SPERMATOGENESIS NOTE

                         SPERMATOGENESIS

-The process by which sperms are from inside the testes is called spermatogenesis.

-The tratarmation of the spermatid into spermatozoon spermis called spermatogenesis .

-Spermatogenesis can be completed in 2phases-formation of spermatids and sperogenesis

FARMATION OF SPERMATIDS

-The formation of formatids fromgerminal epithelial cells can take place in the following 3 phases;-

MULTIPLICATION PHASE;-

-The primodial germ cells contain large sites and choromatin nucleous.

-It divided rippitedly by reppited mitotic division and chromatin nucleous .

-This cells have 2n cells of chromosome.

GROTH PHASE;-

-Are the end of multiplication phase the spermato gonia increase in size by accumulation of nutrient from the nourishing cells and also by the synthetic prot and nucleic acid.

-The enlarged diploid cells are called primary speratocytes.where the nucleus is much than spermatogenial cell.

-Which are ready to follow the maturation phase.

MATURATION PHASE

-It is usually a large and important phase .

-Where each primary spermatocyte under goes meiotic division .

-In meosis each diptoid primary spermatocyte divides two haploid secondary spermatocyes.

-Then each sec spermatocyte follows the melosis II , where each haploid sec spermatocyte divided into two haploid spermatides.

-So each diploid primary spermatocyte divided into four haploid spermatocytes

-The sporm are highly motile and elongated cells .

-So this process involes reduction of weight lassing super flows materials and dwvelopmont of high degree of specialized organs for active movement.

 

 

NCULEAR CHANGE;-

-Due to losses of water from nucieus sap ,size the nucleous is shink and chromatin material become losing park.

FORMATION OF AERASOME

One of the vacuole of galgi complex enlooiges just infornt of the nucleous and called as acroblast .

-Firstly acroblast appears a small chance bady called proacrosomal granule and it’s duble layered covering which from the acrosome and head cap repectively.

-The remain part of the golgi apparatus  are  gradually reduced and discardedfrom sperm as golgirest along with some cytoplasm.

CHANGES IN MITOCONDRIA

-In many mammal , the mitochondria of spermtid clump to grether to from a single continuous body.

-In other animals they from separate clumps called as mitochondrial bodies.

CHANGES IN CYTOPLASM

-The abundant cytoplasm of spermatid is reduce to a condensed thin layer known asd manchette.

-Where most of the cytoplasmic organels like ribosome and endoplasmic reticulum are destroyed.

-The thin cytoplasmic is restricted into the peripheral protion of the posterior bead and whole piece region.

RING CENTRIOL

-In some species , the middle pices and tail is demarcated by a pair of ring centriole having unknown function.

  HORMONAL CONTROL

-The GmRH is secrated from hypothal stimulated act putitary to secreate FSH & L.H.

-FSH stimulates sertali cell to secrets androgen.

STRUCTURE OF SPERM/ SPERMATOZOON

-sperms are microscopic AND MOTILE CELLS

-Where human sperm is about 0.02mm long.

-All most all the sperms have similar structure and each one comprises of nucleous and acrosome .

-The nucleous is called the head , neck , middle piesee and tail.

HEAD:

-Head is the anterior enlarged protion of the sperm.

-It computer of nucleous and acrosome.

- The nucleous contaion almost entairly DNA and protein.

-A double layered cap like bulging body above the nucleous is called the acrosome , which contain hydrolytic enzyme used to dissolve the egg membrane at the time of fertilization .

NEAK:

-It is very shot narrow partion between head and middele piece.

-it contains two centrioles.

-the enterior proximal centriole is located in the small depration of nucleous which enters into egg and play a role in cleavge of zygote as the egg has no entriole.

-the distal centriole froms the basal granule of axial filaments.

MIDDLE PIECE:

-The mitochondria from a coil around the axial filament in man and provides the energy for movement of the sperm.

-At the end of middle piece , there is a pair of ring centriole with unknown function.

-The marchentte forms a peripheral layer around the middle pieces.

TAIL:

-It is the last elongated protion of sperm.

-It is several times longer than the head and comparises of axial filament a very thin cytoplasma coverd by plasma membrane.

-In mammals , the tail comprises of majar portion of principal piece or main piece where the axial filament is surrounded by an another getof nine thicker peripheral fibres.

-The last free end of sporm tail without additional fibre is called end piece.

 

 

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