Sperm
hideThe 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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News tagged with sperm
Newly discovered mechanism allows cells to change state
Dec 09, 2009 |
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Cells are not static. They can transform themselves over time — but change can have dangerous implications. Benign cells, for example, can suddenly change into cancerous ones.
Stem cells battle for space
Dec 04, 2009 |
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The body is a battle zone. Cells constantly compete with one another for space and dominance. Though the manner in which some cells win this competition is well known to be the survival of the fittest, how stem cells duke ...
Hope for men with nonobstructive infertility
Dec 03, 2009 |
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It has been thought that men with non-obstructive azoospermia (NOA), a lack of sperm in the semen not caused by an obstruction within the reproductive system, are poor candidates for IVF. Now, researchers writing in the open ...
'The pill' for him: Scientists find a hormonal on-and-off switch for male fertility
Nov 30, 2009 |
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A new research report published in the December 2009 print issue of The FASEB Journal could one day give men similar type of control over their fertility that women have had since the 1960s. That's because scientists have f ...
For young boys with cancer, testicular tissue banking may be option to preserve fertility
Nov 09, 2009 |
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For parents of children with cancer, the hopeful news is that pediatric survival rates have steadily improved for decades. Among the bad news—treatments that enable survival often cause infertility.
Whales are polite conversationalists
Oct 26, 2009 |
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What do a West African drummer and a sperm whale have in common? According to some reports, they can both spot rhythms in the chatter of an ocean crowded with the calls of marine mammals -- a feat impossible for the untrained ...
Sperm may play leading role in spreading HIV
Medicine & Health / HIV & AIDS
Oct 26, 2009 |
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Sperm, and not just the fluid it bathes in, can transmit HIV to macrophages, T cells, and dendritic cells (DCs), report a team led by Ana Ceballos at the University of Buenos Aires in Argentina. By infecting ...
Sperm donor passed on sudden death heart defect
Oct 20, 2009 |
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(AP) -- A sperm donor passed on a potentially deadly genetic heart condition to nine of his 24 children, including one who died at age 2 from heart failure, according to a medical journal report.
Putting the squeeze on sperm DNA
Sep 30, 2009 |
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(PhysOrg.com) -- In the quest for speed, olympic swimmers shave themselves or squeeze into high-tech super-suits. In the body, sperm are the only cells that swim and, as speed is crucial to fertility, have ...
Childhood kidney disorder has lasting effects
Sep 24, 2009 |
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A kidney condition that can arise in children and was until recently believed to disappear after puberty may persist into adulthood and cause significant long-term complications, according to a study appearing in an upcoming ...
French woman asks court for dead husband's sperm
Sep 23, 2009 |
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A 39-year-old widow asked a French court Wednesday to allow her to retrieve her late husband's frozen sperm so that she can be inseminated and have his child.
Study Positively Identifies Giant Squid Presence in Gulf of Mexico
Sep 21, 2009 |
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(PhysOrg.com) -- During a recent research cruise, a rare giant squid was captured in the Gulf of Mexico.
Taiwan scientists develop sperm 'efficiency' kit
Sep 17, 2009 |
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Scientists in Taiwan said Thursday they have invented a male fertility home test kit that breaks new ground by measuring the efficiency of sperm cells -- a key factor in determining men's ability to father children.
Possible genetic factor for male infertility identified
Sep 15, 2009 |
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Virginia Commonwealth University School of Medicine researchers have discovered a gene involved with the production of sperm that may contribute to male infertility and lead to new approaches to male contraception.
When you've doubled your genes, what's 1 chromosome more or less?
Sep 14, 2009 |
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An individual with Down syndrome and a male calico cat have one thing in common -- each has an extra chromosome. For animals, most instances of an extra chromosome result in birth defects or even death, but plants are another ...
