Infobox Embryology Name Blastula GraySubject GrayPage Image Blastulation.png Caption Blastulation 1 morula, 2 blastula. Image2 Caption2 System CarnegieStage Days 4 Precursor Morula GivesRiseTo Gastrula MeshName MeshNumber DorlandsPre b 14 DorlandsSuf 12188083 Image Blastula PSF .jpg right 200px The blastula from Greek blastos , meaning sprout is a hollow sphere of cell biology cell s formed during an early stage of embryonic development in animals ref http www.britannica.com EBchecked topic 69108 blastula ref . The blastula is created when the zygote undergoes the cell division process known as cleavage embryo cleavage . ref Forg cs & Newman, 2005 http books.google.com books?id rUyVWQhk7CkC&pg PA24 p. 24 ref The blastula is preceded by the morula and is followed by the gastrula in the developmental sequence. citation needed date January 2011 A common feature of a vertebrate blastula is that it consists of a layer of blastomeres , known as the blastoderm , which surrounds an interior central cavity known as the blastocoel . ref cite book author Lombardi, Julian chapter Embryogenesis title Comparative vertebrate reproduction publisher Springer year 1998 isbn 9780792383369 page 226 url http books.google.com books?id cqQX9RMPAegC&pg PA226 ref ref Forg cs & Newman, 2005 http books.google.com books?id rUyVWQhk7CkC&pg PA27 p. 27 ref In mammal s, blastulation leads to the formation of the blastocyst , which must not be confused with the blastula. The blastocyst contains an embryoblast , which is homologous to the blastula. However, it also includes the trophoblast , which goes ... Forg cs, G. & Newman, Stuart A. chapter Cleavage and blastula formation title Biological physics ... Category Developmental biology Category Cloning developmental biology stub ar ca Bl stula cs Blastula de Blastula et Blastula es Bl stula eu Blastula it Blastula ht Blastila lt Blastul ja oc Blastula pl Blastula pt Bl stula ru sk Blastula sr fi Blastula sv Blastula tr Blastula ... more details
The blastoderm is a term for cell layers found in blastula s. In eutherian s File Blastula PSF en rotate 05.jpg right 200px In amniote s A blastoderm is the layer of cell biology cell s formed at one pole of macrolecithal eggs such as the yolk y egg biology egg of Aves bird s. The yolk prevents the division from taking place through the egg, resulting in meroblast ic cleavage during the many cleavage divisions. At the animal pole containing less yolk than the vegetal pole , the zygote divides and subdivides, forming the blastoderm, which gradually spreads around the yolk and forms the embryo . The blastoderm is composed of two layers, the epiblast and the hypoblast , which enclose the fluid filled blastocoel cavity. See also Blastodisc Embryology References MW 1935 date August 2008 Campbell Reece, Biology 7th edition, Pearson Publishing, 2005 Category Embryology developmental biology stub es Blastodermo ru ... more details
Orphan date December 2006 att July 2009 Unreferenced date December 2006 Yolk plug is the remaining patch of endodermal cells that is created during the formation of the ventral lip of the blastopore . It is a patch of large endodermal cells which remains exposed on the vegetal surface of the amphibian blastula that will eventually be internalized by epiboly . External links toast DEFAULTSORT Yolk Plug Category Amphibians Category Developmental biology amphibian stub developmental biology stub ja ... more details
Unreferenced date December 2009 Triploblasty is a condition of the blastula in which there are three primary germ layer s the ectoderm , mesoderm , and endoderm . The germ layers form during gastrulation of the blastula . Additionally, the term may refer to any ovum in which the blastoderm splits into three layers. citation needed date January 2011 All higher and intermediate animals from flat worms to humans , arise from a triploblastic ovum. Triploblastic organisms are organisms which develop from such an ovum. Generally speaking, triploblastic organisms belong to the Bilateria subregnum. Triploblastic organisms generally possess bilateral symmetry, which is where the clade Bilateria takes its name. Simpler animals qualified as diploblasty diploblastic , such as cnidaria which include jellyfish, corals and hydra , possess two germ layers. Even simpler animals such as sea sponge sponges within the formally termed Porifera phylum contain no true tissues. See also Embryo Category Developmental biology Developmental biology stub ca Triplobl stia de Triploblast es Tribl stico fr Triploblastique it Triploblastico it is when an organisim has three layers pl Tr jwarstwowce pt Tribl stico ru ... more details
Unreferenced stub auto yes date December 2009 Diploblasty is a condition of the blastula in which there are two primary germ layer s the ectoderm and endoderm . Diploblastic organisms are organisms which develop from such a blastula, and include cnidaria and ctenophora , formerly grouped together in the phylum Coelenterata, but later understanding of their differences resulted in them being placed in separate phyla. The endoderm allows them to develop true Biological tissue tissue . This includes tissue associated with the gut and associated glands. The ectoderm on the other hand gives rise to the epidermis, the nervous tissue, and if present, nephridia. Simpler animals, such as sea sponges , have one germ layer and lack true tissue organisation. All the more complex animals from flat worms to humans are triploblastic with three germ layers a mesoderm as well as ectoderm and endoderm . The mesoderm allows them to develop true Organ anatomy organs . See also Triploblasty Category Developmental biology Developmental biology stub ca Diplobl stia es Dibl stico fa fr Diploblastique nn Diploblastiske dyr pl Dwuwarstwowce pt Diplobl stico ru sv Diploblastica ... more details
Birds The germinal disc , also called the blastodisc , is a small, circular, white spot approximately 2 3 mm across on the surface of the yellow yolk of a bird s egg biology egg . Mammals The blastodisc refers to a round single cell layer of cells inside the blastula from which the embryo is going to form. References http www.ncbi.nlm.nih.gov bookshelf br.fcgi?book dbio&part A2564 Early Development in Fish http www.ncbi.nlm.nih.gov bookshelf br.fcgi?book dbio&part A2581 Early Development in Birds Category Oology Category Developmental biology biology stub zh yue ... more details
Infobox embryology Name PAGENAME Latin blastomerus GraySubject GrayPage Image Caption Image2 Caption2 MeshName MeshNumber Code Terminologia Embryologica TE E7.0.1.2.0.0.2 A blastomere is a type of Cell biology cell produced by division of the ovum egg after Human fertilization fertilization . See also Blastocoel Blastula Human fertilization Morula References Blastomere. Stedman s Medical Dictionary, 27th ed. 2000 . ISBN 0 683 40007 X Moore, Keith L. and T.V.N. Persaud. The Developing Human Clinically Oriented Embryology, 7th ed. 2003 . ISBN 0 7216 9412 8 Embryology Category Developmental biology Category Embryology ast Blast meru cs Blastomera de Blastomer es Blast mero fr Blastom re it Blastomero pl Blastomer pt Blast mero ru sr tr Blastomer uk zh ... more details
wiktionary Streak or streaking may refer to Streaking , running naked in a public place Streaking microbiology , a method of purifying micro organisms Streak mineralogy , the color left by a mineral dragged across a rough surface Streak moth , in the family Geometridae Streak film , a 2008 film Winning streak sports , consecutive wins in sport or gambling Losing streak sports Dell Streak , tablet computer by Dell Streak camera , device to measure short optical pulses The Streak , a 1974 record by Ray Stevens Archenteron , an indentation on a blastula Heath Streak , former Zimbabwe cricket team captain Aero Flight Streak Streak late 1940s single engine civilian aircraft See also Streaker disambiguation disambig ja ... more details
Unreferenced stub auto yes date December 2009 Invagination means to fold inward or to sheath. In biology , this can refer to a number of processes. Invagination is the morphogenetic processes by which an embryo takes form, and is the initial step of gastrulation , the massive reorganization of the embryo from a simple spherical ball of Cell biology cells , the blastula , into a multi layered organism , with differentiated germ layer s endoderm, mesoderm, and ectoderm. More localized invaginations also occur later in embryonic development, to form coelom, etc. Invagination is the formation of a cleavage furrow during cytokinesis in animal cells. The inner membrane of a mitochondrion invaginates to form cristae, thus providing a much greater surface area to accommodate the protein complexes and other participants that produce ATP. Invagination occurs during endocytosis and exocytosis when a vesicle forms within the cell and the membrane closes around it. Invagination of a part of the intestine into another part is called Intussusception medical disorder intussusception . In the humanities Used to explain a special kind of metanarrative . Used by Rosalind Krauss and Jacques Derrida The Law of Genre , Glyph 7 1980 . In Geology Used to describe a deep depression of strata. Used by Donald L. Baars in The Colorado Plateau Category Cellular processes Category Developmental biology Developmental biology stub es Invaginaci n pt Invagina o ... more details
The primitive gut that forms during gastrulation in the developing blastula is known as the archenteron . It develops into the digestive tract of an animal. Formation of the Archenteron in Sea Urchins See Gastrulation . As primary mesenchyme cells detach from the vegetal pole in the gastrula and enter the fluid filled cavity in the center the blastocoel , the remaining cells at the vegetal pole flatten to form a vegetal plate . This buckles inwards towards the blastocoel in a process called invagination . The cells continue to be rearranged until the shallow dip formed by invagination transforms into a deeper, narrower pouch formed by the gastrula s endoderm . This narrowing and lengthening of the archenteron is driven by convergent extension . The open end of the archenteron is called the blastopore . The filopodia thin fibers formed by the mesenchyme cells found in a late gastrula contract to drag the tip of the archenteron across the blastocoel. The endoderm of the archenteron will fuse with the ectoderm of the blastocoel wall. At this point gastrulation is complete, and the gastrula has a functional digestive tube. The indentation that is actually formed is called the lip of the blastopore in amphibian s and fish , and the primitive streak in bird s and mammal s. Each is controlled by the dorsal blastopore , and primitive node also known as Hensen s node , respectively. External links http chsweb.lr.k12.nj.us mstanley outlines animals antax image51.gif Diagram developmental biology stub Embryology Category Developmental biology ca Arqu nteron cs Prvost evo de Archenteron es Arqu nteron fr Archent ron it Archenteron ja pl Prajelito pt Arqu ntero zh ... more details
Infobox Embryology GraySubject 6 GrayPage 47 DorlandsPre b 14 DorlandsSuf 12188030 A blastopore is an opening into the archenteron during the embryonic stages of an organism. The Embryological origins of the mouth and anus distinction between protostome s and deuterostome s is based on the direction in which the mouth stoma develops in relation to the blastopore. Protostome derives from the Greek word protostoma meaning first mouth whereas Deuterostome s etymology is second mouth from the words second and mouth . The major distinctions between deuterostomes and protostomes are found in embryonic development Mouth anus In protostome development, the first opening in development, the blastopore, becomes the animal s mouth . In deuterostome development, the blastopore becomes the animal s anus . Cleavage embryo Cleavage Protostomes have what is known as spiral cleavage which is determinate , this meaning that the fate of the cells is determined as they are formed. Deuterostomes have what is known as radial cleavage that is indeterminate . See also Blastula External links eMedicineDictionary Blastopore developmental biology stub Embryology Category Developmental biology ca Blast por cs Prvo sta de Urmund es Blastoporo fr Blastopore it Blastoporo ja pl Prag ba pt Blast poro ru sr uk ... more details
ball of at least sixteen cells called the morula . The different cells derived from cleavage, up to the blastulablastula stage , are called blastomere s. Depending mostly on the amount of yolk in the egg ... bare url http education.yahoo.com reference gray subjects subject 6 ref Formation of the blastula After the cleavage has produced over 100 Cell biology cell s, the embryo is called a blastula . ref Campbell The blastula is usually a spherical layer of cells the blastoderm surrounding a fluid filled ... , ref NCBI characterized by an inner cell mass that is distinct from the surrounding blastula. The blastocyst must not be confused with the blastula even though they are similar in structure, their cells ... main Gastrulation During gastrulation cells migrate to the interior of the blastula, as a consequence ... Polar proliferation Cells at the polar ends of the blastula gastrula proliferate, mostly at the animal ... more details
. FoxI1e activates ectoderm formation and controls cell position in the Xenopus blastula. Development ... layer formation. Identification of Ectodermin and FAM A cDNA library from the blastula stage of a frog ... into several Xenopus embryos at a four cell stage and looked in early blastula embryos for an expansion ... Ectodermin mRNA is maternally deposited in the animal pole of the egg. In the early blastula stage ... compared to vegetal region of an early blastula embryo. Also, high expression of this gene was observed ... region of the early blastula embryo, could potentially be the inhibitors of FoxI1e. ref name Mir07 ... and endoderm. Vegetal structures form late blastula masses that normally would give rise to endoderm ... EctodermalSpecification2.png Ectoderm induction in early blastula in Xenopus embryo. gallery References ... more details
lead too long date December 2011 sections date December 2011 Refimprove date July 2007 File Blastulation.png thumb 240px right 1 morula, 2 blastula File Gastrulation.png thumb 240px 1 blastula, 2 gastrula with blastopore orange ectoderm, red endoderm. Embryology from Ancient Greek Greek lang grc , embryon , unborn, embryo and lang grc , logy logia is a science which is about the development of an embryo from the fertilization of the ovum to the fetus stage. After cleavage, the dividing cells, or morula , becomes a hollow ball, or blastula , which develops a hole or pore at one end. In bilateria bilateral animal s, the blastula develops in one of two ways that divides the whole animal kingdom into two halves see Embryological origins of the mouth and anus . If in the blastula the first pore blastopore becomes the mouth of the animal, it is a protostome if the first pore becomes the anus then it is a deuterostome . The protostomes include most invertebrate animals, such as insects, worms and molluscs, while the deuterostomes include the vertebrates . In due course, the blastula changes into a more differentiated structure called the gastrula . The gastrula with its blastopore soon develops three distinct layers of cells the germ layers from which all the bodily organs and tissues then develop The innermost layer, or endoderm , gives rise to the digestive organs, lungs and bladder. The middle layer, or mesoderm , gives rise to the muscles, skeleton and blood system. The outer layer of cells, or ectoderm , gives rise to the nervous system and skin. In humans, the term embryo refers to the ball of dividing cells from the moment the zygote implants itself in the uterus wall until the end of the eighth week after conception. Beyond the eighth week, the developing human is then called a fetus. Embryos in many species often appear similar to one another in early developmental stages. The reason for this similarity is because species have a shared evolutionary h ... more details
Unreferenced date October 2006 File Oocyte Poles.jpg thumb An oocyte with poles depicted In developmental biology , a blastula embryo is divided into two hemispheres the animal pole and the vegetal pole . The animal pole consists of small cells that divide rapidly, in contrast with the vegetal pole below it. The animal pole draws its name from its liveliness relative to the slowly developing vegetal pole. In some cases, the animal pole is thought to differentiate into the later embryo itself, forming the three primary germ layers and participating in gastrulation . The vegetal pole contains large yolky cells that divide very slowly, in contrast with the animal pole above it. The vegetal pole draws its name from its inactivity relative to the lively animal pole. In some cases, the vegetal pole is thought to differentiate into the extraembryonic membranes that protect and nourish the developing embryo, such as the placenta in mammals and the chorion in birds. In frog, Xenopus laevis pigment pattern provides the oocyte with features of radially symmetrical body with a distinct polarity. The animal hemisphere is dark brown, and the vegetal hemisphere is only weakly pigmented. The axis of symmetry passes through on one side the animal pole, and on the other side the vegetal pole. The two hemispheres are separated by an unpigmented equatorial belt. Polarity has a major influence on the mergence of the embryonic structures. In fact, the axis polarity serves as one coordinate of geometrical system in which early embryogenesis is organised. ref P. Hausen, M. Riebesell The Early Embryonic Development of Xenopus Laevis An Atlas of the Histology ISBN 3 921 15 4 9 ref References references See also gastrulation embryogenesis Category Developmental biology Developmental biology stub ... more details
Infobox Embryology Name Blastocyst Latin blastocystis GraySubject GrayPage Image Blastocyst English.svg Caption Image2 Caption2 System CarnegieStage 3 Days 8 Precursor Morula GivesRiseTo Gastrula , Inner cell mass MeshName Blastocyst MeshNumber A16.254.085 Code Terminologia Embryologica TE E2.0.1.2.0.0.12 File PorcineBlastocyst.jpg thumb A pig blastocyst. The bar is 0.1 mm. See also Blastocystis , a single celled parasite. The blastocyst is a structure formed in the early embryogenesis of mammal s, after the formation of the morula . It is a specifically mammalian example of a blastula . citation needed date January 2011 It possesses an inner cell mass ICM , or inner cell mass embryoblast , which subsequently forms the embryo , and an outer layer of cells, or trophoblast , which later forms the placenta . The trophoblast surrounds the inner cell mass and a fluid filled blastocyst cavity known as the blastocoele or the blastocystic cavity. The human blastocyst comprises 70 100 Cell biology cells . Blastocyst formation begins at day 5 after fertilization in humans, when the blastocoele opens up in the morula, a process known as hatching. citation needed date January 2011 Parts of the blastocyst The blastocyst consists of two primary cell types the inner cell mass , also known as the embryoblast this part of the embryo is used in stem cell research the trophoblast , a layer of cells surrounding the inner cell mass and the blastocyst cavity blastocoele The former is the source of embryonic stem cells and gives rise to all later structures of the adult organism. The latter combines with the maternal endometrium to form the placenta in eutherian mammals. Formation of the blastocyst The morula is a solid ball of about 16 undifferentiated, spherical cells. As cell division continues in the morula, the blastomeres change their shape and tightly align themselves against each other. This is called compaction and is likely mediated by cell surface adhesion glycoproteins. Refere ... more details
About the stage in embryonic development the science blog by PZ Myers Pharyngula blog Expert subject biology date September 2008 In developmental biology , the pharyngula is a stage in embryo nic development. ref name Gilbert 2003 cite book author Gilbert SF title Developmental mechanisms of evolutionary change. in Developmental Biology edition 6th publisher Sinauer Associates year 2000 isbn 0 87893 243 7 ref Named by William Ballard , ref name ballard cite journal author Ballard WW title Morphogenetic Movements and Fate Maps of Vertebrates journal American Zoologist year 1981 volume 21 issue 2 pages 391&ndash 9 url http icb.oxfordjournals.org cgi content abstract 21 2 391 doi 10.1093 icb 21.2.391 ref the pharyngula stage follows the blastula , gastrula and neurula stages. At the pharyngula stage, all vertebrate embryos show remarkable similarities, ref name zfin cite web url http zfin.org zf info zfbook stages phar.html title ZFIN Pharyngula Period Description author Sprague, J., et al. publisher Zebrafish Information Network date 2006 accessdate 2007 07 18 ref containing the following features notochord dorsal hollow nerve cord post anal tail, and a series of paired branchial groove s. The branchial grooves are matched on the inside by a series of paired gill pouch es. In fish, the pouches and grooves eventually meet and form the gill slits, which allow water to pass from the pharynx over the gills and out the body. In the other vertebrates, the grooves and pouches disappear. In humans, the chief trace of their existence is the eustachian tube and auditory canal which interrupted only by the eardrum connect the pharynx with the outside of the head. The existence of a common pharyngula stage for vertebrates was first proposed by Germany German biologist Ernst Haeckel 1834&ndash 1919 in 1874. ref Haeckel E 1874 Anthropogenie oder Entwickelungsgeschichte des Menschen. Engelmann, Leipzig ref See also Evolutionary developmental biology Embryogenesis Embryo drawing Reca ... more details
blastula cells ref cite journal journal Proc Natl Acad Sci U S A. date 1952 May volume 38 pages 455 463 pmid 16589125 title Transplantation of Living Nuclei From Blastula Cells into Enucleated Frogs ... more details
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