The meaning of sperm. Life of sperm inside and outside the body. What factors influence sperm viability?

During every minute, a man's body produces 50,000 sperm. During every hour, his testicles produce 3,000,000 sperm. During each day - 72,000,000 sperm. This amazing process, coupled with incredible performance, begins at puberty and continues until death. Compare it with the maturation of eggs within 28 days, that is, once a month, in a woman’s body (and even then before menopause).

However, due to the size of the sperm, the amount of sperm released is not at all that large. If you were to collect together all the sperm that contributed to the conception of every human being who has ever lived or is alive, there would only be enough of them to fill a thimble. The sperm produced by a man during the day, collected together, would be no different from a grain of sand. Naturally, they are not visible to the naked eye, and their structure can only be studied using an electron microscope.

Male sperm is a complex substance consisting of more than 30 different components, including citric acid, fructose, highly concentrated potassium, etc. essential element, like zinc. The composition of sperm also includes sulfur, copper, magnesium, calcium, vitamin C and B12, i.e. all the most important chemical elements for human health. In addition, the seminal vesicles contain 15 various secretions prostate gland, which stimulate muscle contractions and dilation of blood vessels. Despite the presence citric acid, sperm has a slight alkaline property.

There are two types of sperm: some contain the sex chromosome X, others Y. Fusion with an egg of a Y-sperm leads to the birth of a boy, but an X-sperm? girls.

A study by Israeli scientists confirmed that the sex of an unborn child can most likely be determined at conception. It is believed that Y-sperm are more mobile, but have a shorter life expectancy. Therefore, if conception occurs during the period of ovulation, i.e., when a mature egg leaves the ovary, they manage to achieve their goal faster than X-sperm. Then a boy will be conceived. Conversely, if conception occurs a day before ovulation, then there is a greater chance of fertilization of the egg with an X-sperm, which has a longer life expectancy. And a girl will be conceived.

Newborn sperm

"Newborn sperm" are microscopic germ cells. They are grouped in the testicles in ranks, like soldiers on parade. As they develop, they form an oval-shaped head, a thin neck and a tail (flagellum), long compared to their microscopic size. The sperm contains a set of 23 chromosomes, which are located in the head and contain genes that transmit family resemblance traits to future generations. Spermatozoa move using a flagellum. The blows, reminiscent of a whip, propel them forward on the long journey to the awaiting egg.

Of the multi-million army of sperm released during one ejaculation (ejaculation), only one can penetrate the egg. A fertilized egg develops a special kind of protection that prevents other sperm from penetrating into it. For the normal process of fertilization, it is important not only the formation of a sufficient number of full-fledged sperm, but also a certain composition of the liquid part of the sperm: the optimal concentration of fructose, zinc and calcium ions, biologically active peptides and low level acidity. The state of these indicators is influenced by the level of hormones and radiation, the action of certain chemicals and even the psycho-emotional state.

The sperm's tail moves like a snake, bending in several places at once. The lower part of the tail must wag from side to side 800 times for the sperm to move forward 1 cm.

Testicular activity

Testicles can be compared to a conveyor belt, as they work without interruption. The activity of each sperm-producing seminiferous tubule does not stop for a minute. The huge conveyor line moves tirelessly forward without smoke breaks, lunch breaks or overnight downtime. When the finished product comes off the line, some of the cells left behind are halfway through, while others are just beginning to live. At each stage of development, a specific rhythm and speed of movement is observed, which can neither be slowed down nor accelerated. The formation of a germ cell takes a long time, about 72 days. At the end of the production process, not all of them are in perfect shape. Some have no flagellum, others have an underdeveloped head, and others are deformed. This was to be expected with such mass production. Several million poorly formed, unformed sperm do not reduce a man's ability to fertilize. Inside the testicles, male cells can only make small movements.

Activities of the epididymis

The epididymis are long, narrow tubules that lie curled up above both “twins.” When sperm production ends, they move from the testicles to the epididymis. They are not yet sufficiently developed, unable to move properly and fertilize an egg. Sperm motility is an important factor in fertilization ability. To win the race male cage must move forward and only forward, without changing direction. Spermatozoa acquire motility only in the initial part of the epididymis. The walls of the epididymal duct secrete fluid, under the influence of which the sperm begin to move. But they still have a poor sense of direction, which forces them to swim in a circle, that is, to remain in place. This means that they would lose the race to the egg in disgrace. The maturation of sperm in the tubules of the epididymis lasts twelve days before they sufficiently learn to swim. At this time, the most sensitive muscles located in the walls of the tubules push them forward. The enormous distance they have to overcome is about 6 m. The liquid nutrient medium serves as food for them, helps them mature and gain the necessary mobility. To sum it up, we can say that the epididymis is a real school of courage.

Short shelf life of sperm

Sperm need to spend 72 days in the testes and 12 days in the epididymis to reach maturity, a total of almost 3 months. Only after this are they ready to set off on the long journey to the seminal vesicles and further to the prostate gland. Mature germ cells accumulate in the epididymis, but not for long. They have a limited shelf life. They remain “fresh” and active for less than a month. After this, they age sharply and soon die. Dead spermatozoa decompose, and the sperm contained in them nutrients, including proteins, are absorbed by the testicles. If a man ejaculates only once a month, it seems to him that he is no longer able to impregnate a woman. He thinks his sperm are too old, or dying, or have already died. But in fact, the production of male reproductive cells is a continuous process. Millions of new sperm enter and travel through the epididymis in an endless stream. Although the ejaculated sperm may contain old sperm, along with them there are also completely new ones, ready to begin the race to the egg and realize their chances.

The male reproductive cell develops about 75 days from the moment of its occurrence. Therefore, the consequences of harmful effects may take several months to appear. Some relative guarantee of the correct development of germ cells is provided by strict adherence to nutritional standards. Scientific research suggests that excess weight in men leads to changes in testosterone and estrogen levels? the main hormones responsible for the formation of sperm. In addition, when overweight The temperature of the testicles increases, which for successful sperm formation must be below body temperature. For the same reason, frequent hot baths are undesirable.

Sweet seed

Sperm (seminal fluid), produced by the male gonads, consists of sperm, seminal vesicle fluid and prostate secretion. Sperm make up on average only 3% of the ejaculate. The remaining 97% is the secretion of the prostate gland and the fluid of the seminal vesicles. In the first portion of ejaculate, the sperm content is higher than in subsequent ones, and especially in the last. The ejaculate contains approximately 300 to 500 million sperm. Sperm is a complex liquid, saturated with various compounds and sugar, and not all components are known. Fructose (a sugar found in semen) may serve as an energy source for sperm, but this remains to be proven. Semen is alkaline, while vaginal secretions are acidic. It is generally accepted that the alkaline substance coats the sperm and protects them while they are inside the vagina. Prostate secretion contains strong antibacterial compounds. The sperm is released in a liquid state, then it quickly turns into a jelly-like state, and after 20 minutes the sperm liquefies again. It is possible that this helps germ cells survive in the vagina. The average volume of ejaculate, provided that orgasm occurs with 3-day intervals, is from 3 to 5 cm; the quantitative expression of the ejaculate may vary depending on age, health status, amount of fluid drunk, and so on. In a partner, sperm can cause allergic reaction. The allergy manifests itself in the form of a rash or prolonged itching of the reproductive organs. This happens extremely rarely; most often, such symptoms indicate the presence of an infection.

In addition to its direct function of fertilizing the egg, sperm has a positive effect on the woman’s body, except, of course, in those cases when it becomes a carrier of diseases (AIDS, hepatitis, sexually transmitted diseases). Based on this, hormonal contraceptives, on the one hand, are preferable to condoms, on the other? the latter remain the most effective means prevention of infectious diseases transmitted through sexual intercourse.

In a partner, sperm can cause an allergic reaction. The allergy manifests itself in the form of a rash or prolonged itching of the reproductive organs. This happens extremely rarely; most often, such symptoms indicate the presence of an infection.

It is no secret that some French manufacturers use sperm to make cosmetics. This cosmetics is very effective and is not cheap. The thing is that in nature there is no more valuable and unique product than sperm. The cosmetic value of sperm is determined by the presence of extremely useful substances in its composition.

It turns out that the world-famous Viagra and some other popular drugs for impotence do not increase sperm activity, as one might expect, but inhibit it, which negatively affects the ability to fertilize.

Small leak

Before ejaculation, a small drop of liquid wets the end of the penis. It comes from the Cooper's gland and produces a strong alkaline reaction that neutralizes all traces of acid after urination. It cleans and rinses the urethra, preparing it for the passage of sperm. This fluid contains several thousand sperm. There is a theory that this is a "team of superstars" ready to win the race. To avoid conception, even a small part of this fluid should not enter the vagina, otherwise sperm may find their way to the egg. Removing the penis from the vagina just before ejection of semen is called coitus interruptus. This method is often used by young couples trying to avoid pregnancy. However, they are at great risk of becoming mom and dad in nine months. The culprit is often a small drop from the Cooper's gland. Coitus interruptus requires skills and the ability to control one's reactions and manage orgasm, which are most often absent in youth. This can cause a lot of stress for partners. However, many experienced, mature couples choose this particular method of protection, the most ancient and widespread. But it does not protect against infection with sexually transmitted diseases and AIDS, while a condom provides at least partial protection.

The strongest survives

It is generally accepted that only 200 sperm survive the journey to the egg. Some are unable to overcome the very first obstacle - the cervix, while others die while moving through the uterus. Still others may get confused and not get into the right oviduct. A sperm can live in a woman’s birth canal for 2 to 7 days. This is how long it may take for an egg to be fertilized. When it comes to sperm, it is true that quality is more important than quantity. The key issue is the problem of mobility: the cell must swim in only one direction, that is, forward. The average sperm speed is 3 mm per minute. The faster ones have a better chance of reaching the goal before they die. So, speed and mobility are the main conditions for winning races. Those lucky enough to survive accumulate in the widest part of the oviduct. This is where they eagerly await the arrival of the egg. If she is already in place, they gather around her, selflessly trying to break through her protective shell. Wriggling, the sperm sharply hits the outer wall of the cell, releasing chemical compounds that dissolve it protective layer. Eventually small holes appear in the wall and a few lucky sperm make their way inside the egg. From those who succeed, only microscopic heads remain. Now they face the last obstacle, the last bastion that needs to be taken. This thin outer shell protecting the nucleus of the egg is the most difficult obstacle. And only one sperm can overcome it. Perhaps they really will be the best of the best. Its head moves to the middle, and its nucleus connects with the nucleus of the egg. Conception occurs - total implosion, perfect fusion, complete union of two nuclei. According to generally accepted ideas, this reunion is a manifestation of a powerful, all-encompassing micro-force. It is this that determines all the parameters of our personality. Chromosomes join in pairs, once and for all determining a set of hereditary traits. New life is a perfectly proportional, democratic mixture of the genes of both parents.

Infertility problem

Infertility is the body's inability to produce offspring. According to one study, 15% of American and 12% of English married couples face the problem of infertility, and in 35% of cases this is associated with male infertility. In 10-15% of cases, the reason lies in the infertility of both partners. Experts say that there is cause for concern only if conception does not occur within a year of intense sexual activity. Some of them believe that this period should be extended to a full 18 months. Currently, male infertility is becoming more common, and the cause of this phenomenon is unknown. In 1950, the average number of sperm per semen was 40 million higher than in 1988. One of the most important reasons may be overheating of the testicles (staying in hot water is a primitive method of contraception). Tight clothing can act in a similar way, increasing the temperature in the groin and perineum area. Studies to establish the relationship between the type of underwear and fertility have shown that men who wore boxer shorts had a higher sperm count than those who wore tight underwear. Unfavorable factors also have a harmful effect on sperm quality environment(radiation, air pollution with lead compounds and other toxic substances, etc.). Currently, the prevailing opinion is that they cause much more damage to health than was commonly believed. The testicles are more exposed to harmful environmental influences than the internal organs. Therefore, you should remember that the testicles are an extremely sensitive organ, and avoid anything that involves unnecessary risk.

Insufficient intake of vitamin C (less than 60 mg per day) has a negative effect on sperm health and is believed to affect the occurrence of various disorders in the offspring. Well-known risk factors are tobacco, alcohol and drugs. Anabolic drugs that bodybuilders are addicted to are also very dangerous. Not all men remember the health of their offspring when choosing a profession. And statistics show: among painters, floor polishers and other people who work with paints and varnishes, the quantity and quality of sperm changes, and anomalies are more common in their children. And, for example, the wives of dentists have an increased risk of miscarriage due to the fact that their husbands inhale fumes of narcotic substances that are administered to patients. Studies of the sperm and offspring of computer scientists have so far yielded conflicting results. And yet, experts advise both men and women engaged in such work to interrupt or limit it at least a month before possible conception.

Sperm are most mobile in autumn and winter; at the same time, sperm contains the maximum concentration of germ cells. Scientists recommend the months from October to February as the most suitable for conception. In addition, during these months the likelihood of conceiving a boy is greatest because in the summer, due to the heat, the Y chromosomes, carriers of the male genetic code, are much inferior in viability to the female X chromosomes.

A change in the maturation process of sperm, a decrease in their number, motility, and the presence of chromosomal abnormalities in them can cause male infertility, which, although somewhat less common than female infertility, requires no less thorough research and treatment.

Sperm volume

The amount of sperm sufficient for conception is from 2 to 5 cm. If the ejection volume is less, the sperm becomes thick and viscous, and the sperm are poorly protected from the effects of acidic vaginal secretions. If the volume is larger, then the sperm is too diluted, and there is a high probability of germ cells scattering into the vagina. Don't lose hope! If the results of the analysis are not in your favor, do not despair. In vitro, sperm die much faster than in the body. In vitro they live only from 2 to 6 hours. The stress associated with taking the test and the fear of being diagnosed with infertility can negatively affect the results. People tend to make mistakes, and this can easily happen within the walls of a laboratory. The results may be affected poor quality packaging, calculation error, improper storage. Perform several (2 to 3) tests over 6-7 weeks, changing laboratory technicians. Only after this, if all the results are clearly negative, decide what to do next. Rare congenital anomalies include dysfunction of the testicular tubules that produce sperm. The germ cells begin to turn into sperm, but most of them do not mature. Currently, highly qualified specialists can separate mature sperm and use them to fertilize an egg outside the woman’s body. Male infertility remains a poorly understood problem. Therefore, try to avoid treatment in clinics that have not received official recognition. Instead of surgery to remove vas deferens nodes or testicular biopsy, you can resort to artificial insemination partners with their own or donor sperm. However, these operations are expensive both materially and psychologically and do not always give a positive result. Regardless of your decision, try to feel like a man. Drive away gloomy thoughts, they only increase the state of tension and weaken self-confidence. Don't lose hope and keep trying. You should know that there have been cases where men with hopelessly low sperm counts surprised specialists, their partners, and themselves with unexpected paternity.

Myths about sperm

“You may run out of sperm” This naive and ridiculous idea of ​​the processes occurring in the body is widespread among boys who frequently masturbate. But he believes in this amazingly a large number of mature men. Moreover, although the vast majority of men know that the body produces sperm throughout life, this opinion cannot be dispelled. Abstinence does not affect sperm quality in any way. Recently, studies were carried out on sperm 12 and then 120 hours after the last sexual intercourse. Analyzes showed that abstinence had no effect on the shape, motility, or number of sperm. However, long-term abstinence causes a decrease in the number of high-quality sperm.

"Ejaculation depletes the body"

This misconception is closely related to the previous one. For a long time coaches and sports team leaders demanded that their players abstain from sex at best 4-5 days before the start of important sports competitions. Recently, scientists at Colorado State University studied the physical fitness of athletes who: a) abstained from sex for 5 days, b) had sex within the last 24 hours. They were tested: endurance, readiness for effort, mobility, reaction speed, balance, muscle strength and other indicators important for athletes. The researchers noted "no significant or measurable differences" in both groups of athletes.

"In old age, sperm are no longer produced"

At age 70, sperm production declines. But studies show the presence of sperm in the ejaculate of 48% of men aged 80 to 90 years. Currently, most scientists agree that older men have less viable sperm than younger men. There is a slight increase in the number of deformed sperm, which can cause developmental defects in the conceived child. The degree of risk in such cases cannot be determined, since a man at this age no longer strives to become a father.

Everyone knows that sperm is a male reproductive cell. Experts call it a gamete. Male reproductive cells are formed in the testicular tubules. Naturally, without them the process of fertilization of a female egg is simply impossible. What is the structure of the sperm and its functions?

Discovery of sperm

The spermatozoon was discovered by the Dutch naturalist A. Leeuwenhoek in 1677. Thanks to the first microscopes that he designed, the scientist was able to examine and sketch the male reproductive cell. Moreover, he was the first to describe human sperm. Leeuwenhoek then began studying the male gametes of various animals. It was this naturalist who first suggested that they were involved in the process of conception.

In different animals, male reproductive cells are structured differently, although the structure of the sperm is very similar:

Head;

Middle part;

In some animals, the number of tail flagella may vary. Sperm head shape different types living beings also differ.

The structure of the sperm, a photo of which is in the review, has its own characteristics. The morphology of male gametes is fundamentally different from other cells in the body of living beings. Moreover, all the main organelles are present in their structure. The structure of the sperm is as follows:

. The head is ellipsoidal, almost completely filled with the nucleus. It contains hereditary material transmitted from father to offspring. It is presented in the form of chromatin, which is a complex of DNA, RNA, and proteins. The nucleus contains 23 male chromosomes. This is a half set of hereditary material. During fertilization, it combines with the 23 chromosomes of the female egg. The sperm carries one sex chromosome, designated X or Y. If the egg is fertilized by a male gamete carrying the Y chromosome, then a boy will be born in the future, and if X, then a girl. In other words: the sex of the unborn child depends on the sperm.

At the top (anterior end) of the head is located acrosome, which is a modified Golgi complex. It produces the enzyme hyaluronidase, which is capable of breaking down the egg shell, consisting of mucopolysaccharides. Thanks to this property of the acrosome, the sperm can penetrate the female gamete. At the border of the head and its neck there is a centriole, an organelle involved in cell division. It forms the cytoskeleton of the rope-like tail. The head also contains a centrosome, which is the center for organizing microtubules. It ensures the movement of the rope-like tail of the sperm, participates in the bringing together of the zygote nuclei and its first cell division.

. The neck separating the head and the middle part. This small constriction houses the spiral-shaped mitochondrion, which is necessary for energy production. It serves for the active movement of the sperm. The bulk of the energy is in the form of fructose.

.The intermediate (middle) section, which is often called the body. It consists of an axial thread. In the middle part there is a mitochondrion, which contains 28 mitochondria. It has a spiral shape. The mitochondria synthesizes ATP, thereby ensuring the movement of the gamete.

. The tail is in the form of a flagellum. On its cross section you can see 9 pairs of microspopic tubules. Two more pairs are located in the very center of the flagellum. The sperm tail is an important organelle for active movement.

Sperm size

The size of the male gamete is negligible. The sperm are much smaller than the zygote (excluding the tail). They are the smallest in size compared to other human cells. The length of a male sperm is about 50-70 microns, the width is 3.5 microns. The middle section reaches a length of 4.5 microns, and the tail is 45 microns. It is noteworthy that some living creatures have much larger gametes. For example, a newt sperm has a length of about 500 microns, and male mouse reproductive cells are 1.5 times larger than human ones. The small size of gametes is due to the need to travel rather long distances to the egg.

Features of male sperm

The structure and functions of the sperm are closely interrelated. The male gamete has properties determined by its purpose and characteristics:

The ability to move due to a rope-like tail, which ensures the possibility of meeting the sperm and egg.

It carries a negative electrical charge, which prevents male gametes from sticking together in sperm.

In ejaculate (seminal fluid, sperm) healthy man contains approximately 200 million sperm. U various types living beings, the number of male gametes can vary dramatically. For example, there are approximately 100 billion sperm in the ejaculate of a horse.

Thanks to the tail-flagellum, the male gamete in the seminal fluid develops a speed of up to 5 cm/hour.

Properties of male gametes

Experts were able to find out that the cytoplasm of the sperm head has a liquid crystalline state. Thanks to this, the resistance of the male reproductive cell to unfavorable environmental conditions is achieved. Spermatozoa are able to withstand the acidic environment of a woman’s vagina that is aggressive to them. The structure of the sperm makes it more resistant to ionizing radiation. In some animals, the male reproductive cell has an acrosomal apparatus capable of throwing out a long filament designed to capture the egg.

Lifespan of a sperm

After formation in the testicular tubules, sperm are stored in the epididymis for a month. They remain alive in the ejaculate for about 24 hours. The sperm lives in the vagina for about 2-2.5 hours. If he was able to penetrate the cervix or fallopian tubes, then his lifespan increases to 2-3 days.

The structure of the egg

The female reproductive gamete is a large, spherical, immobile cell that has a supply of various nutrients necessary for protein biosynthesis and the production of specific regulatory substances. Its yolk provides nutrition to the embryo throughout the embryonic period. Its diameter reaches 150-170 microns.

The egg cell is protected from the outside by a shell covered with the corona radiata. It is surrounded by follicular epithelial cells, which multiply as it matures. They secrete a specific liquid. It accumulates in the cavity of the primary follicles. The cells of this epithelium are involved in providing the egg with nutrients. The female gamete shell not only nourishes the gamete, but also protects it from penetration by more than one sperm. Since the egg does not have an apparatus designed for active movement, it is characterized by plasma segregation.

The importance of the movement process

The mobility of the male reproductive cell is its main qualitative characteristic. It is provided by the tail of the gamete due to the performance of similar movements. The structural features of the egg and sperm make the process of fertilization most likely. The shell of the male gamete has special receptors that are able to recognize chemicals secreted by the egg. Thanks to this ability, sperm are capable of purposeful rather than chaotic movement. After ejaculation, almost all healthy reproductive cells of a male representative are directed to the female gamete. This movement is called positive chemotaxis.

High sperm motility plays a more important role important role than their number in the ejaculate. This is often discussed by specialists who work with male and female reproductive cells. So, if about forty percent of sperm in the seminal fluid are mobile, then this is already considered a pathology. In this case, the probability of fertilization of the egg is greatly reduced.

If the sperm consists of completely immobile sperm, this often indicates a pathology such as akinospermia. In this case, the germ cells are alive, but they are immobile and therefore are not able to fertilize the egg. Most often, this disorder is caused by various pathologies of the gonads.

Fertilization process

Each male gamete contains a Y or X chromosome, which determines the sex of the child when the egg is fertilized. Most often, one male gamete and one female gamete are involved in this process. In some cases, a cell is fertilized by 2-3 or more sperm, which leads to the birth of identical twins.

The structure of the egg and sperm is such that during fertilization, only the head of the male gamete is able to penetrate the female reproductive cell. At the same time, all other parts of it remain outside. During the process of fertilization (fusion of egg and sperm), a zygote is formed, which is a diploid cell containing a complete double set of chromosomes.

Scientists call the ability to reproduce offspring by the Latin word “fertility” (fertilis means “fertile, fruitful”). To carry out this process, certain conditions are required. If at least one link in this chain drops out, pregnancy either does not occur, or a congenital pathology of the fetus occurs. Necessary conditions for pregnancy to occur are:

1) maturation of the follicle in the ovary, its rupture, release of the egg (ovulation) and formation of the corpus luteum 1 in place of the follicle;
2) the ability of sperm to penetrate the uterus, fallopian tubes and fertilize the egg;
3) free passage of the egg and embryo through the fallopian tube into the uterine cavity;
4) the readiness of the uterus to implant (implant) an embryo.
A favorable combination of the above circumstances, with the spouses in full health, with regular sexual activity in one menstrual cycle, contributes to the occurrence of pregnancy in approximately 20% of cases.

And now - in more detail about the “mechanism of conception” at its different stages.

Egg. The “reserve” of eggs is determined already at the birth of a girl; it is about 400 thousand. Within one menstrual cycle(from the first day of one menstruation to the first day of the next) in one of the ovaries, as a rule, one egg matures.
After the release of an egg from the ovary (ovulation), which occurs approximately on the 14th day of the menstrual cycle, a corpus luteum forms in the ovary. It secretes hormones (gestagens) that prepare the uterus to receive the embryo, and if pregnancy occurs, they maintain the pregnancy. The role of gestagens is especially important in the first trimester of pregnancy. From the ovary, the egg enters the abdominal cavity. Next to each ovary there is an oviduct - a fallopian (uterine) tube, into the funnel of which the egg must enter thanks to the movements of the cilia of the fallopian tube, which “capture” the egg (it itself does not have the ability to move). In 6-7 days, the egg, thanks to contractions of the fallopian tube, must cover a distance of 30-35 cm from the funnel to the uterus. ideal conditions Fertilization occurs while the egg is in the upper third of the oviduct.
After ovulation, the egg remains viable for approximately 24 hours.

Sperm. Sperm are formed and mature in the seminiferous tubules of the male reproductive gland - the testes. The process of their maturation lasts on average 74 days. A mature normal human sperm consists of a head, neck, body and tail, or flagellum, which ends in a thin terminal filament. The total length of the sperm is about 50-60 µm (head - 5-6 µm, neck and body - 6-7 µm and tail - 40-50 µm). Thanks to the “beating” of the tail, the sperm is able to move. Interestingly, the size of the egg is much larger than the size of the sperm: it is 0.1 mm. Mature sperm exit from the seminiferous tubules into the vas deferens of the male gonads, where they can retain fertilizing ability for a long time. At this time they are motionless - they acquire the ability to move only during ejaculation.
In the genital tract of a woman, sperm retain the ability to move within 3-4 days, but they can fertilize an egg only within 24 hours. There is an assumption that sperm “recognize” the egg by smell - for example, receptors similar to those found in the nose have been found on the surface of male reproductive cells.

Fertilization- the fusion of a male germ cell (sperm) with a female one (egg), leading to the formation of a zygote (a new single-celled organism). The biological meaning of fertilization is the union of paternal and maternal genes. Sex cells contain a so-called haploid (half) set of chromosomes; when they combine, a zygote with a diploid (complete) set of chromosomes is formed.
The seminal fluid entering the vagina usually contains from 60 to 150 million sperm. The speed of sperm movement is 2-3 mm per minute. Thus, already 1-2 minutes after sexual intercourse, sperm reach the uterus, and in 2-3 hours in the female body they can travel 25-35 cm and reach the end sections of the fallopian tubes. After ejaculation (ejaculation), sperm quickly rise through the genital tract due to contractions of the uterus and fallopian tubes; These are so-called peristaltic movements, which are similar to intestinal contractions. Intrinsic sperm motility becomes important in later stages. Sperm, which consists of a biologically active liquid part and sperm, has a slightly alkaline reaction: sperm are capable of active movement only in such an environment. If the environment in the vagina is acidic, then seminal fluid can reduce its acidity to the desired level. No more than a few hundred sperm reach the egg: at all stages of their movement, the least viable ones die and are removed. This happens thanks to the mechanisms of natural selection, that is, the goal (egg) is most often reached by the most complete (without structural defects) sperm.
During the movement of sperm along the fallopian tube, capacitation occurs - a series of changes due to which sperm acquire fertilizing ability. During capacitation, special substances that prevent fertilization are removed from the surface of sperm. (Before the capitation process, these substances perform a protective function.) The beating of flagella changes and becomes much faster, which causes overactive motility of spermatozoa. When capacitation has ended and the sperm have reached the site where fertilization is to occur, they undergo the process of acrosome activation. With the help of the acrosome, which is located on the head of the sperm and contains the enzymes necessary for penetration into the female reproductive cell, they destroy the membrane of the egg in the area in front of the sperm, resulting in the fusion of male and female reproductive cells. As soon as the first sperm begins to fuse with the egg, its properties immediately change: it becomes immune to other sperm.
After the embryo enters the uterine cavity on the 6-7th day of development, it “hatches” from the membrane, and then the implantation process begins - the half-millimeter embryo attaches to the wall of the uterus and is completely immersed in it in less than two days.
This is how the long journey of “life before birth” begins, 9 months long.

A sperm is a male reproductive cell that is designed to fertilize a female egg. The size of a sperm is much smaller than the size of a female reproductive cell. Moreover, it is the smallest cell in a man’s body.

Gametes do not have a large volume of cytoplasm, and they are reproduced by the body simultaneously in huge numbers. It is worth saying that sperm and sperm are completely different concepts. The latter contains seminal fluid with germ cells and microparticles of tissue from the urethra.

In 1 ml of seminal fluid there are from 16 to 120 million sperm. During ejaculation, a man releases up to 5 ml of sperm. Thus, during one ejaculation, a man’s body can throw out up to 600 million reproductive cells.

Probably everyone knows what a sperm is, but not everyone knows how this cell appears. The gonads of young children do not produce reproductive cells. That is why the version that diapers harm boys due to the thermal effect on the testicles can be considered untrue.

Sperm production begins between the ages of 9 and 14 years. From this moment until the onset of extreme old age, the work of the sex glands does not stop for a minute.

The real factory for the production of germ cells is the testicles. They are located outside the body, due to which they have more low temperature. This is extremely important: at the classic temperature of 36.6 ° C, the production of reproductive cells slows down greatly or stops altogether.

Each testicle contains thousands of spermatic cords. That is, if you look at this organ from the inside, you will see a huge number of threads, randomly intertwined with each other. This mess is necessary. While passing through the labyrinths, spermatozoa develop Extra time for maturation.

The first period of maturation of the germ cell lasts about 72 days. This process begins in sperm cells. The very first to form is the head, which takes nutrients and energy from the supporting cells.

After the head is fully formed, the reproductive cell enters the spermatic cords (microscopic-sized canals). There she will move from place to place for about 20 days. Here the gamete will mature completely to become ready to perform its function.

It is worth saying that in some cases the maturation process of the germ cell may be disrupted. The reasons for this are still unknown. In this case, the number of chromosomes carried by the gamete increases or, conversely, decreases. At the same time, the health of the unborn child largely depends on how many chromosomes there are in the sperm.

So, if conception occurred with the help of a reproductive cell with an insufficient or excessive number of chromosomes, then the born child will have physical or mental illnesses (for example, Down syndrome).

According to statistics, 50% of such pregnancies are spontaneously terminated even before the woman finds out about her situation.

Structure

The length of the sperm is 55 microns, the width is 3.5 microns, and the height is 2.5 microns. Such small sizes, as well as the special structure of the sperm, are probably due to the fact that it needs to move quickly.

It is worth saying that the sizes of male gametes may be different in different periods. During the maturation of a given cell, some changes occur to it: the nucleus becomes more dense as a result of the process of chromatin condensation (at this moment histones leave the nucleus, and DNA combines with protamine proteins).

In this case, a large percentage of the cytoplasm leaves the sperm under the guise of a “cytoplasmic drop”. At the final stage of sperm maturation, only vital organelles are retained. The volume of the reproductive cell decreases greatly during this period. If we talk about what a sperm consists of, it will be the head, middle part and tail.

Head

It has the shape of an ellipsoid, with minor dents on both sides. There is also a small depression on one side of the sperm. It is thanks to him that the head of the sperm is called “spoon-shaped”. The head itself consists of the following parts:

Sperm diagram

1. Nucleus or haploid nucleus. It is in it that a single set of chromosomes is stored. After the sperm unites with the egg (although the structure of the sperm and the egg is very different, the nucleus of the latter is also haploid), a diploid organism begins to develop,
   which consists of the chromosomes of both parent cells. It is worth saying that the sperm nucleus is much smaller than the nuclei of other cells in the body. This is explained by the special organization of the chromatin structure in sperm. Due to increased condensation, chromatin becomes inactive, and RNA is not produced in the nucleus of the germ cell.
2. An acrosome is a modified lysosome. It is a membrane vesicle containing about 15 lytic enzymes. They are necessary so that the shell of the egg dissolves and the sperm can penetrate it. The most powerful enzyme in this case is acrosin. The size of the acrosome is approximately 50% of the size of the sperm head. The core has approximately the same dimensions. The acrosome is located in front of the nucleus and covers ½ of it. For this reason, the acrosome looks like a cap. Thanks to this structural feature, the sperm easily fertilizes the egg.
3. The centrosome is the part in which all the gamete tubes are assembled. It is responsible for the movement of the back of the cell. Scientists also suggest that it helps bring the nuclei of the zygote closer together and takes part in the first division of its cells.

Body

It is located almost immediately after the head of the reproductive cell. They are separated only by a small narrowing - the “neck”. The human spermatozoon is contained in its middle region by the flagellum cytoskeleton, consisting of microtubules. Around the cytoskeleton there is a mitochondrion - a huge mitochondrion of the germ cell. The mitochondria itself looks like a spiral. It wraps around the cytoskeleton of the flagellum. Its function is to produce ATP, stimulating tail movement.

Tail

The tail is the organ of movement and comes immediately after the middle part. It is much thinner than the middle of the reproductive cell and much longer than it. At the base of the tail of the sperm, mitochondria are concentrated, which supply energy for its movement. In general, the tail has the same structure as the flagella of eukaryotes.

If you look at a diagram of a spermatozoon, what this cell looks like and what parts it consists of, you can understand much better.

The sperm moves thanks to the presence of its tail. The germ cell itself rotates around its own axis during movement. Thus, it can reach speeds of up to 0.1 mm per second. (approximately 30 cm in 60 minutes).

After entering the woman’s body, the gamete reaches the ampullary region of the fallopian tube only after 60-120 minutes.

In the male body, mature sex cells are stored in an inactive state, and their tails are inactive. Sperm move through the male reproductive tract thanks to the rhythmic contractions of the duct muscles and the beating of special cilia. Sex cells become active only after ejaculation, when they are mixed with prostate secretions.

After sperm enters the woman’s genitals, they begin to move on their own. Moreover, they swim against the flow of liquid.

It is worth saying that the environment of a woman’s genital organs is extremely harmful for male gametes, but the components of sperm neutralize it and make it more alkaline. In addition, semen reduces a woman's local immunity. This is necessary to prevent immune cells from eliminating foreign biological material.

After entering the vagina, the reproductive cell moves towards the cervix and cervical canal. It determines its direction thanks to its ability to distinguish pH. Thus, the cell floats to where the alkaline environment predominates (for comparison, the pH of the vagina is 6.0, and the pH of the cervix is ​​7.2). It is worth saying that the vast majority of male reproductive cells are not able to reach the cervix and die in the vagina.

It is also not easy for sperm to pass through the cervical canal, since it contains a large amount of mucus. If sperm cannot pass through the mucus, then cervical infertility is established, in which it is possible to become pregnant using intrauterine insemination.

Next, the germ cells penetrate the uterus. The environment of this organ is ideal for the life of sperm, so their activity increases significantly. This phenomenon called “capacitation.” For successful conception, more than 10 million male germ cells must pass into the uterus.

Once in the uterus, sperm continue to swim towards the fallopian tubes. The direction to them is determined by the cells due to the fluid flow, which is set by the cilia of the tubes and muscle walls.

The sperm performs its function in the final part of the fallopian tube - the “ampule”. However, not all germ cells are able to reach it. As practice shows, out of several million reproductive cells that enter the uterus, only a few thousand reach the ampullary area of ​​the tube.

As for the question of how the sperm searches for and finds the egg in the funnel, this question still remains open. However, it has already been proven that male gametes have chemotaxis - the ability to move towards attractants secreted by the egg.

Kinds

In medicine, it is customary to divide male reproductive cells into 2 types: those that contain X chromosomes (gynospermia) and those that carry Y chromosomes (androspermia). The first cells lead to the conception of a girl, and the second - a boy. It is worth saying that the fact how many chromosomes a sperm has does not depend on its variety. Normally there will always be 23 of them.

Unfortunately, immediately after conception it is impossible to absolutely know the sex of the child, but it can be guessed with a fairly high probability. As observations show, reproductive cells with a Y chromosome are much more active, while cells carrying an X chromosome have longer duration life.

Based on this, we can conclude that couples wishing to conceive a boy should have unprotected sex during ovulation. In this case, sperm with the Y chromosome will reach the goal much faster. If sexual intercourse occurs a day before ovulation, the chances of conceiving a girl increase.

It is worth saying that for successful fertilization, not only the quantity of sperm is important, but also their quality and the composition of the seminal fluid. In the spermogram of even the healthiest man, along with high-quality gametes, there are also pathological forms of reproductive cells. However, their number usually does not exceed 20-25%.

Sometimes there can be an extremely large number of sperm with an atypical structure. This can happen with various diseases of the genital organs (usually inflammatory in nature).

To find out the ratio of healthy and pathological reproductive sperm, to identify the structural features of sperm in a man, doctors traditionally perform the Kruger test.

Its essence is that a man donates sperm in a medical institution through sexual self-satisfaction. The biological material is collected in a sterile container and then sent to the laboratory. There it is stained with a Papanicolaou stain (this is necessary in order to see the germ cells more clearly) and examined under a microscope.

In various pathologies, the sperm may have the following structure:

• excessive thickness of the neck or its curvature;
• presence of a double tail;
• complete absence of a tail;
• head deformation;
• presence of two heads.

In addition, subtle changes in the shape of the sperm are also possible.

This condition requires urgent medical intervention, since an excessive number of abnormal reproductive cells increases the chances of missed pregnancy, miscarriages, and the birth of a child with various pathologies.

Lifespan

After development is complete, sperm can remain in a man’s body for up to 30 days. If during this period ejaculation does not occur, they begin to age sharply and eventually collapse.

Lifespan of gametes different men different. This depends on his diet, lifestyle, the presence of certain diseases, the state of endocrine and nervous system etc. However, the lifespan is most strongly influenced by where the sperm is located.

According to the results of the post-coital test, already 120 minutes after the end of unprotected sexual intercourse, no surviving sperm are observed in the vagina. They can live in the cervical canal and cervix for up to 3 days, and in fallopian tubes– until 7.

In the external environment and high humidity, germ cells can live up to 2-3 hours. This is precisely what explains the onset of pregnancy with repeated PA. Once germ cells are frozen with liquid nitrogen, they can be stored for decades. Moreover, after defrosting they will remain alive and will not lose their properties.

Improvement

In order for sperm to be of high quality and mobility, a man must carefully monitor his health. Reproductive cells are the most sensitive cells in the human body. They are very difficult to tolerate the effects of alcohol, nicotine, narcotic and toxic substances, and a strong increase in temperature.

Healthy eating, refusal bad habits, timely treatment of diseases, normalization of sleep patterns, exercise and avoidance of extreme temperatures (both overheating and hypothermia) - this is what will help to significantly improve the quality of gametes.

During pregnancy planning, it is useful for a man to take vitamin-mineral complexes and antioxidants. Based on this, we can conclude: the healthier a man is, the better the quality of his sperm.

If a representative of the stronger sex has been diagnosed with any pathology, it is not recommended to engage in amateur activities. Only a doctor knows everything about sperm, so it is better to entrust the treatment to him.

The reproduction and maturation of sperm (spermatogenesis) is a continuous process that begins during puberty and ends in old age, unless it is disrupted by any disease or other harmful influence. Spermatogenesis occurs in the male gonads – testicles (testicles).

Anatomy of the testicles - sperm factories

Spermatogenesis is a continuous process that begins during puberty and ends in old age, unless it is disrupted by any disease or other harmful influence. Spermatogenesis occurs in the male gonads – testicles (testicles).
waiting). Both of these phenomena are well known to the male part of the population. These protective mechanisms are carried out reflexively with the participation of the autonomic nervous system, that is, they do not depend on the conscious will of a person. The testicles are oval in shape, slightly flattened on the sides, and with normal development in mature men they become the size of a plum. The left testicle is always slightly larger than the right one and is located in the scrotum below the right one. This phenomenon is associated with the anatomical features of the blood vessels that supply blood to the left and right testicle. Thus, the fears of some adolescents and some adult men regarding the asymmetry of the size and location of the testicles are in vain.

Physiology of the testicles

Sperm development

What conditions are necessary for the normal development of sperm?

What is unfavorable for sperm development?

Taking antibacterial and sulfa drugs, seemingly harmless, such as sulfasalazine, furadonin, long-term use of tranquilizers, antidepressants, alcohol, tobacco smoking, cocaine addiction, cannabism (smoking Indian hemp products - marijuana, hashish), mental influences (strong fear, for example) - all these factors also disrupt the normal course of sperm maturation.

For more information about prostatitis, read the article: Prostatitis

How does fertilization occur?

Then the division and development of the future organism begins from this single cell, formed as a result of the union of the egg and sperm. The process of fertilization is depicted very schematically, but it is important that the two halves of the chromosome set are united, like halves of loving hearts. In reality, these processes are quite complex and are subject to very fine regulation. The regulation of fertilization processes is built with a multiple system of protection and safety nets, however, they can also be vulnerable.

What does sperm consist of?

The prostate produces a secretion that enhances sperm motility. The property of sperm motility is ensured by a large number of enzymes and biologically active substances. The vas deferens flow into the urethra, and the ducts of the Cooper glands flow into it, releasing their secretion before ejaculation. At the peak sexual arousal involuntary contraction of the muscles of the walls of the vas deferens occurs, their lumen expands, the seed comes from the ducts of the testicle. Subsequent muscle contractions expel seminal fluid, causing the man to experience a sensation of orgasm.

For more information about sperm analysis, read the article: