After the stage of puberty for males, which may occur between nine and fifteen years of age, vital reproductive cells, known as sperm or spermatozoa (spermatozoon, singular), have by then reached maturity. Actually, as described in Black et. al. Medical-Surgical Nursing, these male sex or germ cells resemble the appearance of tadpoles. Also, each of these cells’ structures includes a flattened, broad, and oval head with a nucleus in it. Apart from a spermatozoon’s head, an enlarged view of such would reveal the presence of a mid-piece and a tail.
The human sperm are not capable of typical cellular division, as those performed by the ordinary cells in the body. In order for a male sex or sperm cell to carry out its role and participate to a successful reproductive process, it has to fuse with a female egg cell (known as an oocyte) during fertilization, from which it contributes the genetic material it distinctively possesses with that found in the female sex or egg cell. This fusion leads to the formation of a diploid cell, which gives rise to the human zygote. In turn, such zygote develops eventually to a human embryo.
The process which makes the production and development of the sperm possible is called the spermatogenesis. During such process, the precursor cells of the spermatozoa or the mature male sex cells (which are commonly known as the spermatogonia) divide by mitosis. During this initial phase of division, two products are yielded -- namely the primary spermatocyte and one spermatogonium. Basically, the primary spermatocytes mark the beginning of the typical lineage of mature male sex cells. Consequently, these primordial spermatocytes further divide themselves in a process called meiosis. This then gives rise to the production of secondary spermatocytes. In turn, these secondary spermatocytes again divide to form spermatids. Then finally, upon undergoing a process of differentiation, these spermatids will then become the mature male sex or germ cells.
The average production and development of spermatozoa or mature male sex cells takes place in about seventy four (74) days.