Spermatocytogenesis, Biology

Assignment Help:

SPERMATOCYTOGENESIS

In this process four spermatid develop from one PGC.

(i) Multiplication phase

  1. The spermotogonia or sperm mother cells lie next to the basement membrane.
  2. These divide repeatedly by mitosis producing new sex cells.
  3. Some of these cells move towards the lumen of the seminiferous tubule and enter the growth phase.
  4. These are called primary spermatocytes while others produced by the mitotic division of spermatogonia remain in the original condition and continue to produce new spermatogonia throughout the reproductive life of the animal.

(ii) Growth phase

  1. The spermatogonia, formed as a result of repeated divisions of the primordial germ cells, stop dividing and prepare themselves for maturation division.
  2. They increase in size by accumulating nourishing material obtained from germinal cells.
  3. The enlarged cells are known as primary spermatocytes.
  4. Initially, the nucleus of each primary spermatocyte is of ordinary size, but soot it imbides material and enlarges considerably.
  5. At the end of growth phase, when the primary spermatocyte is ready to undergo first maturation division (i.e. the reduction division) its nucleus is much larger than that spermatogonial cell.

(iii) Maturation phase

  1. Each diploid primary spermatocyte undergoes the first maturation division which is a reduction division, with its long drawn out and complicated prophase.
  2. The pairing and spliting of homologons chromosomes take place during zygotene and pachytene and this leads to the formation of tetrads. Due to crossing over, the exchange of homologus chromosomes also take place.
  3. According to some, all these chromosomal events are completed in the growth phase only, so that during first maturation division the chromosomes are equally distributed to the two daughter cells.
  4. As a result of reduction division, the two cells formed are haploid. These haploid cells are called secondary spermatocytes.
  5. The secondary spermatocytes undergo second maturation division which is a simple mitotic division.
  6. As a result, each secondary spermatocyte divides into two equal cells, called spermatids.
  7. In the end of maturation phase four haploid spermatids are formed from each, diploid primary spermatocyte.

Related Discussions:- Spermatocytogenesis

Oogenesis, explain full about this process

explain full about this process

Infective endocarditis, Infective Endocarditis It is an infection of...

Infective Endocarditis It is an infection of the endocardial surface with micro organisms present in the lesion. The endocardium is contagions with the valves of the heart.

Phylum porifera, PHYLUM  PORIFERA Definition and Introduction Low...

PHYLUM  PORIFERA Definition and Introduction Lowest  multicellular animals or metazoans without  true  tissues, i.e. , at  Cellular level or body organization. Familiar

Explain therapy of specific lipid disorders, Q. Explain Therapy of Specific...

Q. Explain Therapy of Specific Lipid Disorders? a) Very high LDL levels usually result from inherited disorders of lipoprotein metabolism and carry a high risk of premature at

Define myocardial infraction and stress testing, Q. Define Myocardial infra...

Q. Define Myocardial infraction and stress testing? Prediction of disease is one of the primary functions of stress testing. We would like to be able to predict in each patient

What are the human tissues affected by malaria, Q. What are the human tissu...

Q. What are the human tissues affected by malaria? What are the main clinical manifestations of the disease? A plasmodium contaminates the human blood causing destruction of RB

The statement is true or false, Anton van Leeuwenhoek was the first to prop...

Anton van Leeuwenhoek was the first to propose placing microorganisms into the Kingdom Monera. True or False

Where can rna are found within cells, In the eukaryote cell nucleus, RNA ca...

In the eukaryote cell nucleus, RNA can be found dispersed in the nuclear fluid, along with DNA, and as the major constituent of the nucleolus. In cytosol (in eukaryotes or in bacte

What is the difference between spermatids and sperm cells, What is the diff...

What is the difference between spermatids and sperm cells? What is the name of the transformation of spermatids into sperm cells? Sperm cells (the male gametes) are matured spe

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd