fertilization

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fertilization

 [fer″tĭ-lĭ-za´shun]
in human reproduction, the process by which the male's sperm unites with the female's oocyte, creating a new life. The sex and other biologic traits of the new individual are determined by the combined genes and chromosomes that exist in the sperm and oocyte. See also conception and reproduction. Called also fecundation and impregnation.

After injection into the vagina, millions of sperm cells (spermatozoa) make use of their whiplike tails to swim through the cervix toward the uterus. Most are destroyed along the way by secretions in the vagina, but some reach the uterus and a few may enter the fallopian tubes. A very small number may survive as long as 48 hours. If during this period only one sperm succeeds in entering a fallopian tube and meeting there an oocyte ready to be fertilized, conception can occur. This event is possible only during a period of about 4 days of the month. After the sperm lodges in the oocyte, the tail disappears, but the head unites with the oocyte to form the zygote.
in vitro fertilization the process by which conception takes place in a laboratory medium; the term literally means fertilization “in glass.” A lay term for the product of in vitro fertilization is “test tube baby.”

The treatment cycle involves the following steps: (1) Induction of ovulation with fertility drugs, such as clomiphene citrate, injectable follicle-stimulating hormone/luteinizing hormone, or both, to produce multiple ovarian follicles. When the largest follicle reaches 20 mm in diameter the patient is given an injection of human chorionic gonadotropin to induce expulsion of the oocyte from the follicle. (2) Laparoscopy and follicular aspiration for the harvesting of oocytes. (3) Maturation of retrieved oocytes and inoculation with the husband's or donor's sperm. (4) Incubation of the resulting embryos until they reach the two- to six-cell stage. (5) Transfer of an embryo via catheter into the patient's uterus; at this point intensive intervention ceases, the pregnancy is considered normal, and no further manipulation is required.
in vivo fertilization union of the sperm and ovum within the reproductive tract of the female; usually taken to mean artificial insemination in which the sperm is artificially introduced into the vagina, cervix, or uterine cavity to overcome the problem of infertility.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

fer·til·i·za·tion

(fer'til-i-zā'shŭn),
The process beginning with penetration of the secondary oocyte by the sperm and completed by fusion of the male and female pronuclei.
Farlex Partner Medical Dictionary © Farlex 2012

fertilization

(fûr′tl-ĭ-zā′shən)
n.
1. The act or process of initiating biological reproduction by insemination or pollination.
2. The union of male and female gametes to form a zygote.
3. The act or process of applying a fertilizer.

fer′til·i·za′tion·al adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

fertilization

Fusion of ovum & spermatozoon Reproduction medicine The penetration of an egg by sperm, resulting in combined genetic material that develops into an embryo
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

fer·til·i·za·tion

(fĕr'til-ī-zā'shŭn)
The process beginning with penetration of the secondary oocyte by the sperm and completed by fusion of the male and female pronuclei.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

fertilization

(fert?il-i-za'shon) [L. fertilis, reproductive]
Enlarge picture
FERTILIZATION
The process that begins with the penetration of the secondary oocyte by the spermatozoon and is completed with the fusion of the male and female pronuclei. This usually takes place in the fallopian tube. Viable spermatozoa have been found in the tube 48 hr after the last coitus. After the ovum is fertilized and the diploid chromosome number is restored in the zygote, cell division begins. The blastocyst then enters the uterus, where it may implant for continued nurture and development. See: illustration

heterologous fertilization

Assisted fertilization of a woman's ova with donor sperm.
See: in vitro fertilization; artificial insemination

homologous fertilization

Artificial fertilization of a woman's ovum by her husband's sperm. The ovum and sperm are united while both are outside the body and then are placed in the uterus during the optimum time for fertilization.

in vitro fertilization

Abbreviation: IVF
Laboratory-produced conception, used to enable pregnancy in infertile women when sperm access to ova is prevented by structural defects in the fallopian tubes or other factors, or in combination with her partner's sterility. After drug-induced follicle maturation, a sample of ova and follicular fluid is removed surgically and mixed with a specimen of the partner's sperm for incubation. The resulting zygote is introduced into the woman's uterus for implantation.
See: embryo transfer; GIFT; ZIFTillustration
Medical Dictionary, © 2009 Farlex and Partners

fertilization

The union of the spermatozoon with the egg (ovum) so that the full complement of chromosomes is made up and the process of cell division, to form a new individual, started.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

fertilization

the fusion of male and female GAMETES to give rise to a ZYGOTE which then subsequently develops into a new organism. See ACROSOME for further details of animal fertilization. See EMBRYO SAC for details of the ‘double’ fertilization of flowering plants.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

Fertilization

The joining of the sperm and the egg; conception.
Mentioned in: Contraception
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

fer·til·i·za·tion

(fĕr'til-ī-zā'shŭn)
Process beginning with penetration of secondary oocyte by one or more sperm(s) and completed by fusion of the male and female pronuclei.
Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about fertilization

Q. i just have my period last november 25 and ended on 28.when is my possible fertile and ovulation period please help me identify my fertile and ovulation period

A. If someone knew it, it'd solve the human race many problems with fertility. The problem is that ovulation (and thus, the period of possible fertility) happens 14 days BEFORE the onset of menses, so you know about it only retrospectively.

However there ways such as serial body temperature measuring, along with kits that measures the level of hormones in the urine in order to estimate the time of the coming ovulation, and help in timing intercourse.

You may read more about it here (www.mayoclinic.com/health/ovulation-signs/AN01521 ) but anyway, consulting a doctor (e.g. gynecologist) may be wise.

More discussions about fertilization
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References in periodicals archive ?
Sperm storage, internal fertilization and embryonic dispersal invent and seep tubeworms (Polychaeta: Siboglinidae: Vestimentifera).
Indeed internal fertilization has been inferred from the presence of seminal receptacles at the posterior end of the oviduct in several vestimentiferan species (Hilario et al., 2005); and, on the basis of observations of spawning in the field (Van Dover, 1994), it seems likely that sperm bundles are released by males into the water column, from which they are collected by the females or find their way into the female gonopores (Macdonald et al., 2002).
grasslei have been tentatively classified as introsperm, since pseudocopulation and internal fertilization has been hypothesized for this species (Zal et al., 1994).
Sperm storage, internal fertilization, and embryonic dispersal in vent and seep tubeworms (Polychaeta: Siboglinidae: Vestimentifera).
However, in rearing the embryos of three species of vestimentiferans in both the laboratory and the field, we found that the number of eggs developing was always less than 100%, suggesting that the internal fertilization mechanism may not function with perfect efficiency in these worms.
Gardiner and Jones (1985) suggested that direct sperm transfer and internal fertilization might occur in Riftia pachyptila, because this species has modified sperm.
Sperm penetration through ovary wall and evidence of internal fertilization. Mar.
Internal fertilization in hermaphroditic colonial invertebrates.
The sexual cycle includes the internal fertilization of the mature eggs soon after the inhalant siphons open (Milkman, 1967); the continuous release of sperm starting 16 h later (Stewart-Savage and Yund, 1997); and the brooding of developing embryos, which are released just before the zooids degenerate at the end of the cycle (Milkman, 1967).
Buckland-Nicks and Scheltema (1995) proposed that internal fertilization, not external, is basal to the Bilateria; evidence for this conclusion came from analysis of similar introsperm design in primitive members of vertebrate and invertebrate phyla.
Rather, there is growing support for viewing limpets as a divergent group (Ponder and Lindberg, 1996) whose ancestors may have had internal fertilization with introsperm, a helicoid larval shell (Page, 1994), and primitive ctenidia.
Spermatozoa of the elasmobranch Squalus suckleyi, a species that has internal fertilization, have a cap-shaped acrosomal vesicle and a subacrosomal rod (Stanley, 1971).