Corona radiata (embryology): Difference between revisions
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Davidindia (talk | contribs) Adding local short description: "Cellular mantle around egg cell", overriding Wikidata description "cellular mantle around egg cell" |
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{{Short description|Cellular mantle around egg cell}} |
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| Caption = Human ovum examined fresh in the [[follicular fluid]]. The [[zona pellucida]] is seen as a thick clear girdle surrounded by the cells of the corona radiata. <br><br>The egg itself shows a central granular [[deutoplasm|deutoplasmic area]] and a peripheral clear layer, and encloses the [[germinal vesicle]], in which is seen the germinal spot. |
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| Caption2 = Histology of the preovulatory follicle |
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{{for|the structure in [[neuroanatomy]]|Corona radiata}} |
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The '''corona radiata''' surround an [[ovum]] or unfertilized egg cell, and consist of two or three strata (layers) of follicular cells. They are attached to the outer protective layer of the [[ovum]], the [[zona pellucida]], and their main purpose in many animals is to supply vital proteins to the cell.{{Citation needed|date=August 2009}} They appear at [[ovulation]], but may disappear eventually after [[fertilization]]. |
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The '''corona radiata''' is the innermost layer of the cells of the [[cumulus oophorus]] and is directly adjacent to the [[zona pellucida]], the inner protective glycoprotein layer of the [[ovum]].<ref>{{Citation | url = https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-12-fertilization | last = Pansky | first = Ben | year = 1982 | title = Chapter 12: Fertilization | work = Review of MEDICAL EMBRYOLOGY | publisher = LifeMap Discovery | accessdate = December 31, 2018 | archive-url = https://web.archive.org/web/20180808203219/https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-12-fertilization | archive-date = August 8, 2018 | url-status = dead }}</ref> Cumulus oophorus are the cells surrounding corona radiata, and are the cells between corona radiata and follicular antrum. Its main purpose in many animals is to supply vital proteins to the cell.{{Citation needed|date=August 2009}} It is formed by follicle cells adhering to the [[oocyte]] before it leaves the [[ovarian follicle]], and originates from the squamous [[granulosa cell]]s present at the primordial stage of follicular development. The corona radiata is formed when the granulosa cells enlarge and become cuboidal, which occurs during the transition from the [[Folliculogenesis|primordial to primary stage]]. These cuboidal granulosa cells, also known as the granulosa radiata, form more layers throughout the maturation process, and remain attached to the zona pellucida after the [[ovulation]] of the [[Graafian follicle]]. For [[fertilization]] to occur, [[sperm]] cells rely on [[hyaluronidase]] (an enzyme found in the [[acrosome]] of spermatozoa) to disperse the corona radiata from the zona pellucida of the secondary (ovulated) oocyte, thus permitting entry into the [[perivitelline space]] and allowing contact between the sperm cell and the nucleus of the oocyte. |
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The corona radiata are layers of follicle cells, that protect the secondary oocyte as it passes through the ruptured follicular wall, on its way to the infundibulum of the uterine (AKA fallopian) tubes. In order for fertilization to occur, the sperm must break through this layer of follicular cells by secreting the enzyme [[hyaluronidase]]. It takes the secretions of dozens of sperm to weaken the layer enough for one sperm to penetrate. |
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==References== |
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{{reflist}} |
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==External links== |
==External links== |
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* [http://mcb.berkeley.edu/courses/mcb135e/fertppt/HTML/sld010.htm Image at Berkeley] |
* [http://mcb.berkeley.edu/courses/mcb135e/fertppt/HTML/sld010.htm Image at Berkeley] |
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* {{BUHistology|18404loa}} |
* {{BUHistology|18404loa}} |
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* [http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter28/animation__maturation_of_the_follicle_and_oocyte.html Animation: Maturation of the Follicle and Oocyte] |
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{{Female reproductive system}} |
{{Female reproductive system}} |
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[[Category: |
[[Category:Mammal female reproductive system]] |
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[[fr:Corona radiata]] |
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[[it:Corona radiale]] |
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[[pl:Wieniec promienisty]] |
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[[pt:Coroa radiada]] |
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[[fi:Korona radiata]] |
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[[sv:Corona radiata (embryologi)]] |
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Latest revision as of 05:54, 27 June 2024
 | This article relies largely or entirely on a single source. (June 2013) |
| Corona radiata | |
|---|---|
 Human ovum examined fresh in the follicular fluid. The zona pellucida is seen as a thick clear girdle surrounded by the cells of the corona radiata. The egg itself shows a central granular deutoplasmic area and a peripheral clear layer, and encloses the germinal vesicle, in which is seen the germinal spot. | |
| Anatomical terminology |
The corona radiata is the innermost layer of the cells of the cumulus oophorus and is directly adjacent to the zona pellucida, the inner protective glycoprotein layer of the ovum.[1] Cumulus oophorus are the cells surrounding corona radiata, and are the cells between corona radiata and follicular antrum. Its main purpose in many animals is to supply vital proteins to the cell.[citation needed] It is formed by follicle cells adhering to the oocyte before it leaves the ovarian follicle, and originates from the squamous granulosa cells present at the primordial stage of follicular development. The corona radiata is formed when the granulosa cells enlarge and become cuboidal, which occurs during the transition from the primordial to primary stage. These cuboidal granulosa cells, also known as the granulosa radiata, form more layers throughout the maturation process, and remain attached to the zona pellucida after the ovulation of the Graafian follicle. For fertilization to occur, sperm cells rely on hyaluronidase (an enzyme found in the acrosome of spermatozoa) to disperse the corona radiata from the zona pellucida of the secondary (ovulated) oocyte, thus permitting entry into the perivitelline space and allowing contact between the sperm cell and the nucleus of the oocyte.
References
[edit]- ^ Pansky, Ben (1982), "Chapter 12: Fertilization", Review of MEDICAL EMBRYOLOGY, LifeMap Discovery, archived from the original on August 8, 2018, retrieved December 31, 2018
External links
[edit]- Image at Berkeley
- Histology image: 18404loa – Histology Learning System at Boston University
- Animation: Maturation of the Follicle and Oocyte
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