Glossary

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  • 2
  • 2‐cell, two gonadotropin model
    Theory that both thecal and granulosa cells (2 follicular cell types) and LH and FSH (2 gonadotropins) are needed for full ovarian stimulation.
  • a
  • Acrosomal cap
    Cap-like structure that develops over the anterior half of the head of the spermatozoa; it contains enzymes that break down the wall of the egg during fertilisation.
  • AMH
    A member of the transforming growth factor βfamily of growth and differentiation factors. In the ovary, AMH has an inhibitory effect on primordial follicle recruitment as well as on the responsiveness of growing follicles to follicle-stimulating hormone (FSH).
  • Ampulla
    The middle portion of the fallopian tube.
  • Androgens
    Generic term for male hormones (e.g. androsterone, testosterone).
  • Anti-Müllerian hormone
    A member of the transforming growth factor βfamily of growth and differentiation factors. In the ovary, AMH has an inhibitory effect on primordial follicle recruitment as well as on the responsiveness of growing follicles to follicle-stimulating hormone (FSH).
  • Assisted reproductive technology (ART)
    All treatments or procedures that include the in vitro handling of both human oocytes and sperm or of embryos for the purpose of establishing a pregnancy. This includes, but is not limited to, in vitro fertilisation and embryo transfer, gamete intrafallopian transfer, zygote intrafallopian(...)
  • b
  • BICA
    BICA is the only professional association for infertility counsellors and counselling in the UK. It seeks to promote the highest standards of counselling for those considering or undergoing fertility investigations and treatment. It offers a variety of training and education services to its(...)
  • Blastocyst
    An early stage of development of the embryo shortly after fertilisation; the stage when it moves into the uterus for implantation.
  • Blastomeres
    Type of cell produced by division of the egg after fertilisation.
  • British Infertility Counselling Association
    BICA is the only professional association for infertility counsellors and counselling in the UK. It seeks to promote the highest standards of counselling for those considering or undergoing fertility investigations and treatment. It offers a variety of training and education services to its(...)
  • c
  • Cervix
    Lower, narrow portion of the uterus that opens into the top end of the vagina.
  • Chorion
    Highly vascular outer membrane that surrounds the embryo.
  • Clinical pregnancy
    A pregnancy diagnosed by ultrasonographic visualisation of one or more gestational sacs or definitive clinical signs of pregnancy. It includes ectopic pregnancy.
  • Corpora cavernosa
    A mass of erectile tissue with large interspaces capable of being distended with blood.
  • Corpus luteum
    The “yellow body” formed from the ruptured follicle after ovulation; composed of remaining granulosa cells that are transformed into luteal cells by the action of LH.
  • Corpus spongiosum
    The longitudinal column of erectile tissue of the penis that contains the urethra and is ventral to the two corpora cavernosa.
  • Cryopreservation
    The freezing or vitrification and storage of gametes, zygotes, embryos, or gonadal tissue
  • d
  • Diploid
    Cells with two copies of each chromosome, usually one from the mother and one from the father; human diploid cells have 46 chromosomes.
  • e
  • Ectopic Pregnancy
    An Ectopic Pregnancy (EP) is one that occurs outside of the uterine cavity. The most common site for an EP is within the fallopian tube but a pregnancy can implant anywhere e.g. on the ovary or within the abdominal cavity.
  • Embryo transfer
    The procedure in which one or more embryos are placed in the uterus or Fallopian tube.
  • Embryoblast
    The mass of cells inside the primordial embryo that will eventually give rise to the definitive structures of the fetus.
  • Endometrium
    The mucous membrane lining the uterus that plays a vital role in nourishing and supporting the developing embryo.
  • Epididymis
    A narrow tightly coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens.
  • ESHRE
    European Society of Human Reproduction and EmbryologyThe main aim of the European Society of Human Reproduction and Embryology is to promote interest in, and understanding of, reproductive biology and medicine. It does this through facilitating research and subsequent dissemination of(...)
  • f
  • Fallopian tubes
    A pair of slender ducts through which eggs pass from the ovaries to the uterus.
  • Fertilisation
    The penetration of an egg by the sperm and the resulting combining of genetic material that develops into an embryo.
  • Fertility
    Normal fertility is the ability to achieve a pregnancy within two years by regular coital exposure.
  • Fertility Network UK
    Fertility Network UK is the nation’s leading patient-focused fertility charity that provides free and impartial support, advice, information and understanding for anyone affected by fertility issues.
  • Fetus
    the product of fertilisation from completion of embryonic development, at 8 completed weeks after fertilisation, until abortion or birth.
  • Fimbriae
    Fringe of tissue at the ovarian end of the fallopian tube which catches the newly released egg and sweeps it into the fallopian tube.
  • Follicle
    A fluid filled sac located just beneath the surface of the ovary. It contains an oocyte and cells that produce hormones. The follicle increases greatly in size and volume before ovulation, at which time it matures and ruptures to release the egg.
  • Follicle-stimulating hormone
    The pituitary hormone responsible for stimulating follicle growth and egg development as well as the production of oestrogen in women. In men, FSH stimulates the testes to manufacture sperm.
  • Frozen-thawed embryo transfer cycle (FET)
    An ART procedure in which cycle monitoring is carried out with the intention of transfering frozen-thawed embryo(s). Note: An FET cycle is initiated when specific medication is provided or cycle monitoring is started with the intention to treat.
  • FSH
    The pituitary hormone responsible for stimulating follicle growth and egg development as well as the production of oestrogen in women. In men, FSH stimulates the testes to manufacture sperm.
  • g
  • Germinal cells
    An embryonic cell that divides to form gametes.
  • Gonadotropin-releasing hormone (GnRH)
    Hormone produced by the hypothalamus that stimulates the pituitary to release gonadotropins (luteinising hormone and follicle-stimulating hormone).
  • Granulosa cells
    FSH-sensitive cells surrounding the oocyte; those of the dominant follicle convert androgens to estrogens under the influence of FSH.
  • h
  • HFEA
    The Human Fertilisation and Embryology Authority (HFEA) was set up in 1991 and comprises members (the majority of whom are clinicians, researchers or other fertility / embryology professionals) and a lay chair.   The Authority oversees a staff which licenses and inspects fertility clinics in(...)
  • Human chorionic gonadotropin (hCG)
    Hormone made by the developing embryo soon after conception and later by placenta. Its role is to prevent the disintegration of the corpus luteum of the ovary and thereby maintain progesterone production, critical for pregnancy.
  • Human Fertilisation and Embryology Act
    According to the Department of Health the Human Fertilisation and Embryology Act's key provisions are:
    • ensure that all human embryos outside the body—whatever the process used in their creation—are subject to regulation.
    • ensure regulation of "human-admixed" embryos created from a(...)
  • Human Fertilisation and Embryology Authority
    The Human Fertilisation and Embryology Authority (HFEA) was set up in 1991 and comprises members (the majority of whom are clinicians, researchers or other fertility / embryology professionals) and a lay chair.   The Authority oversees a staff which licenses and inspects fertility clinics in(...)
  • Hyperprolactinaemia
    Abnormally high levels of prolactin in the blood.
  • Hypothalamus
    Part of the brain above the pituitary that regulates many bodily functions, including hormone release by the pituitary; integrates incoming hormonal and nervous signals and secretes releasing-hormones in response.
  • Hypothalmic-pituitary-gonadal axis
    A term used to describe the effects of the hypothalamus, pituitary gland, and gonads as if acting as a single entity. It is important in the development and regulation of a number of vital body systems, including development and reproduction.
  • i
  • Infertility
    Those couples who do not achieve a pregnancy within two years of regular sexual activity. This group is made up of those defined as sterile or subfertile.
  • Inhibin B
    A glycoprotein hormone that is secreted by the pituitary gland and inhibits the secretion of follicle-stimulating hormone. In the male it is secreted by the Sertoli cells and in the female by the granulosa cells.
  • l
  • Leydig cell
    A cell of interstitial tissue of the testis that is usually considered the chief source of testicular androgens and especially testosterone.
  • Luteinising hormone (LH)
    The hormone that triggers ovulation and stimulates the corpus luteum to secrete progesterone.
  • m
  • Mitosis
    Process of cell division by which a cell separates the chromosomes in its cell nucleus into two identical sets in two nuclei.
  • Mitrochondria
    Round or long cellular organelles that are found outside the nucleus; rich in fats, proteins, and enzymes, they produce energy for the cell through cell respiration.
  • Morula
    An embryo at an early stage of embryonic development.
  • o
  • Oestrogen
    The naturally occurring female sex steroid hormone produced by the ovaries and responsible for development of the reproductive organs and secondary sexual characteristics, as well as for the proliferation of the endometrium.
  • Oocyte
    The immature female gamete, i.e. the cell that divides to form the mature ovum or egg.
  • Ovaries
    Paired oval organs in the female containing thousands of immature egg cells held within the follicles; site of sex hormone production.
  • Ovulation
    The monthly release of an egg from one of the ovaries.
  • Ovum
    A female gamete or egg.
  • p
  • Pelvic ultrasound
    A pelvic ultrasound is a noninvasive diagnostic exam that produces images that are used to assess organs and structures within the female pelvis. A pelvic ultrasound allows quick visualisation of the female pelvic organs and structures including the uterus, cervix, vagina, fallopian tubes and(...)
  • Pituitary gland
    Gland lying at the base of the brain, beneath the hypothalamus, that secretes many hormones, including gonadotropins FSH and LH.
  • Pregnancies of Unknown Location
    Pregnancy of unknown location (PUL) is a term used to describe a situation where there is no evidence of a gestation either intra-or extrauterine on transvaginal sonography (TVS) in women seeking medical attention for various reasons in early pregnancy. The principal tool in PUL management(...)
  • Progesterone
    Naturally occurring female sex steroid hormone primarily responsible for the transition of the endometrium from its proliferative to its secretory stage, regulating fertility.
  • Progestogen
    Synthetic steroid hormone similar in structure to the naturally occurring female sex steroid hormone progesterone.
  • Prolactin
    A protein hormone made in the pituitary, it is secreted in large amounts when the links between the pituitary and hypothalamus are disconnected, therefore regulation of secretion is maintained by inhibition.
  • s
  • Saline Infusion Sonogram
    Saline Infusion Sonogram (usually shortened to SIS) is a procedure carried out under ultrasound and is used to assess the fallopian tubes, as well as to detect abnormalities of the uterus and endometrium such as endometrial polyps, submucosal fibroids and congenital uterine abnormalities (such(...)
  • Scrotum
    The external sac that contains the testes.
  • Semen
    The reproductive fluid ejaculated from the penis consisting of spermatozoa suspended in secretions of accessory glands.
  • Semen Analysis
    Semen analysis, also known as a sperm count test, analyses the health and viability of a man’s sperm. Semen is the fluid containing sperm (plus other sugar and protein substances) that’s released during ejaculation.A semen analysis measures three major factors of sperm health:
    • the(...)
  • Seminiferous tubules
    Coiled threadlike tubules that make up the bulk of the testis and are lined with a layer of epithelial cells from which the spermatozoa are produced.
  • Sertoli cells
    Elongated striated cells in the seminiferous tubules of the testis to which the spermatids become attached and from which they derive nourishment.
  • SIS
    Saline Infusion Sonogram (usually shortened to SIS) is a procedure carried out under ultrasound and is used to assess the fallopian tubes, as well as to detect abnormalities of the uterus and endometrium such as endometrial polyps, submucosal fibroids and congenital uterine abnormalities (such(...)
  • Spermatogonia
    Primitive male germ cell that gives rise to primary spermatocytes in spermatogenesis.
  • Syncytiotrophoblast
    outer layer of the trophoblasts that forms finger-like projections that invade the endometrium to secure the blastocyst firmly in place within the uterus.
  • t
  • Testosterone
    Male hormone produced primarily by the testes that is the main androgen responsible for inducing and maintaining secondary sex characteristics.
  • Theca cells
    LH-sensitive cells surrounding the outside of the follicle; those of the dominant follicle convert cholesterol to androgens under the influence of LH.
  • Trophoblast
    The outer layer of the blastocyst that supplies nutrition to the embryo, facilitates implantation by eroding away the tissues of the uterus with which it comes in contact allowing the blastocyst to sink into the cavity formed in the uterine wall.
  • u
  • Ultrasonography
    Ultrasonography involves the use of high-frequency sound waves to image internal body structures, a developing fetus. Also called echography.
  • Urethra
    The canal through which sperm and urine pass out of the body.
  • v
  • Vas Deferens
    Sperm-carrying duct, which begins at and is continuous with the tail of the epididymis, runs in the spermatic cord through the inguinal canal, and descends into the pelvis where it joins the duct of the seminal vesicle to form the ejaculatory duct.
  • z
  • Zygote
    A cell formed by the union of two gametes.

References:

  1. Johnson MH. Essential Reproduction. Sixth ed. Johnson MH, Evveritt BJ, editors: Blackwell Publishing 2007.
  2. Drummond AE. The role of steroids in follicular growth. Reprod Biol Endocrinol. 2006;4:16.
  3. Levy DP, Navarro JM, Schattman GL, Davis OK, Rosenwaks Z. The role of LH in ovarian stimulation: exogenous LH: let’s design the future. Hum Reprod. 2000 Nov;15(11):2258-65
  4. Filicori M, Cognigni GE, Samara A, Melappoini S, Perri T, Cantelli B et al. The use of LH activity to drive folliculogenesis: exploring uncharted territories in ovulation induction. Hum Reprod Update. 2002 Nov-Dec;8(6): 543-57
  5. Khan-Sabir N, Beshay VE, Carr BR. Chapter 3: The normal Menstrual Cycle and the Control of Ovulation. In:Rebar RW, editor. Female Reproductive Endocrinology: http://www.endotext.org/2008
  6. Sanders S, Debuse M. Endocrine and Reproductive Systems. Second ed. Horton-Szar D, editor: Mosby; 2003

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