Spermatozoa are male reproductive cells, gametes. When they merge with a female egg, fertilization occurs, and a new life begins. It is often necessary to assess the condition of male germ cells, their quantity, quality and mobility in preparation for pregnancy and infertility treatment. But how does their maturation take place and how many spermatozoa are needed for conception?
This is the process of sperm maturation, which goes through several successive stages. The whole process of spermatogenesis takes place in the testicles (testicles), but is controlled by hormones and brain structures, namely the hypothalamus and pituitary gland, which regulate hormone levels and, if necessary, send signals to increase or decrease the concentration of hormones. If there is a decrease in the concentration of testosterone, then the pituitary gland receives the corresponding signal. In response, luteinizing hormone begins to be synthesized, affecting special cells in the testicles. This is how testosterone levels increase. Other hormones distribute it along the seminal tubule (tubules), where sperm precursors are concentrated. Of these, after several successive stages of differentiation, a sperm will turn out – a familiar one from the pictures in the biology textbook “tadpole”. During ejaculation, 39-929 million spermatozoa are released.
Spermatogenesis takes about 72-74 days. In the testicles there is a system of convoluted tubules, which are called seminal tubules: germ cells are located in their walls. Under the influence of hormones, these cells form a head and tail, and from that moment they can penetrate the hemato-testicular barrier. Going out into the lumen of the tubule, they begin their movement into appendages. Spermatozoa accumulate and live here for 4-5 weeks. Almost simultaneously, seminal plasma is released, which is produced by the prostate gland. “Tadpoles” are mixed with it and sperm is obtained.
The composition of sperm
The first component of sperm is spermatozoa. By the way, these are the smallest cells of the human body, but they are capable of a lot – to give new life. There are 23 chromosomes concentrated in the head of these cells, in its structure there is also a neck and a tail, which ensures the movement of the cell. For possible fertilization, about 10 million cells are needed, but in nature everything is thought out, so much more cells are released during ejaculation, because about 80% of them may have defects: two flagella, heads, etc. Such defective cells have no chance of meeting an egg and fertilizing it. Scientists have conducted studies of sperm quality depending on nationality. The data showed that the Scots have the most high-quality and active spermatozoa, the Turks are in second place, followed by Finns, French, etc. The second component of sperm is seminal fluid, plasma. Its benefits and role can hardly be overestimated. Firstly, it is the biochemical protection of male germ cells from the attack of the immunity of a woman’s vagina. Secondly, it is a nutrient medium for cells. If you study the chemical composition, 85-97% of the sperm is water, and the rest is dry residue. This residue is mainly represented by proteins, which are also found here:
- minerals: phosphorus, magnesium, potassium, copper, iron, etc.
Ejaculation and the desire for fertilization
During ejaculation, seminal fluid is ejected at a speed of 70 km/h. Contrary to popular belief, spermatozoa do not run in a crowd towards the egg who is faster, pushing aside rivals. Some of the cells move in a straight direction, others “run” in a circle, others do not move at all. In the process of sperm promotion, not only a given force and speed helps, but also the walls of the uterus, thanks to their contractions, the seminal fluid is directed to the fallopian tubes. After that, the spermatozoa retain high mobility and can overcome 1-4 mm of distance in a minute. It seems that this is an insignificant speed, but the cell size is only 0.055 mm! Still, the forces of sperm are not infinite, and they get tired, then hormones come to the rescue. A surge of progesterone stimulates the cells to move further, they begin to shake their tails and move towards the cherished goal, but you still need to overcome the protective membrane of the cell. As soon as one of them manages to break through, the protein layer is blocked and prevents the penetration of more cells. But if this process is disrupted, then the risk of various mutations leading to the development of Down syndrome, potentially dangerous fatal defects and malformations of the heart, spine and nervous system of the fetus increases.
There are still rumors among the masses concerning spermatogenesis and the state of the male reproductive system. From time to time, new “studies” appear that actually have no scientific justification. One of the most common misconceptions is that tight underwear can reduce the number of active cells. However, no authoritative scientific research has found confirmation of this. In contrast, there is evidence that men who wear underwear-boxers (shorts, family underpants) have a 17% higher sperm count compared to those who prefer to wear swimming trunks. However, a detailed study of this study showed that other factors that could, in one way or another, affect this process were not taken into account. It is known that interrupted sexual intercourse is not the most reliable means of contraception, its reliability is about 60%. And it’s all about the secreted pre-ejaculate, which is released before ejaculation. Despite the fact that this liquid is not intended for depositing cells, it can still contain live and active spermatozoa. One of the studies showed that living cells are contained in more than 15% of pre-ejaculate samples. Therefore, the probability of pregnancy with interrupted sexual intercourse still persists. Men who have become fathers after 50 years and older are admired. There is an opinion that the quality of spermatogenesis does not change with age. However, this is not the case: although sperm is formed in men throughout life, but the quality of seminal fluid deteriorates with age. A number of studies show that with age, the likelihood of developing genetic mutations in the fetus increases, so everything has its time. Including – and even first of all – the planning of the birth of a child.