How different the impressions are by age. Age periods of human development

How different are the impressions of what we read, hear and see depending on age!
I remember when I was a child they took me to the circus.
How much joy, how much pleasure!
In my youth, I also visited it and visited it often - I was drawn there by the grace of the movements of the riders, the courage of the acrobats, the triumph of animal training by the crown of creation - man...
More mature years came - I occasionally and only by chance went to the circus.
Now I don't go there at all. Why?
I remember the last time I was there, very strange thoughts came to me...
The turn came - I vividly remember this - to the last number of the program - taming the lions.
A huge iron cage was wheeled into the arena. Three young African lions walked quickly back and forth in it, emitting a dull growl, shaking their manes and sparkling eyes.
They seemed to be reasoning with themselves, and it seemed to me, from the varied tone of their growls, that these reasonings were on different topics.
One, I understood them, said:
-Who dares to order me? To whom will I bow my head and on whom will I not let out my claws? I'll leave, they only saw me! I will break all the locks, I will cover immeasurable spaces and reach my distant homeland - the quiet desert. Where the gazelles that I will feast on drink by the stream, where I will quench my thirst, beautiful young lionesses with silky fur, with eyes burning with green fire, are waiting for me, basking on the hot sand. I will let out a joyful cry of love, and the one who loves me will respond to my call. We will walk with her through the vast desert, scorched by the sun, happy, free. Having surrendered to the first delights of love, licking our lips, bloodied by the happy prey, we will fall asleep sweetly, and only the moon, frightened and enchanted, will contemplate from the cloudless sky this conjugal dream of the royal couple of the desert...
Another made other plans in a sharper tone:
-Who is thinking of subjugating me? To whom will my proud will bow? Now I will grab the bars and locks with my teeth and chew them easier than a child cracks nuts. But I will not retire into the peace and quiet of the desert, I will run to the cities where my brothers languish in captivity, where they dare to be shown off for fun. I will destroy all the cells and free the unfortunate prisoners. There will be tens, hundreds, thousands of us, and only when there is not a single lion in prison on the entire globe, only then will I return to my native countries, liberated and liberator, with joy in my heart, as befits a victorious king returning to his fatherland at the head of the liberated people.
The third dreamed differently:
- Let them not try to enslave me! This is a waste of time! Not a single glance will make me look down! With one blow of my mighty paw I will break into pieces both the wood and the iron of my prison, I will turn everything into splinters and dust. But I thirst for freedom not for the pleasures of love and not to achieve the glory of the liberator of enslaved brothers. No, absolutely not. I will go to the most remote place, unknown to either people or lions. There I will live alone, contemplating only boundless spaces around me: desert, sea and sky. I will only exchange glances with the stars. Finally, having grown old in the midst of this charming infinity, I will die with my head bowed on my paws, in view of the setting sun.
So, it seemed to me, these three young lions, imprisoned in a cage in the arena, were thinking out loud when the tamer appeared through the quickly opened door.
She did not stand out for either strength or beauty, thin, pale, exhausted, dressed in tights with shiny embroidery.
In her right hand she held a small whip, which even a small dog would hardly be afraid of.
But as soon as they saw her, these three wild lions stopped roaring and, with their tails between their legs, huddled together in the opposite corner of the cage. For one moment an evil light flashed in their eyes, but she slammed the whip and they calmed down. Under the waves of the same whip, she made them jump over barriers and into hoops.
The one who, in love with a wild lioness, longed to lick bloody lips, licked the hands of the tamer. He who was planning to free all three lions bit, like a well-trained dog, one of his comrades who was slow to give his paw, and who dreamed of dying, contemplating the setting sun, trembled with his whole body when the pistol fired blankly.
Finally the show ended. The tamer, leaving the cage, threw a piece of meat to the lions. They held him in their paws and began to devour him, apparently satisfied, with dull eyes.
Isn't it the same with people?
“Aren’t these three lions the wonderful dreams of youth: passionate love, thirst for glory, lofty aspirations?
But... you have to eat!
The tamer is life.
These were my thoughts - and I stopped going to the circus.
Please help me identify the problem with this text))

The age-related development of a person is considered in different ways, which determines the features of the periodization of age-related development:

The order of life events;
Human biological processes;
Development in society;
Ontogenesis of psychology.

The age periodization of a person combines the period from conception to physiological death.

Today there is no unified classification of the age periodization of human life, since it has constantly changed depending on time and cultural development.

The distribution of age periods occurs when certain important changes occur in the human body.

Stages of age periodization are periods between the boundaries of a certain age in the human development system.

Briefly defining age periodization, we can distinguish the following stages:

The birth of man;
Growing up, as well as the formation of certain physical and social functions;
Development of these functions;
Old age and decreased functioning of the body;
Physical death.

Every person after birth goes through all life stages sequentially. These make up the life cycle.

It should be noted that the “passport” age does not always coincide with the social, biological and psychological.

What is age periodization?

Let's consider the main periods of a healthy person's life, which are distinguished by age periodization in psychology. The characteristics of age periods are based on psychological ontogenesis.

Age periodization from a psychological point of view

1. Prenatal segment, in which 3 stages are distinguished:

Pre-embryonic. The duration is determined by two weeks, when fertilization occurs in the egg;
Embryonic. The duration of the period is until the beginning of the third month of pregnancy. The period is characterized by the active development of internal organs.
Fetal stage. Lasts from three months of pregnancy until the birth of the child. All vital organs are formed, which must function clearly and allow the fetus to survive after birth.

2. Childhood.

From zero months to a year;
Early childhood, which lasts from one to three years of age. Characterized by the manifestation of autonomy and independence; intensive development of speech skills.
Preschool period is from three to six years old.

During this period, intensive development of the child occurs, the stage of social manifestations begins;

School age of the younger group. From six to eleven years old, the child is actively involved in social life; intensive intellectual development occurs.

3. Adolescence.

Teenage years.

A time of intense puberty, which lasts up to fifteen years. Significant changes occur in the functioning of body systems. Under their influence, the view of one’s own “I” and ideas about the surrounding reality change.

Youth time.

The duration of the period is from sixteen to twenty-three years. From a biological point of view, the organism has become an adult. However, based on social development, this cannot be said. There is a desire to become independent and independent in the absence of social responsibility.

All important decisions related to later life are made at this time: the choice of life path, profession, self-determination, the formation of self-awareness and attitude towards self-development.

The transition from one age period to another involves the emergence of crises, those moments that are considered to be turning points. They occur due to changes in the physiology and psychology of a growing person. Crises are the most difficult stages of life's journey, which cause certain difficulties for the growing person himself, as well as the people who surround him. There are two types of turning points: small and large.

Small crises (1 and 7 years, youth crisis) appear with the emergence and development of skills and abilities that did not exist before, and the increasing role of independence.

Major crises (birth, three years, adolescence) are characterized by a complete restructuring of social and psychological relationships. This is a time of great change, which is accompanied by emotional outbursts, aggression, and disobedience.

4. Maturity.

Youth. Lasts up to 33 years. A period of active personal relationships associated with building a family and having children. Development of professional activities. Time to assert yourself in all areas of life: sex, love, career.
The crisis of thirty. By this time, many achieve what they strived for. There comes a turning point in life when a person begins to look for the meaning of life. Often disappointed in what he has. Strives to change his place of work, education, circle of acquaintances and friends. According to statistics, most divorces occur during this period.
Stabilization period. From 35 to 45 years old, as a rule, people are satisfied with what they have achieved. They no longer want change, they want stability. Confidence in one’s own abilities comes, and success in one’s career is achieved. Most often, the state of health is consistently good. Family relationships are stabilizing.
Decade of crisis (45 -55 years).

The first signs of approaching old age begin to appear: former beauty fades, well-being and health in general deteriorate.

Coldness appears in the family. Children, having become adults, lead an independent life, and alienation occurs in relationships with them. Fatigue and depressive moods are frequent companions of this age. Some try to find salvation in dreams of a new bright love (or make their dream come true). Others “burn” at work, ensuring a dizzying rise in their career.

Period of balance. The age from 55 to 65 years is characterized by a gradual withdrawal from social life and work activity. This is a period of relative peace in all areas of life.

5. Old age.

There is a rethinking of one’s entire life, reflection on spirituality and a reassessment of actions. Review of the past years from the point of view of philosophy: whether life was wasted or was it rich and unique.

At this time, periods of crisis appear, associated with rethinking the life lived.

Personal assessment that does not affect the professional sphere;
Attitudes towards aging and the appearance of signs of obvious deterioration in health and appearance;
Understanding and accepting death.

1) Thinking about its inevitability, a person initially feels horror from helplessness, since he cannot prevent this event.

2) Anger, which is poured out on all young and healthy people nearby. He comes with the realization that human life is coming to an end and nothing can be done about it.

3) An attempt to make a deal: with doctors or through repentance. A person “begs” for years of life by following all the doctor’s orders, self-medicating, or actively attending church.

4) Depression. The awareness of imminent death does not leave a person. He withdraws into himself, often cries, thinking about his family and friends whom he has to leave. There is a complete lack of social contacts.

5) Acceptance of death. Humble expectation of the inevitable end. A state when a person is already psychologically dead.

6) The onset of clinical death is characterized by complete cardiac arrest and cessation of breathing. Within 15-20 minutes a person can still be brought back to life.

7) Physiological death is associated with the cessation of all body functions.

The determination of this age periodization is associated with the physiological characteristics of the body, the level of mental development, as well as the basic behavioral characteristics of a person.

Philosophical concept of age periodization

Since ancient times, scientists in different countries have had their own idea of the concept of age-related characteristics. Modern age periodization successfully uses the proposed models.

For example, in China it was believed that human life is divided into 7 periods, with the age from 60 to 70 years being considered the best. This time was called the spiritual flowering of man and the manifestation of his highest wisdom.

Hippocrates divided human life into 10 stages, each of which lasted 7 years. The record of time began at birth.

The division of the stages of life according to Pythagoras is very interesting. He believed that age periodization is similar to the seasons.

Spring.

Beginning of life. The period of formation and development of personality. Passes from birth to 20 years.

Summer. Young years from 20 to 40 years.

Autumn. The best years of a person, the blossoming of creative potential. Lasts from 40 to 60 years.
Winter is old age, which begins at 60 years of age.

Pythagoras believed that everything in human life is characterized by numbers that have magical properties.

The scientist assumed that the age periodization of development is the changing “seasons” of life, and man is part of natural life.

The basis of his age periodization and characteristics of periods is the idea of eternal life through reincarnation and change.

Is age really that important?

Each of us is free to determine by what criteria to determine the age period in which he lives. After all, the concept of “age” is very relative.

Some people consider themselves young as long as they remain attractive and in good health. Often people try by all available means to prolong this outward manifestation of youth. And some even 80 lead an active lifestyle, attracting others with their optimism. As a rule, such people get sick very little, remaining active until old age.

Remember that age is determined by your state of mind, not by the numbers in your passport.

Human physical development is a complex of morphological and functional properties of the body, which determine the shape, size, weight of the body and its structural and mechanical qualities.

Introduction

Signs of physical development are variable. The physical development of a person is the result of the influence of hereditary factors (genotype) and environmental factors, and for a person - the entire complex of social conditions (phenotype). With age, the importance of heredity decreases, the leading role passes to individually acquired characteristics.
The physical development of children and adolescents is related to growth. Each age period - infancy, childhood, adolescence and youth - is characterized by specific growth characteristics of individual parts of the body. In each age period, the child’s body has a number of characteristic features that are unique to that age. Between the body of a child and an adult there are not only quantitative differences (body size, weight), but also, above all, qualitative ones.
Currently, there is an acceleration in human physical development. This phenomenon is called acceleration.
In my work I will try to briefly characterize each of the main stages of individual human development.

The main stages of individual human development

When studying human development, his individual and age-related characteristics in anatomy and other disciplines, they are guided by scientifically based data on age periodization. The scheme of age periodization of human development, taking into account anatomical, physiological, and social factors, was adopted at the VII Conference on Problems of Age-Related Morphology, Physiology and Biochemistry (1965). It distinguishes twelve age periods (Table 1). Table 1

Individual development, or development in ontogenesis, occurs during all periods of life - from conception to death. In human ontogenesis, two periods are distinguished: before birth (intrauterine, prenatal - from the Greek natos - born) and after birth (extrauterine, postnatal).

Prenatal ontogeny

To understand the individual characteristics of the structure of the human body, it is necessary to become familiar with the development of the human body in the prenatal period. The fact is that each person has his own individual characteristics of external appearance and internal structure, the presence of which is determined by two factors. This is heredity, traits inherited from parents, as well as the result of the influence of the external environment in which a person grows, develops, learns, and works.
During the prenatal period, from conception to birth, for 280 days (9 calendar months), the embryo (embryo) is located in the mother’s body (from the moment of fertilization to birth). During the first 8 weeks, the main processes of formation of organs and body parts occur. This period is called embryonic (fetal), and the body of the future person is called an embryo (fetus). From 9 weeks of age, when the main external human features begin to appear, the organism is called a fetus, and the period is called fetal (fetal - from the Greek fetus - fruit).
The development of a new organism begins with the process of fertilization (fusion of sperm and egg), which usually occurs in the fallopian tube. The fused germ cells form a qualitatively new one-celled embryo - a zygote, which has all the properties of both sex cells. From this moment the development of a new (daughter) organism begins.
Optimal conditions for the interaction of sperm and egg are usually created within 12 hours after ovulation. The union of the sperm nucleus with the egg nucleus leads to the formation in a single-celled organism (zygote) of a diploid set of chromosomes characteristic of humans (46). The sex of the unborn child is determined by the combination of chromosomes in the zygote and depends on the sex chromosomes of the father. If an egg is fertilized by a sperm with sex chromosome X, then two X chromosomes, characteristic of the female body, appear in the resulting diploid set of chromosomes. When fertilized by a sperm with a Y sex chromosome, a combination of XY sex chromosomes is formed in the zygote, characteristic of the male body.
The first week of embryo development is the period of fragmentation (division) of the zygote into daughter cells (Fig. 1). Immediately after fertilization, during the first 3-4 days, the zygote divides and simultaneously moves along the fallopian tube towards the uterine cavity. As a result of the division of the zygote, a multicellular vesicle is formed - a blastula with a cavity inside (from the Greek blastula - sprout). The walls of this vesicle are formed by two types of cells: large and small. The walls of the vesicle, the trophoblast, are formed from the outer layer of small cells. Subsequently, trophoblast cells form the outer layer of the membranes of the embryo. Larger dark cells (blastomeres) form a cluster - the embryoblast (germinal nodule, embryonic rudiment), which is located medially from the trophoblast. From this accumulation of cells (embryoblast) the embryo and adjacent extra-embryonic structures (except the trophoblast) develop.

Fig.1. A - fertilization: 1 - sperm; 2 - egg; B; B - fragmentation of the zygote, G - morublastula: 1 - embryoblast; 2 - trophoblast; D - blastocyst: 1-embryoblast; 2 - trophoblast; 3 - amnion cavity; E - blastocyst: 1-embryoblast; 2-amnion cavity; 3 - blastocoel; 4 - embryonic endoderm; 5-amnionic epithelium - F - I: 1 - ectoderm; 2 - endoderm; 3 - mesoderm.
A small amount of fluid accumulates between the surface layer (trophoblast) and the germinal nodule. By the end of the 1st week of development (6th - 7th day of pregnancy), the embryo enters the uterus and is introduced (implanted) into its mucous membrane; implantation lasts about 40 hours. The surface cells of the embryo that form the vesicle, the trophoblast (from the Greek trophe - nutrition), secrete an enzyme that loosens the surface layer of the uterine mucosa, which is prepared for the implantation of the embryo into it. The forming villi (outgrowths) of the trophoblast come into direct contact with the blood vessels of the maternal body. Numerous trophoblast villi increase the surface of its contact with the tissues of the uterine mucosa. The trophoblast turns into the nutritious membrane of the embryo, which is called the villous membrane (chorion). At first, the chorion has villi on all sides, then these villi are retained only on the side facing the wall of the uterus. In this place, a new organ develops from the chorion and the adjacent mucous membrane of the uterus - the placenta (baby place). The placenta is an organ that connects the mother’s body with the embryo and provides its nutrition.
The second week of the embryo’s life is the stage when the embryoblast cells are divided into two layers (two plates), from which two vesicles are formed (Fig. 2). An ectoblastic (amniotic) vesicle is formed from the outer layer of cells adjacent to the trophoblast. An endoblastic (yolk) vesicle is formed from the inner layer of cells (embryo rudiment, embryoblast). The anlage ("body") of the embryo is located where the amniotic sac comes into contact with the yolk sac. During this period, the embryo is a two-layer shield, consisting of two layers: the outer germinal layer (ectoderm) and the inner germinal layer (endoderm).

Fig.2. The position of the embryo and germinal membranes at different stages of human development: A - 2-3 weeks; B - 4 weeks: 1 - amnion cavity; 2 - body of the embryo; 3 - yolk sac; 4 - tropholast; B - 6 weeks; G - fetus 4-5 months: 1 - body of the embryo (fetus); 2 - amnion; 3 - yolk sac; 4 - chorion; 5 - umbilical cord.
The ectoderm faces the amniotic sac, and the endoderm is adjacent to the yolk sac. At this stage, the surfaces of the embryo can be determined. The dorsal surface is adjacent to the amniotic sac, and the ventral surface is adjacent to the yolk sac. The trophoblast cavity around the amniotic and vitelline vesicles is loosely filled with strands of extraembryonic mesenchyme cells. By the end of the 2nd week, the length of the embryo is only 1.5 mm. During this period, the embryonic shield thickens in its posterior (caudal) part. Here, the axial organs (notochord, neural tube) subsequently begin to develop.
The third week of the embryo’s life is the period of formation of a three-layer shield (embryo). The cells of the outer, ectodermal plate of the germinal shield are displaced towards its posterior end. As a result, a cell ridge (primary streak) is formed, elongated in the direction of the longitudinal axis of the embryo. In the head (anterior) part of the primary streak, cells grow and multiply faster, resulting in the formation of a small elevation - the primary nodule (Hensen's node). The location of the primary node indicates the cranial (head end) of the embryonic body.
Rapidly multiplying, the cells of the primary streak and primary node grow laterally between the ectoderm and endoderm, thus forming the median germ layer - mesoderm. The mesoderm cells located between the sheets of the scutellum are called intraembryonic mesoderm, and those that migrate beyond its boundaries are called extraembryonic mesoderm.
Part of the mesoderm cells within the primary node grows especially actively forward from the head and tail ends of the embryo, penetrates between the outer and inner layers and forms a cellular cord - the dorsal string (notochord). At the end of the 3rd week of development, active cell growth occurs in the anterior part of the outer germ layer - the neural plate is formed. This plate soon bends, forming a longitudinal groove - the neural groove. The edges of the groove thicken, come closer and grow together, closing the neural groove into the neural tube. Subsequently, the entire nervous system develops from the neural tube. The ectoderm closes over the formed neural tube and loses connection with it.
During the same period, a finger-like outgrowth, the allantois, penetrates from the posterior part of the endodermal plate of the embryonic shield into the extra-embryonic mesenchyme (into the so-called amniotic leg), which does not perform certain functions in humans. Along the allantois, blood umbilical (placental) vessels grow from the embryo to the chorionic villi. A cord containing blood vessels that connects the embryo with the extraembryonic membranes (placenta) forms the abdominal stalk.
Thus, by the end of the 3rd week of development, the human embryo has the appearance of a three-layer plate, or a three-layer shield. In the region of the outer germ layer the neural tube is visible, and deeper - the dorsal chord, i.e. the axial organs of the human embryo appear. By the end of the third week of development, the length of the embryo is 2-3 mm.
The fourth week of life - the embryo, which looks like a three-layer shield, begins to bend in the transverse and longitudinal directions. The embryonic shield becomes convex, and its edges are delimited from the amnion surrounding the embryo by a deep groove - the trunk fold. The body of the embryo turns from a flat shield into a three-dimensional one; the ectoderm covers the body of the embryo on all sides.
From the ectoderm, the nervous system, the epidermis of the skin and its derivatives, the epithelial lining of the oral cavity, anal rectum, and vagina are subsequently formed. The mesoderm gives rise to internal organs (except for derivatives of the endoderm), the cardiovascular system, organs of the musculoskeletal system (bones, joints, muscles), and the skin itself.
The endoderm, once inside the body of the human embryo, curls up into a tube and forms the embryonic rudiment of the future intestine. The narrow opening connecting the embryonic intestine with the yolk sac later turns into the umbilical ring. The epithelium and all glands of the digestive system and respiratory tract are formed from the endoderm.
The embryonic (primary) gut is initially closed in front and behind. At the anterior and posterior ends of the body of the embryo, invaginations of the ectoderm appear - the oral fossa (future oral cavity) and the anal (anal) fossa. Between the cavity of the primary intestine and the oral fossa there is a two-layer (ectoderm and endoderm) anterior (oropharyngeal) plate (membrane). Between the intestine and the anal fossa there is a cloacal (anal) plate (membrane), also two-layered. The anterior (oropharyngeal) membrane breaks through in the 4th week of development. At the 3rd month, the posterior (anal) membrane breaks through.
As a result of bending, the body of the embryo is surrounded by the contents of the amnion - amniotic fluid, which acts as a protective environment that protects the embryo from damage, primarily mechanical (concussion).
The yolk sac lags in growth and in the 2nd month of intrauterine development it looks like a small sac, and then is completely reduced (disappears). The abdominal stalk lengthens, becomes relatively thin and later receives the name umbilical cord.
During the 4th week of embryo development, differentiation of its mesoderm, which began in the 3rd week, continues. The dorsal part of the mesoderm, located on the sides of the notochord, forms paired thickened projections - somites. Somites are segmented, i.e. are divided into metameric regions. Therefore, the dorsal part of the mesoderm is called segmented. Segmentation of somites occurs gradually in the direction from front to back. On the 20th day of development, the 3rd pair of somites is formed, by the 30th day there are already 30 of them, and on the 35th day - 43-44 pairs. The ventral part of the mesoderm is not divided into segments. It forms two plates on each side (the unsegmented part of the mesoderm). The medial (visceral) plate is adjacent to the endoderm (primary gut) and is called the splanchnopleura. The lateral (outer) plate is adjacent to the wall of the body of the embryo, to the ectoderm, and is called the somatopleura.
From the splanchno- and somatopleura the epithelial cover of the serous membranes (mesothelium), as well as the lamina propria of the serous membranes and the subserosal base develop. The mesenchyme of the splanchnopleura also goes to the construction of all layers of the digestive tube, except for the epithelium and glands, which are formed from the endoderm. The space between the plates of the unsegmented part of the mesoderm turns into the body cavity of the embryo, which is divided into the peritoneal, pleural and pericardial cavities.

Fig.3. Cross section through the body of the embryo (diagram): 1 - neural tube; 2 - chord; 3 - aorta; 4 - sclerotome; 5 - myotome; 6 - dermatome; 7 - primary gut; 8 - body cavity (whole); 9 - somatopleura; 10 - splanchnopleura.
The mesoderm at the border between the somites and the splanchnopleura forms nephrotomes (segmental legs), from which the tubules of the primary kidney and gonads develop. Three primordia are formed from the dorsal part of the mesoderm - somites. The anteromedial portion of the somites (sclerotome) is used to build skeletal tissue, which gives rise to the cartilage and bones of the axial skeleton - the spine. Lateral to it lies the myotome, from which skeletal muscles develop. In the posterolateral part of the somite there is an area - the dermatome, from the tissue of which the connective tissue base of the skin - the dermis - is formed.
In the head section, on each side of the embryo, from the ectoderm in the 4th week, the rudiments of the inner ear (first the auditory pits, then the auditory vesicles) and the future lens of the eye are formed. At the same time, the visceral parts of the head are reconstructed, which form the frontal and maxillary processes around the oral bay. Posteriorly (caudally) of these processes, the contours of the mandibular and sublingual (hyoid) visceral arches are visible.
On the anterior surface of the embryo’s body, elevations are visible: the cardiac and behind them the hepatic tubercles. The depression between these tubercles indicates the place of formation of the transverse septum - one of the rudiments of the diaphragm. Caudal to the hepatic tubercle is the abdominal stalk, which contains large blood vessels and connects the embryo to the placenta (umbilical cord). The length of the embryo by the end of the 4th week is 4-5 mm.

Fifth to eighth weeks

During the period from the 5th to the 8th week of the embryo’s life, the formation of organs (organogenesis) and tissues (histogenesis) continues. This is the time of early development of the heart and lungs, the complication of the structure of the intestinal tube, the formation of visceral arches, and the formation of capsules of the sensory organs. The neural tube closes completely and expands in the cerebrum (the future brain). At the age of about 31-32 days (5th week), the length of the embryo is 7.5 mm. At the level of the lower cervical and 1st thoracic segments of the body, fin-like rudiments (buds) of the arms appear. By the 40th day, the rudiments of the legs are formed.
At the 6th week (the parietal-coccygeal length of the embryo is 12 - 13 mm), the buds of the outer ear are noticeable, from the end of the 6-7th week - the buds of the fingers and then the toes.
By the end of the 7th week (embryo length is 19-20 mm), eyelids begin to form. Thanks to this, the eyes are outlined more clearly. At the 8th week (embryo length 28-30 mm), the formation of embryonic organs ends. From the 9th week, i.e. from the beginning of the 3rd month, the embryo (parietal-coccygeal length 39-41 mm) takes on the appearance of a person and is called a fetus.

Third to ninth months

Starting from three months and throughout the entire fetal period, further growth and development of the resulting organs and body parts occurs. At the same time, differentiation of the external genitalia begins. The nails on the fingers are laid. From the end of the 5th month (length 24.3 cm), eyebrows and eyelashes become noticeable. At the 7th month (length 37.1 cm), the eyelids open and fat begins to accumulate in the subcutaneous tissue. In the 10th month (length 51 cm) the fetus is born.

Critical periods of ontogenesis

In the process of individual development, there are critical periods when the sensitivity of the developing organism to the effects of damaging factors of the external and internal environment is increased. There are several critical periods of development. These most dangerous periods are:
1) time of development of germ cells - oogenesis and spermatogenesis;
2) the moment of fusion of germ cells - fertilization;
3) implantation of the embryo (4-8 days of embryogenesis);
4) the formation of the rudiments of the axial organs (brain and spinal cord, spinal column, primary intestine) and the formation of the placenta (3-8th week of development);
5) stage of increased brain growth (15-20th week);
6) formation of functional systems of the body and differentiation of the genitourinary apparatus (20-24th week of the prenatal period);
7) the moment of birth of a child and the neonatal period - the transition to extrauterine life; metabolic and functional adaptation;
8) the period of early and first childhood (2 years - 7 years), when the formation of relationships between organs, systems and organ apparatuses ends;
9) adolescence (puberty - for boys from 13 to 16 years, for girls - from 12 to 15 years).
Simultaneously with the rapid growth of the organs of the reproductive system, emotional activity intensifies.

Postnatal ontogeny. Newborn period

Immediately after birth, there begins a period called the newborn period. The basis for this allocation is the fact that at this time the baby is fed with colostrum for 8-10 days. Newborns in the initial period of adaptation to the conditions of extrauterine life are divided according to the level of maturity into full-term and premature. Intrauterine development of full-term babies lasts 39-40 weeks, premature babies - 28-38 weeks. When determining maturity, not only these terms are taken into account, but also body mass (weight) at birth.
Newborns with a body weight of at least 2500 g (with a body length of at least 45 cm) are considered full-term, and newborns weighing less than 2500 g are considered premature. In addition to weight and length, other dimensions are also taken into account, for example, chest circumference in relation to body length and head circumference in relation to chest circumference. It is believed that the chest girth at nipple level should be 9-10 cm greater than 0.5 body length, and the head girth should be no more than 1-2 cm greater than the chest girth.

Breast period

The next period - the infancy - lasts up to a year. The beginning of this period is associated with the transition to feeding on “mature” milk. During the breast period, the greatest intensity of growth is observed, compared to all other periods of extrauterine life. Body length increases from birth to one year by 1.5 times, and body weight triples. From 6 months baby teeth begin to emerge. In infancy, unevenness in body growth is pronounced. In the first half of the year, infants grow faster than in the second. In each month of the first year of life, new development indicators appear. In the first month, the child begins to smile in response to adults addressing him, at 4 months. persistently tries to stand on her feet (with support), at 6 months. tries to crawl on all fours, at 8 he tries to walk, by the age of one year the child usually walks.

Early childhood period

The period of early childhood lasts from 1 year to 4 years. At the end of the second year of life, teething ends. After 2 years, the absolute and relative values of annual increases in body size quickly decrease.

First childhood period

At the age of 4, the period of first childhood begins, which ends at the age of 7. Starting at the age of 6, the first permanent teeth appear: the first molar (large molar) and the medial incisor on the lower jaw.
The age from 1 to 7 years is also called the period of neutral childhood, since boys and girls are almost the same in size and body shape.

Second childhood period

The period of second childhood lasts for boys from 8 to 12 years, for girls - from 8 to 11 years. During this period, gender differences in body size and shape are revealed, and increased body length growth begins. Girls' growth rates are higher than those of boys, since puberty begins on average two years earlier in girls. Increased secretion of sex hormones (especially in girls) causes the development of secondary sexual characteristics. The sequence of appearance of secondary sexual characteristics is fairly constant. In girls, mammary glands first form, then pubic hair appears, then in the armpits. The uterus and vagina develop simultaneously with the formation of the mammary glands. The process of puberty is expressed to a much lesser extent in boys. Only towards the end of this period do they begin to experience accelerated growth of the testicles, scrotum, and then the penis.

Teenage years

The next period - adolescence - is also called puberty, or puberty. It lasts for boys from 13 to 16 years, for girls - from 12 to 15 years. At this time, there is a further increase in growth rates - a pubertal leap, which affects all body sizes. The greatest increases in body length in girls occur between 11 and 12 years, and in body weight - between 12 and 13 years. In boys, an increase in length is observed between 13 and 14 years, and an increase in body weight between 14 and 15 years. The growth rate of body length in boys is especially high, as a result of which at 13.5-14 years old they overtake girls in body length. Due to increased activity of the hypothalamic-pituitary system, secondary sexual characteristics are formed. In girls, the development of the mammary glands continues, and hair growth is observed on the pubis and in the armpits. The clearest indicator of puberty in the female body is the first menstruation.
During adolescence, boys undergo intense puberty. By the age of 13, their voice changes (mutates) and pubic hair appears, and at the age of 14, hair appears in the armpits. At the age of 14-15, boys experience their first emissions (involuntary eruptions of sperm).
Boys, compared to girls, have a longer pubertal period and a more pronounced pubertal growth spurt.

Adolescence

Adolescence lasts for boys from 18 to 21 years, and for girls from 17 to 20 years. During this period, the process of growth and formation of the organism basically ends and all the main dimensional characteristics of the body reach their definitive (final) size.
In adolescence, the formation of the reproductive system and the maturation of the reproductive function are completed. The ovulatory cycles in a woman, the rhythm of testosterone secretion and the production of mature sperm in a man are finally established.

Mature, elderly, senile age

In adulthood, the shape and structure of the body changes little. Between 30 and 50 years, body length remains constant and then begins to decrease. In old age and senility, gradual involutive changes in the body occur.

Individual differences in growth and development

Individual differences in the process of growth and development can vary widely. The existence of individual fluctuations in the processes of growth and development served as the basis for the introduction of such a concept as biological age, or developmental age (as opposed to passport age).
The main criteria for biological age are:
1) skeletal maturity - (the order and timing of skeletal ossification);
2) dental maturity - (timing of eruption of milk and permanent teeth);
3) the degree of development of secondary sexual characteristics. For each of these criteria of biological age - “external” (skin), “dental” and “bone” - rating scales and normative tables have been developed that make it possible to determine the chronological (passport) age based on morphological features.

Factors influencing individual development

Factors influencing individual development (ontogenesis) are divided into hereditary and environmental (influence of the external environment).
The degree of hereditary (genetic) influence varies at different stages of growth and development. The impact of hereditary factors on total body size increases from the newborn period (tm) to the second childhood, with subsequent weakening by 12-15 years.
The influence of environmental factors on the processes of morphofunctional maturation of the body can be clearly seen in the example of the timing of menarche (menstruation). Studies of growth processes in children and adolescents in various geographical zones have shown that climatic factors have almost no effect on growth and development if living conditions are not extreme. Adaptation to extreme conditions causes such a profound restructuring of the functioning of the entire organism that it cannot but affect growth processes.

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.
table 2
Length, weight and body surface area in post-natal orthogynesis

Table 2
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 education slow down the aging process.

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 circumferences 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 body size, 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.

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 calendar year, and this is completely normal. Girls tend to develop faster.

Literature

1. Medical scientific and educational journal No. 28 [October 2005]. Section - Lectures. The title of the work is PERIODS OF CHILDHOOD. Author - P.D. Vaganov
2. Vygotsky L.S. Collected works in 6 volumes. Volume 4.
3. Vygotsky L.S. article "Problems of age periodization of child development"
4. Obukhova L.F. textbook "Children's (age) psychology". Fundamental and clinical physiology / Edited by A.G. Kamkin and A.A. Kamensky. - M.: "Academy", 2004.
5. Schmidt R., Tevs G. Human physiology: Transl. from English - M.: Mir, 1996.
6. Dragomilov A.G., Mash R.D. Biology: Human. - 2nd ed., revised. - M.: Ventana-Graf, 2004.
7. Sapin. M.R., Bryksina Z.G. Anatomy and physiology of children and adolescents: Textbook. aid for students ped. Universities. - M.: Publishing center "Academy", 2002.
8. Chusov Yu.N. Human physiology: Proc. manual for teachers Schools (specialist No. 1910). - M.: Education, 1981.
9. Encyclopedia "Around the World"
10. "Rusmedservice"
11. Encyclopedia "Wikipedia"

The following age periods of a person are distinguished:

1. Childhood- from birth to the beginning of the period (12-13 years).

2. Adolescence(puberty) - from 12-13 to 16 years for girls and from 13-14 to 17-18 years for boys. This age is characterized by a sharp increase in body length with an annual increase of 5-6 cm. By the age of 15 (compared to a newborn), it triples and reaches an average of 158 cm in boys and 156 cm in girls. Body weight is 48 and 49 kg, respectively. By the age of 14-15, all permanent teeth appear, except wisdom teeth. During this period, one of the most important age-related crises occurs - puberty, which is based on a change in the function of the body's endocrine system, which leads to the appearance of secondary ones, the onset of menstruation in girls and the appearance of menstruation in boys. The general metabolism in the body becomes intense, but unstable and labile. The mental life of a teenager is very complex and unstable and requires great tact and restraint from teachers, doctors and parents.

3. Adolescence- from 16 to 25 years for women and from 17 to 26 years for men. Characterized by slow growth, the average annual gain is 0.5 cm. At this age, wisdom teeth usually appear.

4. Adulthood- from 25 to 40 years for women and from 26 to 45 years for men. A period of relative stabilization of morphological and metabolic processes.

5. Mature age- from 40 to 55 years for women and from 45 to 60 years for men. During this period, the second most important age crisis begins - which is especially pronounced in women. Menopause is associated with the extinction of the functions of the gonads and the restructuring of a number of hormonal systems of the body. The mental sphere and metabolism are characterized by significant lability.

6. Elderly age- from 55 to 75 years for women and from 60 to 75 years for men.

7. Senile age- over 75 years for women and men. The general involution of the body begins to develop.

Sometimes it is proposed to allocate a special age of centenarians for people 90 years and older.

Accurate determination of age is important in clinical and forensic practice. Age can be judged based on data on height, body weight, number of teeth, and skin condition. With age, wrinkles appear on a person's face. By the age of 20 - frontal and nasolabial, by 25 years at the outer edges behind the ears, by 30 years - infraorbital, by 40 years - cervical, by 55 years - on the earlobes, hands, chin. However, all these criteria are very relative.

A more accurate method of determining age is to determine (radiologically) the so-called. Its definition is based on patterns in ossification associated with age periods. For example, ossification points in the distal epiphysis of the radius appear at 12-14 months. in girls and at 16-18 months. in boys. in the distal epiphysis of the ulna at 19 and 20 years old, respectively. As a rule, to determine bone age, an image of the hand and distal bones is used. Knowing the time of appearance of ossification points and synostoses, it is possible to determine a person’s age with a high degree of accuracy.

Age periods in children. The period of childhood is characterized by constant development and growth of the child’s body. There is no strict line between the individual stages of development.

Childhood is preceded by a period in which a distinction is made between the stage of embryonic development (the first 3 months) and the stage of placental development (from the 3rd to the 9th month).

The extrauterine period of development is divided into several periods: 1) newborns, lasting up to 4 weeks of life; 2) infancy, lasting from 4 weeks to 1 year; 3) pre-preschool, or nursery, - from 1 year to 3 years; 4) preschool (kindergarten period) - from 3 to 7 years; 5) junior school - from 7 to 12 years; 6) senior school (adolescence, or puberty) - from 12 to 18 years (see above).

The neonatal period is characterized by incomplete development of all organs and systems. During this period, the child’s body adapts to environmental conditions. Insufficient functional capacity of various organs is the cause of the development of a number of disorders in which it is difficult to draw the line between physiological and pathological conditions (physiological and physiological weight loss and others). A newborn is extremely susceptible to coccal infection, which requires maximum care for a child of this age (see).

Infancy. The period of infancy is characterized by the intensity of growth and development of the child’s body, which determines a relatively greater need for high-calorie food and requires proper nutrition. If the quality and quantity of food is violated, eating disorders and... Due to the relative functional weakness of the digestive organs, the child eats mainly dairy foods. During this period, the child is also helpless and requires special care.

In an infant, the first signaling system is formed. Children begin to recognize objects and faces in their environment.

Rapid exhaustion of the central nervous system. requires a large number of hours of sleep and proper alternation of sleep and wakefulness.

The weakness of immunobiological defense mechanisms makes children in the first months of life more susceptible to septic processes. At 2-5 months. the child is most defenseless to infections due to a decrease in passive and insufficient production of active acquired immunity. In infancy, the manifestation of constitutional abnormalities is characteristic, most often exudative-catarrhal diathesis (see).

Pre-school age in its biological characteristics it has common features with infancy and preschool age. By the end of the first year, especially after two years, it develops intensively. At this age, appropriate organizational measures are required to ensure the correct regime, education, sufficient rest and further development of the child. In preschool age, acute infections become more frequent mainly due to insufficient development of active immunity. This requires timely treatment of the child, as well as measures to protect the child from infection.

Preschool age characterized by the child’s great mobility and activity. Children are much more involved in sports activities.

In this period of childhood, it is especially important to properly organize outdoor games, manual labor, etc. When developing a daily routine, especially organizing walks, one must remember that the child gets tired very quickly when walking slowly and non-stop. In preschool age, household and street injuries become more frequent; The incidence of acute infections increases significantly.

Junior school age characterized by increased muscle development, but the child’s growth slows down somewhat. The child develops in the school community and lives by its interests. Physical education classes should be organized so that they do not tire the child, but help improve metabolic processes and the functions of all body systems.

With a significant school load, improper organization of sleep and rest, the development of neurotic reactions is possible. Primary school age is characterized by a high incidence of acute infections, and diseases that are rare in pre-preschool age appear (functional cardiovascular disorders and others).

Senior school age. Physiologically, it is characterized by the maturation of the gonads. gonads dramatically change the course of all life processes and affect the functional state of the nervous system. In adolescents, a number of changes occur (pulse instability, etc.).

Uneven mood, increased irritability, and fatigue are also noted. During adolescence, the morphological and physiological features that distinguish a child from an adult gradually smooth out and disappear. The course of the disease acquires clinical features characteristic of adults. See also .

(1) How different are the impressions of what is read, heard and seen by age!

(2) I remember when I was a child they took me to the circus. (3) How much joy and pleasure!

(4) In my youth, I also visited it often: I was drawn there by the grace of the movements of the riders, the courage of the acrobats, the triumph of animal training by the crown of creation - man...

(5) More mature years came - I occasionally and only by chance went to the circus.

(6) Now I don’t go there at all. (7) Why?

(8) I remember the last time I was there, very strange thoughts came to me...

(9) A huge iron cage was wheeled out to the arena. (10) Three young African lions walked quickly back and forth in it, emitting a dull growl, shaking their manes and sparkling eyes. (11) They seemed to be reasoning with themselves, and it seemed to me from the varied tone of their growls that these reasonings were on different topics.

(12) One said:

(13) - Who dares to order me? (14) To whom will I bow my head and on whom will I not let out my claws? (15) I will break all the locks, I will cover immeasurable spaces and reach my distant homeland - a quiet desert. (16) Where the gazelles that I will feast on drink by the stream, where I will quench my thirst, beautiful young lionesses with silky fur, with eyes burning with green fire, are waiting for me, basking on the hot sand. (17) I will let out a joyful cry of love, and the one who loves me will respond to my call. (18) We will walk together through the vast desert, scorched by the sun, happy, free.

(19) Another made other plans in a sharper tone:

(20) - Who thinks to subjugate me? (21) To whom will my proud will bow? (22) Now I’ll grab the bars and locks with my teeth and chew them easier than a child cracks nuts. (23) But I will not retire into the peace and quiet of the desert, but will run to the cities where my brothers are languishing in captivity, where they dare to show them off for fun. (24) I will destroy all the cells and free the unfortunate prisoners. (25) There will be dozens, hundreds, thousands of us, and only when there is not a single lion in prison on the entire globe will I return to my native countries, as befits a victorious king.

(26) The third dreamed of something else:

(27) – Let them not try to enslave me! (28) With one blow of my mighty paw I will break into pieces both the wood and the iron of my prison, I will turn everything into splinters and dust. (29) I will go to the most remote country, unknown to either people or lions. (30) There I will live alone, contemplating only boundless spaces around me: the desert, the sea and the sky - and, having grown old, I will die in sight of the setting sun.

(31) So, it seemed to me, these three young lions, imprisoned in a cage standing in the arena, were thinking when the tamer appeared in the quickly opened door. (32) In her right hand she held a small whip, which even a small dog would hardly have been afraid of.

(33) But as soon as they, these three wild lions, saw her, they stopped growling and, with their tails between their legs, huddled together in the opposite corner of the cage. (34) Under the swings of the whip, she made them jump over barriers and into hoops.

(35) He, in love with a wild lioness, licked the hands of the tamer. (36) He who was planning to free all the lions bit, like a well-trained dog, one of his comrades who was slow to give his paw, and who dreamed of dying, contemplating the setting sun, trembled with his whole body when the pistol fired blankly.

(37) The performance ended, and the tamer, leaving the cage, threw the lions a piece of meat, and they, holding it in their paws, began to devour it, apparently satisfied, with dull eyes.

(38) Doesn’t the same thing happen to people? (39) Aren’t these three lions the wonderful dreams of youth: passionate love, thirst for glory, lofty aspirations? (40) But I’m hungry... (41) The tamer is life.

(42) These were my thoughts - and I stopped going to the circus.

(According to N. Heinze)

Answer: