The shape, function and size of the sperm

Pregnancy in the female body comes as a result of the fusion of two sex cells. One of them is called a spermatozoon, and the other is an egg. What is the size of the sperm? What functions are inherent in the sex cell? What is the difference between a sperm and an egg? The answers to all these questions are to be found.

Male reproductive system

The function of reproduction in the body of a representative of the strong half of mankind is performed by certain glands and organs:

• Testicles with appendages;
• Vas deferens;
• prostate;
• Seminal vesicles;
• Bulbourethral glands;
• scrotum;
• penis.

All of the above is collectively referred to as the male reproductive system. Sperm are formed in it. This term denotes male sex cells capable of fertilization. In unprotected sex, spermatozoa leave the male reproductive system and enter the female body.

Functions of a specialized cell

Sperm is a structure in which the genetic information of a man is enclosed. The functions of a specialized cell of the male body are several:

• Passing on the genital tract of a woman (the size and structure of a person's sperm allow him to overcome various obstacles);
• Penetration into the female germ cell, called the egg;
• Insertion of genetic material into it.

It is worth noting that during intimacy in the body of a woman gets sperm. It consists of seminal fluid and suspended spermatozoa in it. Male germ cells in the semen contains a huge amount. But a mature egg in the female body is just the only one. Only one male germ cell manages to fulfill all its functions. A huge role in this is played by the size and shape of the sperm.

Structure of the sperm: head and neck

The male sexual cell is characterized by a specific form that provides the ability to move, fertilize the egg. The spermatozoon is an oval structure with a long flagellum. What is the structure of this cell? So, the spermatozoon is represented by three components:

• Head;
• Neck;
• Tail.

The head is the oval part of the sperm. At its top is the acrosome. This is the name of a vial with special substances necessary for penetration through the protective shell of the egg. The head also contains a core. It stores a half-set of male genetic information (DNA). Another component of the head is the centrosome. It promotes the movement of the tail.

The second part of the sperm is the neck. It is a fibrous area connecting the head and tail. This structure is very flexible. This feature ensures the movement of the sperm. Due to the flexibility, the head oscillates from side to side.

Structure of the tail of the sperm

Before describing the size of the sperm, it is worth considering its third part - it's a flagella. It is also called the tail. It includes several sections:

1. Intermediate. This is the thickest part of the tail of the sperm. It has a spiral mitochondrial layer that produces energy for the movement of the male sexual cell.
2. Main. This section of the spermatozoon consists of microtubules. They are covered by an outer layer of dense fibers and a protective vagina.
3. Terminal. On this part of the spermatozoon, the protective vagina and dense fibers become thinner. The coating is a thin cell membrane.

Having become acquainted with the structure of the last part of the spermatozoon, it can be concluded that the tail gradually narrows from its base to the end. This feature provides a beating movement of the male sexual cell when moving along the female sexual path in search of the egg.

Sperm sizes

The male germ cell is very small. The size of the sperm is the following:

• The total cell length is about 55 μm;
• Head height - 2.5 microns, width - 3.5 microns, length - 5.0 microns;
• The neck of the spermatozoon is about 4.5 μm in length;
• Length of tail - 45 microns.

Male sex cells can not be seen with the naked eye. The size of the sperm can be seen by increasing the microscope. This was once done by Leeuwenhoek. In 1677 he described the spermatozoa. The scientist, having made the discovery, suggested that these cells are involved in fertilization. However, this information was not taken seriously in the society. Still about 100 years the mankind considered spermatozoons parasitic microorganisms.

Formation of male sex cells

When asked about the size of spermatozoa, the answer is given. Now we should consider how these cells form. Spermatozoa arise and mature in special glands called testes. These structures are located in the scrotum. They contain a huge number of seminiferous tubules lined with special cells (spermatogonia). How do male sex cells form here? This process begins in the period of puberty:

• Spermatogonia are divided;
• As a result, new cells appear;
• Spermatozoa mature due to Sertoli cells, secreting various nutrients.

The process of formation of male sex cells is called spermatogenesis. It is quite complicated. On the formation of primary spermatocytes, the process does not end, because the cells that have appeared are inherent in a complete set of chromosomes. Subsequently, these cells undergo meiosis. As a result, spermatids appear with a half-set of chromosomes. Cells gradually grow and develop. As a result, mature spermatozoa arise.

Movement of male germ cells

Having examined the functions and size of the spermatozoon, you need to know how the sexual cell moves. Spermatozoa that are in the male body are inactive. They passively pass through the sexual path. The movements of the tails are quite insignificant. Activity of spermatozoa is obtained after getting into the female body. Their speed can be more than 30 cm per hour.

After ejaculation, more than 300 million spermatozoa penetrate the woman's body. Most of them die in the vagina because of an unfavorable environment. Some male germ cells can reach the cervical canal. However, this part of the path can not be passed to all spermatozoa. Cervical mucus becomes an obstacle for them .

Sperm that passed through the cervical canal enter the uterus. The environment in this internal organ is favorable for the male sex cells. From the uterus, they are sent to the fallopian tubes, where fertilization takes place. Studies have shown that only a few thousand spermatozoa pass this way.

Lifetime of spermatozoa

Cell formation lasts approximately 74 days. Maturation and their passage through the epididymis and the vas deferens takes about 26 days. The conclusion is that spermatozoa can stay in the male body for a long time. A completely different situation is observed after ejaculation. In sperm, the sex cells remain active for no more than a day (the duration of this period depends on external factors such as ambient temperature, amount of light, humidity).

In the female body, the duration of their life can be different. If the speed of movement is affected by the size of the sperm, the duration of existence does not depend on it. For example, male vaginal cells perish in the vagina in 2 hours. In the uterus and fallopian tubes, the medium is more favorable for spermatozoa. Here they can stay up to 5 days in the active state in search of or waiting for the egg.

Comparison of spermatozoa with oocytes

In the body, men periodically form and mature new sex cells. With each sexual act, sperm is released, which contains a huge number of spermatozoa. But in the body of a woman only one sexual cell ripens during one menstrual cycle (approximately for 28-30 days).

Now it is worth comparing the size of the egg and sperm. The male germ cell, as mentioned above, is a tiny structure. The egg is completely different. Its dimensions can be from 0.15 to 0.25 mm. It is also worth noting that the egg is immobile. In addition, she has a fairly short life expectancy. After exiting the ovary and entering the fallopian tube, it can exist for about 24 hours. If fertilization does not occur, the egg dies.

In conclusion, it should be noted that the size of the spermatozoon is very small. Despite this, it has an important function of fertilizing an egg. However, not all spermatozoa are capable of doing this. Getting into the female body, they undergo natural selection. Weak, irregular cells quickly die, not reaching the uterus. The rest just do not have time to get to the goal. Only the fastest and active spermatozoon, which bypasses all obstacles, penetrates into the found egg and adds its genetic information to it.