Why do men have sperm? Sperm composition and function

I believe many people are particularly interested in men's sperm. Such a small thing can combine with the egg, overcome many obstacles and finally develop into an embryo, and then let the baby be born smoothly. So, why do men have sperm, and what magical functions does it have?

What is sperm?

Sperm is the mature reproductive cell of males. Not only humans have sperm, but most male mammals can also produce sperm. What does sperm look like? If we make a smear of the semen discharged by men and observe it under an optical microscope, we will see many tadpole-like cells that keep swimming. They are sperm.

The evolution of sperm

It starts with spermatogonia, and then divides and differentiates continuously, passing through primary spermatocytes, secondary spermatocytes, spermatids, and finally forms sperm. Among them, the transformation from primary spermatocytes to secondary spermatocytes requires two mitosis (including one meiotic division), and secondary spermatocytes contain only half of the chromosomes; the transformation from secondary spermatocytes to spermatids also requires one mitosis; spermatids no longer divide, and develop into sperm after the metamorphosis and maturation process.

Sperm structure and function

Sperm consists of three parts: head, body and tail. The sperm head is oval when viewed from the front and flat when viewed from the side. The head is involved in the fertilization process. The sperm nucleus contains only half of the chromosomes of human cells. After combining with the chromosomes in the egg cell, it returns to 23 pairs of chromosomes. The sperm tail is long and curved, and the whip tail swings to make the sperm active. Therefore, sperm is the main cell representing male fertility and is the carrier of genetic information from the father to the offspring. Maintaining the normal function of sperm is the primary task in treating male infertility.