Astrology  

Sperm maturation period. Spermatogenesis cycle. How long does it take for sperm to mature? Lifespan of sperm in the fallopian tubes

More than four hundred years ago, the famous scientist A. van Leeuwenhoek discovered spermatozoa in the seminal fluid. Doctors for a long time considered them a type of pathological microorganisms until they discovered their role in the fertilization process. Since then, the attention of scientists has been constantly focused on these amazing cells, because they are the ones who give rise to new life.

The process of formation of sperm, which contains sperm, occurs in men throughout their lives. Before the onset of sexual development, its quantity is negligible, and then sperm is actively produced during the sexually mature period. At approximately six years of age, the testes can begin to produce spermatogonia, and spermatogenesis does not fully stabilize until the age of 15. In old age, the male body produces very little sperm, but the process itself does not stop. What are the known features of this process, read below.

General information about sperm and spermatozoa

About three percent of semen volume is sperm. They are released along with sperm with each ejaculation. One ejaculation can contain about 80 million mature germ cells, with the highest concentration contained in the first portion of ejaculate.

The main role of sperm is to act as a nutrient medium in the process of sperm maturation. To do this, it contains a lot of useful substances:

  • Ascorbic acid.
  • Fructose.
  • Lactic acid.
  • Vitamin B 12 and others.

It is extremely important for the male body that the maturation of its sperm is ensured completely, since they are the ones who carry genetic information to the unborn child.

Spermatozoa are one of the most specific cells, since in a number of their characteristics they are not similar to other eukaryotes. In particular:

  1. Sperm have special organelles.
  2. The cell can move independently.
  3. They have half the set of chromosomes.

These features make spermatozoa unique eukaryotes that live according to their own laws. And although they differ from somatic cells, they still obey the general processes occurring in the body. For example, it is better for sperm to mature at a temperature of 34 degrees, which is different from other eukaryotes. However, like all cells of the body, the reproductive cells are also susceptible to the negative influence of external factors, such as alcoholism, smoking, drug use, and a man suffering from severe infectious diseases.

Education process

Sperm maturation has also been a little-studied process for a long time. Now scientists have the opportunity to fully imagine the transformation of a germ cell into a full-fledged carrier of genetic information and a participant in the fertilization process. This makes it possible not only to understand and treat male infertility, but also to directly intervene in the mystery of conception if one of the couple has pathologies and natural procreation is impossible.

Sperm are negatively affected by alcohol consumption.

It takes almost three months for a man’s reproductive cells to mature completely. During this time, sperm undergo cycles of development in the testicles (72 days) and in the epididymis (12 days). Only after this do they move towards the seminal vesicles and further into the prostate gland. Mature eukaryotes “wait in the wings” in the epididymis, however, they also have a limited functioning time - a little less than a month. After the sperm mature, they begin to age and then die.

Since sperm have a rather long period of development, in order to conceive healthy offspring, a man is recommended to lead the healthiest lifestyle possible for at least three months before the intended sexual intercourse. Such a long period of spermatogenesis, during which eukaryotes mature, is more than compensated by the productivity of the male body. In a minute, the body of an adult healthy man produces about 50 thousand sperm, in a day - 2.5 million, and in a month he produces a total of about 72 million germ cells.

Main stages of development

The sperm maturation cycle is extremely complex. It is subject to several biological processes and is called spermatogenesis. At its core, sperm maturation is the process of development of male germ cells, which occurs according to strict hormonal as well as genetic regulations and is regulated by a time frame.

Sperm maturation occurs in 5 stages.

The process that all full-fledged germ cells undergo includes several stages. At the first stage, the process of renewal and commitment of spermatogonial elements occurs. In the second stage, proliferation and apoptosis can be observed. The third stage is characterized by differentiation and meiosis. The final two stages are repair and regeneration of sperm. The key essence of sperm maturation is the formation of a significant number of cells capable of transmitting genetic information.

Spermatozoa in the process of maturation go through a number of stages that are qualitatively different from one another. These stages include:

  • Primary germ cell.
  • Gonocyte
  • Spermatogonial stem cell.
  • Pregenitor spermatogonial cell.
  • Differentiating spermatogonia.
  • Meiocyte.
  • Spermatid.
  • Mature sperm.

Each of these periods is extremely important, because a failure in any of them can lead to the development of a defective cell. In most cases, such germ cells die either at one of the stages of maturation without completing it, or are non-viable, weak in the fight for the egg.

Transformation of male germ cells

The process of sperm formation begins with the division of stem cells called spermatogonia. Following them, subsequent cells divide by meiosis. Sexual eukaryotes divide in geometric progression, as a result of which, when they reach sixteen cells, they are qualitatively transformed. Scientists designated each type with the letter A and special symbols to conveniently indicate the stage at which maturing sperm are now located. But the stages of maturation of reproductive cells in men are indicated by Roman symbols. In each of the subsequent stages, a set of cells is formed that have common characteristics and functions. Let us briefly describe the stages of maturation of sexual eukarytes:

  • Stage I-III - at this time four generations of future sperm mature, the stage ends with the formation of immature spermatids. This cycle lasts 16 days. It is worth noting that it is in this cycle that the future sperm is most vulnerable to external and internal factors. During complex processes, chromosomes shorten and thicken, the nucleolus disappears, and the nuclear membrane dissolves. Cell growth stops, and the genetic system reaches its highest degree of condensation.
  • Stage IV-VIII - five more generations of germ cells mature, which ultimately ends with the formation of sperm. This period consists of 70 days. During this period, the structure of the cell nucleus changes, chromatin condenses and the genome gradually turns off, acrosomes are formed, and sperm shed the bulk of the cytoplasm.


At these stages of maturation, eukaryotes of the usual appearance are formed - with a rounded head and tail, completely viable for participation in fertilization.

Process results

Man is one of the few living creatures in which sperm formation occurs with enviable consistency. However, human sperm are the least effective in terms of fertilization, because 75 percent of the resulting germ cells eventually age and die, and more than half carry defects that prevent them from actively and successfully participating in the fertilization process. Scientists have calculated that only 12 percent of mature eukaryotes are good candidates for the fertilization process. As a man ages, the number of such sperm constantly decreases, which is due to a decrease in Sertoli cells - specific somatic cells that are involved in the regulation of spermatogenesis, in particular, they “recycle” dead germ cells. It is also interesting to note that over the past fifty years the number of healthy representatives has halved, so every twentieth European suffers from infertility.

Staying in the ejaculate

Once the germ cells have matured, they are transferred through the vas deferens into the sperm. Sperm matures in approximately 14 days - this is how long sperm travel to the ejaculate.

While in the ejaculate, male reproductive cells are little active. The sperm flagella move as little as possible to conserve energy. Since such movements are not productive, muscles that perform wave-like peristaltic movements help them move along the seminiferous tubules and vas deferens. Small cilia located on the walls of the ducts also contribute to movement. Without the help of muscles and cilia, the sperm would not be able to quickly reach the ejaculate.

Sperm provides sperm with a protective function.

Prostatic juice, rich in beneficial enzymes, gives activity to mature eukaryotes. During sexual intercourse, up to 6 mg of sperm is released from the vas deferens, which is equal to approximately two teaspoons. The amount of sperm depends on how many days there has been no sexual intercourse. As a rule, the amount of sperm after prolonged abstinence is greater. During one full sexual intercourse, quite a lot of germ cells enter the vagina - about five hundred million mature sperm, which are potentially capable of fertilizing an egg.

Since even mature eukaryotes are not protected from negative external influences, they are deeply immersed in the product of the gonads - sperm. It is sperm that provides mature sperm with protection from the unfriendly acidic environment of the vagina, in which a significant portion of sperm die.

Only the most viable individuals, having a good supply of energy and nutrients to complete fertilization, move forward.

As we can see, the process of spermatogenesis is a rather complex multi-stage period, as a result of which a man matures full-fledged sperm capable of fertilization and transmission of genetic information.


More than four hundred years ago, the famous scientist Leeuwenhoek discovered spermatozoa in the composition. Doctors for a long time believed that they were a type of pathological microscopic organisms, until their role in the fertilization processes was proven. Since then, the attention of all scientists has been constantly focused on these amazing cells, because it is they that give rise to a new life.

In the article we will consider the time of sperm maturation.

Lifelong process

The process of sperm maturation occurs in men throughout their lives. Before the start of sexual development, its quantity is very small, and then sperm is actively produced throughout the sexually mature period. At approximately six years of age, the testes can begin to produce spermatogonia, and spermatogenesis can fully stabilize only by the age of fifteen. In old age, the male body produces very little sperm, however, this process itself does not stop. We will talk about the features of this process further, and also find out what the sequence of formation of this biological substance is and get acquainted with the stages of sperm maturation.

General information about sperm and sperm

About three percent of the total volume of all semen is exclusively sperm. They are usually released along with sperm during each ejaculation. One ejaculation can contain about 80 million mature sex cells, with the highest concentration in the first portion of ejaculates. The main role of sperm is to act as a nutrient medium during sperm maturation. For these purposes, it contains a whole host of different useful substances. We are talking about ascorbic and lactic acid, fructose, vitamin B12 and so on.

Not everyone knows how long it takes for sperm to mature. It is extremely important for the male body that this process is fully ensured, since they are the ones who carry genetic information about the future baby. These elements are one of the most specific cells, since in a number of their characteristics they are in no way similar to other eukaryotes, for example, it is worth noting the following:

  • All sperm have special organelles.
  • Such cells can move independently.
  • They have half the set of chromosomes.

Such features make sperm absolutely unique eukaryotes, living according to their own laws. And, despite the fact that they differ from somatic cells, they still obey the processes that occur in the body. For example, sperm are best matured at a temperature of thirty-four degrees, which is different from other eukaryotes. We will tell you below how long it takes for sperm to mature in men.

True, like all other cells of the body, the reproductive cells are also subject to the negative effects of external factors such as alcoholism, smoking, drug use, a man suffering from severe infectious pathologies, and so on.

Features of the education process

The maturation of sperm in the male body has been an extremely poorly studied process for a long time. Now scientists have a chance to fully imagine the transformation of germ cells into full-fledged carriers of genetic information and participants in the fertilization process. This provides an opportunity not only to understand and treat infertility in men, but also allows one to intervene in the mystery of conception in the event that one of the couple suffers from pathologies and procreation is impossible in a natural way. It is worth noting that alcohol consumption has an extremely negative effect on sperm.

It takes almost three months for sperm to fully mature for conception in men. During this period, sperm go through their development cycle in the testicles (seventy-two days) and in the appendages (twelve days). Only after this can they move towards the seminal vesicles, and then into the prostate gland. Mature eukaryotes, one might say, wait in the wings directly in the epididymis, however, they also have a limited functioning time, which is equal to a period of slightly less than a month. Following the maturation of the sperm, they begin to age, after which they immediately die.

Since sperm have a rather long period of development, in order to conceive healthy offspring, men are recommended to lead the healthiest lifestyle possible for at least three months before the start of the intended intimate act. Such a long period of spermatogenesis, during which the maturation of eukaryotes occurs, is more than compensated by the productivity of the male body. In just one minute, the body of a healthy adult man produces about fifty thousand sperm, and two and a half million in a day. And in one month, approximately seventy-two million germ cells appear. This is the period of sperm maturation.

Main stages

It is worth noting that the sperm maturation cycle in men is extremely complex. It is subject to several biological processes and is called spermatogenesis. At its core, the processes of sperm maturation are a period of development of sexual elements in men, which occurs according to strict hormonal and, in addition, genetic instructions that are regulated by time frames. Typically, the maturation of these male cells occurs in five stages.

At the first stage, the procedure of commitment of the spermatogonial element and renewal occurs. In the second, apoptosis with proliferation can be observed. The third stage of the sperm maturation process is usually characterized by meiosis and differentiation. The final two periods are repair and regeneration of sperm. The key essence of the maturation of male cells is the formation of a significant number of elements capable of transmitting genetic information.

Sequence of sperm maturation

Spermatozoa go through a certain sequence of stages that are qualitatively different from one another. These include:

  • Stage of maturation of primary germ cells.
  • Gonocyte stage.
  • Stage of spermatogonial stem cells.
  • Pregenitor spermatogonial cells.
  • Stage of differentiating spermatogonia.
  • Meiocyte stage.
  • Spermatid.
  • Maturation of mature sperm.

It is worth noting that absolutely each of these periods is extremely important, because a failure in any of them can lead to the development of defective cells. In most situations, such sexual units die either at one of the stages of their maturation without completing it, or act as non-viable elements, and at the same time weak in the fight for the egg. Now let's talk about the processes of sperm transformation and the time of sperm maturation.

The process of transformation of male sex cells and timing

The process of sperm formation usually begins with the division of stem cells called spermatogonia. Following them, subsequent elements are divided through meiosis. Sexual eukaryotes multiply exponentially, as a result of which, when the number reaches sixteen cells, they are qualitatively transformed. Each species is designated by scientists with the letter “A” and certain symbols in order to conveniently indicate the stage at which the maturing cells are located. And the timing of sperm maturation is indicated by Roman symbols. In each of the subsequent stages, a cellular aggregate is formed that has common characteristics and functions. It is worth briefly describing the stages of sperm maturation:

  • The period from the first to the third stage is the time of maturation of four generations of future sperm. This stage, as a rule, ends with the formation of immature spermatids. This cycle lasts sixteen days. It is worth emphasizing that it is during this period that the future sperm is most vulnerable to internal and external factors. During a complex process, the chromosomes are shortened and also thickened, the nucleus disappears, and at the same time its shell dissolves. Cell growth is inhibited, and the genetic system reaches the highest degree of condensation.
  • Starting from the fourth to eighth stages, five more generations of germ cells mature, which ultimately culminates in the formation of sperm. This period consists of seventy days. During this period, the structure of the cell nucleus changes, and, in addition, the genome gradually turns off and chromatin condenses, acrosomes are formed, and the sperm sheds the main part of the cytoplasm.

At the described stages of maturation, eukaryotes of the usual appearance are formed, which looks like a body with a rounded head and tail, completely viable for taking part in fertilization.

Now we know how long it takes for sperm to mature.

Process results

Man is one of the few living creatures in which sperm formation occurs with regular and enviable consistency. True, sperm in humans is the least effective in the matter of fertilization, since seventy-five percent of the resulting germ cells ultimately die and age, and more than half carry a defect that does not allow them to actively and successfully take part in the fertilization processes. Scientists have calculated that only twelve percent of mature eukaryotes are good candidates for fertilization processes.

With age, in men, the number of such spermatozoa constantly decreases, which is due to a decrease in Sertoli cells - these are specific somatic elements that participate in the regulation of spermatogenesis, in particular, they process dead reproductive structures. It is also interesting to note that over the past sixty years the number of healthy representatives has become exactly half as much, and therefore every twentieth European may suffer from infertility.

Staying in the ejaculate

After the germ cell has matured, it is transferred through the vas deferens directly into the sperm. Sperm usually matures in approximately fourteen days. It is worth noting that this is exactly how much it takes for sperm to travel to the ejaculate.

While in the ejaculate, male reproductive cells are little active. The sperm flagella move very weakly, as much as possible in order to conserve energy. Since such movements are not productive, muscles that perform a wave-like peristaltic movement help them move along the seminiferous tubules and vas deferens. Small cilia located on the walls of the ducts also contribute to movement. Without the help of cilia and muscles, the sperm would not be able to quickly reach the ejaculate. Sperm provides sperm with a protective function.

The activity of all mature eukaryotes is usually imparted by prostatic juice, rich in beneficial enzymes. During sexual intercourse, up to 6 milligrams of sperm are released, which is equal to approximately two spoons. The amount of sperm directly depends on how many days there has been no intimate contact. As a rule, the volume of sperm after prolonged abstinence is greater. During one sexual contact, quite a lot of germ cells penetrate into the vagina, namely about six hundred million mature sperm, potentially capable of fertilizing an egg.

Since even mature eukaryotes are not protected from negative external influences, they dive very deeply into the products of the gonads, that is, into sperm. It is this substance that provides mature male cells with protection from the extremely unfriendly acidic environment in the vagina, in which a significant proportion of sperm, one way or another, die.

Only the most viable individuals, which have good reserves of energy and nutritional components to complete the necessary fertilization, move forward. Thus, the process of spermatogenesis is a rather complex multi-stage period, as a result of which full-fledged sperm mature in men, which are capable of fertilization and transmission of the necessary genetic information.

How does it all end?

When the period of sperm maturation ends, the cells enter the appendages, where they must finally form, and then wait their turn during ejaculation. The epididymis plays a very important role in the formation of full-fledged male cells. They are some kind of tubules that are collected in the form of a tourniquet above the surface of the testicles. They secrete fluid, which allows the male reproductive cells to actively move. However, when sperm enter the appendages, they are not yet able to actively move in a certain direction, but only move in a circle. For them to start swimming, at least twelve days must pass. During this period, the sperm gradually pass through the canals of the appendages, where they are completely saturated with the nutrient medium, further maturing and acquiring the ability to move correctly.

Mature male sex cells in sperm do not always have an ideal structure. In some of them, various deformations can be detected in the form of an uneven head, and at the same time an incorrect position of the tail or chaotic movement. True, this is not at all a significant deviation from the norm. It is believed that fifty percent of sperm are formed with various types of abnormalities, but this does not at all interfere with the full fertilization of the egg, and the differences and distinctive shape of the head do not affect the genetic information contained in it. This deformation is explained by the fact that at the final stage of ripening the head fits extremely tightly to the Sertoli.

Conclusion

Thus, concluding the topic, it is worth summarizing that the maturation period of sperm is seventy-four days, and then continues in the appendages for twelve days. It is very difficult to answer how many days this process lasts in general. On average, the process of full maturation of sperm, and therefore the renewal of male fluid, takes about three months. Mature sperm tend to accumulate in the epididymis. If there is no release within one month, then they begin to age and deteriorate very quickly, and the resulting proteins and other components are simply absorbed by the testicles. Spermatozoa that carry the “Y” chromosome are called androspermia, and those with the “X” element are called gynospermia. The possibility of one or another sperm penetrating a woman’s egg is almost the same, which means that it is simply impossible to predict in advance which of them will reach their goal first.

We looked at the duration of sperm maturation.

A man’s ability to conceive is determined by three points: the formation of sperm and their maturation, movement and ability to penetrate.

Spermatogenesis is the scientific name for the development process of male cells. It is one of the most important factors in male fertility.

    How is sperm produced?

    The generation of germ cells occurs in the male body from the beginning of puberty to the end of life. For this reason, men are capable of all my life, unlike women.

    Where and how is sperm formed?

    Sperm are formed in the testicles, which are filled with seminiferous tubules. It is here that they are produced in huge quantities without breaks or weekends. Sperm maturation consists of the following stages:

    • reproduction;
    • growth;
    • maturation;
    • formation.


    The inner surface of the seminiferous tubules is represented by 2 parts: luminal and adluminal. The luminal part contains Sertoli cells and spermatogonia (male germ cells from which the seminal filaments are formed), primary and secondary spermatocytes and spermatids.
    Spermatogonia go through several stages of mitotic division. They are divided into 2 types: A and B. Total spermatogonia There are approximately 1 billion in one testicle. Some type A cells are divided by mitosis and ensure a constant number of spermatogonia, while the other part turns into type B cells, which also divide by mitosis, but then transform into primary spermatocytes and enter into division by meiosis.

    After the first division, 2 secondary spermatocytes are obtained containing haploid set chromosomes, and after the second division 4 spermatids with the same chromosome set are formed.

    It is precisely this set of chromosomes (haploid or 23 chromosomes) that is needed so that when a sperm unites with a 23 pairs of chromosomes(diploid set).

    Then the spermatids change shape: first they become round, then elongated, and the head and tail of the future sperm are formed. This process is called spermiogenesis.

    And also during this period, an acrosome is formed in the area of ​​the head of the future sperm, which contains special enzymes designed to dissolve the membrane so that the sperm can penetrate it.

    After spermiogenesis, through the testicular network, spermatozoa with fluid flow enter the epididymis, They travel this path in a week and already there the survivors are waiting in the wings. If a man does not have sex, then the accumulation of sperm occurs in the area of ​​the tail of the epididymis, where they exist for several more weeks. If during this time the “old” sperm do not ejaculate, then they are destroyed, this process is called phagocytosis.

    How long does it take for sperm to mature?

    Ripening period spermatozoa about 70–74 days. During this time, the sperm are completely renewed, and the formed sperm are “stored” in the man’s body for about 1 month.

    Outside the body, sperm can survive up to a day, taking into account external conditions. When sperm enters the vagina, it lasts only a few hours, since the vagina has an acidic environment, not an alkaline one, but after passing through all the barriers and reaching the cervix, it can last up to a week.

    How many sperm are produced in the male body?

    In a healthy man, with regular sexual intercourse, daily be formed about 250 million sperm. But of these, only 12% are suitable, since 75% die, and 50% of the survivors usually have defects.

    Spermatogenesis is controlled gonadotropic hormones, produced by the pituitary gland, and steroid hormones produced by the testicles.

    The level of hormones produced in the male body is almost constant. The body of a healthy adult male produces an average of 2–5 ml of sperm during ejaculation. 1 ml can contain from 15 to 120 million sperm.

    NOTE! An hour after ejaculation occurs, the amount of sperm in the male body is restored by 70%, and by 100% in 3 days.

    Factors influencing the process of sperm formation

    In order to stimulate the recovery process, it is necessary to take into account factors that can negatively affect spermatogenesis. These factors can be divided into external and internal.

    External factors, affecting spermatogenesis:

    Internal factors are various endocrine disorders, renal or liver failure, inguinal hernias and some other diseases.

    REFERENCE! If there is not enough vitamin E in a man’s food, it can happen, and if there is not enough vitamin C, it can happen. If more than 20% of sperm are affected by such processes, then infertility will occur. And a lack of vitamin B disrupts the process of spermatogenesis itself.

    Useful video

    Development of male germ cells - spermatogenesis

    What's happening all over the world today noticeable decrease in male fertility. At the moment, almost half of the cases of the absence of children in a married couple are the result of male infertility. This is why maintaining reproductive health is so important. And for this it is necessary to take into account the factors influencing spermatogenesis.

Spermatogenesis cycle involves the division of the original stem cells (spermatogonia) to form subsequent cell types, germ cells, through meiosis. Divisions of type A spermatogonia take less time than the entire spermatogenesis cycle, therefore, at each moment of time, spermatogonia located at different stages of the cycle coexist in the spermatogenic epithelium. In humans, spermatocyte maturation takes 25.3 days, spermiogenesis takes 21.6 days, and the total duration of spermatogenesis is 74 days. The distribution of waves of spermatogenesis along the spermatogenic epithelium is not chaotic. Spermatogenic cells are located in the tubules in separate blocks, in which all cells are at the same stage of the cycle and which represent associations of spermatogenic cells at different stages of development. In rats, only one stage can be detected in a transverse section of the seminiferous tubule.

The criteria that distinguish the stages include the degree of severity acrosomes, meiotic division phase and nuclear shape, release of sperm into the lumen of the seminiferous tubule. Stages are designated by Roman numerals. Each cell type at one stage during development is morphologically integrated with the others. At each stage, certain morphological units of developing spermatids can be distinguished, called stages, which are designated by Arabic numerals. Several stages together form a stage, and several stages involve the transformation of immature stem cells into mature sperm. On each individual cross section of the seminiferous tubule, four to five layers of spermatogenic cells can be seen. The cells of each layer form a generation - a set of cells that develop synchronously and are characterized by similar structure and functions.

At stages I-III There are four generations: type A spermatogonia, two generations of primary spermatocytes and immature spermatids. At stages IV-VIII, five generations are distinguished: type A spermatogonia, one generation of primary spermatocytes, one generation of secondary spermatocytes, one generation of spermatids.

Spermatogenesis cycle can be isolated in all types of living organisms, but the duration of this cycle varies among different species. The stages of spermatogenesis are sequentially distributed along the tubule. This distribution of stages leads to the formation of so-called waves of spermatogenesis along the seminiferous tubule. These waves exist in space, while the cycle exists in time. Along the entire length of the seminiferous tubule, there are only a few sections in which released sperm are visible. In rats, all stages are involved in spermatogenesis, but sperm are released only at stage VIII.

Despite the apparent absence or poverty of spatial organizations in human seminiferous tubules, mathematical modeling has shown that the stages of spermatogenesis are tightly organized into a complex helical structure. In addition to the stages organized spatially in the seminiferous tubule, the stages are organized temporally. In other words, the place occupied in the tubule by stage I cells will then belong to stage II cells, then stage III, and then the cycle will repeat. In humans, the cycle length is 16 days, and the transition from spermatogonia to sperm takes 70 days, or 4.5 cycles.

In the process, cytoplasmic bridges connect cohorts of spermatogenic cells that are at the same stage of development, due to which these cells develop synchronously. Groups of these cells at various stages can be seen in transverse histological sections, and often cohorts of germ cells are seen in association only with certain germ cells belonging to other cohorts. In humans, six stages of development of the seminiferous tubule epithelium have been described. The stages of the spermatogenesis cycle within the space of the seminiferous tubules are also specifically organized, forming waves of spermatogenesis. In humans, the wave of spermatogenesis is characterized by a spiral arrangement of cells along the tubule.
This spatial arrangement appears to serve to ensure continuous (rather than pulsed) sperm production.

Efficiency of spermatogenesis in humans

Efficiency of spermatogenesis varies among species, but appears to be relatively constant in humans. Differentiation of spermatogonia into mature sperm takes 70±4 days. Compared to the animal world, human spermatogenesis is less efficient. The daily production of sperm in humans is 3-4 million per 1 g of testicular tissue. According to WHO criteria, the number of sperm in 1 ml of ejaculate should exceed 20 million. Most of the resulting cells (more than 75%) die as a result of apoptosis or degeneration; of the remaining, more than half are defective. Thus, only about 12% of sperm are potentially suitable for fertilization. In addition, sperm production decreases with age, which is associated with the loss of Sertoli cells.

The reasons for this reduction- an increase in degenerative disorders of germ cells during meiotic prophase or loss of primary spermatocytes, as well as a decrease in the number of Leydig cells, non-Leydig interstitial cells, myoid cells and Sertoli cells.


Release process spermatozoa and their transport through the vas deferens of the testicle to where they will be included in the ejaculate takes another 10-14 days. Due to the sufficient duration of this process, qualitative disturbances in sperm production can be revealed when analyzing the ejaculate only after a certain time. The nucleus gradually takes on an elongated shape as its chromatin condenses. The head takes on the shape of a flat, pointed blade, specific to each species. This process is divided into Golgi phase, cap phase, acrosomal phase and maturation phase.

Golgi apparatus phase. The Golgi complex forms a cap-shaped structure called an acrosome. Centrioles move from the cytoplasm to the base of the nucleus. The proximal centriole becomes the implantation apparatus by which the flagellum attaches to the nucleus. The distal centriole becomes an axoneme.

Cap phase. The acrosome forms a clearly visible cap above the nucleus. The Golgi complex is involved in the formation of the acrosome. As the Golgi complex moves away from the nucleus, the flagellum is assembled.

Acrosomal phase. The formation of an acrosome begins with the fusion of a group of granules of the Golgi complex, which moves and comes into contact with the nuclear membrane, resulting in a cap covering 30 to 50% of the surface of the nucleus. The acrosome covers the nucleus and contains hydrolytic enzymes necessary for fertilization of the egg. A cuff is formed and the spermatids are immersed in the Sertoli cells.

Maturation phase. Mitochondria migrate to the growing tail region to form the mitochondrial envelope. The assembly of the tail is completed after the formation of dense outer fibers and a fibrous sheath. Part of the spermatid cytoplasm is ultimately discarded as a residual body. Now the spermatid is called a spermatozoon. The spermatid moves to the lumen of the seminiferous tubule. After completion of spermatid elongation, the cytoplasm of the Sertoli cells envelops the developing germ cell, removing all unnecessary cytoplasm from it and pushing it into the lumen of the tubule. After such extrusion, mature sperm are characterized by an extremely small volume of cytoplasm. Mature sperm are complex, highly specialized cells that are produced in significant quantities (up to 300 per 1 g of testicular mass per second).

Sperm maturation is a complex process through which male reproductive cells not only acquire their final form, but also learn to move, which is especially important for conception. From the moment of puberty, sperm are produced constantly and in large quantities, which provides a man with the ability to fertilize at any age.

Spermatogenesis

Sperm are produced in the seminiferous tubules of the testicles. They are very long and have a convoluted shape. The average length of each seminiferous tubule is 70 cm. These formations occupy approximately 90% of the mass of the testicles. Sperm matures within 74 days at a temperature of 34 degrees.

To maintain the required temperature, the scrotum and testicles are brought out.

Heat exchange is also regulated by a special choroid plexus system, consisting of an artery and vein of the testis. If a man takes a lot of hot baths often or likes to wear tight underwear every day, this can negatively affect sperm and even lead to infertility.

The entire process of sperm formation is divided into the following stages:

  • Proliferation.
  • Meiosis.
  • Spermiogenesis.
  • Formation.

In the area of ​​the inner wall of the seminiferous tubules there are spermatogonia, which are the very first cells of spermatogenesis, and Sertoli cells that secrete nutrients. During the process of proliferation, active reproduction of spermatogonia occurs, and during meiosis, their division occurs. Spermatogonia initially contain a double set of chromosomes, but during division it becomes single and such cells are called spermatids. Thanks to this, the fusion of male and female germ cells produces an embryo with a full set of chromosomes. During spermiogenesis, the final formation of a mature germ cell from spermatids occurs. In this case, the cell nucleus is transformed into the head of the sperm, and the membrane and cytoplasm become the tail and neck. A complete spermatozoon includes the following parts:

  • Head.
  • Sheik.
  • Body.
  • Tail.

The head consists of a nucleus that carries genetic information, an acrosome that secretes special substances to dissolve the egg shell, and a centrosome that regulates the movement of the tail. The neck allows the head to make small movements, and the body contains an axial filament, which ensures the movements of the tail, and mitochondria, which are responsible for providing spermatids with energy. The tail contains fibrils, which, thanks to the rotational movement, allow sperm to actively move in a certain direction.

Sperm formation is a complex process.

How will it all end?

When the process of spermiogenesis is completed, the mature sperm enters the epididymis, where it must finally mature and await its turn during ejaculation. The epididymis plays an important role in the formation of full-fledged sperm. They are tubules collected in the form of a tourniquet above the testicles. They secrete fluid, which allows male reproductive cells to actively move. However, when sperm enter the appendages, they do not yet know how to actively move in a certain direction, but move in a circle. It takes 12 days for them to “learn” to swim. During this period, the sperm gradually move through the canals of the appendages, where they are saturated with the nutrient medium, fully mature and acquire the ability to move correctly.

Thus, the period of sperm maturation is 74 days, and then continues in the epididymis for 12 days. It is difficult to answer how many days this process lasts in general. On average, complete sperm maturation, and therefore sperm renewal, lasts about 3 months. Mature sperm accumulate in the epididymis. If sperm are not released within a month, they begin to quickly age and break down, and the resulting proteins and other components are absorbed by the testicles. Spermatozoa that carry the Y chromosome are called androspermia, and the X chromosome is called gynospermia. The probability of one or another sperm penetrating the egg is almost equal, which means that it is impossible to predict in advance which of them will reach their goal first.

On average, sperm maturation lasts about three months.

Mature germ cells in men's sperm do not always have an ideal structure. In some of them, various deformations can be found in the form of an uneven shape of the head, incorrect position of the tail, or chaotic movement. However, this is not a significant pathology. It is believed that 50% of the sperm in the sperm may have various types of abnormalities, but this will not interfere with the full fertilization of the egg, and a change in the shape of the head does not affect the genetic material contained in it. This deformation is explained by the fact that in the final stages of maturation the sperm head fits very tightly to the Sertoli cells.

Movement of sperm

The movement of sperm along the male genital tract is an important stage in the development of their ability to actively move. The fact is that the passage of sperm through the tubules of the testicles and appendages is carried out due to muscle contraction and the movement of cilia located on the inner surface of the tubules. The mobility of the flagella is insignificant.

During ejaculation, the cells are affected by the secretion of the prostate gland. At the same time, the percentage of sperm in semen is only 5%, the rest is the secretion of the prostate gland and bulbourethral glands. These components are a source of nutrients, a habitat, as well as a means of protection from the effects of chemical components of the female genital tract and means of immunological protection. In addition, seminal fluid contains substances that promote the maturation of sperm. Sperm is released at a speed of 70 km/min.

In order to get to the ampullary section of the fallopian tube, in the area of ​​which fertilization of the egg most often occurs, the sperm in the sperm must overcome a distance of 20 cm. On this way, most of the sperm die. For conception to occur, a significant amount of sperm, approximately 10 million, must enter the uterine cavity.

For successful conception, about 10 million sperm must enter the uterine area.

The extent to which a sperm trapped in sperm is capable of fertilization is determined by the following factors:

  • The presence of a complete nucleus, which is responsible for the transfer of genetic material.
  • The presence of an acrosome, thanks to which the sperm penetrates into the egg.
  • Absence of pathology of the centriole, which is responsible for mitotic divisions during embryo cleavage.

Thus, the formation of sperm is a long and complex process that occurs not only in the testicles, but also in their appendages. They move along the seminiferous tubules in a special nutrient medium, which to a certain extent protects them from negative influences. However, in order not to disrupt the process of sperm formation, you should avoid taking hot baths and wearing tight underwear. You should know that the period of formation of new mature and active sperm is 3 months. This is important to consider if a man planning to procreate has undergone X-rays or taken medications.