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Topic: Blastula


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In the News (Fri 24 May 19)

  
  Quia - Cleavage and Formation of the Blastula
highly ciliated permanent blastula forming from animal cells of sea urchin
layer of bird blastula furthest from the yolk
amphibian blastula cells in the region where blastocoel roof and basement meet
www.quia.com /jg/118816list.html   (316 words)

  
  Blastula | World of Biology
A blastula is an early embryo that has been formed by cleavage, or subdivision, of a fertilized egg.
Instead of a blastula, a thin layer of cells forms on the surface of the yolk known as the blastoderm.
Blastula cells are not considered to have undergone differentiation.
www.bookrags.com /research/blastula-wob   (199 words)

  
  Animal   (Site not responding. Last check: 2007-11-05)
Blastulae are probably representative of the sort of colonies animals evolved from; similar forms occur among other flagellates, e.g.
The outer layer (ectoderm) corresponds to the surface of the blastula and the inner layer (endoderm) is formed by cells that migrate into the interior.
The blastula invaginates without filling in first, so the endoderm is simply its inner lining, and the interior then fills in to become a third layer (mesoderm) between the others.
www.icyclopedia.com /encyclopedia/a/an/animal.html   (1419 words)

  
 Blastula Summary
It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells surrounding a central fluid-filled cavity called the blastocoel.
The blastula follows the morula and precedes the gastrula in the developmental sequence.
A whitefish blastula is often used to help study the processes of mitosis in animal cells.
www.bookrags.com /Blastula   (421 words)

  
 The evolution of embryological development
A blastula still forms after the cleavage of the egg, but the second layer of cells is formed by the inward migration of cells, usually from all parts of the surface of the sphere.
The gradients in the blastula are oriented around the mouth, and once the inner gut cells have migrated inward, formed a solid core, and made contact with the ectoderm, the split forming in their midst could be made to open up toward the mouth's location on the blastula by the gradients in the ectoderm.
After gastrulation is complete and the anus is formed, one cell on each side of the blastopore migrates into the area between the ectoderm and endoderm, multiplies into a solid mass of cells, and a mesodermal coelom is formed by a split that starts in their midst.
www.twow.net /ObjText/OtkCbGeRRS04D.htm   (8435 words)

  
 Lab Practical Study Guide
Blastula – sea urchin embryos in the blastula stage have an outer ring of cells and a hollow blastoceol.
Blastula – The same as that of the sea urchin blastula.
Blastula – Frog embryo that contains a blastoceol located in the animal hemisphere of the embryo.
pages.cabrini.edu /ddunbar/Bio430/lab_practical_study_guide.htm   (460 words)

  
 biology - Blastula
The blastula is an early stage of embryonic development in animals.
It is produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a fluid-filled cavity.
A blastula has around 128 cells, with a large central cavity called the blastocoel.
www.biologydaily.com /biology/Blastula   (82 words)

  
 HE6
This boundary is perpendicular to the animal-vegetal axis and thus is parallel to the horizontal planes that separate blastomere tiers during early cleavage.
Immunolocalization of HE6 protein in prehatching blastulae embryos raised in the presence of Zn could not be distinguished from that of the control embryos.
Immunolocalization of HE6 protein in prehatching blastulae of embryos raised in the presence of Li shows that the size of the territory in which protein is detected is dramatically reduced.
www.bio.davidson.edu /Courses/genomics/mirror/urchin/u1hatc.htm   (855 words)

  
 ap lab 3 sample4 mitosis   (Site not responding. Last check: 2007-11-05)
The whitefish blastula is formed directly after the egg is fertilized.
Explain why the whitefish blastula and onion root tip are selected for a study of mitosis.
The blastula is generally a ball of cells that are rapidly going under mitosis.
sps.k12.ar.us /massengale/ap_lab_3_sample4_mitosis.htm   (1172 words)

  
 27
Blastula: The cells of morula arrange themselves so as to enclose a cavity (blastocoel) surrounded by a layer of cells.
Gastrula: Further rearrangement of cells converts the blastula into a three-layered structure with a new cavity (archenteron) and is called gastrula.
Blastula encloses blastocoel surrounded by a layer of cells whereas gastrula encloses archenteron surrounded by 3 germlayers
www.nos.org /bio12/b4h27.1.htm   (2518 words)

  
 Cleavage - The Blastula   (Site not responding. Last check: 2007-11-05)
The blastula is a hollow ball of cells organized into an epithelial monolayer.
Midway through the blastula stage, the embryo secretes hatching enzyme, which results in proteolytic degradation of the fertilization envelope.
Both are attached to the apices of the cells in the wall of the blastula, which extend microvilli into these extracellular matrix layers.
worms.zoology.wisc.edu /urchins/SUcleavage_blastula.html   (170 words)

  
 Dorlands Medical Dictionary
kystis bladder] the mammalian conceptus in the postmorula stage; it is like a blastula in having a fluid-filled cavity, but unlike it in having the surface layer not exclusively embryoblast but mainly or entirely trophoblast, in having an eccentric embryoblast, and in not being limited to one germ layer.
(blas´tu-lə) pl. blas´tulae [L.] the usually spherical structure produced by cleavage of a zygote, consisting of a single layer of cells (blastoderm) surrounding a fluid-filled cavity (blastocoele); called also blastosphere.
(blas”tu-la´shən) conversion of a morula to a blastula by the development of a central cavity (the blastocoele, blastocyst, or cleavage cavity).
www.mercksource.com /pp/us/cns/cns_hl_dorlands.jspzQzpgzEzzSzppdocszSzuszSzcommonzSzdorlandszSzdorlandzSzdmd_b_14zPzhtm   (2124 words)

  
 lab 3 sample ap mitosis & meiosis   (Site not responding. Last check: 2007-11-05)
It is easily observed in cells that are growing at a rapid pace such as whitefish blastula or onion root tips, which are used in this lab.
Prepared slides of whitefish blastula and onion root tips were observed under the 10X and 40X objectives.
The blastula is a hollow ball of cells that forms from the fertilization of an egg.
sps.k12.ar.us /massengale/lab_3_sample_ap_mitosis__meiosis.htm   (1329 words)

  
 spLBP/p40
Whole mount immunocytochemistry showed that at four- to eight cell and mesenchyme blastula stage embryos spLBP/p40 protein is distributed throughout the cytoplasm of all cells.
Whole mount immunocytochemistry indicated that the distribution of the protein is relatively uniform at four- to eight cell and mesenchyme blastula stage embryos throughout all cells, except for newly ingressed primary mesenchyme cells which stain less intensely than cells of the epithelium.
In late prism stages the significant staining is observed in cells of the gut, primary mesenchyme, and oral epithelium.
www.bio.davidson.edu /Courses/genomics/mirror/urchin/u1lpbp.htm   (482 words)

  
 LBS 144-A Comparison of the Development of Sea Urchins and Medakas   (Site not responding. Last check: 2007-11-05)
The blastula is a ball of cells enclosing a fluid-filled space.
The blastula is formed during the early stages of development.
The meroblastic pattern of cleavage forms a blastula in the shape of a disk.
www.msu.edu /~hartwi15/compare.html   (419 words)

  
 The Story Behind "Blastula"
“Blastula” seemed to be an appropriate name as it is something we’ve all had.
A blastula or blastosphere is a spherical protective covering that forms over fetuses while in the zygotic stage.
In a sense it is a sphere that enabled each of us to pass through time, space, and (perhaps) dimensions.
home.mindspring.com /~darrenmichaels/id3.html   (353 words)

  
 Animal - Facts, Information, and Encyclopedia Reference article
A zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation.
In sponges, blastula larvae swim to a new location and develop into a new sponge.
It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers - an external ectoderm and an internal endoderm.
www.startsurfing.com /encyclopedia/a/n/i/Animal.html   (2023 words)

  
 Amazon.com: blastula   (Site not responding. Last check: 2007-11-05)
The subcellular structure of the blastula of Limnaea stagnalis L. (Mollusca) and the mobilization of the nutrient reserve by J. G Bluemink (Unknown Binding - 1967)
The function of membranes and cell bridges in the formation of the blastula in Echinoderms by Arthur Russell Moore (Unknown Binding - 1931)
as the equivalent of a blastula in embryology.
www.amazon.com /s?ie=UTF8&keywords=blastula&tag=icongroupinterna&index=blended&link_code=qs&page=1   (903 words)

  
 Principles of Developmental Biology
During cleavage, tight junctions form [fig 4.10] and ions are pumped inside the embryo, raising osmotic pressure and causing the blastocoel to form.
While the fate maps show that regions of the late blastula can be predicted to follow a particular fate during normal development, those regions may not yet be committed to that exact fate if developed in isolation.
A third type of map, called a competence map, that describes the developmental potential of different regions of the blastula when developed in different developmental contexts via transplantation experiments can also be constructed.
www.wwnorton.com /college/biology/devbio/chaptersummary/ch4.htm   (1216 words)

  
 Urban Dictionary: blastula
blastula isn't defined yet, but these are pretty close:
You may have heard that embryos go through a blastula stage, then a gastrula stage, then a neurula…pharyngula is next in the series.
At the pharyngula stage, the vertebrate embryo is at the phylotypic stage, an evolutionarily conserved period when vertebrate embryos of all species are most similar to one another.
www.urbandictionary.com /define.php?term=blastula   (294 words)

  
 A Raf/MEK/ERK signaling pathway is required for development of the sea urchin embryo micromere lineage through ...
(A) Sixty-cell stage, (F) early blastula, (B,C) prehatching blastula, (G,H) hatching blastula, (I,J) early mesenchyme blastula, (D,K) mesenchyme blastula, (L,M) early gastrula (arrows in M indicate staining in the ectoderm adjacent to the PMC clusters) and (E,N,O) late gastrula.
ERK activity is required first between the prehatching blastula stage and the swimming blastula stage for ingression of the PMCs (green), and then during gastrulation for differentiation of the PMCs into spicules (yellow).
At the blastula stage, activation of the Raf/MEK/ERK signaling pathway by an unknown factor Y, allows phosphorylation of Ets1, which is crucially required for the maintenance of alx1 and Delta expression in the micromeres, and for the initiation of skeT/Tbr and other downstream genes in this lineage.
dev.biologists.org /cgi/content/full/131/5/1075   (7541 words)

  
 Reconstitution of Membranes and Embryonic Development in Dissociated Blastula Cells of the Sea Urchin by Reinsertion of ...
Reconstitution of Membranes and Embryonic Development in Dissociated Blastula Cells of the Sea Urchin by Reinsertion of Aggregation-Promoting Membrane Proteins Extracted with Butanol -- Noll et al.
Blastula embryos of the sea urchin Paracentrotus lividus, when dissociated into single cells by exposure to Ca - and Mg -free sea water, reassociate spontaneously to form aggregates capable of development to the final larval form (pluteus).
This aggregation is prevented by Fab fragments obtained by immunization with purified membranes from blastula embryos.
www.pnas.org /cgi/content/abstract/76/1/288   (272 words)

  
 ZFIN Embyonic Developmental Stages
Blastula Period (2 1/4 - 5 1/4 h) Description and Stages
Camera lucida drawings of face views during cleavage, showing lineal relationships of the blastomeres from the 4-cell stage through the 64-cell stage.
Face views of embryos during the blastula period.
zfin.org /zf_info/zfbook/stages/stages.html   (448 words)

  
 Animal Developmental Biology
That is, found integrally a part of but nevertheless in one relatively small section of the blastula.
The trophoblast, generally, are the cells which constitute the wall of the hollow ball at the blastula stage.
This is particularly to within the cavity of blastula (i.e., the hollow which defines the blastula and which ultimately becomes a hollow between the endoderm and ectoderm layers).
www.mansfield.ohio-state.edu /~sabedon/biol1130.htm   (1894 words)

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