Development of a human embryo. Development of the fetus for weeks of pregnancy, understandable description of each month with photos

What symptoms are more often found on each Pregnancy stage? How does the fruit develop?

This is normal when these questions arise during pregnancy. A woman should know in advance which symptoms will appear at different stages. Pregnancy may differ from a woman to a woman. Even for the same mother from one pregnancy to the other.

The usual pregnancy lasts about 40 weeks, counting from the first day of the latter menstrual cycle of women, which is about two weeks before conception.

Pregnancy is divided into three trimesters. Each of these periods lasts from 12 to 13 weeks.

Stages of the development of the embryo within 38 weeks

During each trimester, changes occur in the body of a pregnant woman, as well as in developing fruit, and a summary of these stages will be described below.

Concept and implantation

About two weeks after the woman spent his period, she ovulates, and her ovaries produce one ripe egg. The egg can be fertilized within 12-24 hours after its release, when it moves along the phallopy tube towards the uterus.

If the egg is found with a sperm cell, which made his way into the phallopy tube, it is combined into one cell, the process known as fertilization or conception.

In fertilization, the French floor is already defined, depending on whether the egg chromosoma is obtained from spermatozoa. If the egg receives a x-chromosome, the child will be a girl; Y-chromosome means that the child will be a boy.

According to the Cleveland clinic, for a fertilized egg (or embryo) requires about three or four days to go to the lining of the uterus, where it is attached or implanted to the wall of the uterus. After implantation of the embryo cells begin to grow. Ultimately becomes the fruit and the placenta, which is a fabric. This fabric can transport oxygen, nutrients and hormones from maternal blood to a developing fruit throughout pregnancy.

First trimester (weeks 1-12)

The woman will have many symptoms during the first trimester when it adapts to hormonal changes in pregnancy. In the first weeks, pregnancy may not manifest outside of her body, but inside many changes occur.

For example, human chorionic gonadotropin (HCG) is a hormone that will be present in the blood of a woman since conception. HCG levels can be found in the women's urine in about a week after the missed cycle. That is why the woman will have a positive result on the home dough for pregnancy.

Other hormonal changes can contribute to symptoms of pregnancy: an increase in estrogen and hCG may be the cause of nausea and vomiting, known as the morning nausea, which a woman is usually experiencing in the first months of pregnancy. Despite its name, the morning nausea may occur at any time of the day.

Woman will also feel more tired than usual. This is due to the increase in the level of progesterone hormone, which increases drowsiness. It may also need to urinate more often when her uterus grows and presses her bladder.

At the beginning of pregnancy, women's breasts will feel more gentle and swollen, which is another side effect of increasing the level of pregnancy hormones. Her Area, the skin around each nipple, will be dim and increased.

The digestive system of a pregnant woman can slow down to increase the absorption of useful nutrients. But the decrease in the mobility of the digestive system can also cause such general complaints as heartburn, constipation, bloating and gases.

As more blood circulates to the face of a woman, it will give her the skin of a pink color described as a "glow of pregnancy".

In addition to physical changes in the female body, it can also experience emotional maxima and minima in the first months of pregnancy and in everything. These emotions may vary from racing, mood drops and forgetfulness to fear, anxiety and excitement.

Development of the first trimester embryos / fetus

A developing child is called an embryo since the conception, which occurs until the eighth week of pregnancy.

According to the American College of Obstetricians and Gynecologists (ACOG), heart and lungs, hands, legs, brain, spinal cord and nerves begin during the first month of pregnancy.

The embryo will be the size of a pea of \u200b\u200babout a month. For the second month of pregnancy, the embryo will grow to the sizes of beans. In addition, ankles, wrists, fingers and eyelids appear, bones appear, appear genitals and inner ear.

After the eighth week of pregnancy and before the birth of a child emerging child called fruit.

By the end of the second month, the eight ten main bodies of the fetus were formed. At this stage of pregnancy, it is extremely important that pregnant women do not take harmful medicines, such as illegal drugs. The first trimester is also a period when most of the miscarriages and congenital defects occur.

During the third month of pregnancy, the bones and muscles begin to grow, the kidneys appear for future teeth, and the fingers of the hands and legs grow. The intestine begins to form, and the skin is almost transparent.

Second trimester (weeks 13-27)

To the second trimester, some of the unpleasant consequences of early pregnancy can decrease or disappear, since the female body adapts to its changing hormone levels. Sleep can become easier, and the energy level may increase.

Nausea and vomiting usually improve and go. But other symptoms may occur because the fruit continues to grow and develop.

A more noticeable child appears when the uterus grows for a pelvic of a woman, and the skin on her expanding belly may look like a stretching.

As the fruit is becoming more and more, and the woman is gaining more weight, it can also experience the back of the lower back.

Between the 16th and 18th weeks of pregnancy, the mother may feel the first trembling movements of the fetus. If a woman had a child earlier, she would likely feel that the fruit kicks, wriggling or turns even earlier because she knows what to expect.

The 20th week usually denotes half a woman's pregnancy.

Development of embryos / fetus in the second trimester

In the second trimester, the fruit grows faster and will be from 3 to 5 inches long. Between 18 and 22 weeks, ultrasound can reveal the sex of the child if parents want to know this information in advance.

By the fourth month of pregnancy, eyebrows, eyelashes, nails and neck are formed, and the skin has a wrinkled look. In addition, during the fourth month, hands and legs can bend. The kidneys begin to work and can produce urine, and the fruit can hear.

In the fifth month of pregnancy, the fruit is more active, and a woman can feel their movements. The fruit also sleeps and wakes up on regular cycles. Beautiful hair (called Lanugo) and a waxy coating (called Vernix) are covered and protect the thin skin of the fetus.

To the sixth month of pregnancy, hair begins to grow, eyes begin to open, and the brain develops rapidly. Although the lungs are fully formed, they still do not function.

Stages of pregnancy for nine months.

Third trimester (weeks 28-40)

In the third trimester, when an enlarged woman's uterus pushes her aperture. The main muscle involved in breathing may experience a shortage of respiration because the lungs are less than space for expansion. Her ankles, arms, legs and face can swell, because it retains more fluid and blood circulation slows down.

Mother should urinate more often, because on her bladder there will be more pressure. It may also have more pain in the back and pain in the hips and pelvis, since these joints relax when preparing for childbirth.

Dark spots may develop on her face, and stretch marks can appear on her belly, hips, chest and back. It can also notice varicose veins on the legs.

In the third trimester, a female breast may experience some leakage of a colostrum, yellow liquid, because they are preparing for breastfeeding. The child will fall lower in the stomach.

Over the past weeks, pregnancy becomes harder to find a convenient position for sleep, so women can be very tired.

As I approached the birth of some women you like the experience of pregnant, while others can feel that they cannot wait when it end.

Development of embryos / fetus in the third trimester

By the seventh month of pregnancy, the fruit hits and stretches, and even can react to light and sound and music. Eyes can open and close.

During the eighth month of pregnancy, the fruit very quickly gains weight. Bones harden, but the skull remains soft and flexible to alleviate childbirth. According to ACOG, various brain areas are formed, and the fruit is capable of Ikot.

The lungs are now completely mature to prepare for the functioning yourself. The fruit continues to quickly gain weight.

A new definition of long pregnancy is when a child is born through 39-40 weeks.

The conception occurs when the men's field cell (spermatozoa) falls into the female organism and merges with its egg cell. As a result, a new cell (zygote) is formed and the formation of a human embryo. Only for the first eight weeks of intrauterine development, the child is called an embryo or embryo. In the future, it is called the fruit.

In the first eight weeks, the main organs are laid, both internal and external. According to the appearance of the embryo, it is not yet possible to determine the gear of the germ - it will be possible only two weeks later.

The development stage of the human embryo

Make sure how the embryonic development of man occurs. At the time of fertilization in the egg, there are two cores. When they merge, a unicellular embryo is formed, in which 23 chromosomes of the father are added to 23 chromosomes of the mother. Thus, a set of chromosomes in an embryo cell is 46 pieces.

Further, the human embryo begins to gradually move along the phallopyaipe tube towards the uterus. In the first four days, the division of the nucleus cells occurs at about once a day, the cells are beginning to share the faster.

All this time, the uterus is preparing for the adoption of the embryo, its mucosa becomes thicker and additional blood vessels appear in it. Approximately on the seventh day after fertilization begins the implantation of the embryo, which lasts about 40 hours. Pork on the surface of the embryo increase and germinate into the tissue of the uterus. A placenta is created.

At the end of the second week, the length of the human embryo is approaching 1.5 millimeters. Closer to the fourth week, the formation of most organs and tissues begins - the rigging skeleton, bones, kidneys, intestines, liver, leather, eye, ears appear.

By the fifth week, the length of the embryo is about 7.5 millimeters. With the help of ultrasound, this time can be observed as its heart is reduced.

Starting from 32 days, the human embryo appears routine of hands, and a week later - the feet of the legs. When the 8th week of development ends, the embryo acquires length around 3-4 centimeters. Both the inner structure of the embryo and its appearance acquire all signs of man. The laying of all major bodies ends.

Factors affecting the development of the embryo

Smoking

Nicotine can easily strangle the baby in the womb, since the embryo in the first two months is extremely sensitive to the lack of oxygen, and during smoking it is inevitable.

Alcohol

The effect of alcohol on the development of the embryo is no less negative. For example, the use of alcohol at the moment of conception can lead to an alcohol embryo syndrome, which is expressed in multiple developmental anomalies. Even the episodic consumption of alcohol is extremely dangerous if it falls at the time of implantation or the formation of any organ. The development of alcohol syndrome is caused by the effect on the ethyl alcohol embryo, resulting in a slowdown in the body growth, a violation of the central nervous system, anomalies of the face and internal organs.

Drugs

The influence of drugs on the embryo is manifested in slowing development, multiple defects of the development of congenital nervous disorders, intrauterine death. Stretching is often observed caused by the cessation of drug admission to the child's body.

Radiation

The germ of the child is extremely susceptible to the action of radiation. The irradiation of the mother before implantation is the wall of the uterus, entails the death of the embryo. If harmful radiation affects the period of embryogenesis, abnormalities and malformations are manifested, the likelihood of his death increases.

For 9 months of embryonic development, the human embryo passes an amazing path from the cell to a full-fledged, viable organism. Each week of pregnancy marks the formation of new fabrics and organs. If in the early deadlines, the human embryo cannot exist without a mother, then by the end of the gestation, it becomes more and more independent. How is the development of a child in the womb?

The initial period of embryonic development (the first 4 weeks)

The new life is born at the time of the merger of two heams - spermatozoa and egg. If this happens as a result of a natural sexual intercourse, the conception is carried out in a phallopyan tube, where spermatozoa expect an exit of the egg from the follicle. In the process of their compound, a new cell appears - the zygote. After 24-36 hours, it begins to flow, and on the second day after conception, the embryo is already of 2 cells, on the third - from 8, and on 4 from 10-20. This embryo shape is called blastocyan.

Blastocyst, thanks to the reduction of the muscles of the fallopian tube and the movement of the villi, heads towards the uterine cavity. She goes to the uterus for 7-8 days. During this time, the hormone progesterone has time to prepare uterine endometrium to implantation.

Blastocyst throws the fingerprint and attached to the endometrium, the HCG be secreted. Some women at this point feel painful pain in the stomach, they appear osculusing bleeding - implantation bleeding.

If in the first week of pregnancy the size of the embryo is only 0.2 mm, then by the third week it grows up to 4 mm. The initial period of embryogenesis is characterized by rapid changes that occur every day. On the third week, the embryo is a fruit egg. It includes the human germ itself and the provisional organs, which perform the function not yet formed tissues, is chorion, amnion, a yolere bag.

A nervous tube is formed, which passes along the entire length of the embryo. It has several bulges. By the 21st day of embryonic development from the average bulge, a heart is formed, from the one that from above, - a brain. The rest of the tube turns into a spinal cord.

At 4 week, the laying of the main organs - liver, kidneys, stomach, intestines begins. During this period, ontogenesis, the embryo is especially vulnerable, any external impact, the disease of the mother, the reception of medicines can affect the embryonic laying of the organs. By the end of the first month of the gestation, the heart is already beating, circulates blood, there are fading of the limbs and eye depressions. In the photo below, you can see how the child looks like at this stage of ontogenesis.

Development Stages in the following months

The intrauterine development of a person is called a prenatal period. It is divided into two parts - the embryonic period (up to 8 weeks) and the fetal period, when the embryo is already called the fruit. All pregnancy is divided into trimesters:

• first trimester - 1-13 week;
• the second trimester is 14-26 weeks;
• the third trimester is 27 weeks and before birth.

Second (from 5 to

At 5 week of gestation, the embryo is formed by Pupovina. It will bind the fetus with the maternal organism, it is through it that it will receive useful elements and oxygen and give waste after metabolism. As the intestine increases, partially fills the umbilical cord. This is explained by its length, which is disproportionate the magnitude of the embryo. At 10 week, it will be completely hidden inside the body.

By 6 week, the embryo already has feathers, it appears eyes, which are covered with centuries, nose, jaws.

The limbs continue to be formed, but the baby can already bend the hands in the elbows, compress the cams. In the middle of the second month of gestation, the weight is 2 g, and the body length is 2.3 cm.

At 7 week of the embryonic period, a placenta begins to form, which immediately assumes the function of the secretion of hormones. Internal organs develop - blood vessels, endocrine glands, brain, sex glands - eggs or ovaries.

At 8 week of gestation, the Y-chromosome site is activated, which is responsible for the production of sex hormones. If the woman is pregnant with a boy, the testicles secrete a hormone testosterone. Under the influence of this hormone, the boy is formed by men's genitals. The external genitals are still weakly differentiated, although sexual tuberculosis, urogenital and anal membranes are already formed.

Third (from 9 to 12)

In the third month of pregnancy, the embryonic period of ontogenesis ends and fetal begins. By 10 weeks have already formed many structures:

• oral cavity;
• face;
• big hemisphere;
• intestines;
• bile ducts.

Begins to develop a cerebellum. The fruit makes the first movements in the womb, but it is still too small so that the woman felt them.

Initially, the uniform sexiplock under the influence of sex hormones by 12 week begins to differentiate. In the girl, this leads to the formation of the clitoris, large and small sexes, and the boy is a penis and scrotum.

At the 12th week, gestation can already be said which child will be a blood type. On the surface of the erythrocytes, agglutinogens appear, which determine the group affiliation and the rhesus factor. T-lymphocytes appear in Timus, playing an important role in the body's immune response.

Fourth (from 13 to 16)

The table shows the Monday description of the growth and weight of the embryo for 4-5 months of the embryonic stage:

The child has formed many bodies that have already begun to function in accordance with their role in the body:

• pancreas produces hormone insulin;
• the liver secrete bile;
• cardiac muscle runs 600 ml of blood;
• the kidneys allocate urine;
• thyroid gland highlights thyroid hormones;
• bone marrow produces blood cells (erythrocytes, leukocytes);
• potion and salivary glands begin to function;
• fully developed genitals, but on ultrasound to see them still not easy;
• the boys appear the prostate gland;
• girls multiply Oogonia - by the time of birth they will remain only 3-4% of the initial number.

At the beginning of the 13th week, the placenta has already been fully formed. It provides a child with the necessary substances for development, and also produces progesterone and estrogen necessary to maintain pregnancy.

Externally, the fruit is like a small little man. Eyes and ears occupy their usual place, grow eyebrows and hair on the head. The whole body of the kid is covered with flush maps - Lanuga. Milk teeth are laid in the mouth. Skeleton, muscles, ligaments are actively forming. The fetus makes many movements with limbs, fingers, head.

Fifth (from 17 to 20)

In the fifth month there is a phased formation of the following bodies and structures:

• development ends immune system;
• the hearing system is drawn up - the ear bones and the zone of the brain responsible for the rumor; The child can hear sounds;
• the uterus appears in girls, follicles grow in the ovaries;
• milk teeth are covered with dentin, under them are formed the rigids of a constant dentition;
• begins myelinization of nerves.

Many organs are already formed, and from this point on their improvement begins. In the brain there are already zones responsible for smelling, touching, taste, vision and hearing. On the ultrasound you can see the floor of the future baby.

The fruit distinguishes the time of day. He actively moves in the womb of the mother, feeling the space around - his own face, the wall of the fruit bubble, the umbilical cord, puts his fingers into the mouth, and more uses one hand. Most of the time he prefers to sleep.

The body of the fetus is covered with a raw lubricant - a viscous substance that provides protection for skin. Under it, the skin is divided into layers. What does a child look like at this stage of ontogenesis, can be viewed in the photo.

Sixth (from 21 to 24)

The period of active growth of the child comes. If at 21 weeks it weighs 360 g, then on 24 of the 500-600, his body supports the spine, which has 33 vertebrae and 150 joints. The baby continues to move in the abdomen of Mom, he has formed an inner ear, and he knows, in what position he is. An individual drawing appears on his fingers, which will remain so for life.

The source of food becomes an amniotic fluid. The fruit drinks it, and he can already feel the taste due to taste papillars in the language. In the thick intestine from amniotic waters absorbed carbohydrates. Waste is displayed with urine.

The bone marrow takes over the production of red blood cells. Until the sixth month, this was engaged in the liver and spleen.

Alveolas inside are covered by a superval. This substance prevents lung sticking with breathing. However, it is still too small, therefore, when the child occurs during this period, the child is keen in the kouveza.

Internal genital organs and outdoor genitals continue to develop. The girls appear in the girls, the testicles of the boys begin to descend from the abdominal cavity in the scrotum.

Seventh (from 25 to 28)

In the seventh month, the third trimester of pregnancy begins. The rapid growth of the child continues. At the 25th week it weighs 710-760 g, and 27 reaches 1 kg and 35 cm.

The already formed authorities continue to be improved. The eyes are still closed, but the iris is formed - blue or dark. Eyelashes, eyebrows, hair on the head, and the hair on the body, on the contrary, begin to disappear.

Moms celebrate that the baby often moves in his stomach, changes the situation. A woman can already determine when her child sleeps, and when he has a period of activity. In a dream, the fruit can suck finger, smile.

Brain is improved. The hypophies produces an adenocorticotropic hormone, which stimulates the development of adrenal glands and glucocorticoid secretion.

Eighth (from 29 to 32)

On the eighth month, the growth of the fetus occurs according to the individual scheme. This is affected by many factors, including genetic. Some kids are born large, others appear on the light of miniature. On average, the fetal mass is 1150 g, and the growth of 36 cm, for 32 weeks - weight 1400-1900 g.

The child has all organs formed if the mother has premature birth, the baby will survive. However, the souffritant is still a bit, so medical care and exercise will be required.

At this stage of gestation, it is important to find out what position is the fruit. It can be located longitudinally, transversely or oblique. To select a childbirth strategy, it is important to determine the prelation that may be head or pelvic. The most successful is the head location, however, if the child lies with the buttocks down, it is not worth worrying, he has several weeks to turn around. The doctor tracks the location of the fetus on the ultrasound.

Ninth (from 33 to 36)

At 33-34 week, the growth and weight of the baby is 40 cm and 1800-2100 g, and by the end of 9 months - 46 cm and 2400. If the fruit is born right now, he can survive even without the help of medical personnel. All of its organs are formed and functioning. Below is a photo of the fetus immediately before birth.

The nervous and immune system continues to form, the subcutaneous fat required for thermoregulation is increasing. The bones of the skull in the kid are mobile, it will be needed to him when he will go through the cervix and the vagina - the bones will be shifted on each other. The child is already quite large, in the uterus he has little space, so it is practically not moving.

Recent weeks before childbirth (from 37 to 40)

In recent weeks before childbirth, the child is fully formed and waiting for the appearance. During the waiting period, it adds in weight, which at the time of birth on average is 3000-3500.

All organs have already formed and function normally. The raw-like lubricant disappears, which is why some kids are born with skin-wrung from liquid.

Not all women give birth exactly for 40 weeks. Rhodework can occur with a delay or ahead of 1 week, this is normal and depends on the individual characteristics of the flow of gestation.

When passing through the generic routes, the baby's head is deformed, it is born with mucus and blood. The obstetricians who take birth will free their mouth and nose from mucus, the baby makes the first sigh and makes the first cry - he notifies everyone that was born.

Germ. The developing human body in the period before his birth.

The intrauterine human development is normal 280 days. During this time, a new completely unique person, capable of living separately from the parent organism, is formed from the two combined cells.

Science, which studies the development of the embryo, is called embryology. Knowledge of how the human embryo develops is very important to doctors, especially those who work in obstetrics and pediatrics. The ideas about the flow of the embryo development processes are normal, help unmistakably and timely note the occurrence of pathologies from developing embryos, looking for reasons for infertility and solving this problem, create contraceptives, carry out activities that will prevent serious pathology of fruits and newborns.

Periods of human development during pregnancy

The development of a person during its intrauterine life (or embryogenesis) passes through several stages.

• The combination of parental sex cells that served as the formation of the zygota.
• The division of the resulting zygote with the formation of blastocysts.
• The development of germinal leaflets and the start of the bookmarks of all organs (gastrulation).
• The development of various organs and tissues (histo and organogenesis).
• Systemogenesis (formation of organ systems).

A different person's intrauterine life is divided into three very important periods: fertilization with the formation of one cell (zygotes), embryonic and fetal periods.

The embryonic period originates from the second week after fertilization until the eighth week of development of the embryo (until the end of the tenth of the obstetric period of pregnancy).

The beginning of the ninth week of the intrauterine human development (the eleventh week of the obstetric period) marks the beginning of the fetal period (fruit). From this point on, the developing person is no longer called the embryo, it is referred to as the fruit.

Fertilization ─ difficult to connect (fusion) of two genital parent cells. In the process, one egg cell and about 300 million sperm, of which only one will become "winner" are involved in the process. As a result of this process, the diploid set of chromosomes is restored (that is, 46 chromosomes). At the time of the compound of parental cells, the floor of a developing person is determined. A new cell is formed ─ zygote.

Fertilization in humans occurs in the uterine tube, in its ampular part. Distinguish several stages of fertilization:

• The interaction of genital cells at some distance and their convergence.

Egg in this phase of fertilization is distinguished by substances that attract spermatozoa. They become capable of fertilization under the influence of a special secret generated in female sex travers.

• Sex cells are in contact, the egg cell is activated.

It makes rotations, an acrosomal reaction is launched. The result of this is the increase in the permeability of the membrane sperm.

• Penetration of the male sex cell (spermatozoa) under the shell of the mother cell, the merger of parental cells.

After that, on the surface of the fertilized egg, a fertilization shell is formed, it prevents the penetration of other spermatozoa.

Embryo implantation day

For 7 days after conception, the embryo is introduced into the endometrium. This process is the implantation, it is very complex. The duration of the implantation of the embryo ─ a little less than two days (about 40 hours). Then begins the actual embryonic development period.

A woman can still not know about her pregnancy, and in her body is already developing a new life. Many women have suspicions about their pregnancy when menstruation does not come under last time. The future mother sees only two stripes on the display of a pregnancy test, and the embryo already has the first heart cuts.

This indicates the special importance of the embryonic period of development. Woman's body and future child are very sensitive to fluctuations ambient, influence of infections, radiation, toxins and drugs during this period.

Knowledge about how the embryo is developing by day and on weeks during its intrauterine life, help to deal with the layout of certain bodies, with the mechanism of forming congenital defects of embryos, which can even lead to a spontaneous interruption of pregnancy. Based on the information obtained, critical (dangerous) periods relating to the development of the embryo and the fetus of a person are allocated. The period from 3 to 8 weeks of embryonic life is indicated critical in human ontogenesis.

Frucent man's development period

A fetal (fetal) period in the ontogenesis of a person starts from the ninth week of the development of the embryo, since the initiation of fertilization. The obstetric period of pregnancy at the same time is more than two weeks than the actual development time of the embryo. Completed the feet of the birth of a person. Then comes a period of newborn.

Starting from 11 weeks of the obstetric period of pregnancy, a developing person is called a fruit. It is almost fully formed, he has all the organs and the tissue differentiation is active. The fruit is associated with the body of the mother through the placenta formed.

Although the laying of all organs to this period of development of the fetus has already been completed, several critical moments of the fetal period differ. So, from 15 to 20 week of pregnancy rapidly grows brain. And from 20 to 24 week, gestation develop functional systems of the body, the urogenital apparatus is differentiated.

The study of those complex mechanisms as a human embryo is developing after conception, is currently. The way the embryo develops by day in the first week of his life, describes the science of embryology. In the future, embryology describes how the embryo is developing on weeks after fertilization (first trimester).

Starting from the second trimester of pregnancy, the description of the development of the embryo on weeks corresponds to the obstetric date of pregnancy. This means that the term of pregnancy is counted not from the moment of the alleged fertilization, and on the first day of the last menstruation, which is about 2 weeks more than the embryonic term of development.

Changes in the development of embryo by day have special meaning In the first week of the development of the embryo after fertilization. What is characterized by the development of the embryo by day at the very beginning of its intrauterine life?

1-2 day

After the connection of the nuclei of parental cells is formed by the zygote. It begins to share by mitosis on the cells, called blastomer. First, the zygota shares slowly, then faster.

Blastomers are formed by two types: "dark" and "bright". "Light" cells are built up with one layer around the "dark", their trophoblast is formed. He is a link in the nucleus with the mother's organism, provides its nutrition. From the "dark" blastomers begins to form its formation of the Embryoblast ─ the predecessor of the human embryo body, as well as its extraordinary organs.

3-4 day

After the formation of the zygota, the tight accumulation of blastomeres forms Morulu. By 3-4 days is formed blastocyst ─ bubble with cavity. For three days, blastocysts are moving along a phallopyan pipe directly to the uterine cavity. At this time, the embryo and trophoblast cells continue their differentiation. The size of the embryo in this period is up to 0.2 mm.

5-6 day

In the wrestling uterus in a free form is two days. The cells of the trophoblast blastocysts provide germ nutrients due to the disintegration products of the mother's tissues. The embryoblast cells are located a nodule on one of the blastocyst poles, which is attached to the trophoblast from the inside. The embryo is preparing to attach to the uterus wall.

7 day

For 7 days after conception, the embryo is implanted into the mucous membrane of the uterine cavity, that is, it is introduced into it. The implantation of the embryo goes in two stages:

1. Attaching the embryo to endometrial.
2. Direct introduction of a fetal egg to the mucous meter.

Trofoblast has the ability to allocate enzymes that contribute to the attachment of the embryo to the inner layer of the uterus. After that, the destruction of the fertilization shell.

Since the second week, the ethms of the embryonic development period starts. He continues until the end of the eighth week of development (until the end of the tenth of the obstetric period of pregnancy). The human embryo does not stop its development for a second. For the convenience and simplicity of understanding, this period of human development is divided on weeks. How does the embryo develop on weeks during pregnancy?

Embryo Development for 2 weeks

From the part of the cells, blastocysts are formed an amniotic bubble. This happens to 8 days of the development of the embryo. By 11 days the formation of chorion. This nuclear sheath of the embryo is the predecessor of the placenta. Up to 12 days continues the process of embryo implantation, which began several days earlier, and the process of gastrolation is launched.

From 13 days, gastrulation continues. This is a very complex process in which the nucleus fabrics grow and differentiate, as a result of which germinal sheets are formed: ecto, meso, and entoderma. A primary strip is formed from a portion of the cells of the blastocysts, from which the head proceeding of the embryo is formed. From it begins to develop chord of embryo (future vertebrate pillars).

Vessels and blood cells are beginning to be formed at the germ (hematopoEZ). In addition, there is an increase in vessels in the field of chorion. The formation of the first blood cells goes in the yolk bag. On this period, the embryo is connected by a stacker with a placenta, which began its formation.

After 15 days from the day of conception, the embryo reaches the size of 0.4 mm. He is formed by chord, perichordal record. The germ itself has a three-layer structure.

Embryo on time 17-19 days of its development has a length of about 1-1.5 mm. It has a shape of a pear with an extended head end. A nervous plate is formed from the thickening of the ectoderma, and from it is a nervous groove. Fabrics nervous system The embryo takes the beginning of its development from the nervous groove. Blood vessels and cells are further developed.

At the age of 19-21, the human embryo is pulled out. The head end of the embryo on this term is wider than the caudal end. Mesoderm seals are determined. There is a formation of secondary chorion vile. In addition to hemopoietic cells in the yolk bag, endothelium cells are determined, they will subsequently become the inner lining of the arteries and veins.

By the end of the 3rd week of the development of the embryo, a heart is laid. It has the appearance of two tubes, while individual. The prefict is formed, but it is soon reduced.

Embryo Development at 4th World

The size of the embryo at the beginning of the 4th week of its development varies from 1.5 to 2.5 mm, but closer to the finish of this week it reaches 5 mm long. The embryo in this period in shape resembles the letter "C". First, nerve groove is formed, which is then closed into the nervous tube. In the head unit of the embryo, nerve cells are already present, the routines of the ears and eyes.

The previously separated tubes are closed, which were heart predecessors. You can register the first heart cuts, the bloodstream begins in different parts of the body of the embryo. In the middle of the 4th week of intrauterine life, partitions and valves in the heart of the embryo are laid.

The epithelial tissue of the digestive tube gives the beginning of the digestive organs (liver, pancreas), and trachea, esophagus and lungs begin from epithelial tissue.

By the end of the 4th week, the embryo is coated by a semi-rapidity, located in an amniotic bubble. Future of the hands are formed, footplaces are marked. The formation of the skin epithelium. Begins to form bones and muscles.

There is a differentiation of the head of the nervous tube, three brain bubbles are formed. An auditory bubble is formed, a crystal of the eye is formed. It is possible to detect the primary oral cavity (bay) and the incident of the language. There is a formation thyroid glandThe actively develops respiratory and digestion organs, primary kidneys are laid.

A bubble rope is formed, it connects the vessels of placenta and liver, the location of which in this period in the head unit of the embryo.

The size of the embryo at the 5th week from the day of fertilization is 5-7 mm. He arcuately roll, he is noticeable with a cervical bending. Hands are lengthened, the formation of brushes and the innervation of the upper limbs begins.

There is an intense growth of the heart and brain, which is divided into parts: front, rear and medium. The differentiation of the spinal cord is underway, there is an active development and growth of the front lobe of the pituitary gland, the crystal of the eye is performed.

It becomes a well-distinguishable esophagus, which is gradually separated from the trachea. From two sides of it are lungs. The heart has four chambers, its valves are formed. There is a constant kidney and bladder.

Embryo Development for 6 weeks

At 6 week, the embryo is of size from 7 to 13 mm in length. In the first days of 6 weeks, the embryo is planned a primary face, an outdoor ear is formed. Embryos are closed, nasal pits are determined. Increases the brain of the nucleus, there is a bookmark of spinal nodes. The deepening of the oral cavity grows in the direction of the intestinal tube. The digestive tube increases in length, the growth of the esophagus is marked. The kidneys are progressively developing. In the hands of the embryo, segments are determined. Stop the feet and their innervation. Throughout the week, the embryo is rapidly developing, the face and sense authorities change markedly.

The embryo of 6 weeks is characterized by the fact that it is straightened gradually the back, the skeleton is initiated. The muscles of the face and the lower jaw appears. The abnormal sinks are determined, the pituitary is formed. Pigment is formed in the eyes, instantly grow out. There is a laying of teeth of teeth, olfactory bulbs. Embryo in 6 weeks has well-formed hands, although the brush is not yet fully developed.

In total, the development of respiratory organs is underway. The heart has 4 cameras, the lung artery is separated from the aorta. There is a diaphragm. The embryo intestine is directed to the Upholstery Course, which is called the physiological hernia of the embryo. Liver develops, as well as pancreas. Sex glands are populated by sex cells, while still primary. The development of genital organs begins. The kidneys produce the first urine.

Development of the embryo on week 7

The size of the embryo at 7 week of its intrauterine life ranges from 17 to 28 mm. His form resembles an arc. The formation of tissues of the skull and face. The lower jaw is well visualized, and the top is still not clearly defined. Fingers are formed in the hands, the segments are distinguished on the legs, the foot is being developed.

Clear 2 hemispheres in the brain are distinguished, the development of the back of the brain starts. In the abdominal cavity, the mesentery is well distinguished, in which arteries, veins, nerves, lymphatic vessels are determined. There is a lengthening of the ureters, which are sent from the kidneys to the laying bladder.

On the 8th week of its development, the embryo is about 25 to 40 mm. By the beginning of 8 weeks, the embryo is straightened to the head. He has well developed eyes, which are still located on the sides of the head. There is a low location of the ears formed nostrils. In the hemispheres of the brain are noticeable winding. There is a formation of the structures of the inner ear.

Skeleton is actively developing, the back is lengthened, skeletal muscles are developed. The hands bent in the elbows crossed on the stomach. The places of large joints are denoted on the legs, the fingers of the legs differ, although there are membranes between them.

At 8 week after fertilization, the embryo begins to make the first movements, while involuntary. The heart develops the partition between the atria. By the end of 8 weeks, the critical period of heart formation is completed.

Almost formed a language, taste bulbs develop, teeth bookmarks. The bones of solid sky merge. The intestine that has previously reached a poucher rope returns to the abdominal cavity. The genitals are actively developing both external and internal. It becomes to distinguish the sex of the child. Anal membrane is perforated. The tail degeneration occurs.

With the introduction of ultrasound diagnostics to the medical practice (ultrasound), the future parents had the opportunity to look at his child long before his birth. According to pregnancy protocols, the first ultrasound is done under the obstetric period of pregnancy 10-14 weeks (8-12 weeks of embryonic development). This is the study with the fence of venous blood in a future mother for tests.

All these events are called screening during pregnancy.

To see the embryo on the ultrasound earlier than this period, there must be indications. For example, suspicion of ectopic pregnancy, preparation for the interruption of pregnancy, the emergence of some pathological symptoms in a woman, suspected of a frasonal pregnancy.

Some make an embryo ultrasound simply out of curiosity, but this risk is not justified. Currently, there is no sufficient amount of information about how safe an embryo ultrasound and how many times it can be done for the period of having a child.

How does the embryo look like on ultrasound?

In 3-4 weeks of embryonic development, the embryo is still too small so that it is possible to look good parts of the body or forming malformations. At this time on the monitor, the future mother will see only a bright spot and first heartbeat. But it is safe to say about whether the embryo is located in the uterus.

By the end of 7 weeks on the ultrasound of the embryo, you can distinguish your head, torso, limbs formed by the umbilical umbilical. The embryo itself has a characteristic curved shape.

By the end of 8 weeks of embryonic development, according to the ultrasound, you can get a lot of information about the embryo, see some defects in their presence. For the Mother, part of the body of the embryo, some organs, active heartbeats become visible on the screen monitor screen.

To make a qualitative ultrasound of the embryo apply a transvaginal (via vagina) and transabdominal (through the front abdominal wall) of the scan.

Is it possible to make an embryo photo?

More than 50 years ago, people first saw the embryo in the photo. These unique photos reflecting the development of a person at different times of pregnancy, starting from the moment of fertilization, made a photographer from Sweden Lennart Nilsson. To capture the embryo in the photo, he used modern photographic equipment, a light guide and a cystoscope. Thanks to him, the whole world saw such a mysterious internal life of a person. These embryos photos are still very popular, they play a big role in the fight against abortions in the early periods of pregnancy at the request of women.

Modern parents can see their child during ultrasound research. Equipment for the ultrasound allows you to make a photo of an embryo, having received a two-dimensional or three-dimensional image.

In our country, a huge number of fruitless marriages. They are already more than 15%. In total, Russia officially has more than 5 million married couples, whose marriage is recognized as fruitless. Moreover, it grows both female and men's infertility. More than 2.5 million pairs are required to conduct auxiliary reproductive technologies.

The basis of auxiliary reproductive technologies is considered to carry out the classical method of extracorporeal fertilization (ECO) and embryo transfer (PE) in the uterus.

What is eco (extracorporeal fertilization)?

Extracorporeal fertilization (ECO) ─ This is the method of artificial fertilization of the eggs for men with men's sperm, which is subjected to centrifugation and processing in the nutrient medium. Oocytes (egg cells) are also cultivated on nutrient media. Subsequently, the subfolding of the resulting embryos in the uterus occurs.

In most cases, sex cells of spouses are used in the vitral fertilization. The donation of egg (oocytes) and embryos is used if it is impossible to obtain their own sex in a woman or in their inferiority. Survatozoa donation is applied at the request of a woman in the absence of her spouse, as well as in the case of a spouse spermatozoa not capable of fertilization.

Distinguish the following types of Eco:

• Actually eco and the transfer of the resulting embryos.

It occurs in fertilization of the egg with sperm outside the female organism, then the embryo is sitting in the uterus.

• Ixi (from ICSI - IntracyToplasmic Sperm Injection) ─ Eco Auxiliary Method.

A feature is that ECO embryo is formed as a result of a fusion of an egg and a spermatozoa, which was introduced under the shell of the maternal cell using a special microneboard. The method is used for various qualitative and quantitative pathologies of men's genital cells.

There are situations when after several unsuccessful attempts of ECO, it is possible to achieve the onset of pregnancy only by applying the ICSI method.

In addition, surrogate motherhood is distinguished, in which the embryo after Eco is developing in the Women-Volunteer's uterus. After the child appears, the child is transmitted to its genetic parents.

Indications to Eco

Allocate the following testimony to extracorporeal fertilization:

• Infertility in a woman, which is caused by a violation of the patency or the absence of phallopy pipes.
• The impossibility of conception, the reason for which is not installed.
• Infertility, which is not amenable to treatment, or that it is easier to overcome by Eco, rather than other ways.
• Infertility caused by immunological problems (detection of antispermal antibodies).
• Male infertility, which requires the use of the ICSI method.
• Some diseases of the female genital sphere (endometriosis, polycystic ovarian syndrome).

Contraindications to Eco

The list of contraindications for Eco and the transfer of embryos is very wide:

• Various deformations of the uterine cavity, attaching embryos in which it is impossible.
• New formation of any location in the body (even if it was in the past).
• Tumors of uterus, which are benign; Tumors of the appendages of the uterus.
• Inflammatory processes in any localization.
• Other diseases of the internal organs under which pregnancy cannot be launched.
• Some mental disorders.

At the preparatory stage, numerous surveys take place towards Eco, and surrender various analyzes in order to identify indications and contraindications to the procedure. Couples, the age of spouses in which more than 35 years are necessarily consulted by a genetic doctor.

After the pair is prepared for the ECO procedure, it will have to go through the following steps:

• Stimulation of supervision in woman with hormonal drugs. This is necessary in order to occur at the ripening of several eggs at once. As the menstrual cycle flows, the process of ripening the follicles and the state of the inner layer of the uterus (endometrial) is selected. To stimulate supervision, there are different schemes, the choice is made individually.
• Obtaining female sex cells by puncture of ovarian follicles.
• Getting sperm spouse.
• Fertilization of eggs with sperm or the introduction of spermatozoa in the cytoplasm of eggs.
• Transfer of embryos to the uterus and monitoring the effectiveness of the process. If necessary, supporting hormonal therapy is assigned.
• Diagnosis of pregnancy.

How do biological material for Eco get?

Biological material for the production of embryos are eggs and spermatozoa.

• Egg fence

This procedure is done under general anesthesia in sterile conditions. A woman when producing biological material is obtained in a conventional gynecological chair. The process of the fence of eggs is controlled by an ultrasound study. Cells are closed by puncture of the ovarian follicles with a special needle introduced through the vagina. If it is impossible to get eggs in this way, the fence of the egg is carried out using laparoscopy.

• Summer fence

Cum is closed on the same day as eggs. You can get sperm by masturbation or interrupted sexual intercourse (using a condom without lubrication and spermicidation). In the presence of ejaculatory disorders in a man, the spermatozoa is obtained by punctuation of the appendage of eggs.

After the fence procedure, germ cells come to the embryology laboratory, where they are cleaned of impurities. Sometimes an extracorporeal fertilization procedure is carried out immediately (no later than 6 hours after receiving the material). In other cases, the biological material is frozen. Freezing practically does not affect the viability of sex cells, but it allows you to save time with the subsequent IVF attempts if the first of them are unsuccessful.

For fertilization, genital cells are placed in special containers with nutritional environments. Containers are placed in an incubator, the conditions in which are close to natural. After a few hours, the genital cells merge together. If this does not occur, then the spermatozoa is introduced artificially in the cytoplasm of the egg.

After the procedure, observation of fertilized eggs is monitored. Those of them that are well divided can be used for Eco. An excess of fertilized eggs can be freezed (cryopreservation) and use them when they attempt to eco (if necessary).

The embryo after conception naturally does not have differences from the embryo after the ECO in its structure, physiology and the stages of further development. However, sex cells that are used for Eco are more often inferior compared to those with natural conception. Including for this reason, after eco above the risk of congenital pathologies and chromosomal anomalies from the future child. Some signs of these problems can be noted at the embryo on ultrasound or according to the results of pre-impulant diagnostics.

Why do you need pre-implantation diagnostics of embryos?

The pre-implantation diagnosis of embryos with ECO is carried out in order to obtain information on whether there is no serious genetic pathologies from the future child. This is done before the time is suitable for implantation of embryos.

The use of this method of human embryos was led to the fact that the number of spontaneous abortions was reduced to 13% after the occurrence of pregnancy as a result of Eco in those married couples, where one of the parents is a carrier of genes causing chromosomal anomalies in comparison with pairs having similar problems, but Without used services of pre-impulant diagnostics.

Identification of chromosomal anomalies in embryos before the prodigation of them in the uterus not only allows you to get healthy offspring, but also reduce the number of eco attempts, reduce the risk of spontaneous interruption of pregnancy.

How many embryos with Eco is transferred to the uterus?

There are recommendations, according to which there are no more than four embryos in the uterus. First, multiple pregnancy is fraught with complications. Secondly, the reduction of unnecessary embryos is also not a harmless procedure. In our country, as a rule, transplanted in the uterus of two embryos.

On that day, when the embryo is transferred to the uterus, its development time reaches about 3-5 days. The stage of development of the embryo on this period ─ Blastocyst. Studies have been conducted, indicating that it is at the stage of blastocyst embryo in the uterus that is best forbidden. The embryo already has a trophoblast, which is needed for implantation.

Less often, the imbrons is carried out on the third or second day of embryonic life, or after 7-8 days after fertilization. The decision is made individually in each case. The term of the embryo substitution depends on how many eggs managed to fertilize, and how many of them continued their further division.

Embryo size per day transfer it to the uterus

On the 4th day of its existence, the embryo has dimensions about 0.14 mm, for 6 days ─ 0.2 mm, by the end of 1 week of life ─ about 0.3 mm.

How is the embryo subfolder in the uterus?

During the transfer of embryos in the uterus, the future mother is located on a gynecological chair. The procedure requires compliance with the same sterility as with any other operation.

First, the gynecological mirrors should be introduced into the vagina. Then a thin flexible catheter is introduced into the uterus through the cervical channel, through which embryos is transferred.

What are the sensations of a woman when transferring embryos?

Women preparing for an extracorporeal fertilization procedure want to know in advance which they will feel sensations when transferring the embryo.

During the procedure of the embryos, a woman is conscious. Feelings for the transfer of the embryo are comparable with sensations in the usual gynecological examination (mirror introduction). Some describe the sensations when transferring the embryo, as light discomfort.

To avoid unpleasant sensations when transferring the embryo, a woman is recommended to relax, tune in to a good outcome of the procedure, you do not need to strain the abdominal muscles.

Upon completion of the procedure, you need to relax and lie down a couple of hours. After eco, you can come back from the clinic home on the same day. It is desirable that women have accompanying. At home you need to relax and do not worry.

The procedure for the embryo substrate does not guarantee that pregnancy will come. The ECO process was effective, it is possible to judge after the moment the implantation of embryos end.

Attaching the embryo after eco comes usually after 7-10 days after the day of ovulation (2-3 days immediately after ECO).

On the day of the implantation of the embryo in the endometrium, there is a minor selection of a bloody character from the vagina. They are due to the fact that implantation of embryos leads to damage to the mucous membrane of the uterus.

On the days of the estimated implantation of the embryo, some women describe some symptoms: a small soreness at the bottom of the abdomen, drowsiness, weakness, dizziness, a metal taste in the mouth, a slight increase in temperature. Do these symptoms have attitude to implantation of embryos, unknown.

In order for the embryo implantation day successfully, a woman needs to adhere to some rules: rationally eat, limit loads, not lifting gravity, refrain from receiving a bath, wearing loose clothing. Compliance with medical recommendations on the supply regimen, recreation and physical exertion allows you to achieve good results on the day of the embryo implantation.

A reliable sign that embryos implantation occurred successfully will increase the content of chorionic gonadotropin (HCG) in the blood flow of the mother.

Reduction of embryos after eco

Usually, the development of several embryos is the development of several germs. The uterus usually tolerate two embryos. If it turns out that embryos are in the uterus in the amount of more than three, the operation of the reduction of embryos from the uterus is shown (removal of unnecessary). This forced measure is necessary for the normally flowing pregnancy twins or triple.

The method of reduction of embryos with eco has a good base, it is constantly being improved, allows you to get a pair of healthy offspring. This is explained by the fact that tooling in the uterus of three or more fruit threatens with unbearable and birth of deeply premature babies.

Removal of unnecessary embryos was initially conducted through the cervix. Removed the underlying fruit egg in the first trimester of pregnancy. However, this method of removal of the human embryo was very traumatic, followed by a lot of complications.

Currently, other methods of reduction of embryos after ECO are used: transvaginal (via the rear vaginal arch) and transabdominal (through the front abdominal wall). Intervention is carried out under the control of special equipment. The principle of procedure is that a long needle is introduced into the uterus cavity, its tip is supplied to the chest embryo, which must be reduced. Then the chest embryo organs are destroyed with the needle before stopping the heart of the heart.

Features of the course of pregnancy after eco

Pregnancy after extracorporeal fertilization has its own characteristics.

• High risk of pregnancy interrupt early time Development of embryo (25-30% of all cases of pregnancy after ECO), undeveloped pregnancy.
• Increased risk of infectious inflammatory diseases during pregnancy.
• Many pregnancies after Eco are multiple. This creates an increased load on the woman's body during the baby tool. In this regard, chronic diseases are often sharpened, gestosis to join, placental insufficiency, exchange disorders arise.
• Some women have essimic and cervical insufficiency (cervical weakness). Above the risk of birth of premature and low-fat children.
• The birth of children with congenital defects and chromosomal deviations. This may be due to the "defective" sex cells of the parents.

After Eco, the appearance of children to light is possible both through natural generics and by cesarean section. Given the high risk of multiple pregnancy, the presence of various accompanying pathology among the mother, Cesarean section after Eco is made by most women. Other factors that may affect the choice of the method of delivery, are: the age of the mother, the duration of the period of infertility, pregnancy during pregnancy, the state of the fetus. Be sure to take into account whether there were births of a woman earlier, and how children appeared to light.

By itself, the process of generics or operation of cesarean section after an extracorporeal fertilization is nothing different from such when the embryo is conceived by naturally.

Complications of eco

Like any intervention in the human body, Eco has its complications:

• Sometimes allergic to medicines, which are used to stimulate ovaries.
• After eco, various inflammatory processes and bleeding may occur.
• High risk of multiple pregnancy.
• The occurrence of ovarian hyperstimulation syndrome, in which the ovaries increase in size, cysts are formed in them. This condition is accompanied by various vascular and electrolyte violations, problems in the blood coagulation system, hormonal imbalance and other serious pathologies.
• Sometimes the development of embryo after ECO goes outside the uterine cavity (the frequency of ectopic pregnancies varies from 3 to 5%).

ECO efficiency

The effectiveness of the process of extracorporeal fertilization varies in different countries. Not all pregnancies that have arrived after implantation of embryos in the uterus, successfully develop and end in childbirth. Many pregnancies are interrupted in the first trimester. On average, only every fourth woman after Eco is born baby.

The development of the human body begins from the very first day of fertilization of the egg cell spermatozoom. The embryogenesis stages are counted from the start of the cell development, which subsequently forms the embryo, and a full-fledged embryo appears from it.

The development of the embryo is fully starting only from the second week after fertilization, and since the 10th week in the parent organism, the fetal period is already carried out.

The first stage of the zygota

Absolutely all somatic cells of the human body have a double set of chromosomes in themselves, and only sex gamets contain a single set. This leads to the fact that after the fertilization and merger of the male and female sex cells, the chromosome set is restored and becomes double again. The cell formed at the same time is called "zygote".

The characteristic of embryogenesis is such that the development of zigotes is also divided into several stages. Initially, the newly formed cell begins to share new cells, called Morulas on different sizes. The intercellular fluid is also distributed unenoxo. A feature of this stage of embryogenesis is that the Morulas formed as a result of division are not growing in size, but only increase in quantity.

Second phase

When cell division ends of them formed Blastuly. It is a single-layer embryo size with an egg. Blastuly already carries all the necessary DNA information and contains an unequal size of the cell. It happens on the 7th day after fertilization.

After that, a single-layer embryo passes through the stage of gastroaction, which represents the movement of existing cells in several embryonic sheets - layers. First, they are formed 2, and then the third one appears between them. During this period, Blastuly forms a new cavity, called the primary mouth. The existing cavity completely disappears. Gastral allows the future embryo to clearly distribute the cells for further formation of all organs and systems.

From the first external layer formed in the future, all skin covers, connective tissues and a nervous system are formed. The lower formed by the second, the layer becomes the basis for the formation of the respiratory organs, the excretory system. The latter, the average cell layer is the basis for the skeleton, the circulatory system, muscles and other internal organs.

Called layers in a scientific medium, respectively:

• etoderma;
• entoderma;
• mesoderma.

Third stage

After all the listed stages of embryogenesis are passed, the embryo starts growing in size. In a short time, it begins to represent a cylindrical organism with a clear distribution on the head and tail ends. The growth of the finished embryo continues until 20 days after fertilization. At this time, the previously formed from the cell of the plate, the predecessor of the nervous system is converted into the tube, in the future representing the spinal cord. Other nervous endings filling out the whole embryo gradually grow from it. Initially, the processes are divided into the dorsal and abdominal. Also at this time, the cells are distributed to further division between muscle tissues, skin seats and internal organs, which are formed from all cellular layers.

Offshore development

All initial stages of embryogenesis are parallel to the development of extraordinary parts, which will continue to provide the embryo and the fetus nutrition and maintain life.

When the embryo has already been fully formed and left the pipes, an embryo attachment to the uterus is carried out. This process is very important because the life of the fetus depends on the proper development of the placenta in the future. It is at this stage that the embryo is carried out at ECO.

The process begins with the formation of a nodule around the embryo, which is a double layer of cells:

• embryoplast;
• trofoblast.

The latter is an outer shell, so it is responsible for the effectiveness of the attachment of the embryo to the walls of the uterus. With its help, the embryo penetrates the mucous membranes of the female organ, implanting directly into their strata. Only a reliable attachment of the embryo to the uterus gives the beginning of the next stage of development - the formation of a kindergarten. The development of the placenta is carried out in parallel with its separation from litter. The process is ensured by the presence of a torso fold, which pushes the walls from the body of the embryo. At this stage of the development of the embryo, the sole connection with the placenta becomes an umbilical stem, which in the future forms the rope and provides the nutrition of the kid with the entire remaining intrauterine period of his life.

Interestingly, the early stages of embryogenesis in the area of \u200b\u200bthe umbilical stem also have a yellow duct and a gusty bag. Neptentary animals, birds and reptiles, this bag is an egg yolk through which the embryo receives nutrients during its formation. In person, this body is formed, though there is no effect on the further embryonic development of the body, and over time it is simply reducing.

The umbilical rope has blood vessels in which blood comes from the embryo to the placenta and back. Thus, the embryo receives nutrients from the mother and displays the exchange products. This part of the connection from Allantois or part of the blade is formed.

The embryo-developing germs is protected in two shells. In the cavity of the inner is protein fluid, which is an aqueous shell. In her and swims the baby until his birth. This bag of amnion is called, and its filling is amniotic fluid. All concluded in another shell - Chorion. It has a napped surface and provides breathing and protection embryo.

Phased consideration

In order to disassemble the embryogenesis of a person understandable to most of the tongue, it is necessary to start with its definition.

So this phenomenon is the intrauterine development of the fetus from the date of its fertilization until birth. This process begins only after passing 1 week after fertilization, when the cells have already finished sharing and the finished embryo moves into the uterine cavity. It is at this time that the first critical period begins, since its implantation must pass as comfortable as possible for the parent organism, and for the embryo itself.

This process is carried out in 2 stages:

• dense attachment;
• penetration of the uterus.

The embryo can be attached in any, except the bottom, part of the uterus. It is important to understand that this whole process is carried out at least 40 hours, since only gradual actions can provide complete safety and comfort for both organisms. The place of attachment of the embryo after joining is gradually filled with blood and overcomes, after which it begins the most important period of development of the future person - embryonic.

First organs

The embryo attached to the uterus has already possesses the bodies that do something resemble the head and the tail. The very first after successful fastening of the embryo is developing a protective body - chorion. In order to more accurately imagine that it represents, it is possible to draw an analogy with a thin protective film of the chicken egg, which is located right under the shell and separates it from the protein.

After this process, organs are formed providing further nutrition of crumbs. Already after the second week of pregnancy, you can observe the appearance of Allantois, or the umbilical cord.

Third week

The transfer of embryos into the fetus stage is carried out only at the end of its formation, but already in the third week you can see the appearance of clear outlines of future limbs. It was during this period that the body of the embryo is slightly slightly, it becomes a noticeable torsoold, the head is distinguished and the most important thing is that the own heart of the future kid begins.

Power change

This period of development marks and another important stage. Starting with the third week of life, the embryo ceases to receive food through the old system. The fact is that the stocks of the egg at this point are depleted, and for further development, the germ must be obtained for the further formation of the substance already from the mother's blood. By this time, to ensure the effectiveness of the entire process, the allanomis begins to be transformed into an umbilical cord and placenta. It is these organs that the remaining intrauterine time will ensure the fruit of food and free from life products.

Fourth week

At this time, it is already possible to clearly define future limbs and even the places of the eye depressions. Externally, the embryo varies slightly, since the main emphasis is given to the formation of internal organs.

Sixth week of pregnancy

At this time, the future mother should pay special attention to their own health, since in this period there is a fork iron iron of its future kid. It is this authority in the future all life will be responsible for the performance of the immune system. It is very important to understand that the ability of her child will be dependent and the ability of her child to resist the external stimuli from the health of the mother. It should not only pay attention to the prevention of infections, but also to warn themselves from nervous situations, follow the emotional state and the environment.

Eighth Semeima

Only starting from this threshold of time, the future mom you can find out the floor of her child. Exclusively at 8 weeks begin to be laid the sexual signs of the fetus and the production of hormones. Of course, it is possible to learn the floor if the child wants this itself and turns on the ultrasound.

The final stage

Starting from the 9th week ends and the fetal starts. By this moment, all organs should already be formed in a healthy kid - they can only grow. At this time, the mass of the child's body is actively gaining, its muscular tone increases, bleale organs are actively developing; The fruit begins chaotic moving. Interestingly, the cerebellum at this point is usually not yet formed, so the coordination of the movements of the fetus occurs over time.

Danger during development

Different stages of embryogenesis have their weaknesses. To figure out this, you need to consider them in more detail. So, in some periods of human embryogenesis is sensitive to infectious diseases of the mother, and in others - to chemical or radiation waves from the external environment. If problems arise in such a critical period, the risk of developing congenital defects will increase.

To avoid this phenomenon, you should know all the stages of the development of the embryo and the danger of each of them. So, special sensitivity to all external and inner stimuli is the period of Blastuly. At this time, most of the fertilized cells die, but because this stage takes place in the first 2, most women do not even know about it. The total number of perishes at this time of the embryos is 40%. At the moment, it is very dangerous because there is a risk of rejection of the nucleation by the mother's organism. Therefore, during this period, you need to take care of yourself.

The transfer of embryos to the uterus cavity marks the beginning of the period of the greatest vanity of the embryo. At this time, the risk of rejection is no longer so large, but from the 20th to the 70s days of pregnancy, all vital bodies are laid, with any negative impacts on the maternal organism at this time, the likelihood of developing the future of congenital health deviations increases.

Usually, by the end of the 70th day, all organs have already been formed, but there are cases of late development. In such situations, with the beginning of the fetal period, there is a danger to these bodies. Otherwise, the fruit is already fully formed and begins to actively increase in size.

If you want your future child to be born without any pathologies, then watch your health and before, and after the start of conception. Drive the right lifestyle. And then there should be no problems.