Sensory, motor, central and some neurohumoral mechanisms are involved in the organization of behavior. Sensor systems provide recognition of stimuli of the external and internal environment. Motor systems implement the motor program in accordance with sensory information. Central systems connect sensory and motor systems to ensure the adaptive behavior of the whole organism in accordance with changing environmental conditions and on the basis of dominant motivation.

For a person, the most important behavior is communicative behavior. The formation of communicative behavior requires visual, acoustic, olfactory and tactile information.

Eye contact for a child is very important for establishing relationships with others. A child aged 1-1.5 weeks distinguishes well common features presented objects, and it is they, and not their form, that are the most essential for him.

Acoustic contact is carried out in the form of a speech dialogue. It is believed that the child reacts to the sounds of speech from birth. In infants 4-5 months old, an "revitalization complex" of maximum strength and duration, including "cooing", is observed in the speech of an adult.

Tactile sensitivity ensures the perception of external stimuli in a wide range, so for newborns and children younger age it has important educational value. Especially effective are tactile contacts in the first trimester of life.

With age, the role of vision and hearing in ensuring communicative behavior increases. The first communicative interactions occur even before the birth of a child in the "mother-fetus" system. The connection between the mother and the fetus is carried out through tissue contacts. After birth, the mother-child relationship continues in the mother-child system. Already from the 3rd day after birth, a newborn is able to distinguish the smell of milk and the body of his mother from the smell of other people. After the 3rd month of life, the child switches to interactions with other family members. Starting from 2-2.5 years old, children can create groups of 3-4 people. Moreover, boys interact more often than girls. In the presence of mothers, children prefer interaction with adults.

14. Analytical and synthetic activity in different periods of human ontogenesis.

The physiological basis of the processes of higher nervous activity is the analytical and synthetic activity of the cortex hemispheres brain.

Analytical activity of the cortex of the brain lies in its ability to separate, isolate and distinguish between individual stimuli, that is, to differentiate them.

Synthetic activity of the cortex of the cerebral hemispheres is manifested in the unification, generalization of the excitation that occurs in its various parts from the action of various stimuli.

Analysis and synthesis of specific signals are first signal system man and animals. Second signal system- these are nervous processes that occur in the hemispheres of the human brain as a result of the perception of signals from the surrounding world in the form of speech designations. The second signaling system is the basis of human thinking, it is socially conditioned. Outside of society, without communication with other people, it does not develop. The first and second signal systems are inseparable from each other, they function together and determine the unity of the higher nervous activity of a person.

15. Qualitative differences in human GNI. Development of the second signal system.

The main laws of higher nervous activity include:

1) the formation of new temporary connections when a neutral stimulus is reinforced with an unconditioned one;

2) the extinction of temporary connections when the conditioned stimulus is not reinforced by the unconditioned one;

3) irradiation and concentration of nervous processes;

4) mutual induction of nervous processes;

5) the formation of complex dynamic systems of reflexes, the so-called dynamic stereotypes.

The neuroanatomical substrate for the formation and extinction of temporary connections, differentiation and integration of stimuli is the cerebral cortex. In the subcortical regions of the brain there are nerve centers of the most important unconditioned reflexes, which form the basis for the formation of a conditioned reflex. The subcortical sections provide a high level of activity of the nerve cells of the cerebral cortex, thereby creating the necessary conditions for the formation of temporary connections and their differentiation. At the same time, the functioning of the subcortical regions of the brain is controlled by the cortex, which stimulates and inhibits the development of their activity.

The qualitative difference between the higher nervous activity of man and animals is due to the fact that in man there has been a complication of the mechanisms of its mental activity, because a special stimulus appeared - the word.

Short description:

Sazonov V.F. Age anatomy and physiology (a manual for OZO) [ Electronic resource] // Kinesiologist, 2009-2018: [website]. Date of update: 01/17/2018..__.201_).

Attention! This material is in the process of regular updating and improvement. Therefore, we apologize for possible minor deviations from the curricula of previous years.

1. General information about the structure of the human body. Organ systems

A person with his anatomical structure, physiological and mental characteristics is the highest stage evolution of the organic world. Accordingly, it has the most evolutionarily developed organs and organ systems.

Anatomy studies the structure of the body and its individual parts and organs. Knowledge of anatomy is necessary for the study of physiology, so the study of anatomy must precede the study of physiology.

Anatomy is a science that studies the structure of the body and its parts at the supracellular level in statics.

Physiology is a science that studies the processes of vital activity of an organism and its parts in dynamics.

Physiology studies the course of life processes at the level of the whole organism, individual organs and organ systems, as well as at the level of individual cells and molecules. On present stage development of physiology, it again unites with the sciences that once separated from it: biochemistry, molecular biology, cytology and histology.

Differences Between Anatomy and Physiology

Anatomy describes the structures (structure) of the body in static condition.

Physiology describes the processes and phenomena of the body in dynamics (i.e. in motion, in change).

Terminology

Anatomy and physiology use common terms to describe the structure and operation of the body. Most of them are of Latin or Greek origin.

Basic terms ():

Dorsal(dorsal) - located on the dorsal side.

Ventral- located on the ventral side.

Lateral- located on the side.

Medial- located in the middle, occupying a central position. Remember the median from math? She is also in the middle.

Distal- remote from the center of the body. Do you know the word "distance"? One root.

Proximal- close to the center of the body.

Video:The structure of the human body

Cells and tissues

Characteristic of any organism is a certain organization of its structures.
In the process of evolution of multicellular organisms, cell differentiation occurred, i.e. cells of various sizes, shapes, structures and functions appeared. From identically differentiated cells, tissues are formed, the characteristic property of which is structural association, morphological and functional commonality and interaction of cells. Different fabrics are specialized in function. So, a characteristic property of muscle tissue is contractility; nervous tissue - transmission of excitation, etc.

Cytology studies the structure of cells. Histology - the structure of tissues.

Organs

Several tissues combined into a certain complex form an organ (kidney, eye, stomach, etc.). An organ is a part of the body that occupies a permanent position in it, has a certain structure and shape, and performs one or more functions.

The organ consists of several types of tissues, but one of them prevails and determines its main, leading function. In a muscle, for example, this tissue is muscle.

Organs are the working apparatus of the body, specialized to perform complex activities necessary for the existence of a holistic organism. The heart, for example, acts as a pump that pumps blood from the veins to the arteries; kidneys - the function of excreting end products of metabolism and water from the body; bone marrow - the function of hematopoiesis, etc. There are many organs in the human body, but each of them is part of a whole organism.

Organ systems
Several organs that perform a specific function together form an organ system.

Organ systems are anatomical and functional associations of several organs involved in the implementation of any complex type activities.

Organ systems:
1. Digestive (oral cavity, esophagus, stomach, duodenum, small intestine, large intestine, rectum, digestive glands).
2. Respiratory (lungs, airways - mouth, larynx, trachea, bronchi).
3. Circulatory (cardiovascular).
4. Nervous (Central nervous system, outgoing nerve fibers, autonomic nervous system, sensory organs).
5. Excretory (kidneys, bladder).
6. Endocrine (endocrine glands - thyroid gland, parathyroid glands, pancreas (insulin), adrenal glands, gonads, pituitary gland, epiphysis).
7. Musculoskeletal (musculoskeletal - skeleton, muscles attached to it, ligaments).
8. Lymphatic (lymph nodes, lymphatic vessels, thymus - thymus, spleen).
9. Sexual (internal and external genital organs - ovaries (ovum), uterus, vagina, mammary mammary glands, testicles, prostate gland, penis).
10. Immune (red bone marrow at the ends of tubular bones + lymph nodes + spleen + thymus (thymus) - the main organs of the immune system).
11. Integumentary (integuments of the body).

2. General ideas about the processes of growth and development. The main differences between a child's body and an adult

Concept definition

Development- this is the process of complicating the structure and functions of the system over time, increasing its stability and adaptability (adaptive capabilities). Also, development is understood as maturation, the achievement of the full value of a phenomenon. © 2017 Sazonov V.F. 22\02\2017

Development includes the following processes:

1. Height.
2. Differentiation.
3. Formation.

The main differences between a child and an adult:

1) immaturity of the body, its cells, organs and organ systems;
2) reduced growth (reduced body size and body weight);
3) intensive metabolic processes with a predominance of anabolism;
4) intensive growth processes;
5) reduced resistance to harmful environmental factors;
6) improved adaptation (adaptation) to a new environment;
7) underdeveloped reproductive system - children cannot reproduce.

Periodization of age
1. Infancy (up to 1 year).
2. Pre-school period (1-3 years).
3. Preschool (3-7 years).
4. Junior school (7-11-12 years old).
5. Middle school (11-12-15 years old).
6. Senior school (15-17-18 years old).
7. Maturity. At the age of 18, physiological maturity sets in; biological maturity comes from the age of 13 (the ability to have children); full physical maturity in women occurs at the age of 20, and in men at 21-25 years. Civil (social) maturity in our country comes at the age of 18, and in Western countries - at 21. Mental (spiritual) maturity occurs after 40 years.

Age changes, development indicators

1. Body length

This is the most stable indicator characterizing the state of plastic processes in the body and, to some extent, the level of its maturity.

The body length of a newborn child ranges from 46 to 56 cm. It is generally accepted that if a newborn child has a body length of 45 cm or less, then he is premature.

Body length in children of the first year of life is determined taking into account its monthly increase. In the first quarter of life, the monthly increase in body length is 3 cm, in the second - 2.5, in the third - 1.5, in the fourth - 1 cm. The total increase in body length for the 1st year is 25 cm.

During the 2nd and 3rd years of life, the increase in body length is 12-13 and 7-8 cm, respectively.

The body length in children from 2 to 15 years old is also calculated according to the formulas proposed by I. M. Vorontsov, A. V. Mazurin (1977). The length of the body of children at the age of 8 is taken as 130 cm, for each missing year, 7 cm is subtracted from 130 cm, and 5 cm is added for each excess year.

2. Body weight

Body weight, in contrast to length, is a more variable indicator that reacts relatively quickly and changes under the influence of various reasons exo- (external) and endogenous (internal) character. Body weight reflects the degree of development of bone and muscle systems, internal organs, subcutaneous fat.

The body weight of a newborn is on average about 3.5 kg. Newborns weighing 2500 g or less are considered premature or born with intrauterine malnutrition. Children born with a body weight of 4000 g or more are considered large.

As a criterion for the maturity of a newborn child, the weight-growth coefficient is used, which is normally 60-80. If its value is below 60, this indicates in favor of congenital malnutrition, and if it is above 80, congenital paratrophy.

After birth, within 4-5 days of life, the child experiences a loss of body weight within 5-8% of the original, that is, 150-300 g (physiological weight loss). Then the body weight begins to increase and around the 8-10th day reaches the initial level. A weight loss of more than 300 g cannot be considered physiological. The main reason for the physiological drop in body weight is, first of all, the insufficient introduction of water and food in the first days after the birth of the baby. The loss of body weight is important in connection with the release of water through the skin and lungs, as well as the original feces, urine.

It should be taken into account that in children of the 1st year of life, an increase in body length by 1 cm, as a rule, is accompanied by an increase in body weight by 280-320 g. When calculating the body weight of children of the 1st year of life with a birth weight of 2500-3000 g for the initial indicator is taken as 3000 g. The rate of increase in body weight of children after a year slows down significantly.

Body weight in children older than a year is determined by the formulas proposed by I. M. Vorontsov, A. V. Mazurin (1977).
The body weight of a child at 5 years old is taken as 19 kg; for each missing year up to 5 years, 2 kg is deducted, and 3 kg is added for each subsequent year. To assess the body weight of children of preschool and school age, two-dimensional centile scales of body weight at different body lengths, based on the assessment of body weight by body length within age and sex groups, are increasingly used as age norms.

3. Head circumference

The head circumference of a child at birth is on average 34-36 cm.

It increases especially intensively in the first year of life, amounting to 46-47 cm by the year. In the first 3 months of life, the monthly increase in head circumference is 2 cm, at the age of 3-6 months - 1 cm, during the second half of life - 0.5 cm .

By the age of 6, the head circumference increases to 50.5-51 cm, by the age of 14-15 - up to 53-56 cm. In boys, its size is slightly larger than in girls.
The size of the head circumference is determined by the formulas of I. M. Vorontsov, A. V. Mazurin (1985). 1. Children of the first year of life: the head circumference of a 6-month-old child is taken as 43 cm, for each missing month from 43, subtract 1.5 cm, for each subsequent month add 0.5 cm.

2. Children from 2 to 15 years old: head circumference at 5 years old is taken as 50 cm; for each missing year, subtract 1 cm, and for each excess year, add 0.6 cm.

Monitoring changes in the head circumference of children in the first three years of life is an important component of medical activity in assessing physical development child. Changes in head circumference reflect the general patterns of the biological development of the child, in particular the cerebral type of growth, as well as the development of a number of pathological conditions (micro- and hydrocephalus).

Why is the circumference of a child's head so important? The fact is that a child is born already with a full set of neurons, the same as in an adult. But the weight of his brain is only 1/4 of the brain of an adult. It can be concluded that the increase in brain weight occurs due to the formation of new connections between neurons, as well as due to an increase in the number of glial cells. Head growth reflects these important brain development processes.

4. Chest circumference

Breast circumference at birth averages 32-35 cm.

In the first year of life, it increases monthly by 1.2-1.3 cm, amounting to 47-48 cm by the year.

By the age of 5, the chest circumference increases to 55 cm, by 10 - up to 65 cm.

The circumference of the chest is also determined by the formulas proposed by I. M. Vorontsov, A. V. Mazurin (1985).
1. Children of the 1st year of life: the circumference of the chest of a 6-month-old child is taken as 45 cm, for each missing month, 2 cm should be subtracted from 45, and 0.5 cm should be added for each subsequent month.
2. Children from 2 to 15 years old: chest circumference at 10 years old is taken as 63 cm, for children under 10 years old, the formula 63 - 1.5 (10 - n) is used, for children over 10 years old - 63 + 3 cm (n - 10), where n is the number of years the child is. For a more accurate assessment of the size of the circumference of the chest, centile tables are used, based on the assessment of the circumference of the chest along the length of the body within the age and sex group.

Chest circumference is an important indicator that reflects the degree of development of the chest, muscular system, subcutaneous fat layer on the chest, which closely correlates with the functional indicators of the respiratory system.

5. Body surface

The surface of the body is one of the most important indicators of physical development. This sign helps to assess not only the morphological, but also the functional state of the organism. It has a close correlation with a number of physiological functions of the body. Indicators of the functional state of blood circulation, external respiration, kidneys are closely related to such an indicator as the surface of the body. Individual medications should also be prescribed according to this factor.

The surface of the body is usually calculated according to the nomogram, taking into account the length and weight of the body. It is known that the surface area of ​​a child's body per 1 kg of its mass is three times greater in a newborn and twice as large in a one-year-old than in an adult.

6. Puberty

Assessing the degree of puberty is important in determining a child's developmental level.

The degree of a child's puberty is one of the most reliable indicators of biological maturity. In everyday practice, it is most often assessed by the severity of secondary sexual characteristics.

In girls, these are pubic (P) and axillary (A) hair growth, breast development (Ma), and age of first menstruation (Me).

In boys, in addition to the growth of hair on the pubis and in the armpits, the voice mutation (V), facial hair (F) and the formation of the Adam's apple (L) are evaluated.

Puberty assessment should be done by a doctor, not a teacher. When assessing the degree of puberty, it is recommended to expose children, especially girls, in parts due to an increased sense of shame. If necessary, the child should be completely undressed.

Generally accepted schemes for assessing the degree of development of secondary sexual characteristics in children by body regions:

Development of pubic hair: no hair - P0; single hair - P1; hair on the central part of the pubis is thicker, longer - P2; hair on the entire triangle of the pubis is long, curly, thick - P3; the hair is distributed over the entire pubic area, passes to the thighs and extends along the white line of the abdomen - P4t.
The development of hair in the armpit: no hair - A0; single hair - A1; hair is sparse in the central part of the cavity - A2; thick hair, curly throughout the cavity - A3.
Development of the mammary glands: glands do not protrude above the surface of the chest - Ma0; the glands protrude somewhat, the areola together with the nipple forms a single cone - Ma1; the glands protrude significantly, together with the nipple and areola, they are cone-shaped - Ma2; the body of the gland takes a rounded shape, the nipples rise above the areola - Ma3.
Development of facial hair: no hair growth - F0; beginning hair growth above the upper lip - F1; coarse hair above the upper lip and on the chin - F2; widespread hair growth above the upper lip and on the chin with a tendency to merge, the beginning of the growth of sideburns - F3; fusion of hair growth zones above the lip and in the chin area, pronounced growth of sideburns - F4.
Voice timbre change: children's voice - V0; mutation (breaking) of the voice - V1; male voice timbre - V2.

The growth of the thyroid cartilage (Adam's apple): no signs of growth - L0; beginning protrusion of cartilage - L1; distinct protrusion (Adam's apple) - L2.

When evaluating the degree of puberty in children, the main attention is paid to the severity of Ma, Me, P indicators as more stable. Other indicators (A, F, L) are more variable and less reliable. The state of sexual development is usually denoted by the general formula: A, P, Ma, Me, which respectively indicate the stages of maturation of each sign and the age of the onset of the first menstruation in girls; e.g. A2, P3, Ma3, Me13. When assessing the degree of puberty according to the development of secondary sexual characteristics, a deviation from the average age norms is considered to be ahead or behind with shifts in the indicators of the sexual formula for a year or more.

7. Physical development (assessment methods)

The physical development of a child is one of the most important criteria in assessing his state of health.
From a large number morphological and functional characteristics to assess the physical development of children and adolescents at each age, various criteria are used.

In addition to the features of the morphofunctional state of the body, when assessing physical development, it is now customary to use such a concept as biological age.

It is known that individual indicators of the biological development of children in different age periods can be leading or auxiliary.

For children of primary school age, the leading indicators of biological development are the number of permanent teeth, skeletal maturity, and body length.

When assessing the level of biological development of children of middle and older age, the degree of severity of secondary sexual characteristics, ossification of bones, the nature of growth processes are of greater importance, while body length and the development of the dental system are of lesser importance.

To assess the physical development of children, various methods are used: the method of indices, sigma deviations, evaluation tables, regression scales and, more recently, the centile method. Anthropometric indices are the ratio of individual anthropometric features, expressed as formulas. The inaccuracy and fallacy of using indices to assess the physical development of a growing organism has been proved, since as a result of age morphology studies it has been shown that individual dimensions of a child's body increase unevenly (developmental heterochrony), which means that anthropometric indicators change disproportionately. The method of sigma deviations and regression scales, which are currently widely used to assess the physical development of children, are based on the assumption that the sample under study corresponds to the law of normal distribution. Meanwhile, the study of the form of distribution of a number of anthropometric characteristics (body weight, chest circumference, muscle strength of the arms, etc.) indicates the asymmetry of their distribution, more often right-sided. Because of this, the boundaries of sigma deviations can be artificially overestimated or underestimated, distorting the true nature of the assessment.

centile methodassessment of physical development

These shortcomings are devoid of based on nonparametric statistical analysiscentile method, which has recently been increasingly used in the pediatric literature. Since the centile method is not limited by the nature of the distribution, it is acceptable for assessing any indicators. The method is easy to use, due to the fact that when using centile tables or graphs, any calculations are excluded. Two-dimensional centile scales - "body length - body weight", "body length - chest circumference", in which the values ​​​​of body weight and chest circumference are calculated for the proper body length, make it possible to judge the harmony of development.

Usually, the 3rd, 10th, 25th, 50th, 75th, 90th, 97th centiles are used to characterize the sample. 3rd centile - this is the value of the indicator, less than which it is observed in 3% of the sample members; the value of the indicator is less than the 10th centile - in 10% of the sample members, etc. The gaps between the centiles are named centile corridors. With an individual assessment of indicators of physical development, the level of a trait is determined by its position in one of the 7 centile corridors. Indicators that fell into the 4th-5th corridors (25th-75th centiles) should be considered average, in the 3rd (10th-25th centiles) - below average, in the 6th (75th-90th centiles) ) - above average, in the 2nd (3-10th centile) - low, in the 7th (90-97th centile) - high, in the 1st (up to 3rd centile) - very low, in the 8th (above the 97th centile) - very high.

harmonious is a physical development in which body weight and chest circumference correspond to body length, that is, they fall into the 4th-5th centile corridors (25th-75th centiles).

disharmonious physical development is considered in which body weight and chest circumference lag behind due (3rd corridor, 10-25th centiles) or more than due (6th corridor, 75-90th centiles) due to increased fat deposition.

Sharply disharmonious should be considered physical development, in which body weight and chest circumference lag behind due (2nd corridor, 3-10th centile) or exceed the proper value (7th corridor, 90-97th centile) due to increased fat deposition.

"Square of harmony" (Auxiliary table for assessing physical development)

		Percentage (Centile) Series
		3,00%	10,00%	25,00%	50,00%	75,00%	90,00%	97,00%
Body weight by age	97,00%						Harmonious development ahead of age
	90,00%
	75,00%			Harmonious development according to age
	50,00%
	25,00%
	10,00%	Harmonious development below age norms
	3,00%
Body length by age

Currently, the physical development of the child is assessed in a certain sequence.

Correspondence of the calendar age to the level of biological development is established. The level of biological development corresponds to the calendar age, if most of the indicators of biological development are within the average age limits (M±b). If the indicators of biological development lag behind the calendar age or are ahead of it, this indicates a delay (retardation) or acceleration (acceleration) of the rate of biological development.

After determining the correspondence of the biological age to the passport one, the morphofunctional state of the organism is assessed. Centile tables are used to assess anthropometric indicators depending on age and gender.

The use of centile tables allows us to define physical development as medium, above or below average, high or low, as well as harmonious, disharmonious, sharply disharmonious. The allocation to the group of children with deviations in physical development (disharmonious, sharply disharmonious) is due to the fact that they often have disorders of the cardiovascular, endocrine, nervous and other systems, on this basis they are subject to a special in-depth examination. In children with disharmonious and sharply disharmonious development, functional indicators, as a rule, are below the age norm. For such children, taking into account the cause of deviations in physical development from age indicators, individual plans for recovery and treatment are developed.

3. The main stages of human development - fertilization, embryonic and fetal periods. Critical periods of development of the embryo. Causes of congenital deformities and defects

Ontogenesis is the process of development of an organism from the moment of conception (formation of a zygote) to death.

Ontogeny is divided into prenatal development (prenatal - from conception to birth) and postnatal (postpartum).

Fertilization is the fusion of male and female germ cells, resulting in a zygote (fertilized egg) with a diploid (double) set of chromosomes.

Fertilization occurs in the upper third of the woman's oviduct. Best conditions for this, there are usually within 12 hours after the release of the egg from the ovary (ovulation). Numerous spermatozoa approach the egg, surround it, come into contact with its membrane. However, only one penetrates the egg, after which a dense fertilization shell forms around the egg, preventing the penetration of other spermatozoa. As a result of the fusion of two nuclei with haploid sets of chromosomes, a diploid zygote is formed. This is a cell that is actually a single-celled organism of a new daughter generation). It is capable of developing into a full-fledged multicellular human body. But can she be called a full-fledged person? A person and a human fertilized egg have 46 chromosomes, i.e. 23 pairs is a complete diploid set of human chromosomes.

prenatal period lasts from conception to birth and consists of two phases: embryonic (first 2 months) And fetal (3-9 months). In humans, the intrauterine period lasts an average of 280 days, or 10 lunar months(approximately 9 calendar days). In obstetric practice germ (embryo) called a developing organism during the first two months of intrauterine life, and from 3 to 9 months - fruit (foetus) Therefore, this period of development is called fetal, or fetal.

Fertilization

Fertilization most often takes place in the expansion of the female oviduct (in the fallopian tubes). Due to their exceptional mobility and activity, spermatozoa, which have poured into the vagina as part of the sperm, move into the uterine cavity, pass through it to the oviducts, and in one of them meet a mature egg. Here the sperm enters the egg and fertilizes it. The spermatozoon introduces into the egg the hereditary properties characteristic of the male body, contained in a packaged form in the chromosomes of the male germ cell.

Splitting up

Cleavage is the process of cell division into which the zygote enters. The size of the resulting cells does not increase in this case, because. they do not have time to grow, but only divide.

Once a fertilized egg starts dividing, it is called an embryo. The zygote is activated; its fragmentation begins. Crushing is slow. On the 4th day, the embryo consists of 8-12 blastomeres (blastomeres are cells formed as a result of crushing, they are smaller and smaller after the next division).

Drawing: The initial stages of embryogenesis in mammals

I - stage of 2 blastomeres; II - stage of 4 blastomeres; III - morula; IV–V – trophoblast formation; VI - blastocyst and the first phase of gastrulation:
1 - dark blastomeres; 2 - light blastomeres; 3 - trophoblast;
4 - embryoblast; 5 - ectoderm; 6 - endoderm.

morula

Morula ("mulberry") is a group of blastomeres formed as a result of crushing the zygote.

Blastula

Blastula (vesicle) is a single-layer embryo. Cells are located in it in one layer.

The blastula is formed from the morula due to the fact that a cavity appears in it. The cavity is called primary body cavity. It contains liquid. In the future, the cavity is filled with internal organs and turns into the abdominal and chest cavities.

gastrula
The gastrula is a two-layer embryo. The cells in this "germ vesicle" form walls in two layers.

Gastrulation (the formation of a two-layer embryo) is the next stage of embryonic development. The outer layer of the gastrula is called ectoderm. He further forms the skin of the body and the nervous system. It is very important to remember that nervous system comes fromectoderm (outer germ layer, first), therefore, it is closer in its characteristics to the skin than to such internal organs like the stomach and intestines. The inner layer is called endoderm. It gives rise to the digestive system and the respiratory system. It is also important to remember that the respiratory and digestive systems are connected by a common origin.The gill slits in fish are openings in the intestine, and the lungs are outgrowths of the intestine.

Neirula

A neurula is an embryo at the stage of formation of the neural tube.

The vesicle of the gastrula is drawn out, and a groove forms on top. This groove from the depressed ectoderm folds into a tube - this is the neural tube. A cord is formed under it - this is a chord. Over time, bone tissue will form around it and the spine will turn out. Notochord remnants can be found between the vertebrae of the fish. Below the chord, the endoderm extends into the intestinal tube.

The complex of axial organs is the neural tube, notochord, and intestinal tube.

Histo- and organogenesis
After neurulation, the next stage in the development of the embryo begins - histogenesis and organogenesis, i.e. the formation of tissues ("histo-" is a tissue) and organs. At this stage, the third germ layer is formed - mesoderm.
It should be noted that since the formation of organs and the nervous system, the embryo is called fruit.

The fetus, which develops in the uterus, is located in special membranes that form, as it were, a bag filled with amniotic fluid. These waters allow the fetus to move freely in the bag, protect the fetus from external damage and infections, and also contribute to the normal course of childbirth.

Critical periods of development

A normal pregnancy lasts 9 months. During this time, a child weighing about 3 kg or more and 50-52 cm tall develops from a fertilized egg of microscopic size.
The most damaged stages of embryonic development refer to the time when their connection with the mother's body is formed - this is the stage implantation(introduction of the embryo into the wall of the uterus) and stage placenta formation.
1. First critical period in the development of the human embryo refers to the 1st and the beginning of the 2nd week after conception.
2. Second critical period - this is the 3-5th week of development. The formation of individual organs of the human embryo is associated with this period.

During these periods, along with increased embryonic mortality, local (local) deformities and malformations occur.

3. Third critical period - this is the formation of a child's place (placenta), which occurs in a person between the 8th and 11th weeks of embryo development. During this period, the fetus may show general anomalies, including a number of congenital diseases.
During critical periods of development, the sensitivity of the embryo to an insufficient supply of oxygen and nutrients, to cooling, overheating, and ionizing radiation is increased. The ingestion of certain substances harmful to it (drugs, alcohol and other toxic substances formed in the body during mother's illnesses, etc.) into the blood can cause serious disturbances in the development of the child. Which? Slowdown or arrest of development, the appearance of various deformities, high mortality of embryos.
It is noted that starvation or lack of components such as vitamins and amino acids in the mother's food lead to the death of the embryos or to anomalies in their development.
Infectious diseases of the mother pose a serious danger to the development of the fetus. The effect on the fetus of such viral diseases as measles, smallpox, rubella, influenza, poliomyelitis, mumps, is manifested mainly in the first months pregnancy.
Another group of diseases, such as dysentery, cholera, anthrax, tuberculosis, syphilis, malaria, affects the fetus mostly in the second and last third of pregnancy.
One of the factors that has a particularly harmful and strong effect on a developing organism is ionizing radiation(radiation).

Indirect, indirect, the effect of radiation on the fetus (through the mother's body) is associated with general violations of the physiological functions of the mother, as well as with changes that have occurred in the tissues and vessels of the placenta. Cells are most sensitive to radiation nervous system and hematopoietic organs of the embryo.
Thus, the embryo is extremely sensitive to changes in environmental conditions, primarily to changes that occur in the mother's body.
Often disturbed embryonic development in cases where the father or mother suffers from alcoholism. Children of chronic alcoholics are often born with mental retardation. The most characteristic thing is that babies behave restlessly, the excitability of their nervous system is increased. Alcohol has a detrimental effect on the germ cells. Thus, it harms future offspring both before fertilization and during the development of the embryo and fetus.

4. Periods of postnatal development. Factors influencing development. Acceleration.
The body of a child after birth is constantly growing and developing. In the process of ontogenesis, specific anatomical and functional features arise, which are called age. Accordingly, the human life cycle can be divided into periods, or stages. There are no clearly defined boundaries between these periods, and they are largely arbitrary. However, the allocation of such periods is necessary, since children of the same calendar (passport), but of different biological age, react differently to sports and work loads; at the same time, their working capacity may be greater or lesser, which is important for solving a number of practical issues of organizing the educational process at school.
The postnatal period of development is the period of life from birth to death.

Periodization of age in the postnatal period:

Infancy (up to 1 year);
- pre-preschool (1-3 years);
- preschool (3-7 years);
- junior school (7-11-12 years old);
- secondary school (11-12-15 years old);
- senior school (15-17-18 years old);
- maturity (18-25)

At the age of 18, physiological maturity sets in.

Biological maturity - the ability to have offspring (from the age of 13). Full physical maturity occurs at the age of 20, and for men - at 21-25 years. Physical maturity is evidenced by the end of growth and ossification of the skeleton.

The criteria for such periodization included a set of features - the size of the body and organs, weight, ossification of the skeleton, teething, the development of endocrine glands, the degree of puberty, muscle strength.
The child's organism develops in the specific conditions of the environment, which continuously acts on the organism and largely determines the course of its development. The course of morphological and functional rearrangements of the child's body in different age periods is influenced by both genetic and environmental factors. Depending on the specific environmental conditions, the development process can be accelerated or slowed down, and its age periods can come earlier or later and have different durations. Qualitative originality of the child's body, changing at each stage individual development, manifests itself in everything, and above all in the nature of its interaction with environment. Under the influence of the external environment, especially its social side, certain hereditary qualities can be realized and developed, if the environment contributes to this, or, conversely, suppressed.

Acceleration

Acceleration (acceleration) is the accelerated growth of a whole generation of people over any historical period of time.

Acceleration is the acceleration of age-related development by shifting morphogenesis to earlier stages of ontogenesis.

There are two types of acceleration - epochal (secular trend, i.e. "the trend of the century", it is inherent in the entire current generation) and intragroup, or individual - this is the accelerated development of individual children and adolescents in certain age groups.

Retardation is a delay in physical development and the formation of functional systems of the body. It is the opposite of acceleration.

The term "acceleration" (from the Latin word acceleratio - acceleration) was proposed by the German doctor Koch in 1935. The essence of acceleration is in an earlier achievement of certain stages of biological development and completion of the maturation of the organism.

There is evidence that due to intrauterine fetal acceleration, full-fledged mature newborns with a weight of over 2500 g and a body length of more than 47 cm can be born at gestational ages of less than 36 weeks.

A doubling of body weight in infants (compared to birth weight) now occurs by 4, and not by 6 months, as was the case in the early twentieth century. If the "cross" of the chest and head circumference values ​​at the beginning of the 20th century was recorded by the 10-12th month, in 1937 - already at the 6th month, in 1949 - at the 5th, then at present the chest circumference becomes equal to the circumference of the head between the 2nd and 3rd months of life. Modern infants have earlier teething. By the year of life in modern children, the body length is 5-6 cm, and the weight is 2.0-2.5 kg higher than they were at the beginning of the century. The circumference of the chest increased by 2.0-2.5 cm, and the head - by 1.0-1.5 cm.
Acceleration of development is also noticeable in children of toddler and preschool age. The development of modern 7-year-old children corresponds to 8.5-9 years in children late XIX century.
On average, in preschool children, the body length has increased by 10-12 cm over 100 years. Permanent teeth also erupt earlier.

IN preschool age acceleration can be harmonious. This is the name given to those cases when there is a correspondence of the level of development not only in the mental and somatic spheres, but also in relation to the development of individual mental functions. But harmonic acceleration is extremely rare. More often, along with the acceleration of mental and physical development, pronounced somatovegetative dysfunctions (at an early age) and endocrine disorders (at an older age) are noted. In the mental sphere itself, disharmony is observed, manifested by the acceleration of the development of some mental functions (for example, speech) and the immaturity of others (for example, motor skills and social skills), and sometimes somatic (bodily) acceleration is ahead of mental. In all these cases, disharmonious acceleration is meant. A typical example of disharmonious acceleration is a complex clinical picture, reflecting a combination of signs of acceleration and infantilism ("childhood").

Acceleration in early childhood has a number of features. Acceleration mental development compared to the age norm even for0.5-1 year always makes the child "difficult", vulnerable to stress, especially to psychological situations that are not always caught by adults.

During puberty, which begins in modern girls at 10-12 years old, and in boys at 12-14 years old, the growth rate increases greatly. Earlier comes puberty.

In large cities, puberty of adolescents occurs somewhat earlier than in rural areas. The rate of acceleration of rural children is also lower than in cities.

In the course of acceleration, the average height of an adult for each decade increases by about 0.7-1.2 cm, and weight - by 1.5-2.5 kg.

Concerns have been raised that the acceleration-related shortening of the growth period and the acceleration of puberty may lead to earlier wilting and a shorter lifespan. These fears were not confirmed. The life expectancy of modern people has increased, working capacity is preserved for a longer time. In women, menopause has moved to the 48-50th year of life (at the beginning of the 20th century, menstruation stopped at 43-45 years). Consequently, the childbearing period has lengthened, which can also be attributed to the manifestations of acceleration. In connection with the later onset of menopause and senile changes, metabolic diseases, atherosclerosis and cancer "moved" to an older age. It is believed that the milder course of diseases such as scarlet fever and diphtheria is associated not only with the success of medicine, but also with acceleration due to a change in the reactivity of the body. As a result of acceleration, the reactivity of young children acquired features that were previously characteristic of older children (adolescents).
In connection with the acceleration of physical and puberty, the problems associated with early sexual activity and early marriages have acquired particular importance.

The main manifestations of acceleration according to Yu. E. Veltishchev and G. S. Gracheva (1979):

• increased length and body weight of newborns in comparison with similar values ​​of the 20-30s of our century; at present, the growth of one-year-old children is on average 4-5 cm, and body weight is 1-2 kg more than 50 years ago
• earlier eruption of the first teeth, their change to permanent ones occurs 1-2 years earlier than in children of the last century;
• earlier appearance of ossification nuclei in boys and girls, and in general, ossification of the skeleton in girls ends 3 years, and in boys - 2 years earlier than in the 20-30s of our century;
• an earlier increase in the length and body weight of children of preschool and school age, and the older the child, the more it differs in body size from children of the last century;
• an increase in body length in the current generation by 8-10 cm compared to the previous one;
• the sexual development of boys and girls ends 1.5-2 years earlier than at the beginning of the 20th century; for every 10 years, the onset of menstruation in girls accelerates by 4-6 months.

True acceleration is accompanied by an increase in life expectancy and the reproductive period of the adult population.(I. M. Vorontsov, A. V. Mazurin, 1985).

On the basis of taking into account the ratios of anthropometric indicators and the level of biological maturity, harmonic and disharmonic types of acceleration are distinguished. The harmonic type includes those children whose anthropometric indicators and the level of biological maturity are higher than the average values ​​for this age group, the disharmonic type includes children who have increased body growth in length without simultaneous acceleration of sexual development or early puberty without increased growth in length.

Theories of the causes of acceleration

1. Physical and chemical:
1) heliogenic (the influence of solar radiation), it was put forward by the German school doctor E. Koch, who introduced it in the early 30s. the term "acceleration";
2) radio wave, magnetic (influence magnetic field);
3) cosmic radiation;
4) an increased concentration of carbon dioxide caused by an increase in production;

5) lengthening of daylight hours due to artificial lighting of the premises.

2. Theories of individual factors of living conditions:
1) alimentary (improvement of nutrition);
2) nutraceutical (improving the structure of nutrition);

3) the influence of hormonal growth stimulants supplied with the meat of animals grown on these stimulants (hormones have been used to accelerate the growth of animals since the 1960s);
4) increased flow of information, increased sensory impact on the psyche.

3. Genetic:
1) cyclic biological changes;
2) heterosis (mixing of populations).

4. Theories of a complex of factors of living conditions:
1) urban (urban) influence;
2) a complex of socio-biological factors.

Thus, a generally accepted point of view has not yet been formed regarding the causes of acceleration. Many hypotheses have been put forward. Most scientists consider nutritional change to be the determining factor in all developmental shifts. This is due to an increase in the amount of consumed high-grade proteins and natural fats per capita.

The acceleration of the physical development of the child requires the rationalization of labor activity and physical activity. In connection with acceleration, the regional standards that we use to assess the physical development of children should be periodically reviewed.

Deceleration

The acceleration process has begun to decline, the average body size of a new generation of people is decreasing again.

Deceleration is the process of canceling acceleration, i.e. slowing down the processes of biological maturation of all organs and systems of the body. Deceleration is currently replacing acceleration.

currently planned deceleration is a consequence of the influence of a complex of natural and social factors on biology modern man, as well as acceleration.

Over the past 20 years, the following changes in the physical development of all segments of the population and all age groups have been recorded: the circumference of the chest has decreased, muscle strength has sharply decreased. But there are two extreme trends in body weight changes: insufficient, leading to malnutrition and dystrophy; and excess leading to obesity. All this is regarded as a negative phenomenon.

Reasons for deceleration:

Environmental factor;

Gene mutations;

Deterioration of social living conditions and, above all, the structure of nutrition;

All the same growth information technologies, which began to lead to overexcitation of the nervous system and, in response to this, to its inhibition;

Decreased physical activity.

A reflex is a response of the body to irritation from the external or internal environment, carried out through the nervous system (CNS) and has an adaptive value.

For example, irritation of the skin of the plantar part of the foot in humans causes reflex flexion of the foot and toes. This is the plantar reflex. Touching the lips of an infant causes sucking movements in him - a sucking reflex. Illumination with bright light of the eye causes constriction of the pupil - the pupillary reflex.
Thanks to reflex activity, the body is able to quickly respond to various changes in the external or internal environment.
Reflex reactions are very diverse. They can be conditional or unconditional.
In all organs of the body there are nerve endings that are sensitive to stimuli. These are receptors. Receptors are different in structure, location and function.
The executive organ, the activity of which changes as a result of a reflex, is called an effector. The path along which impulses pass from the receptor to the executive organ is called the reflex arc. This is the material basis of the reflex.
Speaking about the reflex arc, it must be borne in mind that any reflex act is carried out with the participation of a large number of neurons. A two- or three-neuron reflex arc is just a circuit. In fact, the reflex occurs when not one, but many receptors located in one or another area of ​​the body are stimulated. Nerve impulses during any reflex act, arriving in the central nervous system, are widely distributed in it, reaching its different departments. Therefore, it is more correct to say that the structural basis of reflex reactions is made up of neural circuits of centripetal, central, or intercalary, and centrifugal neurons.
Due to the fact that any reflex act involves groups of neurons that transmit impulses to different parts of the brain, the entire body is involved in the reflex reaction. And indeed, if you are suddenly pricked with a pin in your hand, you will immediately pull it back. This is a reflex reaction. But this will not only reduce the muscles of the hand. Breathing, the activity of the cardiovascular system will change. You will respond with words to an unexpected injection. Almost the entire body was involved in the response. A reflex act is a coordinated reaction of the whole organism.

7. Differences between conditioned (acquired) reflexes and unconditioned ones. Conditions for the formation of conditioned reflexes

Table. Differences between unconditioned and conditioned reflexes

№	reflexes
	Unconditional	Conditional
1	Congenital	Acquired
2	Inherited	Are produced
3	Species	Individual
4	Nerve connections are permanent	Nerve connections are temporary
5	Stronger	Weaker
6	Faster	Slower
7	Difficult to slow down	Easily braked

In the implementation of unconditioned reflexes, mainly the subcortical parts of the central nervous system take part (we also call them "lower nerve centers" . Therefore, these reflexes can be carried out in higher animals even after the removal of the cerebral cortex. However, it was possible to show that after the removal of the cerebral cortex, the nature of the course of unconditioned reflex reactions changes. This gave grounds to speak of a cortical representation of the unconditioned reflex.
The number of unconditioned reflexes is relatively small. They by themselves cannot ensure the adaptation of the body to the constantly changing conditions of life. A great many conditioned reflexes are developed during the life of the organism, many of them lose their biological significance when the conditions of existence change, they fade away, new conditioned reflexes are developed. This enables animals and humans to best adapt to changing environmental conditions.
Conditioned reflexes are developed on the basis of unconditioned ones. First of all, you need a conditioned stimulus, or signal. A conditioned stimulus can be any stimulus from the external environment or a certain change in the internal state of the organism. If you feed a dog every day at a certain hour, then by this hour, even before feeding, the secretion of gastric juice begins. Time has become the conditioned stimulus here. Conditioned reflexes for a while are developed in a person subject to the regime of work, eating at the same time, and a constant time for going to bed.
In order to develop a conditioned reflex, the conditioned stimulus must be reinforced with an unconditioned stimulus, i.e. one that evokes an unconditioned reflex. The ringing of knives in a nightingale will cause salivation in a person only if this ringing has been reinforced by food one or more times. The ringing of knives and forks in our case is a conditioned stimulus, and the unconditioned stimulus that causes a salivary unconditioned reflex is food.
In the formation of a conditioned reflex, the conditioned stimulus must precede the action of the unconditioned stimulus.

8. Patterns of the processes of excitation and inhibition in the central nervous system. Their role in the activity of the nervous system. Mediators of excitation and inhibition. Inhibition of conditioned reflexes and its types

According to the ideas of IP Pavlov, the formation of a conditioned reflex is associated with the establishment of a temporary connection between two groups of cortical cells - between those that perceive conditioned and those that perceive unconditioned stimulation.
Under the action of a conditioned stimulus, excitation occurs in the corresponding perceiving zone of the cerebral hemispheres. When the conditioned stimulus is reinforced with an unconditioned stimulus, a second, stronger focus of excitation appears in the corresponding zone of the cerebral hemispheres, which, apparently, takes on the character of a dominant focus. Due to the attraction of excitation from the focus of lesser strength to the focus of greater strength, the nerve pathway is cut, the summation of excitation occurs. A temporary neural connection is formed between the two foci of excitation. This connection becomes stronger, the more often both parts of the cortex are simultaneously excited. After several combinations, the connection is so strong that under the action of only one conditioned stimulus, excitation also occurs in the second focus.
Thus, due to the establishment of a temporal connection, a conditioned stimulus initially indifferent to the organism becomes a signal of a certain innate activity. If the dog hears the bell for the first time, he will give a general orienting reaction to it, but will not salivate. Let's back up the sounding bell with food. In this case, two foci of excitation will appear in the cerebral cortex - one in the auditory zone, and the other in the food center. After several reinforcements of the call with food in the cerebral cortex, a temporary connection arises between the two foci of excitation.
Conditioned reflexes can be inhibited. This happens in those cases when in the cortex of the cerebral hemispheres, during the implementation of the conditioned reflex, a new, sufficiently strong focus of excitation arises, which is not associated with this conditioned reflex.
Distinguish:
external inhibition (unconditional);
internal (conditional).

External
internal
Unconditioned brake - a new biologically strong signal that inhibits the implementation of the reflex
Fading inhibition with repeated repetition of SD without reinforcement, the reflex fades
Estimated; a new stimulus precedes the stimulation of the reflex
Differential - when a similar stimulus is repeated without reinforcement, the reflex fades
Limiting inhibition (super-strong stimuli inhibit the implementation of the reflex)
delayed
Fatigue - inhibits the implementation of the reflex
Conditional brake - when a combination of stimuli is not given reinforcement, one stimulus serves as a brake for another

In the central nervous system, unilateral conduction of excitation is noted. This is due to the peculiarities of synapses, the transfer of excitation in them is possible only in one direction - from the nerve ending, where the mediator is released upon excitation, to the postsynaptic membrane. In the opposite direction, the excitatory postsynaptic potential does not propagate.
What is the mechanism of transmission of excitation in synapses? Coming nerve impulse into the presynaptic ending is accompanied by a synchronous release of the neurotransmitter into the synaptic cleft from synaptic vesicles located in close proximity to it. A series of impulses comes to the presynaptic ending, their frequency increases with an increase in the strength of the stimulus, leading to an increase in the release of the mediator into the synaptic cleft. The dimensions of the synaptic cleft are very small, and the neurotransmitter, quickly reaching the postsynaptic membrane, interacts with its substance. As a result of this interaction, the structure of the postsynaptic membrane temporarily changes, its permeability for sodium ions increases, which leads to the movement of ions and, as a result, the emergence of an excitatory postsynaptic potential. When this potential reaches a certain value, a propagating excitation occurs - an action potential.
After a few milliseconds, the neurotransmitter is destroyed by special enzymes.
At present, the vast majority of neurophysiologists recognize the existence in the spinal cord and in various parts of the brain of two qualitatively different types of synapses - excitatory and inhibitory.
Under the influence of an impulse coming along the axon of an inhibitory neuron, a mediator is released into the synaptic cleft, which causes specific changes in the postsynaptic membrane. The inhibitory mediator, interacting with the substance of the postsynaptic membrane, increases its permeability to potassium and chloride ions. Inside the cell, the relative number of anions increases. The result is not a decrease in the internal charge of the membrane, but an increase in the internal charge of the postsynaptic membrane. It is hyperpolated. This leads to the appearance of an inhibitory postsynatic potential, resulting in inhibition.

9. Irradiation and induction

Excitation impulses that have arisen when a particular receptor is irritated, entering the central nervous system, spread to its neighboring sections. This spread of excitation in the CNS is called irradiation. The irradiation is the wider, the stronger and longer the applied irritation.
Irradiation is possible due to numerous processes in centripetal nerve cells and intercalary neurons that connect different parts of the nervous system. Irradiation is well expressed in children, especially at an early age. Children of preschool and primary school age, when a beautiful toy appears, open their mouths, jump, laugh with pleasure.
In the process of differentiation of stimuli, inhibition limits the irradiation of excitation. As a result, excitation is concentrated in certain groups of neurons. Now, around the excited neurons, excitability drops, and they come into a state of inhibition. This is the phenomenon of simultaneous negative induction. The concentration of attention can be seen as a weakening of irradiation and an increase in induction. Dissipation of attention can also be considered as a result of inductive inhibition induced by a new focus of excitation as a result of the emerging orienting reaction. In neurons that have been excited, after excitation, inhibition occurs and, conversely, after inhibition, excitation occurs in the same neurons. This is sequential induction. Sequential induction can explain the increased motor activity of schoolchildren during breaks after prolonged inhibition in the motor area of ​​the cerebral cortex during the lesson. Rest at recess should be active and mobile.

The eye is located in the deepening of the skull - the eye socket. Behind and from the sides, it is protected from external influences by the bony walls of the orbit, and in front - by the eyelids. The inner surface of the eyelids and the anterior part of the eyeball, with the exception of the cornea, is covered with a mucous membrane - the conjunctiva. At the outer edge of the orbit is the lacrimal gland, which secretes a fluid that protects the eye from drying out. Blinking of the eyelids contributes to the even distribution of tear fluid over the surface of the eye.
The shape of the eye is spherical. The growth of the eyeball continues after birth. It grows most intensively in the first five years of life, less intensively - 9-12 years.
The eyeball consists of three shells - outer, middle and inner.
The outer shell of the eye is the sclera. This is a dense opaque white fabric, about 1 mm thick. In the anterior part, it passes into a transparent cornea.
The lens is a transparent elastic formation that has the shape of a biconvex lens. The lens is covered with a transparent bag; along its entire edge, thin, but very elastic fibers stretch to the ciliary body. They are strongly stretched and hold the lens in a stretched state.
In the center of the iris there is a round hole - the pupil. The size of the pupil changes, causing more or less light to enter the eye.
The tissue of the iris contains a special coloring matter - melanin. Depending on the amount of this pigment, the color of the iris ranges from gray and blue to brown, almost black. The color of the iris determines the color of the eyes. The inner surface of the eye is lined with a thin (0.2-0.3 mm), very complex shell - the retina. It contains light-sensitive cells, named rods and cones because of their shape. The nerve fibers from these cells come together to form the optic nerve, which travels to the brain.
The child in the first months after birth confuses the top and bottom of the object.
The eye is able to adapt to a clear vision of objects located at different distances from it. This ability of the eye is called accommodation.
Accommodation of the eye begins already when the object is at a distance of about 65 m from the eye. A distinctly pronounced contraction of the ciliary muscle begins at a distance of 10 or even 5 m from the object. If the object continues to approach the eye, accommodation becomes more and more intense and, finally, a clear vision of the object becomes impossible. The smallest distance from the eye at which an object is still clearly visible is called the nearest point of clear vision. In a normal eye, the far point of clear vision lies at infinity.

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ABSTRACT

AGE PHYSIOLOGY

age physiology is a science that studies the features of the life process of an organism at different stages of ontogenesis.

It is an independent branch of human and animal physiology, the subject of which is the study of the patterns of formation and development of the physiological functions of the body throughout its life path from conception to the end of life.

Depending on what age period the age-related physiology studies, there are: age-related neurophysiology, age-related endocrinology, age-related physiology of muscle activity and motor function; age-related physiology of metabolic processes, cardiovascular and respiratory systems, digestive and excretory systems, physiology of embryonic development, physiology of infants, physiology of children and adolescents, physiology of adulthood, gerontology (the science of aging).

The main objectives of the study of age physiology are as follows:

study of the features of the functioning of various organs, systems and the body as a whole;

identification of exogenous and endogenous factors that determine the features of the functioning of the body in different age periods;

determination of objective age criteria (age standards);

establishing patterns of individual development.

Developmental physiology is closely related to many branches of physiological science and makes extensive use of data from many other biological sciences. Thus, in order to understand the patterns of formation of functions in the process of individual development of a person, data from such physiological sciences as cell physiology, comparative and evolutionary physiology, the physiology of individual organs and systems: the heart, liver, kidneys, blood, respiration, nervous system, etc. are needed.

At the same time, the patterns and laws discovered by age physiology are based on data from various biological sciences: embryology, genetics, anatomy, cytology, histology, biophysics, biochemistry, etc. Finally, age physiology data, in turn, can be used to develop various scientific disciplines. For example, age physiology is of great importance for the development of pediatrics, pediatric traumatology and surgery, anthropology and gerontology, hygiene, developmental psychology and pedagogy.

History and main stages of development of age physiology

The scientific study of the age characteristics of the child's body began relatively recently - in the second half of the 19th century. Shortly after the discovery of the law of conservation of energy, physiologists discovered that a child consumes slightly less energy during the day than an adult, although the size of a child's body is much smaller. This fact required a rational explanation. In search of this explanation, the German physiologist Max Rubner conducted a study of the rate of energy metabolism in dogs of different sizes and found that larger animals per 1 kg of body weight consume much less energy than small ones. Having calculated the surface area of ​​the body, Rubner made sure that the ratio of the amount of energy consumed is proportional to the size of the body surface - and this is not surprising: after all, all the energy consumed by the body must be released into the environment in the form of heat, i.e. the energy flux depends on the heat transfer surface. It was the differences in the ratio of mass and body surface that Rubner explained the difference in the intensity of energy metabolism between large and small animals, and at the same time between adults and children. Rubner's "surface rule" was one of the first fundamental generalizations in developmental and environmental physiology. This rule explained not only the differences in the magnitude of heat production, but also in the frequency of heart contractions and respiratory cycles, pulmonary ventilation and volume of blood flow, as well as in other indicators of the activity of autonomic functions. In all these cases, the intensity of physiological processes in a child's body is significantly higher than in an adult's body. Such a purely quantitative approach is characteristic of the German physiological school of the 19th century, consecrated by the names of outstanding physiologists. E.F. Pfluger, G.L. Helmholtz and others. By their labors physiology was raised to the level natural sciences standing on a par with physics and chemistry. However, the Russian physiological school, although rooted in the German one, has always been distinguished by an increased interest in qualitative features and regularities. An outstanding representative of the Russian pediatric school, Dr. Nikolai Petrovich Gundobin even at the very beginning of the 20th century. argued that the child is not just small, he is also in many ways not the same as an adult. His body is arranged and works differently, and at each stage of its development, the child's body is perfectly adapted to the specific conditions that it has to face in real life. and ideas were shared and developed by a remarkable Russian physiologist, teacher and hygienist Pyotr Frantsevich Lesgaft, laid the foundations of school hygiene and physical education of children and adolescents. He considered it necessary to deeply study the child's body, its physiological capabilities.

The central problem of developmental physiology was most clearly formulated in the 20s of the XX century. German physician and physiologist E. Helmreich. He argued that the differences between an adult and a child are in two planes, which must be considered as independently as possible, as two independent aspects: the child as small organism and child developing organism. In this sense, Rubner's "surface rule" considers the child in only one aspect - namely, as a small organism. Much more interesting are those features of the child that characterize him as a developing organism. One of these fundamental features is the discovery at the end of the 30s Ilya Arkadyevich Arshavsky uneven development of sympathetic and parasympathetic influences of the nervous system on all the most important functions of the child's body. I.A. Arshavsky proved that sympathotonic mechanisms mature much earlier, and this creates an important qualitative originality of the functional state of the child's body. The sympathetic division of the autonomic nervous system stimulates the activity of the cardiovascular and respiratory systems, as well as metabolic processes in the body. Such stimulation is quite adequate for an early age, when the body needs an increased intensity of metabolic processes necessary to ensure the processes of growth and development. As the child's body matures, parasympathetic, inhibitory influences intensify. As a result, the pulse rate, respiratory rate, and the relative intensity of energy production decrease. The problem of uneven heterochrony (time difference) in the development of organs and systems has become the central object of research by the outstanding physiologist academician Petr Kuzmich Anokhin and his scientific school. In the 1940s he formulated the concept systemogenesis, according to which the sequence of events unfolding in the body is built in such a way as to satisfy the changing needs of the body in the course of development. At the same time, P.K. Anokhin for the first time moved from consideration of anatomically integral systems to the study and analysis of functional relationships in the body. Another eminent physiologist Nikolai Alexandrovich Bernshtein showed how algorithms for controlling voluntary movements are gradually formed and become more complex in ontogenesis, how the mechanisms of higher movement control spread with age from the most evolutionarily ancient subcortical structures of the brain to newer ones, reaching an ever higher level of “building movements”. In the works of N.A. Bernshtein, it was shown for the first time that the direction of ontogenetic progress in the control of physiological functions clearly coincides with the direction of phylogenetic progress. Thus, on the basis of physiological material, the concept of E. Haeckel and A.N. Severtsov that individual development (ontogenesis) is an accelerated evolutionary development (phylogenesis) was confirmed.

The largest specialist in the field of the theory of evolution academician Ivan Ivanovich Schmalhausen For many years he also dealt with questions of ontogeny. The material on which I.I. Shmalgauzen drew his conclusions rarely had a direct bearing on the physiology of development, but the conclusions from his works on the alternation of stages of growth and differentiation, as well as methodological work in the field of studying the dynamics of growth processes, carried out in the 30s , and are still of great importance for understanding the most important patterns of age-related development. In the 1960s, the physiologist Hakob Artashesovich Markosyan put forward the concept of biological reliability as one of the factors of ontogeny. She relied on numerous facts that testified that the reliability of functional systems increases significantly as the body grows older. This was confirmed by data on the development of the blood coagulation system, immunity, and the functional organization of brain activity. In recent decades, many new facts have accumulated that confirm the main provisions of A.A. Markosyan's concept of biological reliability. At the present stage of development of biomedical science, research in the field of age-related physiology is also continuing, already using modern research methods. Thus, physiological science currently has at its disposal considerable multifaceted information concerning the functional activity of any physiological system of the child's organism and its activity as a whole.

The main patterns of growth in the development of children and adolescents.

The main feature of childhood and adolescence- a constantly ongoing process of growth and development, during which the gradual formation of an adult is carried out. During this process, the quantitative indicators of the body increase (the size of individual organs and the whole body), and there is also an improvement in the work of organs and physiological systems that ensure the possibility of normal life of a mature person, the main points of which are labor activity and the birth of healthy offspring. How a child and adolescent grows and develops largely determines his future and, therefore, this process from the moment the child is born to the completion of the growth and development processes should be under the constant control of doctors, parents and teachers. While each child is completely different, some patterns of growth and development of children are common to all. The development of a child is a non-stop process in which all stages of slow quantitative changes gradually lead to dramatic transformations in the structures and functions of the child's body. Quite often such changes have a sharp spasmodic form. The normal course of growth and development of a child and adolescent indicates a favorable state of his body, the absence of pronounced harmful influences, and therefore physical development at this age is one of the leading signs of health, on which other indicators depend. The level of achieved physical development is necessarily assessed by a doctor during a medical examination and is a necessary criterion for an overall assessment of the health status of a child and adolescent. The number of indicators that determine the physical development of a person is quite large. For the purposes of medical and pedagogical practice, relatively easy-to-measure indicators called somatometric indicators are most often used: body length, body weight, chest circumference. External examination of the body reveals somatoscopic indicators: the shape of the chest, back, feet, posture, muscle condition, fat deposition, skin elasticity, signs of puberty. To assess the functional capabilities of the body, physiometric indicators are used - vital capacity lungs (VC), force of compression of the hand (dynamometry). All these indicators are taken into account when assessing physical development of children and adolescents, which should be carried out comprehensively, using all of these indicators. For a correct assessment of the physical development of a child, it is necessary to know the basic patterns of development of children and adolescents and the age-related features of the course of this process, which allows us to understand and explain the activity of individual organs and systems, their relationship, the functioning of the whole organism of the child in different age periods and its unity with the external environment.

The human life cycle is conditionally divided into three stages: maturation, mature age and aging. It is possible to draw a chronological boundary for the transition of an organism from one stage to another on the basis of studying the characteristics of its growth and development, interaction with the environment (including social) environment. The stage of maturation is characterized, first of all, by the achievement of puberty, the ability of the organism and the ability to perform the reproductive function, which ensures the preservation of the species. The biological meaning of the individual growth and development of any living being, including humans, lies in the preservation of the species. However, it would be a mistake to judge a person's maturity only by the degree of sexual development. An equally important sign is the readiness of the individual to carry out social functions, labor and creative activity, and this is the social and social meaning of his development. Puberty occurs at 13-15 years of age. Labor maturity comes much later, usually by the end of school or vocational school, that is, at 17-18 years old. It comes only with the approach to the completion of physical development and the acquisition of experience in social and social activity. Currently, there is a discrepancy in the time of onset of sexual and labor maturity. If puberty is modern conditions is observed somewhat earlier, then labor maturity in the conditions of modern production, which requires a sufficiently high level of training, on the contrary, later. Therefore, the chronological boundary of the full maturation of the body and the onset of maturity should be considered 20-21 years. Namely, by this age, not only the process of full maturation and growth is completed, but the necessary knowledge is accumulated, moral foundations are formed, that is, opportunities are created for a person to perform both biological and social functions. At the entire stage of maturation (from the moment of birth to full maturity), the growth and development of the organism proceed in accordance with objectively existing laws, the main of which are:

uneven pace of growth and development,

non-simultaneous growth and development of individual organs and systems (heterochronism),

conditionality of growth and development by sex (sexual dimorphism),

genetic conditioning of growth and development,

conditionality of growth and development by factors habitat children,

historical development trends (acceleration, deceleration).

Uneven rate of growth and development. The processes of growth and development proceed continuously, are progressive in nature, but their rate has a non-linear dependence on age. The younger the body, the more intense the processes of growth and development. This is most clearly reflected in the indicators of daily energy consumption. The child is 1-3 months old. daily energy consumption per 1 kg of body weight per day is 110-120 kcal, for a one-year-old - 90-100 kcal. In subsequent periods of a child's life, the decrease in the relative daily energy expenditure continues. Changes in the body length of children and adolescents testify to the uneven growth and development. During the first year of life, the length of the body of a newborn increases by 47%, during the second - by 13%, during the third - by 9%. At the age of 4-7 years, body length increases annually by 5-7%, and at the age of 8-10 years - only by 3%.

During puberty, a growth spurt is noted, at the age of 16-17 years, a decrease in the rate of its growth is observed, and at 18-20 years, the increase in body length practically stops. Changes in body weight, chest circumference, as well as the development of individual organs and systems as a whole occur unevenly. The unevenness of the rate of growth and development of the organism at the stage of maturation is a general pattern. However, during this period, some individual characteristics also appear. There are individuals whose rate of development is accelerated, and in terms of maturity they are ahead of their chronological (calendar) age. The reverse relationship is also possible. In this regard, the term "child's age" should be specified: chronological or biological. The difference between chronological and biological age can be up to 5 years. Children with a slow rate of biological development can be 10-20%. Such children are most often identified before entering school or during training. The lag of biological age in children is manifested by a decrease in most indicators of physical development compared to the average age and is combined with more frequent deviations in the musculoskeletal system, nervous and cardiovascular systems. Schoolchildren with a slow rate of biological development are less active in the classroom. They have increased distractibility and an unfavorable type of change in performance. During educational process a more pronounced tension of the visual, motor analyzer and cardiovascular system is revealed. The most pronounced changes in working capacity and health status are observed in children with a sharp lag in biological age (a difference of 3 years or more). accelerated pace individual development of the child leads to advance of biological age in comparison with chronological. "Advanced" development is less common in groups of students than "lagging behind". Accelerated development is observed more often in girls. In schoolchildren with an accelerated pace of individual development, the working capacity is lower than in children whose biological age corresponds to the calendar one. Among them, there are more people suffering from hypertension and chronic tonsillitis, they have higher morbidity rates, more often and sharper manifestations of functional abnormalities. The highest frequency of deviations from biological age is found among adolescents.

Thus, individual deviations in the rate of growth and development of the child from the average age cause a discrepancy between biological age and chronological age, which, both in the case of advance and especially lagging, require attention from doctors and parents. Criteria of biological age: the level of ossification of the skeleton, the timing of eruption and change of teeth, the appearance of secondary sexual characteristics, the onset of menstruation, as well as morphological indicators of physical development (body length and its annual increase). With age, the degree of information content of indicators of biological age changes. From 6 to 12 years of age, the main indicators of development are the number of permanent teeth (“dental age”) and body length. Between 11 and 15 years, the most informative indicators of the annual increase in body length, as well as the severity of secondary sexual characteristics and the age of menstruation in girls. At the age of 15 and later, the appearance of secondary sexual characteristics becomes a very important indicator of development, and indicators of body length and development of teeth lose their information content. The level of ossification of the skeleton is determined using radiographic studies only in the presence of special medical indications - with pronounced developmental disorders. Non-simultaneous growth and development of individual organs and systems (heterochronism). The processes of growth and development proceed unevenly. Each age is characterized by certain morphofunctional features. The child's body is considered as a whole, but the growth and development of its individual organs and systems occur non-simultaneously (heterochronously). Selective and accelerated maturation is ensured by those structural formations and functions that determine the survival of the organism. In the first years of a child's life, the mass of the brain and spinal cord mainly increases, which cannot be considered accidental: there is an intensive formation of the functional systems of the body. Through the nervous system, the organism is connected with the external environment: mechanisms of adaptation to constantly changing conditions are formed, optimal conditions are created for receiving information and performing integrative actions. In contrast, the lymphatic tissue does not develop in the first years of life, its growth and formation occur at the age of 10-12 years. Only after 12 years there is an intensive development of the genital organs and the formation of the reproductive function. The growth rates of individual parts of the body are also different. In the process of growth, the proportions of the body change, and the child from a relatively large-headed, short-legged and long-bodied gradually turns into a small-headed, long-legged and short-bodied child. Thus, intensive development and the final formation of individual organs and systems do not occur in parallel. There is a certain sequence of growth and development of certain structural formations and functions. At the same time, during the period of intensive growth and development of a functional system, its increased sensitivity to the action of specific factors is observed. During the period of intensive development of the brain, an increased sensitivity of the body to a lack of squirrel in food; in the period of development of speech motor functions - to speech communication; during the development of motor skills - to motor activity. The ability of the child's body to specific activities, its resistance to various environmental factors are determined by the level of maturation of the corresponding functional systems. Thus, the associative sections of the cerebral cortex, which ensure its integral function and readiness for schooling, mature gradually in the course of the individual development of the child by the age of 6-7. In this regard, the forced education of children at an early age may affect their subsequent development. The system that transports oxygen to the tissues also develops gradually and reaches maturity by the age of 16-17. Given this, hygienists prescribe the restriction of physical activity for children. Only in adolescence, upon reaching the morphological and functional maturity of the cardiovascular and respiratory systems, long-term performance of large physical exertion and the development of endurance are allowed. Thus, functional readiness for certain types of educational, labor and sports activities is formed non-simultaneously, therefore, both types of activities and the impact of environmental factors on various analyzers or functional systems should be normalized differentially. Hygienic norm throughout the entire stage of maturation of the organism changes in accordance with the change in age-related sensitivity to the action of the factor. The heterochrony of the growth and development of individual organs and systems is scientific basis differentiated regulation of environmental factors and activities of children and adolescents.

Conditionality of growth and development by sex (sexual dimorphism).

Sexual dimorphism is manifested in the features of the metabolic process, the rate of growth and development of individual functional systems and the organism as a whole. So, boys before the onset of puberty have higher anthropometric indicators. During puberty, this ratio changes: girls are superior to their peers in terms of length and weight, chest circumference. There is a crossover of the age curves of these indicators. At the age of 15, the intensity of growth in boys increases, and boys, in terms of their anthropometric indicators, are again ahead of girls. A second intersection of curves is formed. This double crossing of curves of age-related changes in indicators of physical development is characteristic of normal physical development. At the same time, there is an uneven rate of development of many functional systems, especially muscular, respiratory and cardiovascular. For example, the strength of the hand or muscles - the extensors of the back in boys of all ages is higher than that of their peers. Differences exist not only in physical performance, but also in psychophysiological indicators. age physiology organism child

And so, along with common to both sexes growth patterns of children and adolescents there are differences in the rate, timing and rates of growth and development of boys and girls. Sexual dimorphism is taken into account when normalizing physical activity, organization educational process. Sex differences in the growth and development of the body are important in vocational guidance schoolchildren, sports selection and training of young athletes. Domestic hygienic science develops the concept of correspondence, first of all, of training loads to the functional capabilities of a growing organism and the expediency of its training in order to protect and promote health. In accordance with this, in our country, activity standards are being developed on the basis of the age-sex principle and recommendations are given for the reasonable training of a growing organism in order to help increase its reserve abilities and more fully use the body's physical capabilities inherent in nature.

Inside the uterineuhstages of development.

In the intrauterine development of a person, three periods are conventionally distinguished:

1 The implantation period lasts from the moment of fertilization to 2 weeks. This period is characterized by a rapid systematic crushing of a fertilized egg, its advancement along the fallopian tube to the uterine cavity; implantation (attachment of the embryo and introduction into the mucous membrane of the uterus) on the 6-7th day after fertilization and further formation of the fetal membranes, creating the necessary conditions for the development of the embryo. They provide nutrition (trophoblast), create a liquid habitat and mechanical protection (fluid of the amniotic sac).

2 The embryonic period lasts from the 3rd to the 10-12th week of pregnancy. During this period, the rudiments of all the most important organs and systems of the future baby are formed, the torso, head, and limbs are formed. The placenta is developing - the most important organ of pregnancy, separating two blood flows (mother and fetus) and providing metabolism between mother and fetus, protecting it from infectious and other harmful factors, from the mother's immune system. At the end of this period, the embryo becomes a fetus with a baby-like configuration.

3 The fetal period begins from the 3rd month of pregnancy and ends with the birth of a child. Nutrition and metabolism of the fetus is carried out through the placenta. There is a rapid growth of the fetus, the formation of tissues, the development of organs and systems from their rudiments, the formation and formation of new functional systems that ensure the life of the fetus in the womb and the child after birth.

After the 28th week of pregnancy, the fetus begins to form a supply of valuable substances needed in the first time after birth - calcium, iron, copper, vitamin B12, etc. There is a maturation of the surfactant, which ensures normal lung function. Prenatal development is influenced by various environmental factors. They have the most significant effect on the organs that develop most intensively at the time of exposure.

postnatal period

The postnatal period is the stage of ontogenesis, during which the growing organism begins to adapt to the influence of the external environment.

The postnatal period goes through three periods of development:

1. Juvenile (before puberty)

2. Mature (or puberty, adult sexually mature state)

3. Sinilny (old age) periods.

In humans, the postnatal period is conditionally divided into 12 periods (age periodization):

1. Newborns - from birth to 10 days

2. Breast age - from 10 days to 1 year

3. Early childhood - from 1 year to 3 years

4. The first childhood - from 4 years to 7 years

5. Second childhood - 8 - 12 years old (boys), 8 - 11 years old (girls)

6. Adolescence - 13 - 16 years old (boys), 12 - 15 years old (girls)

7. Youth period - 17 - 18 years old (boys), 16 - 18 years old (girls)

8. Mature age, I period: 19 - 35 years old (men), 19 - 35 years old (women)

9. Mature age, II period: 36 - 60 years (men), 36 - 55 years (women)

10. Old age - 61 - 74 years (men), 56 - 74 years (women)

11. Senile age 75 - 90 years (men and women)

12. Long-livers - 90 years and older.

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Current page: 1 (total book has 12 pages) [accessible reading excerpt: 8 pages]

Yuri Savchenkov, Olga Soldatova, Sergei Shilov
Age physiology (physiological characteristics of children and adolescents). Textbook for universities

Reviewers:

Kovalevsky V. A. , Doctor of Medical Sciences, Professor, Head of the Department of Childhood Psychology, Krasnoyarsk State Pedagogical University them. V. P. Astafieva,

Manchuk V. T. , MD, Corresponding Member RAMS, Professor of the Department of Polyclinic Pediatrics, KrasSMU, Director of the Research Institute of Medical Problems of the North, Siberian Branch of the Russian Academy of Medical Sciences

© VLADOS Humanitarian Publishing Center LLC, 2013

Introduction

The child's body is an extremely complex and at the same time very vulnerable socio-biological system. It is in childhood that the foundations of the health of the future adult are laid. An adequate assessment of the physical development of a child is possible only if the characteristics of the corresponding age period are taken into account, and the vital signs of this child are compared with the standards of his age group.

Age physiology studies the functional features of the individual development of the body throughout its life. Based on the data of this science, methods of teaching, educating and protecting the health of children are being developed. If the methods of education and training do not correspond to the capabilities of the body at any stage of development, the recommendations may turn out to be ineffective, cause a negative attitude of the child to learning, and even provoke various diseases.

As the child grows and develops, almost all physiological parameters undergo significant changes: blood counts, the activity of the cardiovascular system, respiration, digestion, etc. change. Knowledge of various physiological parameters characteristic of each age period is necessary to assess the development of a healthy child.

In the proposed publication, the features of the age-related dynamics of the main physiological parameters of healthy children of all age groups are summarized and classified according to systems.

The manual on age physiology is an additional educational material according to the physiological characteristics of children of different ages, necessary for the assimilation by students who study in pedagogical higher and secondary specialized educational institutions and are already familiar with the general course of human physiology and anatomy.

Each section of the book provides short description the main directions of ontogenesis of indicators of a particular physiological system. In this version of the manual, the sections "Age characteristics of higher nervous activity and mental functions", "Age characteristics of endocrine functions", "Age characteristics of thermoregulation and metabolism" are significantly expanded.

This book contains descriptions of numerous physiological and biochemical indicators and will be useful in practical work not only for future teachers, speech pathologists, child psychologists, but also for future pediatricians, as well as for young professionals and high school students who are already working, who want to replenish their knowledge about the physiological characteristics of the child's body.

Chapter 1
Age periodization

Patterns of growth and development of the child's body. Age periods of child development

A child is not an adult in miniature, but an organism, relatively perfect for each age, with its own morphological and functional features, for which the dynamics of their course from birth to puberty is natural.

The child's body is an extremely complex and at the same time very vulnerable socio-biological system. It is in childhood that the foundations of the health of the future adult are laid. An adequate assessment of the physical development of a child is possible only if the characteristics of the corresponding age period are taken into account, and the vital signs of a particular child are compared with the standards of his age group.

Growth and development are often used interchangeably. Meanwhile, their biological nature (mechanism and consequences) is different.

Development is a process of quantitative and qualitative changes in the human body, accompanied by an increase in the level of its complexity. Development includes three main interrelated factors: growth, differentiation of organs and tissues, and shaping.

Growth is a quantitative process characterized by an increase in the mass of an organism due to a change in the number of cells and their size.

Differentiation is the emergence of specialized structures of a new quality from poorly specialized progenitor cells. For example, a nerve cell that is laid down in the neural tube of an embryo (embryo) can potentially perform any nervous function. If a neuron migrating to the visual area of ​​the brain is transplanted into the area responsible for hearing, it will turn into an auditory neuron, not a visual one.

Formation is the acquisition by the body of its inherent forms. For example, the auricle acquires the shape inherent in an adult by the age of 12.

In those cases when intensive growth processes simultaneously occur in many different tissues of the body, the so-called growth spurts are noted. This is manifested in a sharp increase in the longitudinal dimensions of the body due to an increase in the length of the trunk and limbs. In the postnatal period of human ontogenesis, such “leaps” are most pronounced:

in the first year of life, when there is a 1.5-fold increase in length and a 3-4-fold increase in body weight;

at the age of 5–6 years, when, mainly due to the growth of the limbs, the child reaches approximately 70% of the body length of an adult;

13-15 years - pubertal growth spurt due to an increase in the length of the body and limbs.

The development of the organism from the moment of birth to the onset of maturity occurs in constantly changing environmental conditions. Therefore, the development of the organism is adaptive, or adaptive, in nature.

To ensure an adaptive result, various functional systems mature non-simultaneously and unevenly, switching on and replacing each other at different periods of ontogenesis. This is the essence of one of the defining principles of the individual development of an organism - the principle of heterochrony, or the non-simultaneous maturation of organs and systems and even parts of the same organ.

The terms of maturation of various organs and systems depend on their significance for the life of the organism. Those organs and functional systems that are most vital at this stage of development grow and develop faster. By combining individual elements of one or another organ with the earliest maturing elements of another organ participating in the implementation of the same function, the minimum provision of vital functions sufficient for a certain stage of development is carried out. For example, to ensure food intake at the time of birth, the circular muscle of the mouth first matures from the facial muscles; from the cervical - the muscles responsible for turning the head; of the receptors of the tongue - receptors located at its root. By this time, the mechanisms responsible for the coordination of respiratory and swallowing movements and ensuring that milk does not enter the respiratory tract mature. This ensures the necessary actions associated with the nutrition of the newborn: the capture and retention of the nipple, sucking movements, the direction of food along the appropriate paths. Taste sensations are transmitted through the receptors of the tongue.

The adaptive nature of the heterochronous development of body systems reflects another general principles development - the reliability of the functioning of biological systems. The reliability of a biological system is understood as such a level of organization and regulation of processes that is able to ensure the vital activity of an organism in extreme conditions. It is based on such properties of a living system as the redundancy of elements, their duplication and interchangeability, the speed of return to relative constancy and the dynamism of individual parts of the system. An example of the redundancy of elements can be the fact that during the period of intrauterine development, from 4,000 to 200,000 primary follicles are laid in the ovaries, from which eggs are subsequently formed, and only 500–600 follicles mature during the entire reproductive period.

Mechanisms for ensuring biological reliability change significantly in the course of ontogeny. In the early stages of postnatal life, reliability is ensured by a genetically programmed association of links of functional systems. In the course of development, as the cerebral cortex, which provides highest level regulation and control of functions, increases the plasticity of connections. Due to this, selective formation of functional systems occurs in accordance with a specific situation.

Another important feature individual development of the child's body is the presence of periods of high sensitivity of individual organs and systems to the effects of environmental factors - sensitive periods. These are periods when the system is developing rapidly and it needs an influx of adequate information. For example, for the visual system, light quanta are adequate information, for the auditory system - sound waves. The absence or deficiency of such information leads to negative consequences, up to the unformedness of a particular function.

It should be noted that ontogenetic development combines periods of evolutionary, or gradual, morphofunctional maturation and periods of revolutionary, turning points in development associated with both internal (biological) and external (social) factors. These are the so-called critical periods. The inconsistency of environmental influences with the characteristics and functional capabilities of the organism at these stages of development can have detrimental consequences.

The first critical period is considered to be the stage of early postnatal development (up to 3 years), when the most intensive morphofunctional maturation occurs. In the process of further development, critical periods arise as a result of a sharp change in social and environmental factors and their interaction with the processes of morphofunctional maturation. These periods are:

the age of the beginning of education (6–8 years), when the qualitative restructuring of the morphofunctional organization of the brain falls on a period of a sharp change in social conditions;

the beginning of puberty is the pubertal period (in girls - 11-12 years old, in boys - 13-14 years old), which is characterized by a sharp increase in the activity of the central link of the endocrine system - the hypothalamus. As a result, there is a significant decrease in the effectiveness of cortical regulation, which determines voluntary regulation and self-regulation. Meanwhile, it is at this time that social requirements for a teenager increase, which sometimes leads to a discrepancy between the requirements and the functional capabilities of the body, which may result in a violation of the physical and mental health of the child.

Age periodization of the ontogeny of a growing organism. There are two main periods of ontogeny: antenatal and postnatal. The antenatal period is represented by the embryonic period (from conception to the eighth week of the intrauterine period) and the fetal period (from the ninth to the fortieth week). Usually pregnancy lasts 38-42 weeks. The postnatal period covers the period from birth to the natural death of a person. According to the age periodization adopted at a special symposium in 1965, the following periods are distinguished in the postnatal development of the child's body:

newborn (1–30 days);

chest (30 days - 1 year);

early childhood (1–3 years);

first childhood (4–7 years);

second childhood (8-12 years old - boys, 8-11 years old - girls);

teenage (13-16 years old - boys, 12-15 years old - girls);

youth (17–21 years old boys, 16–20 years old girls).

Considering the issues of age periodization, it must be borne in mind that the boundaries of the stages of development are very arbitrary. All age-related structural and functional changes in the human body occur under the influence of heredity and environmental conditions, that is, they depend on specific ethnic, climatic, social and other factors.

Heredity determines the potential for physical and mental development of the individual. So, for example, the short stature of African pygmies (125–150 cm) and the tall stature of the representatives of the Watussi tribe are associated with the characteristics of the genotype. However, in each group there are individuals in whom this indicator may differ significantly from the average age norm. Deviations can occur due to the impact on the body of various environmental factors, such as nutrition, emotional and socio-economic factors, the position of the child in the family, relationships with parents and peers, the level of culture of society. These factors can interfere with the growth and development of the child, or vice versa, stimulate them. Therefore, the indicators of growth and development of children of the same calendar age can vary significantly. It is common to form groups of children in preschool institutions and classes in general education schools by calendar age. In this regard, the educator and teacher must take into account the individual psychophysiological characteristics of development.

Growth and developmental delay, called retardation, or advanced development - acceleration - indicate the need to determine the biological age of the child. Biological age, or developmental age, reflects the growth, development, maturation, aging of the organism and is determined by a combination of structural, functional and adaptive features of the organism.

Biological age is determined by a number of indicators of morphological and physiological maturity:

according to the proportions of the body (the ratio of the length of the body and limbs);

the degree of development of secondary sexual characteristics;

skeletal maturity (the order and timing of ossification of the skeleton);

dental maturity (terms of eruption of milk and molars);

metabolic rate;

features of the cardiovascular, respiratory, neuroendocrine and other systems.

When determining the biological age, the level of mental development of the individual is also taken into account. All indicators are compared with standard indicators characteristic of a given age, gender and ethnic group. At the same time, it is important to take into account the most informative indicators for each age period. For example, in the pubertal period - neuroendocrine changes and the development of secondary sexual characteristics.

To simplify and standardize the average age of an organized group of children, it is customary to consider the age of a child equal to 1 month if his calendar age is in the range from 16 days to 1 month 15 days; equal to 2 months - if his age is from 1 month 16 days to 2 months 15 days, etc. After the first year of life and up to 3 years: 1.5 years include a child with an age of 1 year 3 months to 1 year 8 months and 29 days, to the second years - from 1 year 9 months to 2 years 2 months 29 days, etc. After 3 years at yearly intervals: 4 years includes children aged 3 years 6 months to 4 years 5 months 29 days, etc.

Chapter 2
Excitable tissues

Age-related changes in the structure of a neuron, nerve fiber and neuromuscular synapse

Different types of nerve cells in ontogeny mature heterochronously. Most early, even in the embryonic period, large afferent and efferent neurons mature. Small cells (interneurons) mature gradually during postnatal ontogenesis under the influence of environmental factors.

Separate parts of the neuron also do not mature at the same time. Dendrites grow much later than the axon. Their development occurs only after the birth of a child and largely depends on the influx of external information. The number of dendrite branches and the number of spines increase in proportion to the number of functional connections. The most branched network of dendrites with a large number of spines are neurons of the cerebral cortex.

Myelination of axons begins in utero and occurs in the following order. First of all, the peripheral fibers are covered with a myelin sheath, then the fibers of the spinal cord, the brain stem (medulla oblongata and midbrain), the cerebellum, and the last - the fibers of the cerebral cortex. In the spinal cord, motor fibers are myelinated earlier (by 3–6 months of life) than sensitive ones (by 1.5–2 years). Myelination of brain fibers occurs in a different sequence. Here, sensory fibers and sensory areas are myelinated earlier than others, while motor fibers are myelinated only 6 months after birth, or even later. Myelination is generally completed by 3 years of age, although growth of the myelin sheath continues until approximately 9–10 years of age.

Age-related changes also affect the synaptic apparatus. With age, the intensity of the formation of mediators in the synapses increases, the number of receptors on the postsynaptic membrane that respond to these mediators increases. Accordingly, as development increases, the speed of impulse conduction through synapses increases. The influx of external information determines the number of synapses. First of all, synapses of the spinal cord are formed, and then other parts of the nervous system. Moreover, excitatory synapses mature first, then inhibitory ones. It is with the maturation of inhibitory synapses that the complication of information processing processes is associated.

Chapter 3
Physiology of the central nervous system

Anatomical and physiological features of the maturation of the spinal cord and brain

The spinal cord fills the cavity of the spinal canal and has a corresponding segmental structure. In the center of the spinal cord is located gray matter (accumulation of nerve cell bodies), surrounded by white matter (accumulation of nerve fibers). The spinal cord provides motor reactions of the trunk and limbs, some autonomic reflexes (vascular tone, urination, etc.) and a conductive function, since all sensitive (ascending) and motor (descending) paths pass through it, along which a connection is established between various parts CNS.

The spinal cord develops earlier than the brain. In the early stages of fetal development, the spinal cord fills the entire cavity of the spinal canal, and then begins to lag behind in growth and ends at the level of the third lumbar vertebra by the time of birth.

By the end of the first year of life, the spinal cord occupies the same position in the spinal canal as in adults (at the level of the first lumbar vertebra). At the same time, the segments of the thoracic spinal cord grow faster than the segments of the lumbar and sacral regions. The spinal cord grows slowly in thickness. The most intensive increase in the mass of the spinal cord occurs by the age of 3 (4 times), and by the age of 20 its mass becomes like that of an adult (8 times more than that of a newborn). Myelination of nerve fibers in the spinal cord begins with the motor nerves.

By the time of birth, the medulla oblongata and the bridge are already formed. Although the maturation of the nuclei of the medulla oblongata lasts up to 7 years. The location of the bridge differs from adults. In newborns, the bridge is slightly higher than in adults. This difference disappears by 5 years.

The cerebellum in newborns is still underdeveloped. Enhanced growth and development of the cerebellum is observed in the first year of life and during puberty. Myelination of its fibers ends by about 6 months of age. The complete formation of the cellular structures of the cerebellum is carried out by the age of 7–8, and by the age of 15–16 its dimensions correspond to the level of an adult.

The shape and structure of the midbrain in a newborn is almost the same as in an adult. The postnatal period of maturation of midbrain structures is mainly accompanied by pigmentation of the red nucleus and substantia nigra. Pigmentation of the neurons of the red nucleus begins at the age of two and ends by the age of 4. Pigmentation of neurons in the substantia nigra begins from the sixth month of life and reaches a maximum by the age of 16.

The diencephalon includes two major structures: the thalamus, or optic tubercle, and the subthalamic region, the hypothalamus. Morphological differentiation of these structures occurs in the third month of intrauterine development.

The thalamus is a multinuclear formation associated with the cerebral cortex. Through its nuclei, visual, auditory and somatosensory information is transmitted to the corresponding associative and sensory zones of the cerebral cortex. The nuclei of the reticular formation of the diencephalon activate cortical neurons that perceive this information. By the time of birth, most of its nuclei are well developed. Enhanced growth of the thalamus occurs at the age of four. The size of an adult thalamus reaches 13 years.

The hypothalamus, despite its small size, contains dozens of highly differentiated nuclei and regulates most autonomic functions, such as maintaining body temperature and water balance. The nuclei of the hypothalamus are involved in many complex behavioral responses: sexual desire, hunger, satiety, thirst, fear, and rage. In addition, through the pituitary gland, the hypothalamus controls the work of the endocrine glands, and the substances formed in the neurosecretory cells of the hypothalamus itself are involved in the regulation of the sleep-wake cycle. The nuclei of the hypothalamus mature mainly by the age of 2–3 years, although the differentiation of cells of some of its structures continues up to 15–17 years.

The most intense myelination of fibers, an increase in the thickness of the cerebral cortex and its layers occurs in the first year of life, gradually slowing down and stopping by 3 years in the projection areas and by 7 years in the associative areas. First, the lower layers of the bark ripen, then the upper ones. By the end of the first year of life, as a structural unit of the cerebral cortex, ensembles of neurons, or columns, are distinguished, the complication of which continues up to 18 years. The most intense differentiation of the intercalated neurons of the cortex occurs at the age of 3 to 6 years, reaching a maximum by 14 years. The full structural and functional maturation of the cerebral cortex reaches approximately 20 years.

(PHYSIOLOGY OF CHILD DEVELOPMENT)

Tutorial

For students of higher pedagogical educational institutions

M.M. Bezrukikh I (1, 2), III (15), IV (18-23),

V.D. Sonkin I (1, 3), II (4-10), III (17), IV (18-22),

D.A. Farber I (2), III (11-14, 16), IV (18-23)

Reviewers:

doctor of biological sciences, head. Department of Higher Nervous Activity and Psychophysiology, St. Petersburg University, Academician of the Russian Academy of Education,

Professor A. S. Batuev; Doctor of Biological Sciences, Professor I.A. Kornienko

Bezrukikh M. M. and etc.

Age physiology: (Physiology of child development): Proc. allowance for students. higher ped. studies, institutions / M. M. Bezrukikh, V. D. Sonkin, D. A. Farber. - M.: Publishing Center "Academy", 2002. - 416 p. ISBN 5-7695-0581-8

The textbook presents modern concepts of human ontogenesis, taking into account the latest achievements in anthropology, anatomy, physiology, biochemistry, neuro- and psychophysiology, etc. The morphological and functional features of the child at the main stages of age development, their connection with the processes of socialization, including education and upbringing, are considered. The book is illustrated with a large number of diagrams, tables, drawings that facilitate the assimilation of the material, questions for self-examination are proposed.

AGE PHYSIOLOGY 1

Tutorial 1

FOREWORD 3

Section I INTRODUCTION TO AGE PHYSIOLOGY 7

Chapter 1

Chapter 2. THEORETICAL FOUNDATIONS OF AGE PHYSIOLOGY 18

(PHYSIOLOGY OF DEVELOPMENT) 18

Chapter 3. GENERAL PLAN OF THE STRUCTURE OF THE ORGANISM 28

Section II ORGANISM AND ENVIRONMENT 39

Chapter 4. GROWTH AND DEVELOPMENT 39

Chapter 5. ORGANISM AND ITS HABITAT 67

Chapter 6. INTERNAL ENVIRONMENT OF THE ORGANISM 82

Chapter 7. METABOLISM (METABOLISM) 96

Chapter 8. SYSTEM OF OXYGEN SUPPLY OF THE ORGANISM 132

Chapter 9. PHYSIOLOGY OF ACTIVITY AND ADAPTATION 162

Chapter 10

Section III THE ORGANISM AS A WHOLE 199

Chapter 11. NERVOUS SYSTEM: SIGNIFICANCE AND STRUCTURAL AND FUNCTIONAL ORGANIZATION 199

Chapter 12

Chapter 13. REGULATION OF THE FUNCTIONAL STATE OF THE BRAIN 219

Chapter 14. INTEGRATIVE ACTIVITY OF THE BRAIN 225

Chapter 15. CENTRAL MOVEMENT REGULATION 248

Chapter 16

Chapter 17

Section IV STAGES OF CHILD DEVELOPMENT 297

Chapter 18. INFANTITY (from 0 to 1 year) 297

Chapter 19. EARLY AGE 316

(FROM 1 YEAR TO 3 YEARS) 316

Chapter 20. PRESCHOOL 324

(FROM 3 TO 6-7 YEARS) 324

Chapter 21

Chapter 22

Chapter 23. SOCIAL FACTORS OF DEVELOPMENT AT DIFFERENT STAGES OF ONTOGENESIS 369

LITERATURE 382

FOREWORD

Elucidation of the patterns of child development, the specifics of the functioning of physiological systems at different stages of ontogenesis and the mechanisms that determine this specificity is necessary condition ensuring the normal physical and mental development of the younger generation.

The main questions that parents, teachers and psychologists should have in the process of raising and educating a child at home, in kindergarten or at school, at a consultation or individual lessons, - this is what he is, what are his features, what option of training with him will be the most effective. Answering these questions is not at all easy, because this requires deep knowledge about the child, the patterns of his development, age and individual characteristics. This knowledge is also extremely important for developing the psychophysiological foundations for organizing educational work, developing mechanisms for adaptation in a child, determining the impact of innovative technologies on him, etc.

Perhaps, for the first time, the importance of a comprehensive knowledge of physiology and psychology for a teacher and educator was singled out by the famous Russian teacher K.D. Ushinsky in his work “Man as an Object of Education” (1876). “The art of education,” wrote K.D. Ushinsky, “has the peculiarity that it seems familiar and understandable to almost everyone, and even an easy matter to others, and the more understandable and easier it seems, the less a person is theoretically familiar with it. and practically. Almost everyone admits that parenting requires patience; some think that it requires an innate ability and skill, i.e. skill; but very few have come to the conclusion that, in addition to patience, innate ability and skill, special knowledge is also needed, although our numerous wanderings could convince everyone of this. It was K.D.Ushinsky who showed that physiology is one of those sciences in which “facts are stated, compared and grouped, and those correlations of facts in which the properties of the object of education, i.e., a person, are found.” Analyzing the physiological knowledge that was known, and this was the time of the formation of age-related physiology, K.D. Ushinsky emphasized: “From this source, which was just opening, education almost did not draw yet.” Unfortunately, even now we cannot talk about the wide use of age-related physiology data in pedagogical science. The uniformity of programs, methods, textbooks is a thing of the past, but the teacher still does not take into account the age and individual characteristics of the child in the learning process.

At the same time, the pedagogical effectiveness of the learning process largely depends on how the forms and methods of pedagogical influence are adequate to the age-related physiological and psychophysiological characteristics of schoolchildren, whether the conditions for organizing the educational process correspond to the capabilities of children and adolescents, whether the psychophysiological patterns of the formation of basic school skills - writing and reading, as well as basic motor skills in the process of classes.

The physiology and psychophysiology of a child is a necessary component of the knowledge of any specialist working with children - a psychologist, educator, teacher, social pedagogue. “Upbringing and education deals with a holistic child, with his holistic activity,” said the well-known Russian psychologist and teacher V.V. Davydov. - This activity, considered as a special object of study, contains in its unity many aspects, including ... physiological (V.V. Davydov "Problems of developmental education." - M., 1986. - P. 167).

Age physiology is the science of the characteristics of the body's vital activity, the functions of its individual systems, the processes that take place in them, and the mechanisms of their regulation at different stages of individual development. Part of it is the study of the physiology of the child in different age periods.

A textbook on age-related physiology for students of pedagogical universities contains knowledge about human development at those stages when the influence of one of the leading factors of development - education - is most significant.

The subject of age physiology (physiology of child development) as academic discipline are the features of the development of physiological functions, their formation and regulation, the vital activity of the organism and the mechanisms of its adaptation to the external environment at different stages of ontogenesis.

Basic concepts of age physiology:

An organism is the most complex, hierarchically (subordinately) organized system of organs and structures that ensure vital activity and interaction with the environment. The elementary unit of the organism is the cell. A collection of cells that are similar in origin, structure and function forms a tissue. Tissues form organs that perform specific functions. A function is a specific activity of an organ or system.

Physiological system - a set of organs and tissues related by a common function.

A functional system is a dynamic association of various organs or their elements, whose activities are aimed at achieving a specific goal (useful result).

As for the structure of the proposed textbook, it is built in such a way that students have a clear idea of ​​the patterns of development of the body in the process of ontogenesis, the features of each age stage.

We tried not to overload the presentation with anatomical data and at the same time considered it necessary to give basic ideas about the structure of organs and systems at different stages of age development, which is necessary for understanding the physiological patterns of organization and regulation of physiological functions.

The book consists of four sections. Section I - "Introduction to developmental physiology" - reveals the subject of developmental physiology as an integral part of developmental physiology, gives an idea of ​​the most important modern physiological theories of ontogenesis, introduces basic concepts, without which it is impossible to understand the main content of the textbook. In the same section, the most general idea of ​​​​the structure of the human body and its functions is given.

Section II - "The Organism and the Environment" - gives an idea of ​​the main stages and patterns of growth and development, the most important functions of the body that ensure the interaction of the body with the environment and its adaptation to changing conditions, the age development of the body and the characteristic features of the stages of individual development.

Section III - "The Organism as a Whole" - contains a description of the activities of systems that integrate the body into a single whole. First of all, it is the central nervous system, as well as the autonomic nervous system and the system of humoral regulation of functions. The main patterns of age-related development of the brain and its integrative activity are the key aspect of the content of this section.

Section IV - "Stages of child development" - contains a morpho-physiological description of the main stages of child development from birth to adolescence. This section is most important for practitioners who work directly with the child, for whom it is important to know and understand the basic morphological and functional age-related characteristics of the child's body at each stage of its development. To understand the contents of this section, it is necessary to master all the material presented in the previous three. This section concludes with a chapter that examines the impact of social factors on child development.

At the end of each chapter, there are questions for independent work of students, which allow you to refresh the memory of the main provisions of the studied material that require special attention.

Section I INTRODUCTION TO AGE PHYSIOLOGY

Chapter 1

The relationship of age physiology with other sciences

By the time of birth, the child's body is still very far from a mature state. A human cub is born small, helpless, it cannot survive without the care and care of adults. It takes a long time for it to grow and become a full-fledged mature organism.

The section of physiological science that studies the biological patterns and mechanisms of growth and development is called age physiology. The development of a multicellular organism (and the human body consists of several billion cells) begins at the moment of fertilization. The entire life cycle of an organism, from conception to death, is called individual development, or ontogenesis.

Regularities and features of the life of the organism in the early stages of ontogenesis are traditionally the subject of research. age physiology (physiology of child development).

The physiology of child development concentrates its interest on those stages that are of greatest interest to the educator, teacher, school psychologist: from birth to morphofunctional and psychosocial maturation. Earlier stages related to intrauterine development are explored by science embryology. Later stages, from reaching maturity to old age, study normal physiology And gerontology.

Man in his development obeys all the basic laws established by Nature for any developing multicellular organism, and therefore developmental physiology is one of the sections of a much broader field of knowledge - developmental biology. At the same time, in the dynamics of growth, development and maturation of a person, there are many specific, special features that are inherent only in the species Homo sapience (Reasonable Man). In this plane, developmental physiology is closely intertwined with science anthropology which aims at the comprehensive study of man.

A person always lives in the specific conditions of the environment with which he interacts. Continuous interaction and adaptation to the environment is the general law of the existence of living things. Man has learned not only to adapt to the environment, but also to change the world around him in the necessary direction. However, this did not save him from the influence of environmental factors, and at different stages of age development, the set, strength of action and the result of the influence of these factors may be different. This determines the relationship of physiology with ecological physiology, which studies the impact on a living organism of various environmental factors and ways of adapting the organism to the action of these factors.

During periods of intensive development, it is especially important to know how environmental factors act on a person, how various risk factors influence. This has traditionally received increased attention. And here the physiology of development closely interacts with hygiene, since it is the physiological patterns that most often act as theoretical foundations hygiene requirements and recommendations.

The role of living conditions, and not only "physical", but also social, psychological, in the formation of a healthy and adapted person is very great. A child should be aware of the value of his health from early childhood, possess the necessary skills to preserve it.

Formation of the value of health and a healthy lifestyle is the task of pedagogical valeology, which draws factual material and basic theoretical provisions from developmental physiology.

Finally, developmental physiology is the natural science basis pedagogy. At the same time, the physiology of development is inextricably linked with the psychology of development, since for each person his biological and personal make up a single whole. No wonder any biological damage (illness, injury, genetic disorders, etc.) inevitably affects the development of the individual. The teacher should be equally well versed in the problems of developmental psychology and physiology of development: only in this case his activity will bring real benefit to his students.