Editing Blastocoel (section)

{{Short description|Fluid-filled or yolk-filled cavity that forms in the blastula}}
{{Infobox embryology
| Name          = Blastocoel
| Latin         =
| Image         =Blastocyst_-_2.png
| Caption       = Mammalian blastocoel
| Image2        = Diagram of Blastocyst stage.png
| Caption2      = <br>Schematic diagram showing the [[blastocyst]], with its [[inner cell mass|embryoblast (inner cell mass)]] and its [[trophoblast]] layer, alongside the surface of the [[endometrium]].
| System        =
| CarnegieStage = 3
| Days          = 5
| Precursor     = [[Morula]]
| GivesRiseTo   = [[Gastrula]], <br>[[primitive yolk sac]]
}}
The '''blastocoel''' ({{IPAc-en|ˈ|b|l|æ|s|t|ə|ˌ|s|iː|l}}), also spelled '''blastocoele''' and '''blastocele''', and also called '''cleavage cavity''', or '''segmentation cavity'''<ref name="MW2">{{cite web |title=Definition of BLASTOCOEL |url=https://www.merriam-webster.com/dictionary/blastocoel |website=Merriam-Webster |language=en}}</ref> is a fluid-filled or yolk-filled cavity that forms in the [[blastula]] during very early [[embryonic development]]. At this stage in mammals the blastula is called the [[blastocyst]], which consists of an outer [[epithelium]], the [[trophectoderm]], enveloping the [[inner cell mass]] and the blastocoel .

It develops following [[cleavage (embryo)|cleavage]] of  the [[zygote]] after [[fertilization]].<ref name="CIBA">{{cite book |last1=Biggers |first1=JD |last2=Borland |first2=RM |last3=Powers |first3=RD |chapter=Transport Mechanisms in the Preimplantation Mammalian Embryo |title=Ciba Foundation Symposium 52 - the Freezing of Mammalian Embryos |journal=Ciba Foundation Symposium |series=Novartis Foundation Symposia |date=1977 |volume=52 |issue=52 |pages=129–53 |doi=10.1002/9780470720332.ch7 |pmid=145938|isbn=9780470720332 }}</ref><ref name="Kalt">{{cite journal |last1=Kalt |first1=Marvin R. |title=The relationship between cleavage and blastocoel formation in Xenopus laevis. I. Light microscopic observations |journal=Journal of Embryology and Experimental Morphology |volume=26 |issue=1 |pages=37–49 |year=1971 |pmid=5565077 |url=http://dev.biologists.org/content/26/1/51.short }}</ref> It is the first fluid-filled cavity or [[lumen (anatomy)|lumen]] formed as the embryo enlarges,<ref name="Heasman">{{cite journal |last1=Heasman |first1=Janet |last2=Crawford |first2=Aaron |last3=Goldstone |first3=Kim |last4=Garner-Hamrick |first4=Peggy |last5=Gumbiner |first5=Barry |last6=McCrea |first6=Pierre |last7=Kintner |first7=Chris |last8=Noro |first8=Chikako Yoshida |last9=Wylie |first9=Chris |title=Overexpression of cadherins and underexpression of β-catenin inhibit dorsal mesoderm induction in early Xenopus embryos |journal=Cell |volume=79 |issue=5 |pages=791–803 |year=1994 |pmid=7528101 |doi=10.1016/0092-8674(94)90069-8 |s2cid=33403560 }}</ref> and is the essential precursor for the [[Cellular differentiation|differentiated]] [[gastrulation|gastrula]].<ref name="Gilbert">{{cite book |last1=Gilbert |first1=Scott F. |title=Developmental biology |date=2010 |publisher=Sinauer Associates |location=Sunderland, Mass. |isbn=978-0-87893-384-6 |edition=9th}}</ref>{{page needed|date=April 2016}} In the ''[[Xenopus]]'' a very small cavity has been described in the two-cell stage of development.<ref name="Wolpert1">{{cite book |last1=Wolpert |first1=Lewis |title=Principles of development |date=2015 |location=Oxford, United Kingdom |isbn=9780199678143 |page=375 |edition=Fifth}}</ref>