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

Explain about the spinal trauma, Explain about the Spinal Trauma? Spina...

Explain about the Spinal Trauma? Spinal trauma or spinal cord injury, commonly clue to accidents, fills, sports injury can result in serious disabling consequences. The spinal

Autoradiography, Autoradiography Autoradiography is a modification of t...

Autoradiography Autoradiography is a modification of the radioactive tracer technique. In this technique, the radioactivity is detected by a thin film of photographic emulsion

Explain the resting membrane voltage, At 1 AM, a researcher places a health...

At 1 AM, a researcher places a healthy squid giant axon in a bath of normal squid physiological extracellular saline and internally perfuses the axon with normal squid intracellula

Explain about insulin concentrations, Insulin Concentrations The doctor...

Insulin Concentrations The doctor always prescribes insulin dosage in units. Thus all types of insulin (crystalline, NPH, Lente, and so forth) is available in 10-ml vials that

Animal nutrition, Briefly explain the following feeding mechanisms in holoz...

Briefly explain the following feeding mechanisms in holozoic organisms: filer feeding,fluid feeding and deposit feeding.

The cell, how autophagy help in converting a tadpole larva into adult amphi...

how autophagy help in converting a tadpole larva into adult amphibian

Explain epididymitis, Epididymitis  Acute epididymitis in men less than...

Epididymitis  Acute epididymitis in men less than 35 years old is usually caused by C. trachomatis or, less frequently, N. gonorrhoeae. Older men or those who have had urinary

Ganong''s potometer, What happens to the movement of the air bubble if the ...

What happens to the movement of the air bubble if the apparatus is kept in i. In the dark ii. In sunlight iii.In front of a fan

The formation of macro and micronuclei of daughter paramoeci, The formation...

The formation of macro and micronuclei of daughter paramoeci: Each exconjugant has a single micronucleus and four macronuclei. This type of exconjugant divides twice and f

Problem with role of lymphatic system, Normal 0 false false ...

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

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