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

Risk analysis - definition of hazard, Risk analysis - Definition of Hazard ...

Risk analysis - Definition of Hazard Hazard   :  A  biological, chemical  or  physical  agent  in or property  of food that might be have an adverse health effect.

Explain about the energy requirements in elderly, Explain about the Energy ...

Explain about the Energy Requirements in elderly? Based on the Benedict - Harris equation for men and women, the daily energy requirements can be calculated. For Men: 66 t

What do you mean by congenital long qt syndrome, Q. What do you mean by Con...

Q. What do you mean by Congenital Long QT Syndrome? There is a rare group of young patients who suddenly pass out due to a spontaneous ventricular tachycardia and often have fa

How many cells are in the human body, How many cells are in the human body?...

How many cells are in the human body? According to "The Handy Science Answer Book" noted by the Science and Technology Department of the Carnegie Library of Pittsburgh (1994) th

Describe the working of immune system, Q. What is the function of the immun...

Q. What is the function of the immune system? The immune system performs specific defense against agents the antigens that are harmful to the body or foreign. Exogenous anti

Explain the localized aggressive periodontitis, Explain the Localized Aggre...

Explain the Localized Aggressive Periodontitis Localized Aggressive Periodontitis: It has been in literature that transmission of peridontopathic microorganisms from periodon

Compare between mummers of dna vs monomers of rna, Name few polymers in the...

Name few polymers in the eukoratic cell? Name the mummers that make up the DNA? Compare and contrast between mummers of DNA VS monomers of RNA?

In which phase of the cell cycle does the dna duplicate, Q How are the conc...

Q How are the concepts of chromosome, chromatids and chromatin related? In which phase of the cell cycle does the DNA duplicate? Chromatin is a set of filamentous the DNA molec

Reproductive mechanisms, Normal 0 false false false EN-...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What are the general necessities for surgery, General necessities for surge...

General necessities for surgery The actual surgical technique of dental implant placement, it would be appropriate to recapitulate the basic principles of surgery. The two prin

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