permatogenesis is defined as the process of origin and development of male gametes, within the male reproductive organs. Sperms are called as male gametes
Process of Spermatogenesis:
There are two stages in the spermatogenesis
Formation of spermatids
Formation of spermatozoa
Formation of spermatids:
This process completes in three stages namely multiplication phase, growth phase and maturation phase.
Multiplication phase: the germ cells that are present within seminiferous tubule of testes are undivided and called as spermatogonia
From the primary germ cell they undergo mitotic division and proliferate
Spermatogonia contain diploid numbers of chromosomes i.e 2n.
Spermatogonia undergo repeated mitotic divisions and increase in numbers.
Growth phase: some of the spermatogonia stops dividing and increases in size due to accumulation of cytoplasm and nutrients.
Now they are known as primary spermatocytes, they are double in size of spermatogonia.
Remaining spermatogonia continues undergoing mitotic division .
Maturation phase: in this phase primary spermatocytes undergo first meiosis division.
Homologous chromosomes of primary spermatocytes start pairing and split longitudinally.
Crossing over takes place between chromatids and homologous chromosomes
Two Secondary spermatocytes are formed after the first meiotic division
Later on secondary spermatocytes undergo second meiotic division which results in four spermatids. All are haploid.
Formation of spermatozoa:
Now in sertoli cells spermatids lose its cytoplasm and get coveted into sperms
condensation of the nucleus results formation of head and flagellated tail
Final Answer
Hence, process of development of male germ cells in male reproductive organ is call as spermatogenesis
