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

What are infructescences fruits and pseudofruits, What are infructescences,...

What are infructescences, pseudofruits and parthenocarpic fruits? Infructescences are aggregated fruits created from inflorescences, aggregated flowers. Grape clusters are inst

Define a technique of implant by using a tissue punch, Using a Tissue Punch...

Using a Tissue Punch The implant heads are located and using a suitable sized tissue punch(depending on the implant diameter), the tissue punch is used and takes a circular pie

Biological functions in which chlorine ions participate, What are the main ...

What are the main biological functions in which chlorine ions participate? Like sodium cations, chlorine anions actively participate in the regulation of the osmolarity of tiss

In what form is most carbohydrate taken in the normal diet, In what form is...

In what form is most carbohydrate taken in the normal diet? Most carbohydrate is taken normal diet in as starch.

Define the streak plate method - pure culture techniques, Define the Streak...

Define the Streak Plate Method - Pure Culture Techniques? The method was developed by Loeffler and Gaffkey in the laboratory of Robert Koch. The streak plate method depends on

What are zoonotic diseases, Q. What are Zoonotic Diseases? The World He...

Q. What are Zoonotic Diseases? The World Health Organization defines Zoonoses (Zoonosis, sing.) as "Those diseases and infections, which are naturally transmitted between verte

Define criteria for assessment of riboflavin status, Define Criteria for As...

Define Criteria for Assessment of Riboflavin Status? Riboflavin status can be assessed by measuring urinary excretion of the vitamin in fasting, random, and 24-hour specimens o

Probation/parole client , Write a report on a special probation/parole clie...

Write a report on a special probation/parole client and programs that have been situated to address this problem client. Focus on 1type of special requires offender (substance abus

Aschelminthes, in what part of the human body aschelminthes found?

in what part of the human body aschelminthes found?

Restructured meat products, Re s t r u c t u re d Meat Products ...

Re s t r u c t u re d Meat Products Restructuring technique is used for developing convenience products with texture in between intact steak and a comminuted product.

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