Sperm cell: Difference between revisions

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Revision as of 09:40, 21 June 2008

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Intentionally permanent red link (edit | talk | history | protect | delete | links | watch | logs | views)

full protect. High level of IP vandalism. Frederikfederspiel (talk) 09:26, 21 June 2008 (UTC)

The sperm cell is the male cell used for procreation. It is a haploid, so that the its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell with 46 chromosomes.

Spermatogenesis

Initially in spermatogenesis, a spermatogonium divides by mitosis into two so-called primary spermatocytes. A primary spermatocyte is also diploid, and, in turn, gives place by meiosis to two secondary spermatocytes, which this time are haploid. The two secondary spermatocytes undergo a second meiotic division thereby expelling half the amount of chromosomes to form 4 haploid cells called spermatids. The spermatids mature into sperm cells, who travel through the seminiferous tubules to mature further in the epididymis.

Anatomy

The sperm cell consists of a head, a midpiece and a tail. The head is the nucleus with densely coiled cromatinfibres, surrounded anteriorly by an acrosome, which contains enzymes used for penetrating the female egg. The midpiece has a central milamentous core with many mitochondria spiralled around it, used for ATP production for the journey through the female cervix, uterus and uterine tubes. The tail or "flagellum" executes the lashing movements that propel the spermatocyte, and it consists of microtubules in an extension of the cell membrane.

Maturization

A sperm cell is not motile as it reaches the epididymis. It is transported through the epididymis by peristalsis, and as it reaches the end of this 6 meters long tube, it is a fully functional sperm cell ready for ejaculation.