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Topic: Spermatozoon


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  The penetration of the spermatozoon into the oocyte
At the molecular level the recognition of the spermatozoon and its attachment to the oolemma, the oocyte membrane, functions via a key-lock principle.
The course of the acrosome reaction is the precondition for the membrane coalescence between spermatozoon and oocyte.
Due to the docking of the spermatozoon onto the oocyte a cascade of events are triggered.
www.embryology.ch /anglais/dbefruchtung/eindring01.html   (0 words)

  
 Definition of spermatozoon - Merriam-Webster Online Dictionary
Learn more about "spermatozoon" and related topics at Britannica.com
Find more about "spermatozoon" instantly with Live Search
See a map of "spermatozoon" in the Visual Thesaurus
www.m-w.com /dictionary/spermatozoon+   (46 words)

  
  Abortion access: all viewpoints
That human life, in the form of an ovum and spermatozoon, becomes a human person at the time of conception.
That human life becomes a human person after conception -- perhaps when the fetus looks human, or becomes sentient, or when it has half emerged from its mother's body, or is born, or is functioning completely independent of its mother.
Some forms of human life, like an individual ovum or spermatozoon, are generally considered to have little or no value.
www.religioustolerance.org /abortion.htm   (915 words)

  
  Dorlands Medical Dictionary
a spermatozoon that cannot adhere to the ovum, such as when the acrosome is deficient.
(sper´mə-tid) a cell derived from a secondary spermatocyte by fission, and capable of undergoing spermiogenesis to develop into a spermatozoon; called also spermatoblast.
Spermatozoa, formed in the seminiferous tubules, are derived from spermatogonia, which first develop into spermatocytes, which, in turn, undergo meiosis to produce spermatids; the spermatids then differentiate into spermatozoa.
www.mercksource.com /pp/us/cns/cns_hl_dorlands.jspzQzpgzEzzSzppdocszSzuszSzcommonzSzdorlandszSzdorlandzSzdmd_s_17zPzhtm   (3348 words)

  
  Thèse Isabelle Mollaret: Bibliographie
Ultrastructure of spermiogenesis and the spermatozoon of Mathevotaenia herpestis (Cestoda), intestinal parasite of Atelerix albiventrix in Senegal.
A spermatozoon with undulating membrane in a parasitic Flatworm, Gotocotyla (Monogenea, Polyopisthocotylea, Gotocotylidae).
Ultrastructure of spermiogenesis and the spermatozoon of Anoplocephaloides dentata (Cestoda, Cyclophyllidea, Anoplocephalidae), intestinal parasite of Arvicolidae rodents.
www.mnhn.fr /mnhn/bpph/Theses/Mollaret/These_mollaret_biblio.html   (8641 words)

  
 Bioline International Official Site (site up-dated regularly)
The present study deals with the processes of spermatogenesis, spermiogenesis and the spermatozoon in a species of the family Didymozoidae, Didymocystis wedli Ariola, 1902, a parasite of Thunnus albacares recovered from the coast of the State of Rio de Janeiro, Brazil.
The data obtained in the present study may contribute towards elucidating the phylogeny of the family Didymozoidae, given that differences in the processes of spermiogenesis and in ultrastructure of the spermatozoon were observed in members of the same family.
Spermatozoon and spermiogenesis in Mesocoelium monas (Platyhelminthes, Digenea): ultrastructure and epifluorescence microscopy of labelling of tubulin and nucleus.
www.bioline.org.br /request?oc01220   (1454 words)

  
 Kartagener syndrome: Encyclopedia of Genetic Disorders
One spermatozoon consists of a head, midpiece, and a tail or flagellum.
The tail of a spermatozoon is a long flagellum consisting of a central axoneme.
In Kartagener syndrome, these cilia are either immotile, or are not able to move normally to complete the journey to the fallopian tubes, nor may they be able to burrow through the egg coat.
health.enotes.com /genetic-disorders-encyclopedia/kartagener-syndrome   (1862 words)

  
 Spermplaty: a bibliography on sperm of Platyhelminthes
The spermatogenesis and the spermatozoon in Brachylaima sp.
Swiderski, Z. Ultrastructure of spermatogenesis and the mature spermatozoon of Glaridacris catostomi Cooper, 1920 (Cestoidea; Caryophyllidea).
Ultrastructure of mature spermatozoon in dilepidid cestode Molluscotaenia crassiscolex (Linstow, 1890).
www.mnhn.fr /mnhn/bpph/Data/Spermplaty   (6544 words)

  
 spermatozoon
...bishops said that from the moral aspect, the fecundated egg has to be respected and treated as a human person from the moment of penetration of the spermatozoon...
The fecundated egg, from the moment of the penetration of the spermatozoon, has to be respected and treated as a human person, Archbishop Joseph Mercieca, Gozo...
However, from the moral aspect, the fecundated egg, from the moment of the penetration of the spermatozoon, has to be respected and treated as a human person...
www.mongabay.com /igapo/biotech/spermatozoon.html   (181 words)

  
 STAZIONE ZOOLOGICA ANTON DOHRN - Activity Report 1991
As to the counterpart of the FP on the spermatozoon, a fucosidase has been isolated from spermatozoa, which appears to play a role in the early stages of the interaction with the VC.
In particular, Dr. Dale wishes to determine the nature of the factors in the spermatozoon responsible for egg activation and to establish the role of the phosphoinositide cycle of the sperm.
The spread of lucifer yellow across the germ layers of pre-organogenetic squid embryos and into the yolk syncytium indicated a ubiquitous distribution of gap-junctions, while experiments with fluorescein isociocynatedextran showed that small groups of mesoendoderm cells are interconnected by cytoplasmic bridges during interphase and de-coupled during mitosis.
www.szn.it /actrep91/aqua_2.htm   (2561 words)

  
 Unit 1: The First Week | Human Prenatal Development Article
Fertilization begins with the spermatozoon contacting the cells surrounding the oocyte and ends with the mixing of the 23 male and 23 female chromosomes.
Penetrating the surface cells of the oocyte (corona radiata) is accomplished in part through the spermatozoon’s "active swimming movements" 17 and in part through the use of digestive enzymes contained in the acrosome of the spermatozoon.
The spermatozoon now travels quickly across the perivitelline space (a fluid filled space between the inside of the zona and the cell membrane of the oocyte) and attaches to the cell membrane of the oocyte.
ehd.org /dev_article_unit1.php   (3392 words)

  
 The Importance of Sperm Morphology in the Evaluation of Male Infertility
However, the definition of a normal spermatozoon as described by WHO in 1992 is different from that used by other authors (17,21,22,31).
While most investigators agree on the appearance of a normal spermatozoon, standardized analysis is difficult because of the use of different staining techniques which are not always suitable for optimal examination from head to tail (Figure 1).
A normal spermatozoon has an oval head shape with regular outline and a well-defined acrosomal region covering 40-70 % of head; vacuoles occupy less than 20% of the head area.
www.gfmer.ch /Endo/PGC_network/Sperm_morphology.htm   (3765 words)

  
 Guyer
An adult spermatozoon as it exists in the vas deferens of the pigeon is shown in Fig.
If a spermatozoon and an egg containing characteristics of the same species unite, then the reversion will be to that species; if a sperm-cell containing the characteristics of one species happens to unite with an ovum containing characteristics of the other species, then the offspring will be of the mixed type again.
Although a middle piece appears to be absent in the adult spermatozoon, it seems probable that this centrosome within the nucleus may function as a middle piece which has become obscured by a covering of chromatin.
post.queensu.ca /~forsdyke/guyer.htm   (12236 words)

  
 Spermatozoon - Wikipedia, the free encyclopedia
Sperm cells contribute half of the genetic information to the diploid offspring.
In mammals, the sex of the offspring is determined by the sperm cells: a spermatozoon bearing a Y chromosome will lead to a male (XY) offspring, while one bearing an X chromosome will lead to a female (XX) offspring (the ovum always provides an X chromosome).
Sperm cells were first observed by a student of Antoni van Leeuwenhoek in 1677.
en.wikipedia.org /wiki/Spermatozoon   (1162 words)

  
 Questions éthiques soulevées par le développement de l'ICSI
Fertilisation is achieved by the direct injection of a single spermatozoon into the cytoplasm of the oocyte.
Injecting the sperm therefore bypasses the normal process of interaction with the oocyte which is replaced by the deliberate selection of a spermatozoon for this assisted fertilisation.
Indications, which do not yet exist, involving the selection of an X or a Y spermatozoon after screening would require the use of ICSI, and clearly would raise an ethical issue even though the presence of sex-linked genetic diseases could justify such a course.
www.ccne-ethique.fr /english/avis/a_075.htm   (1732 words)

  
 Green Left - Regular Feature: Life of Riley: Mr spermatozoon finds a home
But your average spermatozoon is really a dumb, pig headed brute -- albeit hard-working.
Devoid of culture and unfamiliar with the gracious niceties of the many other forms of social intercourse, all he wants out of life is to swim north and spawn.
With such chronically high unemployment among the fruits of many a gentlemen's loins, we should be pleased that she can find him work to do.
www.greenleft.org.au /1997/262/17680   (484 words)

  
 Volume 48/Number 4/Abstract 03   (Site not responding. Last check: )
Celine Levron*, Sonia Ternengo and Bernard Marchand - Ultrastructure of spermiogenesis and the spermatozoon of Helicometra fasciata (Digenea, Opecoelidae), a parasite of Labrus merula (Pisces, Teleostei)
The mature spermatozoon possesses five regions and two axonemes with the 9 + '1' pattern, nucleus, mitochondrion, glycogen granules and two bundles of parallel cortical microtubules.
A centriolar derivative and a lateral expansion were observed in the anterior region.
www.actaparasitologica.pan.pl /archive/48/toc48142.html   (188 words)

  
 CATHOLIC ENCYCLOPEDIA: Life
The complexity of living structures varies from that of the single cell amoeba up to the elephant or man. All higher organisms start from the fusion of two germcells, or gametes.
When these are unequal the smaller one -- the spermatozoon -- is so minute in relation to the larger, or ovum, that their fusion is commonly spoken of as the fertilization of the ovum by the spermatozoon.
The ovum thus fertilized is endowed with the power, when placed in its appropriate nutrient medium, of building itself up into the full-sized living being of the specific type to which it belongs.
www.newadvent.org /cathen/09238c.htm   (5505 words)

  
 PROTEST AT THE VATICAN MISSION TO THE U.N.
The spermatozoon can easily pass through the 'net' that is formed by the condom.
The spermatozoon can easily pass through the 'net' that is formed by the condom." That latex has holes or pores through which HIV (or sperm) can pass is a total canard.
The spermatozoon can easily pass through the 'net' that is formed by the condom," Lopez Trujillo is quoted as saying in the BBC interview late last month.
www.actupny.org /reports/vatican_nyc.html   (4030 words)

  
 Saladin/Anatomy and Physiology - Lecture Outline   (Site not responding. Last check: )
1. When a spermatozoon and egg meet, the spermatozoon undergoes an acrosomal reaction that releases the enzymes necessary for penetration of the egg.
a. To fertilize an egg proper, a spermatozoon must first penetrate the granulosa cells and zona pellucida, which may actually require hundreds of spermatozoa to clear the path for the one that penetrates the egg.
b. When a path has been cleared, a spermatozoon binds to the zona pellucida and releases its enzymes by exocytosis.
www.mhhe.com /biosci/ap/saladin/outline29.mhtml   (2682 words)

  
 Life of Riley: Mr spermatozoon finds a home
But your average spermatozoon is really a dumb, pig headed brute -- albeit hard-working.
Devoid of culture and unfamiliar with the gracious niceties of the many other forms of social intercourse, all he wants out of life is to swim north and spawn.
With such chronically high unemployment among the fruits of many a gentlemen's loins, we should be pleased that she can find him work to do.
ratbaggy.blogspot.com /2005/08/mr-spermatozoon-finds-home.html   (398 words)

  
 Gametes - The Spermatozoon - Cambridge University Press   (Site not responding. Last check: )
This volume, and its companion volume on the oocyte, provide an authoritative and wide-ranging account of the gametes, and their reproductive role and function in humans.
The volume starts with an evolutionary perspective before focusing on the molecular and cellular biology of the sperm cell, and its structure and function.
Bioethics and the spermatozoon: reproductive destiny R. Jansen.
www.cambridge.org /catalogue/print.asp?isbn=0521479967&print=y   (477 words)

  
 Presence of Sodium–Potassium-stimulated ATPase in Boar Epididymal Spermatozoon
Presence of Sodium–Potassium-stimulated ATPase in Boar Epididymal Spermatozoon
Department of Biochemistry, School of Medicine, University of Gunma, Maebashi, Japan.
It seems very likely that active ion transport mechanism is also present in the spermatozoon, as its motility is affected by ionic environment.
www.nature.com /nature/journal/v209/n5021/abs/209403a0.html   (158 words)

  
 The Genetics of the Spermatozoon Proceedings of an International Symposium Held at the University of Edinburgh, ...
The Genetics of the Spermatozoon Proceedings of an International Symposium Held at the University of Edinburgh, Scotland, on August 16-20, 1971 specs at MSN Shopping
The Genetics of the Spermatozoon Proceedings of an International Symposium Held at the University of Edinburgh, Scotland, on August 16-20, 1971: Product details
The Genetics of the Spermatozoon Proceedings of an International Symposium Held at the University of Edinburgh, Scotland, on August 16-20, 1971
shopping.msn.com /specs.aspx?itemId=18430298   (69 words)

  
 Gametes - The Spermatozoon:0521479967:Edited by J. G. Grudzinskas, J. Yovich:eCampus.com
This volume, and its companion volume on the oocyte, provide a wide-ranging analysis of the gametes and their reproductive role in humans.
The authors give a detailed account of the spermatozoon that includes particularly helpful information on male infertility and its treatment.
The book starts with an evolutionary perspective before focusing on the molecular and cellular biology of the sperm cell and its structure and function.
www.ecampus.com /bk_detail.asp?isbn=0521479967&referrer=CJ   (227 words)

  
 AnimalPhysiology-LivestockSystems - La spermiogenèse et le spermatozoïde d'Anguilla anguilla L. Etude ...   (Site not responding. Last check: )
Billard, R. and Ginsburg, A.S. La spermiogenèse et le spermatozoïde d'Anguilla anguilla L. Etude ultrastructurale [Spermiogenesis and spermatozoon of d'Anguilla anguilla L. Study of ultrastructure)].
The microtubular associations subsist in the emitted spermatozoon.
Other temporary structures identified during spermiogenesis (lamellar structures, fibrous rod and flagella roots) appear at the time of morphological alteration which accompanies nucleus elongation.
phy043.tours.inra.fr:8080 /archive/00000107   (508 words)

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