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( Sperm)
The term sperm is derived from the Greek word (sp??µa) 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. Mammalian sperm cells can live for up to 3 days inside the female reproductive system.[citation needed] The spermatozoa of animals are produced through spermatogenesis inside the male gonads (testicles) via meiotic division. 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. The sperm cell consists of a head, a midpiece and a tail. The head contains the nucleus with densely coiled chromatin fibres, surrounded anteriorly by an acrosome, which contains enzymes used for penetrating the female egg. The midpiece has a central filamentous 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. Motile sperm cells typically move via flagella and require water in order to swim toward the egg for fertilization. The uniflagellated sperm cells (with one flagellum) produced in most animals are referred to as spermatozoa, and are known to vary in size. Motile sperm are also produced by many protists and the gametophytes of bryophytes, ferns and some gymnosperms such as cycads and ginkgo. The sperm cells are the only flagellated cells in the life cycle of these plants. In many ferns and lycophytes, they are multi-flagellated (carrying more than one flagellum).[1]
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Sperm Subcategories
Sperm Articles
Pregnancy- Ovulation by Elise Fisher
Ovulation is when the ovary releases an egg into the fallopian tube. The egg then travels down the tube to the uterus. This is considered the fertile stage of the menstrual cycle and doesn't last more than 24 hours. If the egg is fertilized, it'll th...
ONLINE Drugstore by mts kvls
Online drugstore is 100 EFFECTIVE, 100% NATURAL place for drugs.. All your products are made off natural herbal medications. If you searched for natural products you came to a right place. Chose products you need and pursue them right now. It is s...
Spermicides by Amanda Johnson
Spermicides are one of the best birth control methods. It comes in the form of gel, cream, foam, film and suppositories. All the spermicides are similar in work but only thing is the amount of chemical (Nonoxynol-9) that contain, which may vary from ...
Sperm Flow Enhancement - Not Only A Way To Impress Your Girl by Alexander Stomanec
Upping the quantity of semen that is ejaculated seems to be a near- universal male concern -- and there are a number of reasons underlying this. For many men, it is a matter of confidence; a bigger load is associated with increased libido, ferti...
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