Template:Oocyte terms

From Embryology

Oocyte Development

  • antral follicle - (secondary) the stage following preantral in the decription of the sequence ovarian follicle development.
  • antrum - (L. a cave), cavity; a nearly-closed cavity or bulge. In the ovary this refers to the follicular fluid-filled space within the follicle.
  • atretic follicle - An ovarian follicle that fails to mature and degenerates. Also called "atresia" refering to the process of degeneration of the ovarian follicle. This process can occur at any stage of follicle development (folliculogenesis).
  • clomiphene citrate - drug taken orally to promote the process of follicle/egg maturation.
  • corona radiata - Layer of follicle cells of cumulus oophorus remaining attached to zona pellucida of oocyte after ovulation. Also called granulosa cells.
  • corpus albicans - (L. corpus = body, L. albicans = whitish); a degenerating corpus luteum in ovary.
  • corpus luteum - (L. corpus = body, L. luteum = yellow) The remains of ovarian follicle after ovulation that acts as an endocrine organ supporting pregnancy and preventing menstruation (loss of the endometrial lining). de Graaf first observed it in the ovary of a cow as a yellow structure.
  • cortical - (L. corticalis) at the outside (like the bark of a tree), usually combined with medulla meaning the core.
  • cumulus oophorus - (L. cumulus = a little mound G. oon = egg + phorus = bearing); part of the wall of an ovarian follicle surrounding and carrying the ovum (oocyte).
  • follicle - (L. folliculus = little bag,dim. of L. follis). A structure which develops in the ovary and contains a developing egg (oocyte).
  • follicle stimulating hormone - (FSH, gonadotropin) A glycoprotein hormone secreted by anterior pituitary (adenohypophysis gonadotrophs, a subgroup of basophilic cells) and acts on gametogenesis and other systems in both males and females. Females, FSH acts on the ovary to stimulate follicle development. Males, acts on the testis Sertoli cells to increase androgen-binding protein (ABP) that binds androgens and has a role in spermatogenesis.
  • follicular fluid - the fluid found in the antrum of a secondary follicle. Secreted by cells in the wall of the follicle. This fluid is released along with the oocyte at ovulation.
  • germinal epithelium - cellular component covering surface of ovary, it is continuous with mesothelium covering mesovarium. Note that it is a historical misnomer, as it is not the actual site of germ cell formation.
  • Graafian follicle - named after Regnier de Graaf (1641-1673), an historic Dutch physician embryologist who studied pregnancy using rabbits.
  • granulosa cells - the supporting cells that surround the developing egg within the follicle thecal layers.
  • Izumo1 - a protein located on the equatorial segment of acrosome-reacted spermatozoa recognizes its receptor Juno, on the oocyte surface, for plasma membrane binding and fusion. Named for a Japanese shrine dedicated to marriage. OMIM609278
  • Juno - (folate receptor-δ; FOLR-δ) a glycophosphatidylinositol (GPI)-anchored, cysteine-rich glycoprotein on the oocyte surface for fertilisation that is the receptor of Izumo1 on the spermatozoa, for plasma membrane binding and fusion. OMIM615737
  • luteinizing hormone - (LH, gonadotropin, lutropin, Interstitial Cell Stimulating Hormone, ICSH) glycoprotein hormone releasd from anterior pituitary hormone that acts on the gonad and has a role in male and female reproduction. Female, LH triggers ovulation (release of the oocyte). Male, LH stimulates testis interstital cell (Leydig cell) production of testosterone. Have been used clinically in humans for the treatment of female infertility.
  • mesovarium - mesentry of the ovary formed from a fold of the broad ligament that attaches the ovary.
  • medullary - (L. medius = in the middle) relating to the medulla; pith, marrow, inner portion of an organ. Usually combined with cortex (cortical) meaning the outer layer.
  • oocyte - (Greek, oo = egg, ovum) The term used to describe the haploid egg or ovum formed within the ovary (female gonad) and released to enter the uterine tube and be transported to the uterus. The mature oocyte is the cell released from the ovary during ovulation.
  • oocyte retrieval - (egg retrieval) A clinical in vitro fertilization (IVF) procedure to collect the eggs contained in the ovarian follicles.
  • oogenesis - (Greek, oo = egg + genesis = origin, creation, generation) process of diploid oogonia division and differentiation into an haploid oocyte (egg) within the ovary (female gonad). Mammalian meiosis will only be completed within the oocyte if fertilization occurs.
  • oogonia - (Greek, oo = egg) diploid germ cells within the ovary (female gonad) which provide the primary oocytes for oocyte (egg) formation. In humans, all oogonia form primary oocytes within the ovary before birth.
  • oolemma - (zona pellucida, vitelline membrane).
  • oophorus - (Greek, oo = egg + phorus = carrying, egg-bearing) cumulus oophorus, used to describe the granulosa cells within the follicle that tether or link the oocyte to the wall of the follicle.
  • ovulation - release of the oocyte from the mature follicle. In humans generally a single oocyte is released from a cohort of several maturing follicles.
  • preantral follicle - (primary) the stage following primordial in the description of the sequence ovarian follicle development.
  • primary follicle - (preantral) the stage following primordial in the description of the sequence ovarian follicle development.
  • primordial follicle - the first stage in the description of the sequence ovarian follicle development. Present in the ovary from birth, located in the stroma of the ovary cortex beneath the tunica albuginea. The primordial follicle is the oocyte and the surrounding follicular cells.
  • primordial germ cell - oocyte present in the primordial follicle ovary from birth, located in the stroma of the ovary cortex beneath the tunica albuginea. The primordial follicle is the oocyte and the surrounding follicular cells.
  • secondary follicles - the stage following primary in the description of the sequence ovarian follicle development.
  • stromal cells - in the ovary, cells surrounding the developing follicle that form a connective tissue sheath (theca folliculi). This layer then differentiates into 2 layers (theca interna, theca externa). This region is richly vascularized and involved in hormone secretion.
  • superovulation therapy - a fertility drug treatement (oral clomiphene citrate and/or injectable FSH with or without LH) aimed at stimulating development/release of more than one follicle during a single menstrual cycle.
  • tertiary follicle - (preovulatory, Graffian) the stage following secondary in the description of the sequence ovarian follicle development.
  • theca folliculi - stromal cells in the ovary, cells surrounding the developing follicle that form a connective tissue sheath. This layer then differentiates into 2 layers (theca interna, theca externa). This region is vascularized and involved in hormone secretion.
  • theca externa - stromal cells forming the outer layer of the theca folliculi surrounding the developing follicle. Consisting of connective tissue cells, smooth muscle and collagen fibers.
  • theca interna - stromal cells forming the inner layer of the theca folliculi surrounding the developing follicle. This vascularized layer of cells respond to LH (leutenizing hormone) synthesizing and secreting androgens which are processed into estrogen.
  • transzonal projection - (TZP) ovarian follicle term describing the cellular membraneous extension from the granulosa cell through the zona pellucida to the oocyte cell membrane where it forms gap junctions or adherens junctions allowing signalling and adhesion between the two cells.
  • tunica albuginea - dense connective tissue layer lying between germinal epithelium and cortical region of ovary.
  • uterus - site of embryo implantation and development. Uterine wall has 3 major layers: endometrium, myometrium, and perimetrium. Endometrium can be further divided into the functional layer (shed/lost during menstruation) and basal layer (not lost during menstruation).
  • zona pellucida - extracellular layer lying directly around the oocyte underneath follicular cells. Has an important role in egg development, fertilization and blastocyst development. This thick extracellular matrix consists of glcosaminoglycans and 3 glycoproteins (ZP1, ZP2, ZP3). (More? Zona pellucida)
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