Many people have minimal knowledge about eggs. Everyone knows that this is a female reproductive cell, without which conceiving a child is impossible. This, unfortunately, is where the knowledge ends. Even women themselves know little about their reproductive cells and what can affect them. Let's fill in these "gaps" and learn a lot of interesting facts about the female egg.
What it is?
The ovum is the reproductive cell of the female body. Quite often it is called an oocyte. It is considered one of the largest in the human body, except for some nerve cells and smooth muscle cells. The ovum is a unique living organism. This is a real masterpiece created by nature for the continuation of the human race.
It used to be thought that only the male reproductive cell - the sperm cell - was responsible for the formation of a human embryo. Now science and medicine have revised their attitude to the egg, recognizing that it participates in the formation of the embryo in the most direct way.
Eggs are monogamous in nature. This means that its fusion is only possible with one of the millions of sperm that move along the female genital tract after ejaculation. Sometimes two or three sperm penetrate into the egg cell at once, but such an embryo is certainly doomed to death - its genetic makeup cannot be normal.
The ovaries, the female sex glands, are responsible for the production of eggs. First, a large number of primary cells - oogonia - are formed in them. Then, in the structure of these precursors, significant changes appear at the intracellular level. The third phase of development is the maturation of the egg. Only a mature egg can leave the follicle, a process called ovulation.
Structure
The structure of the female ovum is very complex. Everything is provided in it in order to provide the best environment for the development of a new life. The size of a woman's reproductive cell is 0.1-0.15 microns. The large, rounded cage is motionless. It is this feature that makes it easier for sperm cells. If the egg was moving, fertilization would be more difficult.
In the structure of the cell, as can be seen in the structure diagram, the cytoplasm, nucleus and membrane are clearly defined. The outer cell membrane has a multilayer structure. Each of the components performs its main functions. The membranes are arranged in such a way that after one sperm cell has entered the cell, they become completely impervious to other male cells. At the same time, the membranes have a sufficient margin of safety so that when the egg is transported through the fallopian tube into the uterine cavity after fertilization, the cleavage cell does not suffer and could safely complete its "journey" and be implanted.
The egg nucleus contains a sufficient amount of proteins that can ensure the division and development of new life. Also, the nucleus contains the X chromosome set. If there is no chromosome in the egg, it is unsuitable for fertilization, such a cell is considered "defective." The protoplasm of the cell contains RNA and nutrients that are needed during the cleavage stage after fertilization.
How are they formed and developed?
When a mother carries a girl under her heart and does not yet realize that her fetus is female, the baby is already developing cells in the ovaries, which are the precursors of the eggs. They are called first-order oocytes. The female fetus has tens of millions of them. But these cells do not differ in strength and vitality, and therefore the vast majority of them die. By the time a girl is born, about two million cells remain in her ovaries, and by puberty, their number reaches only 400-500 cells. Their number does not change over a lifetime.
This oocyte supply is strictly defined; it cannot increase or decrease. Further, the cells of the first order develop in the follicles. The hormonal background, sensitivity to its changes allow the follicles to independently regulate these processes. During puberty, under the influence of female sex hormones, the follicles increase, some eggs mature, the development of others is artificially inhibited so that the supply does not dry out quickly.
One ovum grows in one follicle. In the first phase of the menstrual cycle, several follicles grow, but only one of them will become dominant. A mature reproductive cell, ready for fertilization, will "hatch" from it. The older a woman gets, the fewer immature eggs she has. After 40 years, the stock is practically exhausted. Some of the oocytes matured and came out, and some underwent degeneration, the precursors of the eggs died.
With the onset of puberty in a girl, first-order oocytes are transformed into second-order oocytes, which have half the set of chromosomes. 23 pairs - this is the "contribution" that a woman makes at the time of fertilization. Exactly the same number of pairs of chromosomes "gives" the male reproductive cell.
By the time of ovulation, the size of the egg reaches its maximum, the follicle ruptures and the egg is released into the fallopian tube. There she can wait for a sperm for 1-2 days, after which, if fertilization has not occurred, the cell dies, after two weeks the woman begins her period. The process is repeated in a new cycle.
Ovulation
The process of release of an egg from the follicle, which is called ovulation, usually occurs in the very middle of a woman's menstrual cycle. If 28 days pass from menstruation to menstruation, then ovulation usually "drops out" on the 14th day, if the cycle is longer, ovulation shifts in proportion. Conception is possible only on the day of ovulation or days later, while the egg remains viable.
If sexual intercourse took place 2-3 days before ovulation, fertilization is possible in the very first minutes after the release of the egg. Spermatozoa are more tenacious, they can "wait" for a female cell in the fallopian tube for about 3-4 days. Sexual intercourse on the day of ovulation or the day after it is also likely to end with the onset of pregnancy.
Ovulation in women is often accompanied by certain physical sensations. Nature has foreseen everything so that a woman who cannot see the processes at the cellular level can feel the most favorable period for procreation, because this time is very short. Often, a woman experiences increased sexual desire before ovulation and on the day the egg is released. The discharge becomes more abundant, there is a feeling of warmth and moisture in the perineum. The secretions under the influence of hormones become more viscous, less acidic, so that male germ cells can survive in a different environment and get to the egg.
From time to time, even in a healthy and procreative woman, anovulatory cycles are observed in which there is no release of an egg. It is impossible to define such cycles on your own. This can be done only with the help of ultrasound. If their number is large, they speak of ovarian dysfunction and anovulatory infertility.
Sometimes a woman will have two or three eggs at the same time. In this case, fertilization of all of them is possible, and then twins or triplets are born.
Fertilization and implantation
Sperm begin to move towards the location of the egg immediately after ejaculation. They do not have the intelligence to understand where to swim, but they have a very developed apparatus that analyzes the chemical composition of the environment. Where the acidity is lower, they need to get. Only the strongest and most enduring of the sprays get to the fallopian tube, where the meeting with the egg is to take place.
They begin to "attack" the transparent membranes of the egg, trying to find a "gap" and get inside. In some sources, you can find the assumption that the egg itself chooses who can be allowed to penetrate, screening out defective sperm. This assumption has no scientific confirmation, besides, the incompetent male germ cells simply do not get to the egg. The sperm head secretes special substances that can dissolve shell structures.
As soon as one sperm penetrates inside, a command about the accomplished conception spreads through the body, the hormonal background changes rapidly, progesterone begins to be produced in large quantities, which is necessary for the preservation of pregnancy and the development of the embryo. In the egg, a meeting of sex chromosomes occurs. It is at this moment that it is decided who the baby should be - a boy or a girl. At the same moment, almost everything is determined - what color the baby's eyes will be, his height, who he will be more like - like dad or mom, what will be his state of health.
The ovum becomes a zygote. Despite the fact that the female reproductive cell looks clumsy and immobile, it begins to show activity. Now, with every hour, it will slowly move into the uterine cavity. The mobility is given by the villi that cover the inner part of the fallopian tube. This path takes on average 7-8 days, after which implantation occurs.
On the fifth day after the start of cleavage, the cell changes its status and becomes a blastocyst. It differs from the zygote in a large number of cells and a spherical shape. In the uterine cavity, the blastocyst is released from the zona pellucida, which provides it with better and closer contact with the walls of the uterus. The cell literally grows in from the tissue of the inner wall of the uterus.
If the implantation is successful, a new stage in the development of the embryo begins. Now he is where he will spend the coming months. During pregnancy, already at this stage, the work of all organs and systems of the female body undergoes colossal restructuring. If for some reason there are disruptions in transportation, the zygote will continue to develop in the fallopian tube or in the cervix. And then the pregnancy will be ectopic.
Many women are also able to feel the signs of implantation. 7-8 days after ovulation, they may have a slight pulling pain in the lower abdomen, as well as weak spotting spotting, which indicates a violation of the integrity of the inner layer of the uterus during implantation. This discharge is called implantation bleeding, and it usually stops within a few hours or the first day. Such symptoms do not always accompany implantation, and for many, it proceeds completely unnoticed.
Aging
After 35-36 years, the quality of the eggs is noticeably reduced in a woman. Affects the effect of an overwhelming nature, which monthly does not allow the entire supply of eggs to ripen at the same time, environmental factors, harmful effects, dietary habits, alcohol, chronic and acute diseases.
The X chromosome is also subject to aging, which is why women who decide to become mothers after 35 years have a higher risk of giving birth to a child with chromosomal abnormalities and abnormalities. The older the expectant mother is, the higher such risks are. However, age is not a sentence, and many successfully give birth after 40 years.
When there are no eggs suitable for ripening in the ovaries, menopause occurs. At this stage, conception is impossible, monthly menstruation is absent, since the body no longer needs to free the uterus from dead eggs as an unusable biomaterial.
How much is left?
A woman's fertility directly depends on how many percent of normal and immature eggs remain in her body. In men, spermatozoa are produced constantly, the composition of the sperm is updated every three months, a woman has to be content with only the supply that she has, new oocytes are no longer produced, their renewal is impossible.
The number of cells remaining depends on age and health status. In a newborn girl, 100% of the cells are alive and well; by the age of 10, their number reaches 70%. At 20, a girl retains 37% of her lifelong supply of eggs, and at 25, 22%. At 30 years old, a woman has only 12% of a large supply of eggs, at 35 - 7%, at 40 years old - about 4%, and at 45 - only 2%.
To find out how many eggs are left, a special analysis allows. This is a simple hormonal test called the egg timer. This analysis is very useful for women who are planning a pregnancy after a previous course of chemotherapy, long-term treatment with antibiotics or hormones, as well as those who are planning to conceive over the age of 35.
Qualitative characteristics
Usually, the assessment of the quality of eggs is faced by women who are undergoing treatment for infertility who are shown to conceive by in vitro fertilization (IVF). Their eggs undergo laboratory and genetic research, during which deviations from normal characteristics may be revealed. An ovum with disorders in the state or structure of at least one of the organelles will be considered defective.
The ovulatory supply and quality of female reproductive cells are also indicated by the hormones FSH and AMH, the concentration of which is determined in the woman's blood by laboratory methods. But only a microscopic puncture of the resulting egg can be used to establish what the defect is.
The reasons why a woman produces poor-quality sex cells can be very diverse. Most often, doctors associate them with hereditary factors, because the health of future eggs is determined even when the female fetus develops in the mother's womb. However, the influence of external factors should not be underestimated either. These include bad habits - the systematic intake of alcohol or drugs, smoking. The reason for the deterioration in the quality of eggs may be unhealthy diet, a tendency to eat fast food. A large amount of preservatives and dyes in food causes slow mutations in germ cells.
The excess weight that a woman can suffer from causes changes in the hormonal background, namely, hormones regulate the life cycle of the eggs. Sometimes being overweight is generally an obstacle to conception, and only by dropping interfering kilograms, a woman gains the opportunity to finally become a mother.
In our crazy age, when both men and women do not spare themselves, they work at night, eggs often lose their basic functions due to chronic fatigue, stress, and overwork.
The health of the eggs can be affected by long courses of treatment, chemical and radiation effects on the woman's body, her work in hazardous industries, where there is contact with toxins, nitrates, heavy metal salts, varnishes and paints.
It is not possible to increase the number of oocytes, but medicine may well fight for the quality of eggs. The woman is prescribed appropriate therapy to improve the quality of the germ cells. This includes vitamins, dietary supplements to improve women's reproductive health, as well as a radical change in lifestyle, the elimination of all bad habits and nutritional correction.
To improve the quality of eggs, dietary supplements such as "Ovariamin", "Inositol" are often prescribed. A woman is recommended to take folic acid, sometimes, if the cause of cell failure lies in hormonal disorders, the endocrinologist, together with a gynecologist, prescribe hormonal drugs to the woman to regulate the menstrual cycle and improve the quality of cells.
The characteristics of the oocytes are restored gradually, you should not expect a quick result.
For the period of treatment, a woman is recommended a normal full night's sleep - at least 8 hours a day. This sometimes requires giving up the night shift. Nutrition should be healthy and balanced, and your own weight should also be normalized. Walking in the fresh air, playing sports, an active lifestyle are useful.
To improve the quality of the oocyte after 40 years, even more desire and effort is required, because natural aging and structural changes are almost inevitable. But this is also possible. A woman is advised to completely abandon bad habits, as well as acquire a useful habit of being less nervous.
Under stress, the female body is enriched with stress hormones, many of which block the work of sex hormones. That is why you need to monitor your mood and psychological state, study well the characteristics of your body in order to prevent psychogenic infertility.
The verdict of a reproductive specialist about the low quality of oocytes is not permanent and irreparable. In most cases, a woman, while observing medical recommendations, manages to improve the quality of her sex cells. Problems can arise only with autoimmune forms of infertility, when antibodies and antigens interfere with the fusion of the sperm and the egg. But even in such cases, doctors can offer several effective treatment regimens that will increase the couple's chances of conceiving a baby.
If a woman's eggs do not mature to the desired condition, ovulation does not occur, methods of stimulating ovulation with hormonal drugs are widely used in medicine. In the first phase of the cycle, hormones are usually injected that promote the growth and development of the egg, and then drugs are injected that cause the follicle to rupture.
Feedback on improvement methods
Women who have gone through the procedure for improving the quality of eggs from their own experience are encouraged to be patient, because this is a rather long and consistent process. According to women, the main treatment prescribed by the doctor does not interfere and even promotes auxiliary treatment with folk remedies.
So, fish oil is very useful for improving eggs. It is taken both in liquid form and in capsules. Only edible fat is used, which has significant differences from other types of product. Cod liver and fatty sea fish are added to the diet. Cinnamon is also good for a woman. It is taken in capsules.
The course of treatment is often prescribed just before IVF in order to obtain the highest quality eggs for fertilization. But for conception naturally, women are often advised to take vitamins and dietary supplements.
Those who want to get pregnant, especially after 30 years, have to give up coffee and strong tea, because caffeine negatively affects the state of the eggs. Women have to change their whole way of life in order to achieve their goals and become mothers.
For the structural features, functions and quality of eggs, see the next video.
