Histology, Spermatogenesis

Excerpt

The union of male and female gametes creates offspring. The production of these vital reproductive cells occurs in the testis and ovary during the processes of spermatogenesis and oogenesis, respectively. The primary male reproductive organs, the testes, are located inside the scrotum and function to produce sperm cells as well as the primary male hormone, testosterone. As mentioned above, spermatogenesis is the process by which sperm cell production occurs; the germ cells give rise to the haploid spermatozoa. Sperm production takes place inside the seminiferous tubules, which is a convoluted cluster of tubes located inside the testes. Testosterone production occurs in cells surrounding the seminiferous tubules, called Leydig cells. After being formed, sperm cells travel outside of the tubules into the epididymis, where they mature and prepare for ejaculation.

The complex process of spermatogenesis occurs in three steps. The first step involves mitotic cell division that allows the early cell stage, spermatogonia, to multiply. The second step requires meiosis, in which the diploid cells form haploid cells. A division occurs until a round spermatid formation occurs. The final stage of spermatogenesis includes spermatozoa production, mature and motile sperm cells, from round spermatids, through a process called spermiogenesis.

Diminished fertility or infertility may result from a decrease in spermatozoa number, alteration in shape, and inefficient motility.

The three steps represent the foundation of spermatogenesis. Functional abnormalities may occur in any one of them, which can cause the entire process to fail. These abnormalities can lead to defective or reduced sperm production. In more severe conditions, a complete absence of spermatozoa can result, leading to infertility. Therefore, we must expand our knowledge of spermatogenesis as a whole to provide essential information regarding the regulatory mechanisms. The testicular environment is complex; therefore, the study of spermatogenesis can be quite tricky in most species. To achieve this understanding, experimental studies completed in rodents and primates are the cornerstone of this crucial knowledge.