Name = Spermatid
GraySubject = 258
GrayPage = 1243
Caption = "Germinal epithelium of the
4: spermatocyte 2nd order
6: mature spermatid
tight junction( blood testis barrier)
Caption2 = Transverse section of a
tubuleof the testisof a rat. X 250.
MeshName = Spermatids
MeshNumber = A05.360.490.890.860
The term spermatid refers to the
haploidmale gametidthat results from division of secondary spermatocytes. 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
mitochondriabecome 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 protaminesduring spermatid elongation. The resultant tightly packed chromatinis transcriptionally inactive.
* - "Male Reproductive System: testis, early spermatids"
* - "Male Reproductive System: testis, late spermatids"
* [http://www.cvm.okstate.edu/instruction/mm_curr/histology/MR/HiMRp3.htm Histology at okstate.edu]
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Look at other dictionaries:
spermatid — spermatid. См. сперматида. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
spermatid — [spʉr′mə tid] n. [ SPERMAT(O) + ID] Zool. any of the four haploid cells formed by the two consecutive meiotic divisions of a primary spermatocyte, each of which develops into a spermatozoon … English World dictionary
spermatid — noun Date: 1889 one of the haploid cells that are formed by the second division in meiosis of a spermatocyte and that differentiate into spermatozoa … New Collegiate Dictionary
spermatid — n. [Gr. sperma, seed] One of four haploid cells of the male after the meiotic divisions; an immature spermatozoon … Dictionary of invertebrate zoology
spermatid — /sperr meuh tid/, n. Cell Biol. one of the cells that result from the meiotic divisions of a spermatocyte and mature into spermatozoa. [1885 90; SPERMAT + ID3] * * * … Universalium
spermatid — noun A haploid cell, produced by meiosis of a spermatocyte, that develops into a spermatozoon … Wiktionary
spermatid — A cell in a late stage of the development of the spermatozoon; it is a haploid cell derived from the secondary spermatocyte and evolves by spermiogenesis into a spermatozoon. SYN: nematoblast. [spermat + id (2)] * * * sper·ma·tid spər mət əd … Medical dictionary
spermatid — n. any of four haploid cells that develop into a sperm cell … English contemporary dictionary
spermatid — [ spə:mətɪd] noun Biology an immature male sex cell formed from a spermatocyte, which may develop into a spermatozoon without further division. Derivatives spermatidal ˌspə:mə tʌɪd(ə)l adjective … English new terms dictionary
spermatid — Cell that differentiates and becomes a mature sperm … Expanded glossary of Cycad terms