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Yuri Savchenkov, Olga Soldatova, Sergey 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. 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-related physiology is an additional educational material on the physiological characteristics of children of different ages, which is necessary for assimilation by students who study at 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 a brief description of the main directions of the ontogeny 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 the practical work of not only future teachers, speech pathologists, child psychologists, but also future pediatricians, as well as young specialists 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 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 of the general principles of 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 later 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 the highest level of regulation and control of functions, matures, the plasticity of connections increases. Due to this, selective formation of functional systems occurs in accordance with a specific situation.

Another important feature of the 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 onset 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 generally accepted to form groups of children in preschool institutions and classes in secondary schools according to 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 the age of development, 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 of the 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.

MM. Bezrukikh, V.D. Sonkin, D.A. farber

Age physiology: (Physiology of child development)

Tutorial

For students of higher pedagogical educational institutions

Reviewers:

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

Doctor of Biological Sciences, Professor I.A. Kornienko

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 specifics, is a necessary condition for ensuring the normal physical and mental development of the younger generation.

The main questions that parents, educators and psychologists should have in the process of raising and educating a child at home, in kindergarten or at school, at a consultative appointment or individual lessons, are what kind of child he is, what are his features, what option of training with him will be the most efficient. 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 highlighted 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 familiar with it theoretically and practically. Almost everyone admits that parenting requires patience; some think that it requires an innate ability and skill, that is, a habit; 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 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 physiology, K.D. Ushinsky emphasized: “From this source, which is just opening up, education has almost not yet scooped.” 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- the science of the features of the life of the body, the functions of its individual systems, the processes occurring 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 developmental physiology (physiology of child development) as an academic discipline is 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.

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 (the historical development of the 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 of 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. Bile plays an important role in intestinal digestion.

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 of 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 catabolicly broken down into smaller fragments (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 (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, the insufficient functional maturity of the musculoskeletal, cardiovascular and respiratory systems limits the adaptive capabilities of the energy metabolism reaction 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 conditions of 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 at 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 the O 2 tension in the tissues, or by the method of 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 bioenergy 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 at an early and preschool age (up to 5 years) are especially strong and retain their significance 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 to develop the conditioned reflexes necessary for life with their help.

Speech development. The development of speech is the process of development of the second signal 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 clearly distinguishes the general features of the presented objects, and it is they, and not their shape, that are the most significant 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 provides perception of external stimuli in a wide range, so for newborns and young children it is of great cognitive importance. 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 child-mother 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 cerebral cortex.

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 are the 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 a person has become more complex in the mechanisms of his mental activity, since a special stimulus has appeared - the word.

Two main trends are clearly expressed in the development of modern science. On the one hand, there is a specialization of a particular science, its deepening in its own sphere. On the other hand, there is a close connection between different branches of knowledge, the integration of scientific knowledge is constantly taking place. These trends are clearly manifested in the biological sciences, among which age-related physiology occupies a significant place. There are a number of basic integration links of age-related physiology in the system of modern science.

Age physiology is associated with a number of related sciences and its successes reflect the achievements of anatomy (the science of the structure of the human body), histology (the science that studies the structure and function of tissues), cytology (the science that studies the structure, chemical composition, life processes and cell reproduction), embryology (the science that studies the patterns of development of the cell, tissues, and organs of the embryo), biochemistry (the science that studies the chemical patterns of physiological processes), and others. It makes extensive use of their methods and achievements in the process of studying body functions. Age physiology is based on the data of the sciences that study the structure of the body, since structure and function are closely related. It is impossible to deeply understand the functions without knowing the structure of the body, its organs, tissues and cells, as well as those structural and histochemical changes that occur during their activity. With the development of science and technology, the methods that are used for physiological research are being developed and improved. Without knowledge of genetics (the science of the laws of heredity and variability of organisms), it is impossible to understand the laws of evolutionary and individual development of the human body). General patterns, namely the laws of heredity, also apply to the human body. Their study is necessary to identify the specific features of the functioning of the organism at different stages of ontogenesis. Multifaceted and numerous links have long existed between physiology and medicine. According to I.P. Pavlov "Physiology and medicine are inseparable". On the basis of the knowledge gained about the physiological mechanisms and their features of the course in ontogenesis, the doctor detects their deviations from the norm, finds out the nature and extent of these disorders, determines the ways of healing the sick organism. For the purpose of clinical diagnostics, physiological methods of studying the human body are widely used.

The knowledge of physiological phenomena is based on an understanding of the laws of chemistry and physics, because all life activity is determined by the transformation of substances and energy, that is, chemical and physical processes. Age physiology, based on the general laws of chemistry and physics, gives them new qualitative features and raises them to a higher level, which is inherent in living organisms.

Fruitful and promising links with mathematics - the most schematized of all sciences, which has significantly changed physics, chemistry, genetics and other branches of scientific knowledge. The importance of mathematical principles for processing the results of physiological experiments and establishing their scientific validity is well known. Such, for example, are the methods of variational statistics in the process of comparative study of wave electrical phenomena in the brain and other physiological processes in the organism.

In physiology, the methods of holography are being introduced - obtaining a three-dimensional image of an effective object, based on the mathematical imposition of the wave-like processes associated with it. Holographic methods allow a flat two-dimensional image to be replaced by a three-dimensional one and thus reveal the subtle mechanisms of the sensory system - from its receptive field to the final neural projections in the cerebral cortex.

Physiology has common tasks with the technical sciences, namely: it opens up promising methodological possibilities in the study of physiological phenomena. On this path, an adjacent direction, electrophysiology, which studies the electrical phenomena of a living organism, has achieved great development. Modern age-related physiology includes new generations of electronic amplifiers, microelectronic equipment, telemetry, computer equipment, etc.

The interaction of age-related physiology with cybernetics, the science of the general principles of control and communication in machines, mechanisms and living organisms, has great prospects. A variety of cybernetics is physiological cybernetics, which studies the general patterns of perception, transformation and coding of information and its use in order to control physiological processes and self-regulate living systems.

Various connections of age physiology with pedagogy. There is no doubt that understanding the physiological patterns of growth and development of children, taking into account the characteristics of the functioning of the body in various age groups, is based on the natural science basis of teacher training and the entire school education system. So, the teacher must know the features of the structure and vital activity of the child's body. Numerous issues of physiological and hygienic support of the educational process at school, the formation of the student's personality, his hardening, and the prevention of diseases that are studied by school hygiene are intertwined with the problems of age physiology.

A special place is occupied by the relationship of age physiology with philosophy. Like other branches of natural science, age physiology is one of the natural science foundations of philosophical knowledge. It is natural that many concepts and theoretical generalizations that were formed within the framework of age-related physiology went beyond its limits and received general scientific, philosophical significance. A similar general theoretical meaning has, for example, the idea of ​​the growth and development of an organism, its integrity and systemic functioning, adaptation to changing environmental conditions, and the neurophysiological mechanisms of complex forms of behavior and the psyche.

School hygiene as a science develops on the basis of age physiology and anatomy. As a field of science, it also widely uses the methods and data of related disciplines: age physiology, bacteriology, toxicology, biochemistry, biophysics, and the like. It makes extensive use of the general biological laws of development. School hygiene is closely connected with all medical disciplines, as well as with technical and pedagogical sciences. Correct regulation of the activities of children and adolescents is impossible without understanding the basic principles of pedagogy and psychology. School hygiene is closely related to biology, it is considered the data of physiology and at the same time expands the understanding of the characteristics of the reaction of the body in children and adolescents to loading and the influence of the environment.

age physiology

a section of human and animal physiology that studies the patterns of formation and development of the physiological functions of the body throughout ontogeny - from egg fertilization to the end of life. V. f. establishes the features of the functioning of the body, its systems, organs and tissues at different age stages. The life cycle of all animals and humans consists of certain stages or periods. Thus, the development of mammals goes through the following periods: intrauterine (including the phases of embryonic and placental development), newborns, milk, puberty, maturity and aging.

The following age periodization has been proposed for humans (Moscow, 1967): 1. Newborn (from 1 to 10 days). 2. Breast age (from 10 days to 1 year). 3. Childhood: a) early (1-3 years), b) first (4-7 years), c) second (8-12 years old boys, 8-11 years old girls). 4. Adolescence (13-16 years old boys, 12-15 years old girls). 5. Youthful age (17-21 years old boys, 16-20 years old girls). 6. Mature age: 1st period (22-35 years old men, 21-35 years old women); 2nd period (36-60 years old men, 36-55 years old women). 7. Old age (61-74 years old men, 56-74 years old women). 8. Senile age (75-90 years). 9. Long-livers (90 years and above).

I. M. Sechenov (1878) pointed out the importance of studying physiological processes in ontogenetic terms. The first data on the features of the functioning of the nervous system in the early stages of ontogenesis were obtained in the laboratories of I. R. Tarkhanov a (1879) and V. M. Bekhterev a (1886). Researches on V. f. carried out in other countries. The German physiologist W. Preyer (1885) studied blood circulation, respiration, and other functions of developing mammals, birds, and amphibians; Czech biologist E. Babak studied the ontogeny of amphibians (1909). The publication of N. P. Gundobin's book "Features of Childhood" (1906) laid the foundation for a systematic study of the morphology and physiology of the developing human body. Works on V. f. received a large scale from the 2nd quarter of the 20th century, mainly in the USSR. The structural and functional features of the age-related development of individual organs and their systems were revealed: higher nervous activity (L. A. Orbeli, N. I. Krasnogorsky, A. G. Ivanov-Smolensky, A. A. Volokhov, N. I. Kasatkin, M M. Koltsova, A. N. Kabanov), the cerebral cortex, subcortical formations and their relationships (P. K. Anokhin, I. A. Arshavsky, E. Sh. Airapetyants, A. A. Markosyan, A. A. Volokhov and others), the musculoskeletal system (V. G. Shtefko, V. S. Farfel, L. K. Semyonova), the cardiovascular system and respiration (F. I. Valker, V. I. Puzik, N V. Lauer, I. A. Arshavsky, V. V. Frolkis), blood systems (A. F. Tur, A. A. Markosyan). Problems of age-related neurophysiology and endocrinology, age-related changes in metabolism and energy, cellular and subcellular processes, as well as acceleration are being successfully developed (See Acceleration) - accelerate the development of the human body.

The concepts of ontogenesis and aging were formed: A. A. Bogomolets - on the role of the physiological system of connective tissue; A. V. Nagorny - on the significance of the intensity of protein self-renewal (decaying curve); P. K. Anokhin - about systemogenesis, i.e. maturation in ontogenesis of certain functional systems that provide one or another adaptive reaction; I. A. Arshavsky - about the importance of motor activity for the development of the body (energy rule of skeletal muscles); A. A. Markosyan - about the reliability of a biological system that ensures the development and existence of an organism under changing environmental conditions.

In researches on V. f. they use the methods used in physiology, as well as the comparative method, i.e., comparing the functioning of certain systems at different ages, including the elderly and senile. V. f. closely related to related sciences - morphology, biochemistry, biophysics, anthropology. It is the scientific and theoretical basis of such branches of medicine as pediatrics, hygiene of children and adolescents, gerontology, geriatrics, as well as pedagogy, psychology, physical education, etc. Therefore, V. F. is actively developing in the system of institutions related to the protection of children's health, which have been organized in the USSR since 1918, and in the system of physiological institutes and laboratories of the Academy of Sciences of the USSR, the Academy of Sciences of the USSR, the Academy of Medical Sciences of the USSR, and others. introduced as a compulsory subject at all faculties of pedagogical institutes. In coordination of researches on V. f. an important role is played by conferences on age-related morphology, physiology and biochemistry, convened by the institute of age-related physiology of the Academy of Pedagogical Sciences of the USSR. The 9th conference (Moscow, April 1969) united the work of 247 scientific and educational institutions of the Soviet Union.

Lit.: Kasatkin N. I., Early conditioned reflexes in human ontogenesis, M., 1948; Krasnogorsky N. I., Proceedings on the study of higher nervous activity of humans and animals, vol. 1, M., 1954; Parkhon K. I., Age biology, Bucharest, 1959; Paper A., ​​Features of the activity of the child's brain, trans. from German, L., 1962; Nagorny A. V., Bulankin I. N., Nikitin V. N., The problem of aging and longevity, M., 1963; Essays on the physiology of the fetus and newborn, ed. V. I. Bodyazhina. Moscow, 1966. Arshavsky I. A., Essays on age physiology, M., 1967; Koltsova M. M., Generalization as a function of the brain, L., 1967; Chebotarev D. F., Frolkis V. V., Cardiovascular system during aging, L., 1967; Volokhov A. A., Essays on the physiology of the nervous system in early ontogenesis, L., 1968; Ontogeny of the blood coagulation system, ed. A. A. Markosyan, L., 1968; Farber D. A., Functional maturation of the brain in early ontogenesis, M., 1969; Fundamentals of morphology and physiology of the organism of children and adolescents, ed. A. A. Markosyan. Moscow, 1969.

A. A. Markosyan.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

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