News tagged with sperm

Related topics: eggs , fertilizer , genes , infertility , females

Study confirms that sperm quality decreases with age

Conflicting evidence about the extent to which men's semen quality declines with age—likely lowering their fertility—is being cleared up by new University of Otago research that has collated and reviewed ...

Dec 01, 2014
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A new angle on infertility

Scientists from the RIKEN BioResource Center in Tsukuba, Japan, have discovered that a single mutation in the beta-catenin gene, which codes a protein known to be deeply involved in a number of developmental and homeostatic ...

Nov 07, 2014
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Sperm

The term sperm is derived from the Greek word (σπέρμα) sperma (meaning "seed") and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell. A uniflagellar sperm cell that is motile is referred to as a spermatozoon, whereas a non-motile sperm cell is referred to as a spermatium. Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a totipotent zygote is formed with the potential to develop into a new organism.

The spermatozoa of animals are produced through spermatogenesis inside the male gonads (testicles) via meiotic division. They are carried out of the male body in a fluid known as semen. Mammalian sperm cells can live for up to 3 days inside the female reproductive system.[citation needed]

Sperm cells in algal and many plant gametophytes are produced in male gametangia (antheridia) via mitotic division. In flowering plants, sperm nuclei are produced inside pollen.

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