A child is not a miniature of an adult; his body has its own anatomical and physiological characteristics, which constantly change throughout the entire period of childhood. To study physical development, anthropometric research methods are used, which make it possible to determine quantitative and qualitative indicators of development, to develop standards for the physical development of children and adolescents for each age, gender and region of residence:
Somatometric - measurement of height, weight, chest circumference;
Somatoscopic - determination of the development of the skeleton, the shape of the spine, chest, legs and feet, posture, development of muscles and subcutaneous fat, the degree of sexual development, the appearance and change of teeth;
Physiometric - determination of vital capacity of the lungs, hand strength, respiratory rate and heart rate, blood pressure, etc.). A child's growth is a direct reflection of his developmental process. If the baby doesn't grow, he doesn't develop! An increase in body length is a very important and subtle indicator of the development of the child as a whole. After birth, the child grows especially rapidly in the first year of life, adding 10-11 centimeters in height. After a year to 3-5 years, the growth rate decreases. The so-called period of first rounding, or first completeness, begins. At this age, children have a truly “angelic” appearance: the body, arms and legs resemble cylinders in shape, well-defined subcutaneous fat gives the baby a plump appearance, there are strings on the arms and legs, the tummy always looks full and protrudes slightly forward. At this time, all the children look alike with their doll faces. At the end of this period, the child begins to assert himself and win back his own “I”.
At 5-6 years old, the “angelic” appearance gradually disappears, the child stretches out, his “plumpness” seems to “dry out”, the contours of muscles and bone landmarks become visible, the baby very quickly grows out of his clothes.
At the end of primary school, from about 8-10 years of age, a period of prepubertal rounding begins, when the rate of growth slows down somewhat compared to the rate of accumulation of subcutaneous fat. As a rule, starting at this age, appetite sharply increases and the question “what to feed the child?” is replaced by concern “how to feed him.” As mentioned above, during this period girls are ahead of boys in height, weight, and in terms of sexual development. After 2-3 years, everything falls into place, boys again find themselves ahead of girls in all respects. BODY MASS.
With a body weight of 3500 to 4000 g they speak of a large child. Children born with a body weight of more than 4200 g are considered “giant children”. The body weight of a premature baby is 2500 g and below. During the first days of life, the body weight of a newborn decreases by 150-300 g (transient (physiological) weight loss) and amounts to about 5-9% of birth weight. A decrease of more than 9-10% (more than 300 g) is considered pathological weight loss.
Physiological weight loss is caused by the following factors: evaporation of moisture from the skin and during breathing; mummification of the umbilical remnant; insufficient amount of food and drink in the first days of life; vomiting of amniotic fluid swallowed during childbirth; relative starvation; passage of meconium, urine. The body weight of children over 1 year of age is calculated using the formulas:
For children from 2 to 10 years old M(kg) = 10+2n, where n is the child’s age in years. Over 10 years old: M = 30+4(n-10), where n is the child’s age in years. CHANGES IN BODY PROPORTIONS DURING CHILD DEVELOPMENT
The growth of different parts of the body during a child's life also occurs unevenly. Thus, from the moment of birth to adulthood, the height of the head doubles, the length of the body increases three times, the length of the arms increases four times, and the length of the legs increases five times. That is, human growth occurs to a greater extent due to the lengthening of the legs. Due to the uneven growth of the skeleton in length throughout childhood, the proportions of the body also change. We would be very upset if we retained the proportions of the newborn period as adults! A newborn has a relatively large head - it accounts for a quarter of his total height, short arms and legs. In an adult, the height of the head is only a tenth of the length of the body. The midpoint in a newborn corresponds to the navel, and in an adult it is located in the projection of the pubis. It has been noticed that a greater increase in growth, like everything in living nature, occurs in the spring and summer; in the fall and winter, the child grows less intensively. In cold climates and at high altitudes, people tend to be shorter. The growth rates of a child's organ systems and tissues are different. The growth of all major internal organs, bones and muscles has a fairly uniform upward pattern, corresponding to periods of accelerated growth. The brain grows rapidly only in the first years of life and by the age of five it almost reaches the size of an adult. Growth of immune lymphoid tissue, its relative mass reaches 200% at the age of 3 to 6-7 years. This is a normal age-related physiological reaction of hypertrophy of lymphoid tissue, when enlarged lymph nodes can be felt in a child, enlarged adenoids can be identified, and huge tonsils can be seen. If they are not inflamed and “do not interfere with life,” there is no need to touch them, but you should wait patiently until they begin to decrease on their own. This process of reverse development begins with the appearance of signs of puberty and the development of the organs of the reproductive system: for the time being, this system is in a “dormant” state, and from 11-12 years old in girls, and from 12-13 years old in boys it begins to “wake up”, at the same time, in boys the scrotum and testicles enlarge, the penis and prostate gland grow, and in girls the mammary glands, uterus, tubes, ovaries, and external genitalia begin to develop.
It is very important for parents to know and take into account such asynchrony in the growth of various organs and systems of the child. This can protect the family from unnecessary worry and making ill-conceived decisions, especially related to the issue of removal of adenoids and tonsils.
Cell structure and functions
The human body has a cellular structure. Cells are located in the intercellular substance, which provides them with mechanical strength, nutrition and respiration. The cell is the smallest structural unit of all living organisms, with the exception of viruses, capable of metabolism and self-reproduction.
Cytoplasm is the internal semi-liquid environment in which the nucleus and all organelles of the cell are located. It has a fine-grained structure, penetrated by numerous thin threads. It contains water, dissolved salts and organic matter. The main function of the cytoplasm is to unite into one and ensure the interaction of the nucleus and all organelles of the cell.
The outer membrane surrounds the cell with a thin film consisting of two layers of protein, between which is a fatty layer. It is permeated with numerous small pores through which the exchange of ions and molecules occurs between the cell and the environment. The endoplasmic reticulum (ER) is a complex system of channels and cavities consisting of membranes that penetrate the entire cytoplasm. There are two types of EPS - granular (rough) and smooth. On the membranes of the granular network there are many tiny bodies - ribosomes; there are none in a smooth network. The main function of the EPS is participation in the synthesis, accumulation and transportation of the main organic substances produced by the cell. Protein is synthesized in granular EPS, and carbohydrates and fats are synthesized in smooth EPS.
Ribosomes are small bodies, 15-20 nm in diameter, consisting of two particles. There are hundreds of thousands of them in each cell. Most ribosomes are located on the membranes of granular ER, and some are located in the cytoplasm. They consist of proteins and r-RNA. The main function of ribosomes is protein synthesis.
Mitochondria are small bodies, 0.2-0.7 microns in size. Their number in a cell reaches several thousand. They often change shape, size and location in the cytoplasm, moving to their most active part. The outer cover of the mitochondrion consists of two three-layer membranes. The outer membrane is smooth, the inner membrane forms numerous outgrowths on which respiratory enzymes are located. The inner cavity of mitochondria is filled with fluid, which houses ribosomes, DNA and RNA. New mitochondria are formed when old ones divide. The main function of mitochondria is ATP synthesis. They synthesize a small amount of proteins, DNA and RNA.
Plastids are characteristic only of plant cells. There are three types of plastids - chloroplasts, chromoplasts and leucoplasts. They are capable of mutual transition into each other. Plastids reproduce by fission.
Chloroplasts are green and oval in shape. Their size is 4-6 microns. From the surface, each chloroplast is bounded by two three-layer membranes - outer and inner. Inside it is filled with liquid, in which there are several dozen special, interconnected cylindrical structures - grana, as well as ribosomes, DNA and RNA. Each grana consists of several dozen flat membrane sacs superimposed on each other. In cross section, it has a round shape, its diameter is 1 micron. All the chlorophyll is concentrated in the granas; the process of photosynthesis occurs in them. The resulting carbohydrates first accumulate in the chloroplast, then enter the cytoplasm, and from there into other parts of the plant.
Chromoplasts determine the red, orange and yellow colors of flowers, fruits and autumn leaves. They have the form of multifaceted crystals located in the cytoplasm of the cell.
Leucoplasts are colorless. They are found in uncolored parts of plants (stems, tubers, roots) and have a round or rod-shaped shape (5-6 microns in size). Spare substances are deposited in them. The Golgi complex was named after the Italian scientist who first discovered it in nerve cells. It has a varied shape and consists of cavities bounded by membranes, tubes extending from them and vesicles located at their ends. The main function is the accumulation and excretion of organic substances synthesized in the endoplasmic reticulum, the formation of lysosomes.
Lysosomes are round bodies with a diameter of about 1 micron. On the surface, the lysosome is bounded by a three-layer membrane; inside it there is a complex of enzymes capable of breaking down carbohydrates, fats and proteins. There are several dozen lysosomes in a cell. New lysosomes are formed in the Golgi complex. Their main function is to digest food that has entered the cell by phagocytosis and remove dead organelles.
Organelles of movement - flagella and cilia - are cell outgrowths and have the same structure in animals and plants (their common origin). The movement of multicellular animals is ensured by muscle contractions. The main structural unit of a muscle cell is myofibrils - thin filaments more than 1 cm long, 1 micron in diameter, located in bundles along the muscle fiber.
Cellular inclusions - carbohydrates, fats and proteins - are among the unstable components of the cell. They are synthesized periodically, accumulate in the cytoplasm as reserve substances and are used in the process of vital activity of the body. The nucleus is one of the most important organelles of the cell. It is separated from the cytoplasm by a nuclear envelope consisting of two three-layer membranes, between which there is a narrow strip of semi-liquid substance. Through the pores of the nuclear membrane, substances are exchanged between the nucleus and the cytoplasm. The cavity of the nucleus is filled with nuclear juice. It contains a nucleolus (one or more), chromosomes, DNA, RNA, proteins and carbohydrates. The nucleolus is a round body ranging in size from 1 to 10 microns or more; it synthesizes RNA. Chromosomes are visible only in dividing cells.
Cell functions
The nucleus stores genetic information.
Mitochondria produce energy.
The Gopji apparatus is the “transport” system of the cell.
Lysosomes remove waste and break down protein.
Desmosomes communicate with other cells.
Organelles take part in cell metabolism.
The cell membrane maintains the shape of the cell.
Depending on the function they perform, all cells are divided into certain types. The most important cells, according to their type and “tasks performed,” are divided into: cells of bone, cartilage (a type of connective tissue), connective, muscle, nervous, integumentary tissue, as well as gland and blood cells. Different cells even “divide the work” among themselves, and each is responsible for its own. For example, muscle cells do not produce glucose, but receive it from other cells that perform this function
Chemical composition of the cell
The cell consists of the same chemical elements as inanimate nature: it contains most of the elements of Mendeleev’s periodic table. The cells of living organisms have a particularly high content of four elements - oxygen (O), carbon (C), hydrogen (H), nitrogen (N), called macroelements. Together they make up about 98% of the total contents of the cell. Together with sulfur and phosphorus, these elements are part of biopolymers - proteins, fats, carbohydrates and nucleic acids.
Microelements: sulfur (S), phosphorus (P), potassium (K), sodium (Ma), calcium (Ca), magnesium (Mg), iron (Fe), chlorine (CI), total about 1.9% cell contents.
Ultramicroelements: zinc (Zn), copper (Cu), iodine (J), fluorine (F), etc., make up less than 0.1% of the cell contents. All elements play an important role in the cell and are needed in strictly defined quantities; their deficiency or excess leads to various metabolic disorders in the body.
Organic substances of the cell:
Proteins are macromolecules, or biopolymers. The monomers of proteins in living cells are 20 different amino acids. A peptide (covalent) bond is formed between the carboxyl group COOH (acidic) and the amine group H - N - H (basic) of two neighboring amino acids. Different combinations of amino acids in protein molecules give proteins specificity. The sequential combination of amino acids in a protein forms its primary structure - a polypeptide. In most cases, the polypeptide is twisted into a helix - the secondary structure of the protein. Functions of proteins:
Construction: proteins are part of cellular structures.
Transport: the ability of proteins to bind and transport many chemical compounds through the bloodstream (for example, transport of oxygen by hemoglobin).
Receptor function: ensures the interaction of cells with each other, as well as with various macromolecules of proteins to reversibly change the structure in response to the action of physical and chemical factors; it is the basis of irritability.
The contractile function is provided by special contractile proteins, due to which the movement of flagella, cilia, muscle contraction, etc. occurs.
Energy function: proteins are a reserve source of energy.
Catalytic function: Enzyme proteins speed up chemical reactions.
Protective function: antibody proteins (immunoglobulins) neutralize antigens (foreign substances) that cause diseases in the body.
The regulatory function is provided by hormone proteins that regulate metabolism.
Carbohydrates are divided into simple - monosaccharides (ribose, deoxyribose, glucose, fructose, etc.) and complex - disaccharides (sucrose, lactose, maltose) and polysaccharides (starch, glycogen, cellulose, chitin, etc.).
Functions of carbohydrates: they are part of nucleic acids and ATP, they are a universal source of energy in the body, they participate in the neutralization and removal of toxic substances from the body, polysaccharides play the role of reserve products.
Lipids are neutral fats, waxes, phospholipids and steroid hormones. They are insoluble in water, but highly soluble in organic solvents (gasoline, ether, benzene, etc.). They usually contain glycerin and fatty acids.
Functions of lipids: used as a reserve source of energy; are part of cell membranes; perform protective functions (thermal insulation).
Nuclevonic acids are molecules of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). DNA is a biopolymer, its monomers - nucleotides - consist of a nitrogenous base (adenine, guanine, cytosine, thymine), a monosaccharide (deoxyribose) and a phosphoric acid residue. The DNA molecule itself is 2 polynucleotide chains twisted into a spiral, united by hydrogen bonds.
Function of DNA: recording, storage and reproduction of hereditary information.
Ribonucleic acid (RNA) is a single-stranded biopolymer consisting of nucleotides in which the nitrogenous base thymine is replaced by uracil, and the carbohydrate deoxyribose is replaced by ribose. There are 3 types of RNA: messenger RNA (i-RNA), transport RNA (t-RNA) and ribosomal RNA (r-RNA).
Functions of RNA: participation in the reproduction of hereditary information (in protein synthesis).
Adenosine triphosphoric acid (ATP) is a mononucleotide consisting of ribose, adenine and three phosphoric acid residues.
Function: ATP is a universal source of energy in the cell.
Many artists and scientists have been trying to unravel the mysteries of the human body for years and have been looking for perfect human proportions. This question remains open today, since on a subconscious level each of us strives for harmony and perfection.
What are the ideal proportions of a person?
The answer to this complex question is very simple. First of all, the ideal proportions of a person should be in harmony taking into account his physique, height and age.
If you carefully examine your body, you will notice that the distance from the wrist to the beginning of the elbow bend is equal to the size of the foot. The length of the lower leg (including the foot) will be equal to the length of the thigh, and the kneecap will divide the leg into two completely equal parts.
The femur is definitely longer than the tibia, and it is longer than the foot. Also, the forearm is shorter than the humerus, but longer than the hand. The hand lowered down will reach exactly half the thigh with the fingertips.
The length of the head is usually taken as the unit of measurement for the human body. The ideal parameters for the ratio of head length to body height of a person are 1/8 and 1/7.5 for men and women, respectively. Recently, there has been a tendency to change body proportions, and today a ratio of 1:9 for humans is considered the norm.
Because the height of an ideal human figure is eight heads. In general, the head is the most universal unit of measurement when it comes to a person :).
The width of the figure at its widest point is equal to two whole and one third of the head.
The female figure has two heads at its widest part. The nipples drop a little lower than those of a man. The waist width is equal to one head. The hips are slightly wider in front than the armpits, and narrower in the back. Depending on the constitution, the legs below the knees can be lengthened. The wrists are at the same level as the crotch. A height of approximately 170 cm is considered ideal for a girl in heels, although, of course, in reality, the average girl has much shorter legs and heavier hips. A woman's navel is below the waist line, and a man's is either lower or at the same level. Vertically, the distance between the nipples and the navel is equal to one head, but both the nipples and the navel are lower than the division lines. The elbows are above the navel.
If you look at drawings of people made using different relative proportions, you can see why real or, in other words, normal proportions do not look very attractive. This is especially important in manga, where distortion is used as the main artistic device. Most artists draw people taller than eight heads, and when drawing a variety of heroes and “supermen”, using the “nine head” measure will be very effective. It is also worth noting that as the figure grows, its center shifts lower and lower.
Ideal human facial proportions
A person’s face, like his body, must have strict proportional relationships:
The distance from the border of the hair to the beginning of the chin should be 1/10 of the person’s height;
- the length from the top of the head to the beginning of the chin should be 1/8 of the person’s height;
- the distance from the beginning of the chin to the tip of the nose is equal to 1/3 of the length of the entire face;
- the distance from the hairline to the eyebrow line should be 1/3 of the length of the face;
- the length of the ears is equal to 1/3 of the total length of the face.
This pattern can be seen on the face of every person. But in life, people with ideal facial proportions are quite rare. As a result of certain deviations from perfect proportions, individual facial features arise. This is why all people are different.
Change in human proportions with age
With age, body proportions change. Children are noticeably different from adults with a long body, short legs and a large head. So, in a newborn, the length of the head is equal to 1/4 of his height, at two years - 1/5 of the part, at six years - 1/6 of the part, and in an adult - already 1/8 of the part. As you can see, only as the child grows older do the proportions begin to correspond to an adult.
Main body types
To calculate the Pignier index, it is necessary to sum up body weight and chest circumference. Next, you need to subtract the result obtained above from the body length value.
If the Pinier index is 30 or more, then the person belongs to the asthenic type and has a thin physique.
If the index is equal to a value of up to 30, then the person can be classified as an athletic type with a normal physique.
If this index is less than 10, then the person belongs to the picnic type with an obese physique.
Research results
As a result of numerous studies, it has been proven that the proportions of a person’s body directly affect his life expectancy. This fact was argued by scientists from the UK together with the German Institute for Healthy Nutrition. Experts conducted studies on the relationship between the risk of premature death and body proportions and came to the unanimous conclusion that with a large waist circumference, the likelihood of premature death increases.
Conclusion
Almost all parts of the human body have certain proportional relationships, but their values may have individual deviations. If your proportions do not match the ideal parameters, do not be upset. After all, the main qualities in a person are his individuality, harmony and health!
Based on materials from sites FB.ua And "Body Harmony"
4.2 Sizes and proportions, body weight
Among the body sizes, total (from the French total - whole) and partial (from the Latin pars - part) are distinguished. Total (general) body dimensions are the main indicators of human physical development. These include body length and weight, as well as chest girth. Partial (partial) body sizes are components of the total size and characterize the size of individual parts of the body.
Body sizes are determined through anthropometric surveys of various populations.
Most anthropometric indicators have significant individual variations. Table 2 shows some average anthropometric indicators in postnatal ontogenesis.
Body proportions depend on the age and gender of the person (Fig. 4). Body length and its age-related changes, as a rule, vary from person to person. For example, differences in the body length of newborns during a normal pregnancy range from 49-54 cm. The greatest increase in the body length of children is observed in the first year of life and averages 23.5 cm. In the period from 1 to 10 years, this indicator gradually decreases by an average of 10.5 - 5 cm per year. From the age of 9, sex differences in growth rate begin to appear. Body weight gradually increases in most people from the first days of life until about 25 years of age, and then remains unchanged.
Fig.4. Changes in the proportions of body parts during human growth.
KM - middle line. The numbers on the right show the ratio of body parts in children and adults, the numbers below show age.
After 60 years, body weight, as a rule, begins to gradually decrease, mainly as a result of atrophic changes in tissues and a decrease in their water content. Total body weight is made up of a number of components: skeletal mass, muscle mass, fatty tissue, internal organs and skin. For men, the average body weight is 52-75 kg, for women - 47-70 kg.
In old and senile age, characteristic changes can be observed not only in body size and weight, but also in its structure; These changes are studied by the special science of gerontology (gerontos - old man).
It should be especially emphasized that an active lifestyle and regular physical exercise slow down the aging process.
5. Acceleration
It should be noted that over the past 100-150 years there has been a noticeable acceleration in the somatic development and physiological maturation of children and adolescents - acceleration (from the Latin acceleratio - acceleration). Another term for the same trend is "epochal shift." Acceleration is characterized by a complex set of interrelated morphological, physiological and mental phenomena. To date, morphological indicators of acceleration have been determined.
Thus, the body length of children at birth over the past 100-150 years has increased by an average of 0.5-1 cm, and their weight has increased by 100-300 g. During this time, the weight of the mother’s placenta has also increased. An earlier equalization of the ratios of chest and head girths is also noted (between the 2nd and 3rd month of life). Modern one-year-old children are 5 cm longer and 1.5-2 kg heavier than their peers in the 19th century.
Over the past 100 years, the body length of preschool children has increased by 10-12 cm, and for schoolchildren - by 10-15 cm.
In addition to an increase in body length and weight, acceleration is characterized by an increase in the size of individual parts of the body (segments of limbs, thickness of skin-fat folds, etc.). Thus, the increase in chest girth in relation to the increase in body length was small. The onset of puberty in modern adolescents occurs approximately two years earlier. The acceleration of development also affected motor functions. Modern teenagers run faster, jump farther from a standing position, and do more pull-ups on the horizontal bar.
The epochal shift (acceleration) affects all stages of human life, from birth to death. For example, the body length of adults also increases, but to a lesser extent than in children and adolescents. Thus, at the age of 20-25 years, the body length of men increased by an average of 8 cm.
Acceleration covers the entire body, affecting the size of the body, the growth of organs and bones, and the maturation of the gonads and skeleton. In men, changes in the acceleration process are more pronounced than in women.
Men and women are distinguished by sexual characteristics. These are primary signs (genital organs) and secondary ones (for example, development of pubic hair, development of mammary glands, change in voice, etc.), as well as body features, proportions of body parts.
The proportions of the human body are calculated as a percentage based on measurements of longitudinal and transverse dimensions between boundary points established on various protrusions of the skeleton.
The harmony of body proportions is one of the criteria when assessing a person’s health status. If there is a disproportion in the structure of the body, one can think about a violation of growth processes and the causes that determined it (endocrine, chromosomal, etc.). Based on the calculation of body proportions in anatomy, three main types of human physique are distinguished: mesomorphic, brachymorphic, dolichomorphic. The mesomorphic body type (normosthenics) includes people whose anatomical features are close to the average normal parameters (taking into account age, gender, etc.). People with a brachymorphic body type (hypersthenics) have predominantly transverse dimensions, well-developed muscles, and are not very tall. The heart is positioned transversely due to the high-standing diaphragm. In hypersthenics, the lungs are shorter and wider, the loops of the small intestine are located predominantly horizontally. Persons with a dolichomorphic body type (asthenics) are distinguished by a predominance of longitudinal dimensions, have relatively longer limbs, poorly developed muscles and a thin layer of subcutaneous fat, and narrow bones. Their diaphragm is located lower, so the lungs are longer, and the heart is located almost vertically. Table 3 shows the relative sizes of body parts for people of different body types.
Table 3.
Body proportions (according to P.N. Bashkirov)
Conclusion
What conclusion can be drawn from the above?
Human growth is uneven. Each part of the body, each organ develops according to its own program. If we compare the growth and development of each of them with a long-distance runner, it is not difficult to discover that during this multi-year “run” the leader of the competition is constantly changing. In the first month of embryonic development, the head is in the lead. In a two-month fetus, the head is larger than the body. This is understandable: the brain is located in the head, and it is the most important organ that coordinates and organizes the complex work of organs and systems. The development of the heart, blood vessels and liver also begins early.
In a newborn baby, the head reaches half its final size. Until 5-7 years of age, there is a rapid increase in body weight and length. In this case, the arms, legs and torso grow alternately: first - the arms, then the legs, then the torso. The size of the head increases slowly during this period.
In primary school age from 7 to 10 years, growth is slower. If earlier the arms and legs grew more quickly, now the torso becomes the leader. It grows evenly, so that the proportions of the body are not disturbed.
During adolescence, hands grow so rapidly that the body does not have time to adapt to their new sizes, hence some clumsiness and sweeping movements. After this, the legs begin to grow. Only when they reach their final size is the body included in growth. First it grows in height, and only then begins to grow in width. During this period, the human physique is finally formed.
If you compare the body parts of a newborn and an adult, it turns out that the size of the head has only doubled, the torso and arms have become three times larger, and the length of the legs has increased five times.
An important indicator of the development of the body is the appearance of menstruation in girls and wet dreams in boys; it indicates the onset of biological maturity.
Along with the growth of the body comes its development. Human growth and development in different people occurs at different times, so anatomists, doctors, and physiologists distinguish between calendar age and biological age. Calendar age is calculated from the date of birth, biological age reflects the degree of physical development of the subject. The latter is different for each person. It may happen that people who are at the same biological age may differ by 2-3 years in calendar terms, and this is completely normal. Girls tend to develop faster.
Literature and Internet sources
Medical scientific and educational journal No. 28 [October 2005]. Section - Lectures. The title of the work is PERIODS OF CHILDHOOD. Author - P.D. Vaganov
Vygotsky L.S. Collected works in 6 volumes. Volume 4.
Vygotsky L.S. article "Problems of age periodization of child development"
Obukhova L.F. textbook "Children's (age) psychology". Fundamental and clinical physiology / Edited by A.G. Kamkin and A.A. Kamensky. - M.: "Academy", 2004.
Schmidt R., Tevs G. Human physiology: Transl. from English - M.: Mir, 1996.
Dragomilov A.G., Mash R.D. Biology: Human. - 2nd ed., revised. - M.: Ventana-Graf, 2004.
Sapin. M.R., Bryksina Z.G. Anatomy and physiology of children and adolescents: Textbook. aid for students ped. Universities. - M.: Publishing center "Academy", 2002.
Chusov Yu.N. Human physiology: Proc. manual for teachers Schools (specialist No. 1910). - M.: Education, 1981.
Encyclopedia "Around the World": http: // www. krugosvet. ru/
Website "Rusmedservice": www. rusmedserv. com/endocrinology/
Encyclopedia "Wikipedia": http: // ru. wikipedia. org/wiki/
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A characteristic feature of the growth process of a child’s body is its unevenness and undulation. Periods of increased growth are followed by some slowdown. This pattern can be seen especially clearly when expressing the growth rate of a child’s body graphically.
The child’s growth is most intense in the first year of life and during puberty, i.e. at 11–15 years. If at birth the child’s height is on average 50 cm, then by the end of the first year of life it reaches 75–80 cm, i.e. it increases by more than 50%; body weight triples over the year - at the birth of a child it is on average 3.0 - 3.2 kg, and by the end of the year - 9.5 - 10.0 kg. In subsequent years until puberty, the growth rate decreases and the annual weight gain is 1.5 - 2.0 kg, with an increase in body length by 4.0 - 5.0 cm.
The second growth spurt is associated with the onset of puberty. Over the course of a year, body length increases by 7–8 and even 10 cm. Moreover, from the age of 11–12 years, girls are slightly ahead of boys in growth due to the earlier onset of puberty. At the age of 13–14, girls and boys grow almost equally, and from the age of 14–15, boys and young men outstrip girls in height, and this excess of height in men over women persists throughout life.
Body proportions also change greatly with age. From the neonatal period to adulthood, body length increases by 3.5 times, body length by 3 times, arm length by 4 times, and leg length by 5 times.
A newborn differs from an adult in having relatively short limbs, a large body and a large head. The height of a newborn’s head is 1/4 of the length of the body, for a 2-year-old child – 1/5, 6-year-old – 1/6, 12-year-old – 1/7 and for adults – 1/8. With age, head growth slows down and limb growth accelerates. Before the onset of puberty (prepuberty), there are no gender differences in body proportions, but during puberty (puberty), boys' limbs become longer, their torso shorter, and their pelvis narrower than girls'.
Three periods of difference in the proportions between the length and width of the body can be noted: from 4 to 6 years, from 6 to 15 years, and from 16 years to adulthood. If in the prepubertal period general height increases due to the growth of the legs, then in the puberty period it increases due to the growth of the torso.
The growth curves of individual parts of the body, as well as many organs, basically coincide with the growth curve of body length. However, some organs and parts of the body have a different type of growth. For example, the growth of the genital organs occurs intensively during puberty, and the growth of lymphatic tissue ends by this period. The head size of 4-year-old children reaches 75% of the size of an adult’s head. Other parts of the skeleton continue to grow rapidly even after 4 years.
Uneven growth is an adaptation developed by evolution. The rapid growth of the body in length in the first year of life is associated with an increase in body weight, and the slowdown in growth in subsequent years is due to the manifestation of active processes of differentiation of organs, tissues, and cells.
We have already noted that development leads to morphological and functional changes, and growth leads to an increase in the mass of tissues, organs and the entire body. During the normal development of a child, both of these processes are closely interrelated. However, periods of intense growth may not coincide with periods of differentiation.
Along with the typical characteristics for each age period, there are individual developmental characteristics. They vary and depend on the state of health, living conditions, and the degree of development of the nervous system.
2. Spinal column. The main parts of the skeleton are the trunk skeleton, consisting of the spinal column and chest, the skeleton of the upper and lower extremities and the skeleton of the head - the skull.
The human spinal column is the axial part, the core of the skeleton, the upper end connecting to the skull, the lower end to the pelvic bones. The spinal column occupies 40% of the body length. It distinguishes the following sections: cervical, consisting of 7 vertebrae, thoracic - of 12 vertebrae, lumbar - of 5 vertebrae, sacral - of 5 vertebrae and coccygeal - of 4 - 5 vertebrae. In an adult, the sacral vertebrae fuse into one bone - the sacrum, and the coccygeal vertebrae - into the coccyx. The vertebral foramina of all vertebrae form the spinal canal, which houses the spinal cord. Muscles are attached to the processes of the vertebrae.
Between the vertebrae are intervertebral discs made of fibrocartilage; they promote mobility of the spinal column. With age, the height of the discs changes.
The growth of the spinal column occurs most intensively in the first 2 years of life. During the first year and a half of life, the growth of various parts of the spine is relatively uniform. Starting from 1.5 to 3 years, the growth of the cervical and upper thoracic vertebrae slows down and the growth of the lumbar region begins to increase faster, which is typical for the entire period of growth of the spine.
An increase in the rate of growth of the spine is observed at 7–9 years of age and during puberty, after which the increase in the growth of the spine is very small.
The structure of the tissues of the spinal column changes significantly with age. Ossification, which begins in the prenatal period, continues throughout childhood. Until the age of 14, only the middle parts of the vertebrae ossify. During puberty, new ossification points appear in the form of plates, which merge with the vertebral body after 20 years. The process of ossification of individual vertebrae is completed with the end of growth processes - by 21 - 23 years. Late ossification of the spine determines its mobility and flexibility in childhood. The curvature of the spine, which is its characteristic feature, is formed in the process of the individual development of the child. At a very early age, when the child begins to hold his head, a cervical curve appears, convexly directed forward ( lordosis ). By 6 months, when the child begins to sit, a thoracic curve is formed with a convexity backwards ( kyphosis ). When a child begins to stand and walk, lumbar lordosis . With the formation of lumbar lordosis, the center of gravity moves posteriorly, preventing the body from falling in an upright position.
By the age of one year, all the curves of the spine are already present. But the resulting curves are not fixed and disappear when the muscles relax. By the age of 7, there are already clearly defined cervical and thoracic curves, fixation of the lumbar curve occurs later - at 12 - 14 years.
The curves of the spinal column are a specific feature of humans and arose in connection with the vertical position of the body. Thanks to the bends, the spinal column is springy. Impacts and shocks when walking, running, jumping are weakened and attenuated, which protects the brain from concussions. Disturbances in the curvature of the spinal column, which can arise as a result of improper seating of the child at the table and desk, lead to adverse consequences in his health.
3. Chest. The rib cage forms the bony base of the thoracic cavity. It protects the heart, lungs, liver and serves as an attachment point for the respiratory muscles and muscles of the upper limbs. The rib cage consists of the sternum, 12 pairs of ribs, connected at the back to the spinal column.
The shape of the chest changes significantly with age. In infancy, it is as if compressed from the sides, its anteroposterior size is larger than the transverse one ( conical shape ). In an adult, the transverse size predominates.
During the first year of life, the shape of the chest gradually changes, which is associated with changes in body position and center of gravity. The angle of the ribs relative to the spine decreases. According to the change in the chest, the volume of the lungs increases. Changing the position of the ribs helps to increase the movement of the chest and allows for more efficient breathing movements.
Further changes in the structure of the chest with age occur in the same direction. The conical shape of the chest lasts up to 3–4 years. By the age of 6, the relative sizes of the upper and lower parts of the chest characteristic of an adult are established, and the inclination of the ribs sharply increases. By the age of 12–13, the chest acquires the same shape as that of an adult.
The shape of the chest is influenced by exercise and posture. Under the influence of physical exercise, it can become wider and more voluminous. With prolonged incorrect sitting, when the child leans his chest against the edge of a table or desk lid, deformation of the chest can occur, which impairs the development of the heart, large vessels and lungs.
4. Skeleton of limbs. The skeleton of the upper limbs consists of the girdle of the upper limbs and the bones of the free limbs. The girdle of the upper limbs is formed by the shoulder blades and collarbones.
The skeleton of the free upper limb is formed by the humerus, movably connected to the scapula, the forearm, consisting of the radius and ulna, and the bones of the hand. The hand consists of small bones of the wrist, five long bones of the metacarpus and bones of the fingers.
The clavicles are stable bones that change little during ontogenesis. The shoulder blades ossify in postnatal ontogenesis; this process ends after 16–18 years. Ossification of free limbs begins in early childhood and ends at 18–20 years of age, and sometimes later.
The carpal bones of a newborn are just emerging and become clearly visible by the age of 7 years. From 10 to 12 years of age, gender differences in ossification processes appear. In boys they are late by 1 year. Ossification of the phalanges of the fingers is completed by 11 years of age, and of the wrist by 12 years of age. These data should be taken into account in the pedagogical process.
A hand that is not fully formed quickly tires, and primary school children are unable to write fluently. At the same time, moderate and accessible movements contribute to the development of the hand. Playing musical instruments from an early age delays the process of ossification of the phalanges of the fingers, which leads to their lengthening (“musician’s fingers”).
The skeleton of the lower extremities consists of the pelvic girdle and the bones of the free lower extremities. The pelvic girdle is formed by the sacrum and the two pelvic bones fixedly connected to it. In a newborn, each pelvic bone consists of three bones (iliac, pubic and ischial), the fusion of which begins at 5–6 years of age and is completed by 17–18 years of age.
During adolescence, the sacral vertebrae gradually fuse into a single bone - the sacrum. In girls, when jumping sharply from great heights or wearing high-heeled shoes, the unfused pelvic bones can shift, which will lead to improper fusion and, as a consequence, narrowing of the outlet from the pelvic cavity, which can further make it very difficult for the fetus to pass during childbirth.
After 9 years, differences in the shape of the pelvis in boys and girls are noted: boys have a higher and narrower pelvis than girls.
The pelvic bones have round sockets into which the heads of the femurs fit. The skeleton of the free lower limb consists of the femur, two bones of the lower leg - the tibia and fibula, and the bones of the foot. The foot is formed by the bones of the tarsus, metatarsus and phalanges of the toes.
The human foot forms an arch that rests on the heel bone and the anterior ends of the metatarsal bones. There are longitudinal and transverse arches of the foot. The longitudinal, springy arch of the foot is unique to humans, and its formation is associated with upright walking. The weight of the body is evenly distributed over the arch of the foot, which is of great importance when carrying heavy loads. The arch acts like a spring, softening the shock of the body when walking.
In a newborn child, arching of the foot is not pronounced; it develops later, when the child begins to walk.
The arched arrangement of the bones of the foot is supported by a large number of strong articular ligaments. With prolonged standing and sitting, carrying heavy loads, or wearing narrow shoes, the ligaments are stretched, which leads to flattening of the foot.
5. Skull. Skull – skeleton of the head. There are two sections of the skull: the brain, or cranium, and the facial, or facial bones. The cerebral part of the skull is the seat of the brain.
In a newborn, the cranial bones are connected to each other by a soft connective tissue membrane. This membrane is especially large where several bones meet. These are fontanelles. The fontanelles are located at the corners of both parietal bones; There are unpaired frontal and occipital and paired anterior lateral and posterior lateral fontanelles. Thanks to the fontanelles, the bones of the roof of the skull can overlap each other with their edges. This is of great importance when the fetal head passes through the birth canal. Small fontanelles overgrow by 2–3 months, and the largest one, the frontal one, is easily palpable and overgrown only by one and a half years.
In children at an early age, the cerebral part of the skull is more developed than the facial part. The bones of the skull grow most rapidly during the first year of life. With age, especially from 13 to 14 years, the facial region grows more vigorously and begins to dominate over the brain. In a newborn, the volume of the cerebral part of the skull is 6 times larger than the facial part, and in an adult it is 2 – 2.5 times.
Head growth is observed at all stages of child development; it occurs most intensively during puberty. With age, the relationship between head height and height changes significantly. This ratio is used as one of the normative indicators characterizing the age of the child.
Every person at least once in his life thought about his external data and would like to change something. Some people dream of losing excess weight, others want to gain weight, and others are not satisfied with their height and body proportions. At the same time, few people know that the human constitution and the features of its changes during life are programmed genetically. Therefore, when starting to work on bringing your figure closer to the ideal one, you need to find out what types of human physique scientists distinguish, and which one you belong to.
Human physique
The human physique is a set of proportions and specific structure of body parts, as well as features of the development of its tissues: muscle, bone and fat. All these parameters are determined during the period of intrauterine development, and further changes in a person are subject to this genetic program. Researchers also identify such a concept as somatotype. This is not only the actual constitutional features of a person’s physique, but also an option for its further change under the influence of external factors. Somatotype is determined as a result of various body measurements. It is characterized by certain metabolic parameters, predisposition to certain diseases and mental characteristics.
Somatotyping techniques
Since ancient times, people have tried to determine the main human body types and classify all people according to this principle. Researchers began to notice that men and women with different somatotypes react to various external factors (age, nutrition, illness) with unequal changes in physique. Currently, there are many classifications of people according to their constitutional type. They are all similar to each other. Let's look at some of them.
Proportions and body types of a person
Body proportions are one of the important indicators of people's physical health. Of course, each person is unique, but over the course of numerous studies and measurements, scientists have determined the average parameters that they usually focus on. If there is a noticeable disproportion between parts of the human body, we can talk about the presence of growth disorders. They can be caused by deviations in the normal functioning of the endocrine system, chromosomal abnormalities. In accordance with proportions, the following human body types are distinguished, the anatomy of which is different:
Mesomorphic type. It includes people whose proportions are close in value to the average parameters. This takes into account gender, age and some other characteristics.
Brachymorphic type. People of this type are strong and muscular, usually short in stature. The transverse dimensions of their body parts prevail over the longitudinal ones. This also applies to internal organs. The lungs, for example, in people of brachymorphic body type are wide, but short. The heart is located almost transversely.
Dolichomorphic type. A person with such a constitution is tall, has long arms and legs. He has a small layer of fat under the skin, with poorly developed muscles. People with a dolichomorphic physique are characterized by a predominance of longitudinal over transverse dimensions.
E. Kretschmer: the relationship between the psyche and physique
In addition to the relationship between body type and a person’s physical health, some researchers have noted the influence of the constitution on the individual’s psyche. Among them we can distinguish the German scientist E. Kretschmer, who classified 3 types of people according to their physique:
Athletic. Such a person has well-developed muscles and is usually tall or average height. An athlete has broad shoulders and narrow hips. Kretschmer believed that such people are responsible and good organizers. They always finish what they start and do not like long discussions and red tape. They can become good managers and production workers.
Asthenic. These people are tall, but because of their thinness, they seem even taller than they actually are. They have long limbs, a flat chest, a pale, elongated face, and a long nose. For asthenics, according to Kretschmer, the main type of behavior is a thinker. These are people of mental work with a well-developed imagination. They love to fantasize, read a lot, but cannot organize their activities well.
Picnic. People of this type are short in stature, have a dense physique with a tendency towards obesity. They have a small, wide face and a short and thick neck. People of this type are sociable, they get along well with colleagues, friends, and relatives. They don't like to read. They prefer to get all the information they need from communicating with other people.
W. Sheldon's technique
One of the founders of somatotyping was Professor W. Sheldon. Back in 1940, he suggested that it is necessary to evaluate not the human physique as a whole, but its individual components. Their combination will determine one or another somatotype, which, according to Sheldon, remains unchanged throughout life. The scientist proposed to evaluate the components using a point system ranging from 1 to 7 (minimum and maximum severity, respectively). This should be done by a trained specialist. Sheldon identified three components:
- endomorphic;
- ectomorphic;
- mesomorphic.
For each of them, a certain value is selected, and the resulting triple of numbers is the somatotype of a particular person. Of course, it is rare to find people who have the maximum score for one component and the minimum for the rest. In most cases, researchers observe average values, among which one component still predominates. Based on Sheldon's research, three human body types are distinguished.
Ectomorph
People with an ectomorphic body type are thin, tall, and have a small amount of subcutaneous fat. The muscles are poorly developed. Parts of the body are slightly elongated, this is especially evident in the structure of the face and chest. A person with an ectomorphic physique has long arms and legs relative to his body. The more pronounced the ectomorphic trait in a person, the less likely it is that under the influence of any factors he will become overweight.
Mesomorph
The constitution of a person with a mesomorphic physique is dominated by bones and muscles. There is little subcutaneous fat. The muscles are well developed, especially in the limbs. Such a person has a broad chest and shoulders.
Endomorph
The main feature of the endomorphic body type is the predominance of the profile dimensions of its various parts over the transverse ones. Such people have a large amount of fat under the skin, some of which is concentrated in the shoulders and hips. The arms and legs are flaccid and have poorly developed muscles. The belly is large and round in shape. Unlike people with ectomorphic or mesomorphic body types, an individual with pronounced endomorphic characteristics is very prone to obesity.
Medical practice
There are many classifications based on a person’s physique. The types and characteristics of constitutional features are similar to each other. In medicine, for example, it is customary to focus on the following classification:
Normosthenic type. It includes people with a proportional body, consistency in the development of the skeletal and muscular systems.
Asthenic type. Such people have a slender, tall body. Their chest dominates the size of their abdomen, and their limbs are longer when compared with their body. The muscles of people of the asthenic type are poorly developed.
Hypersthenic type. Such people differ from normosthenics in their shorter stature, dense build, and predominance of transverse dimensions over longitudinal ones.
Every doctor knows the body types of a person and their effect on the condition of the body. Having assessed a person according to his constitution, it is easier for a specialist to determine a tendency to a particular disease and give recommendations regarding lifestyle and treatment methods.
