| 单词 | sperm |
| 释义 | sperm1[ spurm ] / spɜrm / SEE SYNONYMS FOR sperm ON THESAURUS.COM noun, plural sperm, sperms for 2.semen. a male reproductive cell; spermatozoon. Origin of sperm11350–1400; Middle English sperme<Late Latin sperma<Greek spérma seed, equivalent to sper- (base of speírein to sow seeds) + -ma noun suffix of result Definition for sperm (2 of 4)sperm2 [ spurm ] / spɜrm / nounspermaceti. sperm whale. sperm oil. Origin of sperm2First recorded in 1830–40; by shortening Definition for sperm (3 of 4)sperm- variant of spermo- before a vowel: spermine. Definition for sperm (4 of 4)-sperm a combining form with the meaning “one having seeds” of the kind specified by the initial element: gymnosperm. Origin of -sperm<Greek -spermos;see -spermous Dictionary.com UnabridgedBased on the Random House Unabridged Dictionary, © Random House, Inc. 2020 British Dictionary definitions for sperm (1 of 3)sperm1 / (spɜːm) / noun plural sperms or spermanother name for semen a male reproductive cell; male gamete Word Origin for spermC14: from Late Latin sperma, from Greek; related to Greek speirein to sow British Dictionary definitions for sperm (2 of 3)sperm2 / (spɜːm) / nounshort for sperm whale, spermaceti, sperm oil British Dictionary definitions for sperm (3 of 3)-sperm n combining form(in botany) a seedgymnosperm Derived forms of -sperm-spermous or -spermal, adj combining formCollins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cultural definitions for spermsperm The male sex cell, typically consisting of a head, midpiece, and tail. (See fertilization.) notes for spermSperm are much smaller than the ova they fertilize. The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved. Medical definitions for sperm (1 of 2)sperm [ spûrm ] n. pl spermA male gamete or reproductive cell; a spermatozoon. Semen. Medical definitions for sperm (2 of 2)sperm- pref.Variant ofspermi- The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company. Scientific definitions for spermsperm [ spûrm ] The smaller, usually motile male reproductive cell of most organisms that reproduce sexually. Sperm cells are haploid (they have half the number of chromosomes as the other cells in the organism's body). Sperm often have at least one flagellum. During fertilization, the nucleus of a sperm fuses with the nucleus of the much larger egg cell (the female reproductive cell) to form a new organism. In male animals, sperm are normally produced by the testes in extremely large numbers in order to increase the chances of fertilizing an egg. Motile sperm cells produced by some multicellular protist groups (such as the algae), the bryophyte plants, and the seedless vascular plants, require water to swim to the egg cell. In gymnosperms and angiosperms, sperm do not need water for mobility but are carried to the female reproductive organs in the pollen grain. In the cycads and the gingko (both gymnosperms), the sperm are motile and propel themselves down the pollen tube to reach the egg cell. In the conifers and angiosperms, the sperm are not themselves motile but are conveyed to the ovule by the growing pollen tube. A Closer LookThe human sperm cell is divided into a head that contains the nucleus, a mid-section that contains mitochondria to provide energy for the sperm, and a flagellum that allows the sperm to move. When fertilization occurs, the nucleus and other contents from the sperm cells are drawn into the cytoplasm of the egg, but the mitochondria in the sperm are destroyed and do not survive in the zygote. Since mitochondria contain their own DNA (thought to be a relic from an existence as separate symbiotic organisms), all of the mitochrondrial DNA in humans is thus inherited from the female. The semen produced by the male reproductive tract as a medium for sperm typically contains over 100 million sperm cells, all of which have but one purpose: to fertilize the single available egg. The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved. |
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