In our article we will talk about how the newborn period goes. This time requires special care and handling of the baby. The development of the child during this period plays an important role. In addition, parents should know some interesting and important facts about newborns. After all, a newly born person behaves differently than an adult. But he is also significantly different from a child who has crossed the newborn line.

So what should you pay attention to at first? What characterizes the development of a baby? What important information should every parent know? The answers to all these questions will be discovered further. In fact, all the facts and tips offered to your attention will be useful to every new mother.

Duration

The first thing to find out is how long the newborn period lasts. The question is quite difficult. After all, doctors still cannot say for sure until what point the baby is considered such.

It is generally accepted that the period under study is the first weeks of a child’s life. More precisely, it lasts about 30 days. This is the opinion held by many pediatricians and obstetricians. But some believe that a child is a newborn as long as its mother has the status of a puerper.

Accordingly, the neonatal period is the first month of a baby’s life. It is important to understand that at this time he is adapting to life and he needs special care. In addition, some newborn phenomena can be frightening for new parents. What exactly? What should every parent know?

a brief description of

Now a little more about what a newly born baby has to endure. The development of a child during the neonatal period is associated with his adaptation to independent life. That is, outside the mother's body.

This begins when blood circulation in the umbilical cord stops. In other words, after the baby is born, the umbilical cord will be cut, the atrium oval will close and the baby will begin to breathe on its own. It's not uncommon for a newborn to be slapped on the bottom to get him to cry for the first time. This is the first adaptation to independent extrauterine life.

Changes in one way or another are constantly occurring in the body. For example, the newborn period is always accompanied by healing of the umbilical wound, as well as weight gain. In the first days of life, the baby usually loses a few grams, but after some time the weight is restored.

It is important to understand that some organ systems are not yet fully developed in newborns. For example, the skin of babies is extremely sensitive and delicate. In addition, the child has a weakened immune system and can easily get sick.

Chair

What else makes a newborn stand out? The characteristic of the period usually emphasizes the formation of special stool in recently born children. As a rule, in the first days after birth, the child goes to the toilet with dark stool. Usually it has a black tint. This is a normal phenomenon that should not scare mom.

The fact is that during the neonatal period, children develop the so-called “chest stool”. Initially it is black, but over time the stool changes color. Ideally it should be yellow. The newborn's stool is liquid.

Black feces, as a rule, persist during the newborn period of the child. Therefore, there is no need to be afraid that they did not turn yellow after discharge from the hospital - this will happen gradually. As for the usual stool, it will appear around the age of one year, when the child begins to eat not only breast milk, but also adult food.

The frequency of stool varies from child to child. In the first time after birth, the baby goes to the toilet very often. This is also normal. The gastrointestinal tract of a newborn is formed throughout the year. It is at this point that the frequency of stool is more or less established. Therefore, in the maternity hospital and in the first days at home you will have to use a lot of diapers or nappies. They should be changed after each bowel movement.

Cloth

As already mentioned, the neonatal period is characterized by reduced immunity in the child and increased skin sensitivity. In the past, diapers were always used for reliable protection. The baby was swaddled tightly. This way he was safe, he had no chance of scratching himself with his own nails.

However, with the development of society, diapers were replaced by children's clothing. Today, newborns are dressed in bodysuits, vests or rompers. In some maternity hospitals, it is allowed to accustom a child to clothes from the first days. This is not entirely convenient, given the frequency of diaper/diaper changes.

For walks, newborns should be dressed as warmly as possible, but without excess. As a rule, the baby is given overalls, a hat, and scratches. After this, the baby is placed in a warm envelope. The latter attribute, as a rule, remains for a long time as an element of protection for the child’s skin. The main thing is that the baby is not cold. Hypothermia can cause illness.

Jaundice

Often in the maternity hospital, a child develops a yellowish tint to his skin. This phenomenon scares inexperienced mothers. Is it normal for a healthy baby's skin to change color?

Not really. The fact is that this is a clear sign of jaundice in the newborn period. It appears in most newly born babies. Doctors emphasize that this phenomenon is associated with the vulnerability of the baby.

Should jaundice scare newborns? No. This is not common jaundice, which is dangerous. Infantile jaundice can be treated without much difficulty. Typically, children are placed under a special ultraviolet lamp for several hours. Depending on the degree of yellowness of the baby’s skin, the number of such procedures also changes.

Main problems

The problems of the newborn period are different. They are mainly observed in inexperienced mothers. After all, children who are born know themselves how to develop. But new parents are not aware of child care.

The most common problems of the period under study are the following:

• establishing a daily routine for the baby;
• feeding a newborn;
• daily care;
• changing diapers/diapers;
• childhood infections.

It's no secret that young children easily adapt to certain conditions. Therefore, establishing a daily routine in the first month of life plays an important role. Parents can “dictate” the baby’s life schedule themselves. The main thing is not to violate it after it has been established.

About feeding

The main thing a newborn baby needs is established breastfeeding. A woman in labor begins to produce milk in the first days after birth. Until this point, the baby is fed colostrum. As a rule, it is enough. Some maternity hospitals offer supplementary feeding with formula. Ideally, it is better not to use this opportunity - the mother should “come” with milk for further feeding of the child.

Some prefer to accustom babies to nipples and bottles from the first days. Such a decision does not always have a good effect on the baby - he may forget how to properly grasp the breast while sucking, which will lead to colic due to air trapped in the stomach.

Breast milk is the best food for a baby. It is well absorbed. In addition, the child strengthens the immune system with the help of mother's milk. If the mother is sick, antibodies are transferred to the baby, protecting it from infections.

Eye care

Many people are interested in how newborns see. The fact is that the picture before the child’s eyes blurs. During the first time after birth, the baby sees everything blurry. The people around the baby are just dark spots that over time begin to take on clear outlines.

Babies' visual organs are extremely sensitive, as is their skin. Therefore, they require daily care. What is it about?

It is necessary to wash the baby's eyes every morning. This is done using boiled water and a cotton pad. It is moistened, after which it is rubbed in the direction from the outer corner of the eye to the inner. Sometimes a solution of furatsilin is used for a similar procedure.

It is important to protect children's vision from the first days. You should not allow him to look at bright light and the sun, or carefully work with the flash, trying to photograph the baby. Sudden changes in light must also be excluded.

Bathing and washing

Caring for a newborn requires special attention from parents. Daily procedures should include washing and bathing. The first such processes are carried out in the maternity hospital.

Wash children under running water. This is done after each bowel movement. It is not recommended to wash children in a bathtub or basin. This is due to the fact that children’s genitourinary tract in this case may be affected by infection.

Girls are correctly washed with their hands in the direction from front to back. This is done under warm running water. It is necessary to dry the skin on the changing table. The remaining water is blotted with a clean diaper or a special baby towel. The folds are wiped with cotton swabs soaked in vegetable oil/baby cream.

Bathing is a process that is mandatory for all people. It is recommended to bathe babies in the morning and before bedtime, in the evening. It is allowed to fill the bath with boiled water, not too hot. You can check the temperature with your elbow. At first, it is allowed to add a little potassium permanganate for disinfection purposes. Bathing during the newborn period should not be too long. 10-15 minutes is enough.

Ears and nose

The organs of vision are not the only important ones for humans. What does a newborn baby need? It is important to take care of his ears and nose weekly.

It is noted that the baby’s nose is very susceptible to odors at first. It is easily affected by cigarette smoke. In addition, a clogged nose cannot be ruled out. Therefore, it will have to be cleaned. How exactly?

You will have to make a flagellum from cotton wool, moisten it with Vaseline or vegetable oil, and insert it into the nose with a rotational motion (no more than 1 centimeter). You will have to use a different tourniquet for each nostril. It is recommended to humidify and purify the air in the room.

But caring for a child’s ears does not require any special action. This is the simplest activity. Cleaning children's ears in the first years of life is only caring for the auricle. Foreign objects such as cotton swabs should not be introduced into the auditory canals. They only need to clean wax from the ears. It is recommended to use cotton swabs with special restrictions - they do not allow them to penetrate deep into the child’s ears.

Nails

The early neonatal period is the time when the baby is actively developing. Many children are born with long nails. In addition, they actively grow in the first time after birth. The nails are sharp and hard, the baby can easily be scratched. Caring for a newborn is also about ensuring its safety.

Overgrown nails must be trimmed. Otherwise, they will bend, break and grow back. But you can’t cut a newborn’s nails very short - it will cause him pain. In addition, during the procedure, you must gently press on the pad of your fingers so as not to touch the skin.

It is best to cut your baby's nails during sleep. Then the child is relaxed, and you can bring the idea to life without any problems.

Umbilical wound

The features of the newborn period and baby care have been almost completely studied. Every parent should understand that for the first time after discharge from the hospital, the umbilical wound will have to be treated. It must heal.

As a rule, children are discharged with a special clamp at the navel. There is no need to remove it. The clamp will fall off on its own after a few days. But you will have to treat your baby’s navel every day. Especially in the first month, until the wound formed after cutting the umbilical cord has not healed.

Usually the treatment comes down to dropping hydrogen peroxide on the navel, and when the liquid stops fizzing, remove it with a cotton pad. Next, the navel is smeared with brilliant green. Such a toilet should become a habit for new parents.

Peculiarities

From the above we can conclude that the early neonatal period is the first week of the baby’s life. The rest of the time (3 weeks) is the normal neonatal period. Such a segment has a huge number of features and nuances. At this time, you have to adapt to life with a baby. Caring for him will play an important role in the formation of habits, daily routine, feeding and overall health.

The following features of the newborn period are distinguished:

• immaturity of organs;
• lack of maturity of the nervous system;
• changes of morphological, biochemical and functional type;
• strong exposure to external factors;
• reduced immunity;
• The baby sleeps almost all the time;
• conditioned reflexes develop.

We talked about how newborns see, but even despite blurry vision in the first days, the baby will be able to distinguish his mother from a stranger. This is normal.

All the love, affection and care for a newborn is manifested in satisfying its basic needs. And this is due to the fact that such behavior helps a vulnerable person to survive.

Results

From now on, it is clear how a child develops during the newborn period. In fact, everything is not as difficult and scary as it seems. Babies are vulnerable, but with proper care you can help them gain health and strong immunity.

All the listed rules and tips really help parents. The mother should be informed about proper care during the newborn period upon discharge. The most important thing that a baby needs at this time is attention and care from his mother!

Early neonatal period. - Late neonatal period. - Full-term newborn. - Assessment of the newborn's condition
Human extrauterine life begins from the moment the umbilical cord is ligated. The child enters the neonatal period. From the moment of birth, the cessation of placental blood circulation, the lungs begin to function. A child's first cry is his first breath. The breathing rate of a newborn is 40-60 per minute, shallow breathing; frequency and depth can change very quickly. During the neonatal period, the child’s body adapts to extrauterine existence. This period lasts 4 weeks. In the neonatal period, two subperiods are distinguished: early neonatal (from birth to the 7th day of life) and late neonatal (from the 8th to the 28th days of life). At this time, the pulmonary circulation begins to function (the ductus arteriosus and the foramen ovale, the pathways of intrauterine hemodynamics, close), and the reverse development of the umbilical cord vessels begins. The child switches to enteral nutrition. Urine begins to form and be released. All systems of the child’s body are in a state of unstable equilibrium; adaptation to extrauterine existence is easily disrupted, which can affect the general condition of the child and even lead to his death. Therefore, qualified observation of the child during this period and the creation of special conditions for his better adaptability to environmental conditions are necessary.
A full-term newborn is considered a child born at term (at 38-40 weeks of pregnancy) and functionally mature. The body weight of a full-term newborn ranges from 2500 to 5000 g, averaging 3000-3500 g; the length ranges from 45 to 57 cm. A mature newborn has a well-developed subcutaneous fat layer, elastic, pink skin with a delicate downy covering on the shoulders and back. The hair on the head can be up to 2 cm long. The ears are elastic, the nails are dense, protruding beyond the edges of the fingers. The umbilical ring is located midway between the pubis and the xiphoid process. In boys, the testicles are lowered into the scrotum; in girls, the labia majora cover the labia minora. The baby's cry is loud, muscle tone and movements are of sufficient strength, and the sucking reflex is well expressed.
To assess the condition of the newborn, the Apgar scale is used (Table 2.1). The assessment is made within 1 minute after the birth of the child and consists of the sum of digital indicators of five signs: heartbeat, breathing, muscle tone, reflex excitability, skin color. If the newborn is in good condition, the Apgar score is 8-10 points, with a score of 6-7 points the condition is assessed as satisfactory, below 6 - severe.

Table 2.1. Apgar score Index 0 points 1 point 2 points Heartbeat Absent Low frequency (less than 100 beats per minute) Frequency more than 100 beats per minute Breath Absent Weak cry (hypoventilation) Shout Muscle tone Lethargic Weak degree of flexion Active movements Reflex excitability (heel reflex) Absent Weakly expressed Well expressed Skin coloring Blue or pale Pink coloration of the body and bluish coloration of the limbs Pink

5 minutes after birth, the newborn’s condition is reassessed.

More on the topic Newborn period:

1. Regular P waves with a sinus node shape and normal sinus node frequency. Predominantly AV dissociation: 1:1 conduction with negative P waves in leads II, III and aVF after QRS complexes, separate capture complexes is also possible (see above). Clinical picture and therapy. The constant nature of tachycardia can lead to the development of circulatory decompensation, the danger of which is especially high during the neonatal period and in the postoperative period. In newborns, note

There are several significant periods in a child’s life. The first of them begins immediately after birth, or more precisely, at the moment of cutting the umbilical cord, when the baby’s breathing and blood circulation become autonomous. This time interval is called the newborn period or neonatal period. Its essence is to adapt the baby to extrauterine life.

The neonatal period begins after the baby is born and the umbilical cord is cut.

Time frame

For most young parents, it remains a mystery on what basis children are divided into newborns, infants and infants. Let's look into this issue. Let's find out how many days make up the duration of the neonatal period. According to medical sources, a baby is considered a newborn from the moment of birth until 28 days, that is, 4 weeks.

In turn, the neonatal period is divided into:

• early – 1-7 days;
• late – 7-28.

Infant, infant, infant are identical concepts. They refer to a baby whose age is more than 28 days, but less than 1 year. The infant period in pediatrics is divided quarterly - 3 months from the date of birth, 6, 9, 12.

General characteristics of the neonatal period

All organs and systems of a newborn baby are immature, both in terms of morphology (structure) and taking into account functional activity. After birth, they undergo intensive restructuring, the purpose of which is to adapt the body to extrauterine existence, to the conditions of the external environment.

After birth, the child actively adapts to the conditions of the surrounding world.

An important feature of the neonatal period is the instability of the balance in which all systems of the baby’s body are. Minimal changes in external conditions can significantly affect its internal state.

The main changes that occur in the baby’s body when the blood pulsation in the umbilical cord vessels stops:

• starting the pulmonary circulation;
• the beginning of the functioning of pulmonary respiration;
• transition to enteral nutrition, in which food is absorbed through the mucous membrane of the gastrointestinal tract.

Crisis moment

Life begins with stress. The moment the baby passes through the birth canal is called the neonatal crisis. Experts in the field of psychology consider this stage difficult and turning point for a new person. Components of the crisis:

1. Physiological factors. There is a physical separation of the child from the mother. He ceases to be part of her body and becomes autonomous.
2. Psychological aspects. The actual distance from the mother causes the baby to feel helpless and anxious.
3. Changes in external conditions. After birth, the child finds himself in a completely new world, where everything is different from the previous living conditions - temperature, air, light, a different way of eating, breathing, and so on.

The life of a little man begins with stress caused by a difficult passage through the birth canal

A person is born absolutely helpless. To protect him and ensure his survival, nature has laid in him a certain set of unconditioned reflexes - sucking, swallowing, grasping and others.

Early neonatal period

In the early neonatal period, which lasts one week from the moment of birth, not only the baby’s introduction to the world occurs, but also the first contacts with the mother. The baby's actual appearance may differ from the image she imagined. This is due to the physiological borderline states of his body.

Skin tone

A child’s uneven and uncharacteristic skin tone may be due to:

• erythema;
• vascular response to external conditions;
• jaundice.

Erythema is redness of the skin with a bluish tint. It usually appears on the feet and hands. The cause of erythema is a sharp change in ambient temperature: from 37° in the womb to 20-24° in a hospital room. In addition, the water environment familiar to the child is replaced by an air environment. Erythema is not a pathological condition and does not require treatment. The baby's body temperature, general health and appetite are within normal limits. After a few days, peeling of the epidermis may begin in places of redness.

The cause of erythema is a sharp change in ambient temperature

The physiological reaction of blood vessels more often occurs in premature infants during the neonatal period. It is a consequence of the immaturity of the vascular system. Its manifestations:

• marbling of the integument, bluish spots;
• uneven body color, on one part the skin is red, and on the other it is pale with blue, this happens after sleeping on one side.

This condition can occur within 2-3 days after birth. The child does not need treatment, but doctors are monitoring him.

During the newborn period, jaundice occurs due to functional liver failure due to its immaturity. The organ cannot neutralize the increased amount of bile pigment entering the blood. Normally, physiological jaundice, in which the baby’s skin acquires a characteristic shade, lasts about a week. For babies born prematurely, it can last up to 6 weeks. Yellowness of the skin that persists longer than expected is a reason to consult a doctor.

Milia and acne

The work of the sebaceous and hormonal glands in a newborn is not established. After birth, you can notice miles and acne on his face.

• Milia are white spots that usually appear on the nose, forehead and cheeks. They occur due to blockage of the sebaceous glands. It is strictly forbidden to touch them. Milia goes away on its own within a few weeks.

Milia does not require treatment and goes away on its own in the child

• Newborn acne is red pimples with a purulent white tip, similar to juvenile acne (more details in the article:). They usually appear on the face, but can appear on the back and neck. The cause of acne in babies is an excess of maternal hormones in the blood and imperfect functioning of the sebaceous glands. They go away within 2-3 months. Pimples do not need to be treated. Careful hygiene must be observed. In addition, you can apply Bepanten cream in a thin layer once every 3 days.

During the neonatal period, not only the described physiological phenomena related to the normal development of the child are discovered. Structural anomalies, hereditary pathologies, fetopathies, and so on can be identified. The mother is required to pay increased attention to the child, which will help to notice deviations in physical and mental development in time.

Late neonatal period

The late neonatal period lasts 3 weeks. Pediatricians call it the time of recovery from maladaptive syndromes. Main characteristics:

• the baby is actually separated from the mother, but is strongly connected to her physiologically and emotionally;
• the child’s organs and systems are in the process of development, they have not fully matured, especially the central nervous system;
• water-salt metabolism is very dynamic;
• the newborn’s body undergoes changes in biochemical, functional and morphological aspects;
• the child’s condition is significantly dependent on external factors;
• When living conditions are violated, physiological processes quickly transform into pathological ones.

The condition of a child during the late neonatal period greatly depends on the quality of care

At this age, the baby needs care. It is important to satisfy his needs for food, drink, sleep, affection. This is what ensures the child's survival. The newborn spends most of the day sleeping, but over time the number of hours of wakefulness increases. The visual and auditory systems develop, and instead of unconditioned automatisms, conditioned reflexes arise. The baby overcomes the crisis and gradually adapts to new conditions.

Features of the functioning of various organs and systems of the child

The mental and physical development of children has certain age-related patterns. Until what age the maturation of a particular system lasts depends on the individual characteristics of the child and the external conditions of his life. However, doctors identify general norms that are typical for most healthy babies.

Vision

The muscles responsible for the movements of the eyeballs, as well as the optic nerves in newborns, are not 100% formed. As a result, physiological strabismus occurs. This phenomenon, caused by insufficient development of the oculomotor muscles, is considered normal and goes away over time. At the early newborn stage, the baby distinguishes light from darkness, that is, distinguishes between day and night.

Physiological strabismus is considered normal and goes away without treatment

Hearing

During the first 3-4 days of life, the child’s ear cavities are not filled with air, so his hearing is somewhat reduced. Then the hearing system gradually develops and the baby hears almost like an adult. He flinches at very loud noises. At the same time, you can notice how the frequency and depth of his breathing, as well as facial expressions, change.

Touch, taste, smell

Due to the uneven distribution of nerve endings, the newborn reacts differently to touch on different parts of the body. The skin of the face and limbs is more sensitive than the skin of the back. In general, the sense of touch is well developed.

An age-related feature of the baby is the love for the sweet taste that mother’s milk has. Having tasted something sweet, he licks his lips, makes swallowing movements, and calms down. If the liquid is bitter or salty, the child stops sucking, cries, and grimaces.

The baby's sense of smell is developed. Strong aromas cause a reaction in him, expressed in a change in breathing rate.

The baby's favorite sweet taste is supplied by his mother's milk.

Leather

The skin of a child is supplied with blood much more intensively than that of adults, due to the large number and increased diameter of capillaries. Any damage, the cause of which has been eliminated, heals quickly. However, the development of sweat glands is insufficient. As a result, a child under one month old easily overheats due to high air temperatures or too warm clothes.

urinary system

The baby's kidney development ends after birth. The bladder contains a small amount of urine, the properties of which differ from the standards characteristic of an adult. For newborns, their own age standards are used regarding protein content, specific gravity, and biochemical reactions. In the first week, urination occurs 4-5 times a day, then 15-25 times.

Respiratory system

Children at the newborn stage, as well as in infancy, have narrow upper respiratory tracts, which include the nasal passages, larynx, and trachea. The mucous membranes lining them are actively supplied with blood. They are very sensitive to mechanical irritants and dry air. The normal breathing rate is 40-60 movements per minute.

Children's breathing is quite shallow even during sleep

The cardiovascular system

After birth, the functioning of the child’s cardiovascular system changes dramatically. The vessels and openings through which placental blood flow was carried out are closed. The lungs fill with blood. Normal heart rate is 110-140 beats per minute. Any external influence leads to its change.

Digestive system

The maturation of the digestive organs continues after birth. The child is born with developed chewing muscles and a large tongue. Thanks to this, he can actively suck without getting tired for a long time. The salivary glands are underdeveloped and therefore produce little secretion.

During the first day, the baby’s gastrointestinal tract is sterile, but is quickly populated by flora. The volume of the stomach grows daily: after birth its capacity is 20 ml, after a week - 50 ml, after 4 weeks - 100 ml. The optimal food is breast milk. The baby's body produces enzymes specifically for its digestion.

The appearance of stool changes gradually. At first it is brown, then yellow-green, then yellow, mushy with a sour odor. Transformations are associated with the process of colonization of mucous membranes by bacteria.

Breast milk is considered the optimal food for a child of this age group.

Nervous system

During the first months of life, the child’s nervous system develops most actively. At first, he spends most of the day (20-22 hours) in sleep, since in the cerebral cortex the processes of inhibition prevail over excitation. Over time, periods of wakefulness increase.

The baby's excitability, reflexes and reactions are constantly transforming. The tone of the muscles of the arms and legs is very pronounced. During this period, for example, physiological tremor may be observed - trembling of the muscles of the limbs. In addition, there are a number of unconditioned reflexes associated with brain immaturity, which all children initially have, but fade away in the first year of life.

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Newborn period

INTRODUCTION

1. Newborn period.

2. The body of a newborn child and its nutritional conditions.

CONCLUSION

INTRODUCTION

The neonatal period is a crucial period in a child’s life. During this period, all organs and systems, including the digestive tract, adapt to the conditions of extrauterine existence. One of the most important environmental factors that require constant adaptation is nutrition.

The period of infancy is characterized by an intensive increase in body weight and growth, which is ensured by a high level of metabolism, which requires the intake of sufficient amounts of nutritional and biologically active substances into the body. Body weight doubles by 4-4.5 months of life, triples by 10-11 months. Monthly weight gain is: up to 3-4 months on average 800 g, from 4 to 6 months 600 g, in the second half of the year - 400 g.

A child grows most vigorously in the first months of life: up to 3 months he gains 3 cm in height per month, from 3 to 6 months by 2-2.5 cm, from 6 to 9 months by 2 cm, by the end of the year by 1, 5 cm. Thus, in the first half of the year the child grows by 15-16 cm, and in the entire first year of life - by 25-27 cm.

By the tenth day of a child’s life, the amount of milk the child receives reaches approximately 1/5 of body weight (600-900 ml), from 1 to 4 months it is 1/6 of body weight (800-1000 ml), from 4 to 6 months - 1/ 7 body weight (900-1100 ml).

But these are only indicative figures. When determining them, it is necessary to take into account the individual characteristics of the child.

During the newborn period, diseases may appear that are characteristic only of children of this age, as they are associated with the developmental features of various systems of their body. Despite constant medical supervision, the baby's health is largely in the hands of the parents.

1. Newborn period

The process of birth is a difficult, turning point in the life of a child. Psychologists talk about the neonatal crisis. At birth, the child is physically separated from the mother. He finds himself in completely different conditions: cold, bright light, an air environment that requires a different type of breathing, the need to change the type of food. Hereditarily fixed mechanisms - unconditioned reflexes - help the child adapt to these new, alien conditions. This is, first of all, a system of food reflexes. When you touch the corners of the lips or tongue, sucking movements appear, and all other movements are inhibited. Because the baby is completely focused on sucking, this response has been called "feeding focus." A number of other unconditioned reflexes are given in Table 1 Kuraev G.A., Pozharskaya E.N. Age-related psychology. Lecture course. - Rostov-on-Don, 2002. .

Table 1

Conditioned reflexes of a newborn

One should also name as unconditioned a group of reflexes that promote self-preservation and development of the child’s body. They are associated with the regulation of digestion, blood circulation, respiration, body temperature, metabolic processes, etc. Undoubtedly, sucking, protective, orientation, grasping, musculoskeletal and a number of other reflexes are innate; all of them clearly manifest themselves already in the second month of the child’s life Kuraev G.A., Pozharskaya E.N. Age-related psychology. Lecture course. - Rostov-on-Don, 2002. .

So, a newborn is a child from birth to 4 weeks. There are full-term (born between the 38th and 42nd weeks of pregnancy), premature (born between the 28th and 38th weeks of pregnancy) and post-term (born at 42 weeks and later). As a rule, full-term babies are morphologically and physiologically prepared for extrauterine life - they are active, take the breast well, actively suck, have a loud cry, weight - from 2600 to 5000 g, height - from 48 to 57 cm. The newborn period is the period of the child’s adaptation to new living conditions. It begins after birth from the moment of ligation of the umbilical cord and lasts 18-24 days.

From the moment of birth, a number of changes occur in the child’s body: pulmonary respiration occurs, blood circulation changes, the processes of sucking and digestion begin, energy metabolism changes, and basal metabolism increases. During this period of life, there are no significant gender differences between the female and male bodies. The period of childhood is characterized by relative rest of the female and male reproductive systems.

Consideration of the newborn period as a transitional period reveals the processes of restructuring of the child’s individual organization at its different levels. At the somatic level, various kinds of adaptive changes occur in vital functions and systems. A general indicator of adaptation processes: weight loss is 5-6% of the initial one. Under normal conditions, the process of weight loss and subsequent weight restoration occurs during the first three weeks of life.

The weakness of the processes of excitation and inhibition in the first time after birth determines a peculiar transitional state from sleep to wakefulness, expressed in the fact that the child spends 80% of the time in sleep, which is not concentrated at a certain time of day. In newborns with low and unstable excitability, an increase in rheobase and chronaxy under the influence of extraneous stimuli indicates rapid depletion of nerve cells Rybalko E.F. Developmental and differential psychology: Textbook. allowance. - L.: Publishing house of Leningrad University; 1990. - 256 p. .

All the main functions of the child’s body are in a position of unstable equilibrium, and even minor changes in the state of the environment can lead to severe disruptions of important life processes. The newborn’s body is very susceptible to pyogenic microbes, in particular to staphylococci, streptococci, and some strains of Escherichia coli. These pathogens often cause severe toxicosis in newborns. These include sepsis, pemphigus and other purulent skin diseases, diseases of the umbilical cord, umbilical wound and umbilical vessels. Newborns can get whooping cough, which is very severe.

Along with this, newborns are immune to a number of diseases. They almost never get measles, scarlet fever, or rubella. The reduced or complete immunity of newborns to certain infections is explained by the passive transfer of maternal antibodies to the child through the placenta during fetal development and through milk during breastfeeding.

2. The body of a newborn baby and its nutritional conditions

The newborn period is a period of adaptation of all the child’s organs, including the digestive tract, to the conditions of extrauterine existence. All functions of the body, in particular metabolic processes, undergo peculiar, but quite constant in all newborns and, therefore, natural changes in the first days of a child’s life. The macroscopic and microscopic structure of the central and peripheral nervous system is not yet complete; a newborn has only some unconditioned reflexes, and there are no conditioned reflexes acquired during life and which are of great importance for the nutrition of infants.

The nature of nutrition is undergoing major changes. If during the period of intrauterine development the child received all the nutrients from the mother’s blood, then after birth he receives food from the outside and his digestive processes begin to form. A full-term baby is born with an average body weight of 3200-3400 g. In the first days of life, a so-called physiological loss of body weight of 8-10% (200-300 g) is noted. By the 8-10th day of a child’s life, his body weight is restored.
During the newborn period, all the organs and tissues of the child are still imperfect, easily vulnerable, all the main functions of the body are, as it were, in a state of unstable equilibrium.

The skin of a newborn baby is very delicate, thin, easily injured and susceptible to various diseases. Bone tissue is imperfect in its structure, contains few lime salts, and instead of some bones there is cartilage. The muscles are poorly developed. The body temperature of a newborn is unstable and can vary depending on the ambient temperature.

The breathing and blood circulation of a newborn is in a state of great tension. He needs a lot of oxygen. The digestive system of a newborn is still immature. The oral cavity is relatively small, the salivary glands secrete little saliva. The esophagus is relatively wide. The stomach is located almost vertically, the muscular layer of the entrance to the stomach is poorly developed, which predisposes to regurgitation and vomiting. Stomach capacity 30-35 ml. The digestive glands of the stomach are underdeveloped, the acidity of gastric juice is low. The intestines of a newborn are relatively longer than those of an adult. Its walls are thin, passable for microbes and toxic substances, and are easily stretched by gases, which are formed in excess during malnutrition, which is often the cause of abdominal pain.

Bowel movements in newborns usually occur up to 4-5 times a day.

Along with insufficient maturity and imperfection of many functions, the newborn’s body has a certain “margin of safety”. Thus, it is known that newborns rarely suffer from infectious diseases, which is associated with the transfer of special protective factors to the child from the mother - through the placenta during intrauterine development and through milk during breastfeeding. For a newborn, the only physiological nutrition is natural breastfeeding from the mother. From the above it is clear that colostrum secreted in the first days after the birth of a child is a concentrated, calorie-rich food, with which the child receives not only the amount of plastic and energy material he needs, but also a large number of protective bodies.

The amount of food received by a newborn should gradually increase in accordance with his increasing needs and the functional capabilities of his body. Improper feeding of a child from the first days of his life is often the cause of early-onset nutritional and digestive disorders, which severely disrupt and for a long time delay all subsequent physical, mental and motor development.

Only natural breastfeeding ensures the full development of the child and opens up opportunities for the maximum reduction in early childhood morbidity and mortality.

The small body of a newborn child is very complex. Each day of the 28 days of the neonatal period is a whole stage. The child adapts to new living conditions, which is reflected in changes in many organs and systems of the body. During this period of life, the child, more than ever, needs careful and thorough observation, first by doctors and nurses in the maternity hospital, and then by a personal pediatrician at home.

newborn reorganization organism child

CONCLUSION

The neonatal period covers the first month of a child's life. The human child is one of the immaturely born creatures. By the time a child is born, none of its organs and systems has completed its development. Once born, the baby continues to grow and develop rapidly.

During the newborn period, there is an intensive restructuring of all life-supporting systems to their activity in conditions outside the womb. The successful course of the period depends on the degree of development of the child, the presence or absence of exposure to various harmful factors during pregnancy, and the course of labor.

From birth, a child has a need not only for physiological comfort (food, warmth, long sleep, dry diapers, etc.), but also for psychological comfort (a feeling of closeness and attention from a mother or another adult). A newborn is not able to satisfy any of its needs on its own, but nature has endowed it with the ability to signal its needs by screaming. The mother eliminates the causes of discomfort, and the baby calms down and most often falls asleep. An attentive, sensitive mother quickly learns to recognize the reason for the baby’s crying and anticipate it, thereby establishing harmonious relationships from the very first days of life.

So, by the end of the newborn period, a normally developing child is characterized by the ability to focus attention on the influences of an adult and objects, look into the eyes of an adult and smile at him. Newbornhood acts as a preparatory stage in the development of communication between a child and an adult. Raising a baby in a family from birth to three years: Advice from a psychologist / E.O. Smirnova, N.N. Avdeeva, L.N. Galiguzova, A.O. Drobinskaya, T.V. Ermolova, S.Yu. Meshcheryakova. - M.: ARKTI, 2004. - 160 p. .

LIST OF REFERENCES USED

1. Raising a child in a family from birth to three years: Advice from a psychologist / E.O. Smirnova, N.N. Avdeeva, L.N. Galiguzova, A.O. Drobinskaya, T.V. Ermolova, S.Yu. Meshcheryakova. - M.: ARKTI, 2004. - 160 p.

2. Kuraev G.A., Pozharskaya E.N. Age-related psychology. Lecture course. - Rostov-on-Don, 2002.

3. Rybalko E. F. Age and differential psychology: Textbook. allowance. - L.: Publishing house of Leningrad University; 1990. - 256 p.

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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 outer ear buds 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 for 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

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