The birth of a new life is a touching, amazing, almost fantastic process. Expectant mothers have always been interested in the question of how a child is conceived. Two small autonomous cells, uniting, create a new person. And if the period when the fetus begins to move is more or less noticeable for the expectant mother, then the first days and even weeks of pregnancy remain “behind the scenes.”
After intercourse
Mother Nature is a wonderful and wise creator. Everything related to procreation is thought out to the smallest detail. Approximately in the middle of the menstrual cycle, a “girl of marriageable age” appears from the ovary - an egg ready for fertilization. It will remain in a state of readiness from 12 to 36 hours. If during this time conception does not occur after sexual intercourse, the egg dies and is excreted from the body along with menstrual bleeding. Thus, conception by days after ovulation can occur within a period of one to three days. In some cases, during the period of ovulation, not one, but several eggs are formed. In this case, there is a high probability of multiple pregnancy.
It is no secret how egg fertilization occurs. A female cell alone is not enough to generate a new life. The immediate process of conception begins when potential “suitors” - sperm - quickly burst into the female body. Like heroes from fairy tales and epics, they face a long and dangerous path to their cherished goal. The road ahead is not close - from the cervix to the fallopian tube - about 20 cm. Considering the tiny size of the sperm, this is a very decent distance.
First test
First of all, the “tadpoles” end up in the vagina. This happens in the first seconds after the act of intimacy. Here the first danger awaits them. Due to the acidic environment of the vagina, weak sperm (and these are the majority) die within 2 hours, never reaching the cervix. Thus, out of 500 million sperm that enter the vagina after sex, only a third reaches the cervix. This is how natural selection works.
Second test
For successful conception, there must be at least 10 million sperm in the uterus. Not everyone will be able to achieve the goal, because the second barrier - the cervix - is no less difficult and dangerous. There is also a high acidity environment here; in addition, there is a mucus plug in the cervix that interferes with further movement. True, during ovulation the amount of mucus decreases somewhat. The mucus usually moves towards the sperm, as if “washing away” the weak and indecisive on its way. The remaining specimens have sufficient strength to move “against the flow.”
Third test
Having passed the cervix, the sperm end up in the uterus. The reproductive organ helps the “tadpoles” in every possible way, increasing the speed of their movement. Gradually they make their way to the last point - the fallopian tube. The catch with this test is that the tube is covered with epithelial cilia. Vibrating, they block the path to the final goal for most applicants. So, from the multi-million army of sperm that find themselves in the uterus, by the end of the fallopian tube only a few thousand fighters remain in the row.
During their movement through the uterus and tubes, sperm change qualitatively, becoming capable of fertilization. Gentlemen are more patient: if the egg is “late,” they will wait for it, and fertilization can take up to 3-5 days.
What happens after conception
Let's look at the fertilization of an egg by day. We will consider the first day of the life of an intrauterine baby not the day of sexual intercourse, but the great moment when the sperm meets the egg.
Day one: fertilization
And now the coveted egg appears in the field of view of the applicants. They surround her in an attempt to complete the task at hand.
But a reliable barrier stands in their way - the protective membrane of the egg. To break through it, sperm will have to try very hard. But nature again came to the aid of the “tadpoles” by placing an acrosome in their heads. This is a special substance that helps the sperm dissolve the shell of the egg and penetrate inside.
Trying to break through the barrier, most of the “fighters” die, having exhausted their vitality. But the protective layer is weakened in some places by the action of the acrosome. At this moment, that very single sperm detects a “crack” in the membrane armor of the egg. He overcomes it and finds himself directly inside the egg.
Thus, the number of sperm entering the vagina plays a primary role in conception. The statement that only one sperm is needed for fertilization is not entirely true. Millions of “tadpoles”, having gone through a difficult thorny path, thus pave the way for one, the most successful.
It is not always possible to accurately predict how long it will take for pregnancy to occur after ejaculation. This largely depends on the presence of ovulation, sperm motility and the state of the woman’s gynecological health. The answer to the question of when conception occurs after intercourse is ambiguous. On average, up to 3 days can pass from the time sperm enter the female body to the direct meeting with the egg. Sometimes this happens faster - within one day. However, sometimes the partner’s sperm are so tenacious that they are ready to wait for an egg for a whole week.
Fertilization, that is, the fusion of male and female reproductive cells, cannot yet be considered the onset of a full pregnancy. This will happen in about another week, when the embryo implants in the uterus. It usually takes 6-12 days from sexual intercourse to pregnancy.
Days two to four: division
The sperm and egg become one, forming a zygote. About 36 hours will pass after fertilization and the zygote will begin to divide. Still in the fallopian tube, the zygote is now an entire cellular complex. Modern medicine can accurately indicate on what day the division of the zygote will end. After the fourth day after fertilization, the division process is considered complete. The zygote is represented by two cells - blastomeres. It remains the same in size, although the number of blastomeres will gradually increase. A future person needs space for growth and development. The pipe becomes cramped and uncomfortable.
On the third day, the zygote already has about 8 blastomeres, but still remains motionless. Only a day later, on the fourth day, the zygote of 16 blastomeres begins to move towards the uterus. At the same time, the blastocyst (embryo) itself remains tiny for all four days, practically unchanged in size. This is necessary for convenient passage through the fallopian tube. Full growth from this moment will begin directly in the uterus.
Days five to seven: embryo in the uterus
For the first few days, the woman does not suspect that such amazing events are happening in her body. Meanwhile, the embryo is already moving freely across the expanses of the uterus, in search of its place of residence. Having chosen a place convenient for itself, the future baby is attached to the wall of the uterus. The long and exciting journey is over. In this place he will live and develop for the next 9 months.
Days seven to twelve: implantation
The egg has implanted into the endometrium.
The zygote appears in the uterus 5-7 days after fertilization. After a few days (9-10 days following the fusion), the embryo will be completely immersed in the wall of the uterus. This process is called implantation. It lasts about 40 hours. It is reliably known how many days later implantation is completed - on the 12th day. From this moment on, the woman is considered pregnant.
After implantation, around day 20 of the cycle, a woman may experience certain symptoms indicating that a new life has arisen in her body. These include:
- Implantation bleeding. It is often confused with menstruation. However, it is less abundant and ends, as a rule, on the same day it began. But if spotting brown discharge continues for up to 10-14 days, the woman should immediately consult a doctor.
- The production of hCG is a special “pregnancy hormone”. It begins to be produced 5-6 days after conception. It is because of it that a woman feels morning sickness, weakness or drowsiness.
- Sensitivity and swelling of the mammary glands;
- Increased ;
- Aversion to certain odors;
- You may feel a tingling sensation in the uterus or a feeling of heaviness in the lower abdomen.
All the events described occur in the body before a woman starts to miss her period or the main symptoms of pregnancy appear.
If it is the first pregnancy, a woman often writes off such symptoms as a common malaise. Ladies who have been pregnant before are usually more sensitive to such manifestations and quickly realize that they are pregnant.
Days thirteen to twenty: delay
The most important sign by which a woman finds out about her pregnancy is a delay in menstruation. If it does not start on a certain day of the cycle, pregnancy can be suspected. Sometimes the delay can be caused by menstrual irregularities. One way or another, a woman should do a test to make sure her guesses are correct.
This period corresponds to approximately 5 weeks of pregnancy. At this stage, the fetus is still very small - its size does not exceed 7 mm, and its weight is 4 g. But the doctor will already be able to see it on an ultrasound. The future person himself at this time resembles the shape of the letter C. Despite its tiny size, upon careful examination on the monitor you can see processes - future arms and legs. Sometimes you can even distinguish small tubercles in the area of the top of the processes - future fingers.
Facial contours also begin to appear during this period: dimples of the eyes and cheeks, nasal and oral slits. The tiny embryo floats freely in the amniotic fluid, which begins to be produced around 5 weeks.
It is during this period that the rudiments of the internal organs of the future person begin to form. At the initial stage of formation are the respiratory, circulatory and nervous systems. The cells of the small organism continue to actively divide. Very soon the heart of the unborn baby will begin its work.
How to keep your baby safe
It often happens that a woman finds out about her pregnancy even before the test results and consultation with the doctor. Women's intuition tells the expectant mother that a new life is growing inside her. But this does not always happen, and many women are not aware of their situation.
The first days and weeks are considered the most dangerous period for the unborn baby. After all, a potential pregnancy can end at any early stage. That is why a woman should worry about her health and do her best to help her body accept a tiny creature.
To do this, you should follow some recommendations:
- It is worth preparing for conception in advance. In a few months (ideally, six months), potential parents should give up smoking, drinking alcohol and other bad habits.
- The expectant mother needs to be thoroughly examined to study her women's health. The presence of inflammation or adhesions in the uterus or tubes can lead to dire consequences. A fertilized egg, without passing through the adhesive barrier, can begin to develop in the fallopian tube and subsequently lead to its rupture (ectopic pregnancy).
- A woman is advised to drink. Preparations containing folic acid and vitamin E are especially recommended for expectant mothers. They significantly increase fertility (the ability to conceive).
- Proper nutrition should become a woman’s companion for the entire period of pregnancy. Harmful foods should be excluded from the diet, but water, on the contrary, should not be neglected.
- Serious physical activity is strictly not recommended for a potential mother. You should also avoid lifting weights. You can practice leading a calm lifestyle even before conception - the movements of the expectant mother should be smooth, unhurried and soft.
Pregnancy is a complex and simple process at the same time. It is complex due to the fact that the baby goes through a long journey from the fusion of two cells to birth. And at the same time, nature has simplified and thought through everything - the process of conceiving a child and its further development is thought out almost day by day. All that is required from the expectant mother is a little effort and unconditional love for the being within herself to make bearing a child as simple and enjoyable as possible.
Fantastic video
An incredibly exciting and realistic video about the conception and subsequent development of a child. Everything about the intrauterine life of a future person. A touching and at the same time very educational fantastic video.
The fusion of a male reproductive cell (sperm) with a female (egg, egg), leading to the formation of a zygote - a new single-celled organism. The biological meaning of fertilization is the unification of the nuclear material of male and female gametes, which leads to the unification of paternal and maternal genes, restoration of the diploid set of chromosomes, as well as activation of the egg, that is, stimulation of its embryonic development. The union of the egg with the sperm usually occurs in the funnel-shaped dilated part of the fallopian tube during the first 12 hours after ovulation.
Seminal fluid, entering a woman’s vagina during sexual intercourse, usually contains from 60 to 150 million sperm, which, thanks to movements at a speed of 2-3 mm per minute, constant wave-like contractions of the uterus and tubes and an alkaline environment, already after 1-2 minutes after sexual intercourse they reach the uterus, and after 2-3 hours - the end sections of the fallopian tubes, where fusion with the egg usually occurs. There are monospermic (one sperm penetrates the egg) and polyspermic (two or more sperm penetrate the egg, but only one sperm nucleus fuses with the egg nucleus). The preservation of sperm activity while passing through the woman’s genital tract is facilitated by the slightly alkaline environment of the cervical canal of the uterus, filled with a mucus plug. During orgasm during sexual intercourse, the mucous plug from the cervical canal is partially pushed out and then retracted into it again, thereby facilitating the faster entry of sperm from the vagina (where normally in a healthy woman the environment is slightly acidic) into the more favorable environment of the cervix and uterine cavity. The passage of sperm through the mucous plug of the cervical canal is also facilitated by the sharply increasing mucus permeability on the days of ovulation. On the remaining days of the menstrual cycle, the mucus plug has significantly less permeability to sperm.
Many sperm found in a woman’s genital tract can retain the ability to fertilize for 48-72 hours (sometimes even up to 4-5 days). An ovulated egg remains viable for approximately 24 hours. Taking this into account, the most favorable time for fertilization is considered to be the period of rupture of a mature follicle followed by the birth of an egg, as well as the 2-3rd day after ovulation. Women using a physiological method of contraception should remember that the timing of ovulation may fluctuate, and the viability of the egg and sperm may be significantly longer. Soon after fertilization, the zygote begins to fragment and form an embryo.
In recent years, the method of in vitro fertilization has been used to treat infertility - fertilization of a human egg outside the body, culturing it to a certain stage and transferring the embryo (fetus) to the uterus. The absolute indication for this method of fertilization is tubal infertility, which develops due to obstruction or absence of the fallopian tubes. In cases of male infertility, instrumental introduction of the husband's or donor's sperm into the woman's genital tract is used in order to ensure her conception ( cm. Artificial insemination).
(Source: Sexological Dictionary)
(syngamy), merging male and wives germ cells (gametes) in plants, animals and humans, resulting in the formation of a zygote that can develop into a new organism. O. underlies sexual reproduction and ensures the transmission of hereditary characteristics from parents to offspring.
(Source: Dictionary of Sexual Terms)
Synonyms:See what “Fertilization” is in other dictionaries:
Syngamy, the fusion of a male reproductive cell (sperm, sperm) with a female (egg, ovum), leading to the formation of a zygote, gives rise to a new organism. In animals O. is preceded by insemination. In the process of O., the egg is activated,... ... Biological encyclopedic dictionary
The processes associated with fertilization in cycads are so unusual that their identification, especially the discovery of spermatozoa in them at the end of the last century, created a real sensation among specialists. These processes take place in the following... Biological encyclopedia
FERTILIZATION, the key process of sexual REPRODUCTION, when as a result of the fusion of male and female GAMETES (sex cells) a ZYGOTE is formed. The zygote contains genetic information (CHROMOSOMES) from both parents (see HERITANCE). U... ... Scientific and technical encyclopedic dictionary
Modern encyclopedia
- (syngamy) the fusion of male and female reproductive cells (gametes) in plants, animals and humans, resulting in the formation of a zygote that can develop into a new organism. Fertilization underlies sexual reproduction and ensures transmission... ... Big Encyclopedic Dictionary
FERTILIZATION, fertilization, pl. no, cf. (book). 1. Action under Ch. fertilize fertilize. 2. In animals and plants, the formation and emergence of a fetus due to the fusion of male and female germ cells. Reproduction by fertilization... Ushakov's Explanatory Dictionary
Chasmogamy, syngamy, gynogenesis, insemination Dictionary of Russian synonyms. fertilization noun, number of synonyms: 9 gynogenesis (1) ... Synonym dictionary
FERTILIZATION- FERTILIZATION, the union of an egg with a sperm, characterizes sexual reproduction, which is one of the most common methods of reproduction in nature. Already phenomena, conjugation (see) in protozoa and what occurs at the same time... ... Great Medical Encyclopedia
Fertilization- FERTILIZATION, the fusion of male (sperm) and female (egg, ovum) germ cells in plants, animals and humans, resulting in the formation of a zygote capable of developing into a new organism. Fertilization is the basis of sexual... Illustrated Encyclopedic Dictionary
FERTILIZE, ryu, rish; renny (yon, ena); owls, who what. Ozhegov's explanatory dictionary. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 … Ozhegov's Explanatory Dictionary
Fertilization. See syngamy. (Source: “English-Russian Explanatory Dictionary of Genetic Terms”. Arefiev V.A., Lisovenko L.A., Moscow: Publishing House VNIRO, 1995) ... Molecular biology and genetics. Dictionary.
Books
- In vitro fertilization. Just the facts. Information for thought, Kuzmichev Leonid Nikolaevich, Shtyrya Yulia Aleksandrovna. The book includes research results, methodological recommendations for reproductive specialists, embryologists, and obstetricians-gynecologists. In addition, key events in the history of ART are highlighted.…
and still make a lot of effort to get inside her. Only after this can conception be considered complete.
Fertilization process
Pregnancy occurs as a result of conception, i.e. To increase the likelihood of pregnancy, sexual intercourse should occur a few days before or in the first 12-24 hours after it. This is due to the short time frame.
ON A NOTE! After ejaculation, the living creatures move quickly. Within 1–2 hours they may end up in the fallopian tubes, where they merge with. If it hasn’t happened yet, then they are waiting in the wings. They can remain fertile for 5–7 days.
When does pregnancy occur?
Pregnancy begins from the moment of conception, but it will be considered full only after the embryo has successfully completed all stages of division and securely anchor on the lining of the uterus. Implantation, as a rule, begins 6–7 days after fertilization and lasts about 3 days.
After implantation, the embryo begins produce the hormone hCG, it can be detected in blood earlier than in urine. Therefore, experts recommend carrying out pregnancy tests only after 14 days from the moment of conception.
REFERENCE! According to statistics, about 80% of all conceptions do not result in full-fledged pregnancies.
For successful pregnancy development The following conditions must be met:
- Good performance.
- Patency of the fallopian tubes.
- Completeness of genetic material.
Many women begin to guess about their situation even before it becomes obvious. They experience a change in appetite and taste preferences. Apathy and drowsiness appear. Sometimes these signs can be confused with symptoms of premenstrual syndrome.
In certain situations, uterine tone may occur. It is characterized uterine contractions causing discomfort to a woman. Some women experience a feeling of “fullness” in their abdomen. Pregnancy can also be felt on an intuitive level.
ON A NOTE! To confirm an interesting situation before the delay occurs, you can donate blood to determine the hCG hormone. Its increase will indicate successful conception.
Actions after conception
First month of pregnancy is extremely important. It is he who determines how the child will develop in the future.
At the initial stage of pregnancy, a woman has the power to protect herself from possible problems. It is not recommended during this period lift weights. This may cause miscarriage.
Experts advise insuring yourself against occurrence of stressful situations. All life support systems are inextricably linked with each other. Under the influence of stress, intense contractions of the uterus occur, which can prevent the full attachment of the fertilized egg.
Even at the stage of preparation for conception, a woman should take care of replenishing the deficiency . These include folic acid, magnesium, calcium, iodine, iron, etc.
REFERENCE! There are special complexes for young mothers and women planning pregnancy. They contain the right amount of useful substances.
The fertilization process can be influenced by many different factors. This is why attempts to conceive a child are not always successful. You should consult a specialist only after a year of unsuccessful attempts to conceive. Only in this case can the question of infertility treatment.
Birth of a child is the result of thousands of amazing processes occurring inside the female body. A caring mother wants to be aware of everything related to her baby.
It is for this reason that many future parents are interested in how fertilization occurs.
Fertilization process
Nature decided to arrange it so that a woman can become pregnant only on one day during the entire cycle, this day is called. It is on this day that it leaves the follicle and moves along the fallopian tube in the hope of being fertilized.
REFERENCE! At average speed after a few hours reach the goal, however, due to the “harsh conditions” of overcoming the path, most of the tadpoles will die and the most persistent and “worthy” will reach the goal.
2. Only one tadpole will take part in the fertilization process, the rest are destined to die. Performing intense thrusts, he breaks through the covering of the female egg. Once the tadpole is inside, fertilization occurs. From this moment on, the cell is called zygote, which soon begins its division.
Movement towards the uterus
For next days the zygote continues to divide and continues to move along the fallopian tube towards the uterus. The flickering of the cilia of the fallopian tube helps her in this. From time to time, contraction of the tube muscles is performed to accelerate the movement of the zygote, which, as a result of divisions on the 5th day, is called a blastocyst. 6-7 days after fertilization the embryo is ready for implantation.
IMPORTANT! After the blastocyst is fixed in the body of the uterus, it begins to actively interact with it, which contributes to the synthesis of a huge number of new hormones.
For successful attachment of the fertilized egg, the following conditions are necessary:
- the outer layer must have suitable thickness for the subsequent development of the embryo, and also contain the required amount of nutrients;
- in the female body the concentration of progesterone should be exceed norm, because it is this hormone that blocks the onset of menstruation, allowing pregnancy to develop.
If such conditions are not met, the egg is not able to attach to the uterine lining, which leads to menstrual bleeding. Thus it happens embryo rejection, and they begin in the ovaries.
How does the woman feel?
Symptoms
After fertilization, the expectant mother is able to detect some symptoms, which manifests itself in the period from the moment of union and before the embryo is implanted into the uterine wall. During this period of time, the female body undergoes changes:
- changes slightly intensity breathing. This can be explained by the fact that the splitting zygote experiences a huge oxygen need;
- the metabolism of substances such as calcium, phosphorus and carbohydrates changes. The expectant mother can detect this by an increased appetite and specific taste preferences;
- the level increases free amino acids;
ON A NOTE! All these symptoms are not obvious; it is quite difficult to identify them and independently discover that fertilization has occurred.
Responsible future parents carefully plan conception: they watch videos on this topic, read books, articles, etc. This helps them consciously approach their new situation and allows them to give maximum care to the long-awaited baby. To be born, he will have to go a long way, from conception to birth. How and where does the fertilization process occur, can the expectant mother feel it?
Where does fertilization take place?
To talk about the place of fertilization, you need to know the structure of the female internal genital organs. They are located in the pelvic cavity.
These include:
- ovaries;
- uterus;
- fallopian tubes;
- vagina.
Ovaries are sex glands that participate in the formation of female reproductive cells and hormones. They can reach three centimeters in length. During ovulation, the egg is released into the abdominal cavity through the fallopian tubes. Since the ovaries do not even have a cavity and store eggs, it is logical to assume that fertilization in them is impossible at any time and under any conditions.
The fallopian tubes are otherwise called oviducts. Their structure resembles a funnel into which the egg enters a wide opening. They are lined with ciliated epithelium, the outgrowths vibrate, causing fluid to move. This current directs the reproductive cell into the oviducts. They open into the uterus.
The uterus is a muscular, hollow organ that is located in the abdominal cavity, behind the bladder. The inside is lined with mucous membrane, which has a dense network of capillaries. The organ is connected to the vagina by a cervix - a muscular ring.
The vagina is a tube formed from muscles. It starts from the uterus and ends at the outlet. You can see the structure of the female genital organs in more detail in the photo.
In the vagina of the expectant mother?
The female genital organs have a rather complex structure. Leaving the ovaries, the egg enters the oviducts, which enter the uterine cavity, which has an outlet into the vagina. To get here, the cell will have to go through a long and difficult path. In addition, if the moment of fertilization or conception occurred in the vagina, the ovaries could excrete cells directly into it, bypassing the oviducts and the uterus.
Nature strives for conciseness and organization, so conceiving an unborn child in the vagina is impossible. Previously, only the path of eggs was considered, but sperm also have a difficult time. To begin with, billions of male reproductive cells enter the vagina, the internal environment of which is unfavorable for them. For this reason, most of them die after a few minutes. The rest are in the vagina, trying to get further, for about two hours.
So, conception in the vagina is impossible for two main reasons. The first is the structural features of the female reproductive system. The second is the characteristics of sperm.
In the uterine cavity?
Theoretically, it would be easier if fertilization took place in the uterus. However, by the time a man’s gametes enter this organ, the egg does not always have time to pass through the fallopian tubes, since it is large in size relative to male gametes. It should also be taken into account that the inner surface of the oviducts is folded, which also makes movement along them difficult.
Sperm selection also matters. For fertilization, the reproductive cell needs the best one, who has gone through many tests. Otherwise, there would be a high probability of having a weakened child. So, the uterus also cannot serve as a meeting place for male and female gametes.
In the fallopian tube!
It turns out that the ideal place for fertilization is the oviduct. After going through the unfavorable environment of the vagina, overpowering the immune system and managing to get through numerous folds, the sperm finally gets to the egg.
By the way, about the immune system. The female body perceives a man’s reproductive cells as foreign, and therefore tries to actively fight them. Normally, this process does not kill all sperm. However, there are cases where a couple could not conceive a child due to immune incompatibility - the female body destroyed absolutely all foreign cells.
With normal functioning of the immune system and compatibility between men and women, at least one cell survives. It is she who fertilizes the egg in the fallopian tube.
How and when does conception occur?
Without delving into the process of conception, you might think that fertilizing eggs is simple. However, this is not at all true. For a zygote to appear—the fused sex cells of a man and a woman—several factors must coincide. If at least one of them falls out, pregnancy is impossible. Those who are thinking about having a child should pay attention to this.
Is the “bride” ripe?
Upon reaching puberty, a girl's body ovulates every month. This term refers to the release of a mature egg from the ovaries into the oviducts. Any woman can calculate the time of ovulation.
The study that gives the most accurate indicators is measuring the temperature in the rectum. It must be done daily for several months. It is recommended to do this in the morning, before breakfast, using a regular thermometer. It is advisable to carry out the procedure in the same time period and enter the data into a table or list. The maximum decrease in temperature signals ovulation, which occurs the next day.
To calculate the date of ovulation, you can determine the maturation cycle of germ cells. There is a long duration, lasting about thirty-five days. Moment X occurs approximately three weeks after the first day of menstruation. A normal cycle is exactly four weeks, with ovulation occurring in the second week. A short cycle includes 22 days, the egg is released after eight days.
There is a myth about the existence of “safe days” during which conception is impossible. You shouldn't take risks and rely on them. The human body does not always work like a clock. Cycles may shift, sperm may become resistant to protective mechanisms, etc.
Will the “suitors” wait?
To get into the fallopian tubes, sperm have to overcome many obstacles. Let's look at them in more detail.
They first pass through the vagina, which has an acidic environment that destroys weak cells. More than half of the sperm die before reaching the uterus.
The second mechanism for sifting out germ cells is the cervix and the mucous plug in it, which impedes movement. Thus, no more than ten million sperm enter the uterus directly. The uterus increases the speed at which cells move, helping them reach the fallopian tube. However, the oviducts are covered with cilia, which vibrate, trapping sperm. Only a few thousand make it to their final destination. Going through this difficult path, the germ cells are modified and become capable of fertilization.
In this state, they can exist in the female body for no more than five days, lingering in folds or villi. If during this period they meet an egg and are able to break through its two shells, it will be fertilized; if not, the sperm will die, and the “impregnable” female will come out with her period.
Fusion of parent cells
Fertilization takes place in the oviduct, close to the ovary. Dozens of sperm reach this stage. It is noteworthy that only one of them merges with the egg; the rest help him in this and quickly die.
The strongest and fastest is attached to the outer membrane of the cell. Thanks to the Golgi apparatus, the head of the sperm contains an acrosome - a complex of enzymes that splits the integument of the egg.
The female reproductive cell has two membranes; upon reaching the inner one, the sperm quickly merges with the contents. After this, a series of reactions are triggered in the membranes of the egg. Substances are released that prevent other sperm from attaching to the cell.
At the same time, all organ systems in the body are notified of the onset of pregnancy so that they can be reorganized to preserve and ensure the vital activity of the embryo. First of all, the activity of the immune system decreases, since it can mistakenly mistake the embryonic cell for a foreign one.
The sperm is small in size, so the genetic information is packed compactly, opening only inside the egg. A pronucleus is formed, which contains 23 chromosomes, the same number as the female gamete. Merging together, they determine the physical characteristics of the unborn child.
However, calling fertilization conception is not entirely correct; during this process, only a zygote is formed. Thirty hours after cell fusion, it begins to actively divide with the formation of blastomeres. The number of cells constantly increases and a blastula is formed - a single-layer embryo of a new person (look at the photo).
What happens after conception?
After fertilization of the egg and formation of the blastula, the zygote moves freely through the fallopian tubes and uterus for about a week, trying to attach to the walls. At this stage, there is a high risk of ectopic pregnancy - attachment of the embryo to the mucous membrane of the oviduct. This does not bode well for a woman.
Successful implantation may be accompanied by the release of a small amount of blood, which is sometimes perceived as the beginning of menstruation. After the egg is fertilized and attaches to the wall of the uterus, the production of the pregnancy hormone, human chorionic gonadotropin, begins.
After the embryo has implanted itself on the wall, it begins to develop. This description is primitive, but it is sufficient to understand the basic mechanisms. You can watch the video for more details.
When does a woman feel she is pregnant?
Women rarely recognize their first pregnancy, mistakenly believing that their sensations are a manifestation of malaise. However, experienced mothers are more sensitive in this matter.
Many people experience bleeding as a result of the implantation of the embryo. It is short-lived and not very abundant, unlike menstrual. There is also a feeling of nausea in the morning, constant drowsiness and general weakness. Breast engorgement and increased sensitivity are often noted. There is a slight tingling sensation in the bladder area and a slight heaviness in the lower abdomen.
All these sensations appear exclusively after implantation of the embryo, when a special hormone is released. Until this moment, a woman cannot feel the onset of pregnancy.
