What is spermatogenesis ? Briefly describe the process of spermatogenesis.
What is spermatogenesis ? Briefly describe the process of spermatogenesis.
Spermatogenesis is the process of formation of mature male gametes, the sperm cells from male germ cells.
(i) The germ cells called spermatogonia are present on the inside wall of the seminiferous tubules.
(ii) These cells are diploid and multiply by mitosis to increase in number.
(iii) Some of the spermatogonia undergo meiosis, they will be referred to as primary spermatocytes.
(iv) It completes first meiotic division leading to formation of two equal haploid cells called secondary spermatocytes. They have only 23 chromosomes, but they are still duplicate.
(v) Each of the two secondary spermatocytes undergoes second cell division to separate the duplicate chromosomes in two different cells producing four haploid spermatids. Each has one copy of 23 chromosomes.
(vi) Spermatids transform into spermatozoa (sperm cells) by developing a head, neck , middle piece and a tail. This process is called spermiogenesis.
(vii) Sperm heads become embedded in the Sertoli cells.
(viii) Final release of sperm (spermiation) from seminiferous tubules is under the influence of hormonal and physiological factors.
(Remember in meiosis, there are two cell divisions, one after the other. The first one seperates the pairs of chromosomes and the second one separates the duplicate copies. That is why, the result is four cells each having one set of chromosome and one copy of each means unpaired, uncopied chromosome set.)
Summary of spermatogenesis Diploid spermatogonia (germ cells in the seminiferous tubules) →
→ Primary spermatocytes → Meiosis (first division) → Two haploid cells secondary spermatocytes → Second cell division → Four haploid cells
Spermatogenesis is the process of formation of mature male gametes, the sperm cells from male germ cells.
(i) The germ cells called spermatogonia are present on the inside wall of the seminiferous tubules.
(ii) These cells are diploid and multiply by mitosis to increase in number.
(iii) Some of the spermatogonia undergo meiosis, they will be referred to as primary spermatocytes.
(iv) It completes first meiotic division leading to formation of two equal haploid cells called secondary spermatocytes. They have only 23 chromosomes, but they are still duplicate.
(v) Each of the two secondary spermatocytes undergoes second cell division to separate the duplicate chromosomes in two different cells producing four haploid spermatids. Each has one copy of 23 chromosomes.
(vi) Spermatids transform into spermatozoa (sperm cells) by developing a head, neck , middle piece and a tail. This process is called spermiogenesis.
(vii) Sperm heads become embedded in the Sertoli cells.
(viii) Final release of sperm (spermiation) from seminiferous tubules is under the influence of hormonal and physiological factors.
(Remember in meiosis, there are two cell divisions, one after the other. The first one seperates the pairs of chromosomes and the second one separates the duplicate copies. That is why, the result is four cells each having one set of chromosome and one copy of each means unpaired, uncopied chromosome set.)
Summary of spermatogenesis Diploid spermatogonia (germ cells in the seminiferous tubules) →
→ Primary spermatocytes → Meiosis (first division) → Two haploid cells secondary spermatocytes → Second cell division → Four haploid cells
