Function

The main function of spermatozoa is to fuse with the ovum. Sperms are the male gametes that are destined to fertilize the female gamete which is the ovum. By the fusion of these two new offspring is formed that is called a zygote. Then this zygote will be transformed into an embryo which gets implanted into the uterus from where pregnancy starts. Sperms are initially ejaculated into the reproductive tract of females from where it reaches the ovary after breaking many walls and then after some chemical reactions fusion between male and female gamete happens.

Another major function of sperms is the determination of the sex of the child. As we all know that females carry two similar sets of chromosomes i.e., XX whereas males carries two different sets of chromosomes i.e., XY. During the gamete formation due to meiotic division, these diploid chromosomes get divided into haploid gametes. According to the Mendal law of independent assortment, any male gamete can fuse with any female gamete. So, the sex of the child depends only on male gametes i.e., spermatozoa or sperms. If X of male gets to fuse with X of female then the offspring will be XX i.e., girl and if Y of male gets to fuse with X of female then the offspring will be XY i.e., boy.

Sperms also carry chemicals that are used when reactions between sperm and ovary occur. Moreover, sperms also give signals to the ovary through which the ovary recognizes that the sperms if from the same species. For example, the human ovary will recognize the human sperm with the help of these signals, the same goes with any other species like dogs, etc. 

Spermatogenesis is the development of haploid spermatozoa from germ cells of testis in seminiferous tubules. In the basement membrane of the tubules, there are stem cells that divide mitotically to start the procedure of spermatogenesis. Spermatogenesis stem cells is another name for these stem cells. Type A and B are the two cells that are produced by the division of stem cells. One type of cell refills the stem cells i.e., type A and primary spermatocytes are formed by the differentiation of type B cells. The final product of spermatogenesis is the production of haploid spermatids which is obtained by meiotic II division of secondary spermatocytes and this secondary spermatocyte is formed by meiotic I division of primary spermatocyte. One primary spermatocyte gives rise to two secondary spermatocytes and these two secondary spermatocytes give rise to two spermatids each. Through the process of spermiogenesis, the spermatids are transformed into spermatozoa. 

Sperms are basically adult spermatozoa. So, four haploid spermatozoa are produced by a single primary spermatocyte. In most sexually reproducing organisms sperms are the mature male gametes. So, it can be said that oogenesis in females and spermatogenesis in males is the version of gametogenesis in them. In mammals, this process occurs in seminiferous tubules of male testes. Spermatogenesis is a very important process for sexual reproduction and this process occurs under some optimal conditions. These optimal conditions are important to be followed in order to complete this process with full efficiency. In the regulation of this process, there are some implications that are done like histone modifications and DNA methylation. With the increasing age decrease in quality and count of sperms in males can be seen. 

Usually, this process starts with the onset of puberty and endures till death. Lumen is the storage for mature spermatozoa. The starting point of this process is seminiferous tubules. Cells move along tubes until they get mature and reach the lumen. Specifically speaking the bottom part is where the process starts and from there cells move deeper inside tubes and flow in it until they get mature and reach the lumen where they are finally stored. In the tube, there are simultaneously many divisions going on. These stages can be seen after cutting a tube transversely. A spermatogenic wave is known when different maturation stages are seen at the same time.