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 ?
'As the number of men with lower sperm counts appears to be increasing, it is very important that we learn how to maximise fertilisation of the remaining cells.'
"All that can be said is that a genetically novel kind of cell comes into existence at fertilisation. The question is, at what point should a new creation of this kind be accorded the status of a human individual or a human subject?"
Theologians had tended to speak of the embryo resulting from fertilisation as being endowed with a human soul by God at that moment, he said.
But scientific research shows, Archbishop Carnley said, that fertilisation is not the same as conception.
Allowing the appeal, the Master of the Rolls, Lord Phillips, sitting with two other judges, said: 'I hold that an organism which is CNR falls within the definition of the Human Fertilisation and Embryology Act.'
He said that an organism created by CNR did fall within the definition of an embryo even though no fertilisation had taken place.
Alan Milburn, the Health Secretary, immediately introduced the Human Reproductive Cloning Bill - passed by Parliament last December - which outlawed placing in a woman any embryo that was not created by a fertilisation process.
He then took the case to the Court of Appeal to ask for a ruling that an organism created by CNR is an embryo even if it is not the product of fertilisation.
Lord Phillips said the 1990 Act contained a definition of an embryo which referred to fertilisation - then the only known means of creating the organism which could eventually develop into a fully grown being.
Even though CNR did not involve fertilisation, the organism formed was identical in every way to an embryo and scientists involved in cloning research believed that the technique was covered by the Act, said Lord Phillips.
Fitting fertilisation kinetics models for free-spawning marine invertebrates.