Pregnancy in the female body occurs as a result of the fusion of two germ cells. One of them is called a sperm, and the other is called an egg. What is the size of the sperm? What functions are inherent in the germ cell? How is a sperm different from an egg? The answers to all these questions remain to be found.
Male reproductive system
The function of reproduction in the body of a representative of the strong half of humanity is performed by some 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 cells form in it. This term refers to male germ cells capable of fertilization. With unprotected sex, sperm leave the male reproductive system and enter the female body.
Specialized Cell Functions
A sperm is a structure in which a man’s genetic information is contained. The functions of a specialized cell of the male body are several:
- passage through the female genital tract (the size and structure of the human sperm allow him to overcome various obstacles);
- penetration into a female reproductive cell called an egg;
- the introduction of genetic material into it.
It is worth noting that during intimacy, sperm enters the body of a woman. It consists of seminal fluid and sperm suspended in it. Male germ cells in semen contain a huge amount. But a mature egg in the female body is just the only one. Only one male reproductive cell manages to fulfill all its functions. A huge role in this is played by the size and shape of the sperm.
Sperm structure: head and neck
The male reproductive cell is characterized by a specific form that provides the ability to move and fertilize the egg. The sperm is an oval structure with a long flagellum. What is the structure of this cell? So, the sperm is represented by three components:
The head is the oval portion of the sperm. At its top is an acrosome. This is the name of the bubble with special substances necessary for penetration through the protective membrane 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 tail movement.
The second part of the sperm is the neck. It is a fibrous region connecting the head and tail. This structure is very flexible. This feature provides sperm movement. Thanks to its flexibility, the head oscillates from side to side.
The structure of the tail of the sperm
Before describing the size of the sperm, it is worth considering its third part - this is the flagellum. It is also called the tail. It includes several sites:
- Intermediate. This is the thickest part of the tail of the sperm. It has a spiral mitochondrial layer, which produces energy for the movement of the male reproductive cell.
- Main. This sperm site consists of microtubules. They are covered by the outer layer of dense fibers and a protective vagina.
- Terminal. On this part of the sperm, the protective vagina and dense fibers are thinned. The coating is a thin cell membrane.
Having become acquainted with the structure of the last part of the sperm, we can conclude that the tail is gradually narrowing from its base to the end. This feature provides the bichoid movements of the male reproductive cell when moving along the female genital tract in search of an egg.
Sperm size
The male reproductive cell is very small. The human sperm size is as follows:
- total cell length - about 55 microns;
- head height - 2.5 microns, width - 3.5 microns, length - 5.0 microns;
- sperm neck - about 4.5 microns in length;
- tail length - 45 microns.
Male reproductive cells cannot be seen with the naked eye. Sperm size can be viewed under an enlarged microscope. This was once done by Levenguk. In 1677, he described sperm. The scientist, having made a discovery, suggested that these cells are involved in fertilization. However, this information was not taken seriously in society. For about 100 years, humanity considered sperm to be parasitic microorganisms.
Male germ cell formation
To the question regarding what size of sperm, the answer is given. Now it’s worth considering how these cells form. Sperm cells arise and mature in special glands called testicles. These structures are located in the scrotum. They contain a huge number of seminiferous tubules lined with special cells (spermatogonia). How are male germ cells formed here? This process begins during puberty:
- spermatogonia are divided;
- as a result, new cells appear;
- spermatozoa mature due to Sertoli cells secreting various nutrients.
The formation of male germ cells is called spermatogenesis. It is quite complicated. The process does not end on the formation of primary spermatocytes, because a full set of chromosomes is inherent in the appearing cells. These cells are subsequently subjected to meiosis. As a result, spermatids with a half set of chromosomes appear. Cells gradually grow and develop. As a result, mature sperm cells appear.
Male germ cells movement
Having examined the function and size of the sperm, you need to familiarize yourself with how the germ cell moves. Sperm in the male body are inactive. They passively move through the genital tract. Tail movements are completely insignificant. Sperm gain activity after entering the female body. Their speed can be more than 30 cm per hour.
After ejaculation, more than 300 million sperm enter the body of a woman. Most of them die in the vagina due to the adverse environment. Some male reproductive cells manage to reach the cervical canal. However, this section of the path does not work out for all sperm. An obstacle for them is cervical mucus.
Sperm that have passed through the cervical canal enter the uterus. The environment in this internal organ is favorable for male germ cells. From the uterus, they are sent to the fallopian tubes, where fertilization takes place. Studies have shown that only a few thousand sperm go this way.
Sperm life span
Cell formation lasts approximately 74 days. Maturation and their passage through the epididymis and vas deferens takes about 26 days. The conclusion is that sperm can stay in the male body for a long time. A completely different situation is observed after ejaculation. In sperm, 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, their life expectancy can be different. If the speed of movement is affected by the size of the sperm, then the duration of existence does not depend on this. For example, in the vagina, male sex cells die in 2 hours. In the uterus and fallopian tubes, the medium is more favorable for sperm. Here they can be up to 5 days in an active state in search of or waiting for an egg.
Comparison of sperm with egg
In the body, men periodically form and mature new germ cells. At each sexual intercourse, sperm is released containing a huge amount of sperm. But in the body of a woman, only one reproductive cell matures in one menstrual cycle (in about 28-30 days).
Now it is worth comparing the size of the egg and sperm. The male reproductive cell, as mentioned above, is a tiny structure. The egg is completely different. Its dimensions can range from 0.15 to 0.25 mm. It is also worth noting that the egg is motionless. In addition, she has a rather short lifespan. After exiting the ovary and entering the fallopian tube, it can exist for about 24 hours. If fertilization does not occur, then the egg dies.
In conclusion, it is worth noting that the size of the sperm is very small. Despite this, it has an important function, which is to fertilize the egg. However, far from all sperm can do this. Once in the female body, they undergo natural selection. Weak cells with an irregular structure die very quickly without reaching the uterus. The rest just do not have time to get to the goal. Only the fastest and most active sperm, bypassing all obstacles, penetrates the found egg and adds its genetic information to it.