Spermatid
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{{Infobox Anatomy |
Name = Spermatid |
Latin = |
GraySubject = 258 |
GrayPage = 1243 |
Image = Germinal_epithelium_testicle.svg |
Caption = ''Germinal epithelium of the [[testicle]].''<BR>1: [[basal lamina]]<BR>2: [[spermatogonia]]<BR>3: [[spermatocyte]] 1st order<BR>4: spermatocyte 2nd order<BR>5: [[spermatid]]<BR>6: mature spermatid<BR>7: [[Sertoli cell]]<BR>8: [[tight junction]] ([[blood testis barrier]]) |
Image2 = Gray1150.png |
Caption2 = Transverse section of a [[tubule]] of the [[testis]] of a [[rat]]. X 250. |
System = |
MeshName = Spermatids |
MeshNumber = A05.360.490.890.860 |
}}
The term '''spermatid''' refers to the [[haploid]] male [[gametid]] that results from division of secondary [[spermatocyte]]s. As a result of [[meiosis]], each spermatid contains only half of the genetic material present in the original primary spermatocyte.
Spermatids are connected together by cytoplasmic material and have superfluous cytoplasmic material around their nuclei.
When formed, ''early round spermatids'' must undergo further maturational events in order to develop into [[spermatozoa]], a process termed [[spermiogenesis]] (also termed ''spermeteliosis'').
The spermatids begin to grow a tail, develop a thickened mid-piece where the [[mitochondria]] become localised and form an [[acrosome]]. Spermatid DNA also undergoes packaging, becoming highly condensed. The DNA is packaged firstly with specific nuclear basic proteins, which are subsequently replaced with [[protamines]] during spermatid elongation. The resultant tightly packed [[chromatin]] is transcriptionally inactive.
==Additional images==
<gallery>
Image:Gray7.png |Scheme showing analogies in the process of maturation of the [[ovum]] and the development of the [[spermatids]] (young [[spermatozoa]]).
</gallery>
==External links==
* {{BUHistology|17804loa}} - "Male Reproductive System: testis, early spermatids"
* {{BUHistology|17805loa}} - "Male Reproductive System: testis, late spermatids"
* [http://www.cvm.okstate.edu/instruction/mm_curr/histology/MR/HiMRp3.htm Histology at okstate.edu]
{{Male reproductive system}}
[[Category:Reproductive system]]
[[Category:Germ cells]]
[[Category:Andrology]]
[[ar:نطفة أرومية]]