Primitive Streak

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primitive streak [′prim·əd·iv ′strēk]

(embryology)

A dense, opaque band of ectoderm in the bilaminar blastoderm associated with the morphogenetic movements and proliferation of the mesoderm and notochord; indicates the first trace of the vertebrate embryo.

Primitive Streak

a longitudinal thickening of the outer layer of the embryonic disk, or blastodisk, in the embryos of birds, mammals, and humans; it is formed during the process of gastrulation. Mesodermal cells migrate from the primitive streak to the area between the ectoderm and endoderm. These cells later form the somites and lateral plates. In the anterior end of the primitive streak, the cell accumulation known as Hensen’s node develops. This cellular material becomes the notochord.

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No references found			Furthermore, at about 14 days, the appearance of the primitive streak in the embryo corresponds to the beginning of neural functions. Selected annotated bibliography on stem cell research and cloning by Daly, Conrad C. / Southern Medical Journal For example, bioethics commissions in England, Canada, and the United States that have studied embryo status have all recommended drawing the moral line at the development of the so-called primitive streak at about fourteen days, when twinning is no longer possible and the trajectory of individual development has begun. Catholics & IVF: the next big battleground? by Lauritzen, Paul / Commonweal Last year Irish apprentice Sean Cleary died after suffering severe head injuries in a fall at Galway and Caroline Pratt, 42, was killed just two weeks ago when her horse, Primitive Streak, fell on her in the Burghley Horse Trials. Racing: Risk jockeys; RACING IS THE SPORT OF KINGS BUT IT'S FULL OF ... by Daily Record (Glasgow, Scotland)			primibrach priming priming coat priming composition priming of the tides priming pump Primitiopsacea Primitive primitive abstract data type primitive abundant number Primitive Accumulation of Capital primitive cell primitive circle Primitive Communal System primitive element primitive equations primitive gut Primitive Human Herd primitive lattice primitive period primitive period parallelogram primitive plane primitive polynomial primitive pseudoperfect number Primitive Root Primitive Streak primitive translation primitive water Primitivism Primo de Rivera Primo de Rivera, Jose Antonio Primo de Rivera, José Antonio Primo de Rivera, Miguel Primofilices Primogeniture Primogeniture, Decree on primordial primordial black holes primordial germ cell primordial gut primordium Primore Krai Primore Operation of 1922 Primorsk Primorskii Primorskii Kurort Primorskii Range Primorsko-Akhtarsk Primorskoe Primorsky Kray primrose			Primitive ovum Primitive ovum primitive ovum, primordial ovum primitive ovum, primordial ovum primitive ovum, primordial ovum primitive period primitive period parallelogram primitive person Primitive pit Primitive plane Primitive plane Primitive polynomial Primitive pseudoperfect number Primitive Pythagorean Triple Primitive Recursive Kernel Primitive reflex Primitive reflexes Primitive reflexes Primitive reflexes primitive ridge Primitive rocks Primitive root Primitive root of unity Primitive Securities Primitive security Primitive segments Primitive segments Primitive segments Primitive semiperfect number Primitive sheath Primitive Streak primitive streaks primitive streaks primitive streaks Primitive Switching Element primitive translation Primitive Trigeminal Artery Variant primitive water Primitive yolk sac Primitive yolk sac Primitive yolk sac Primitive, Grain and Point Configuration primitively primitively primitively primitively primitiveness primitiveness primitiveness primitiveness Primitives Primitives Primitives Primitives primitivism primitivism Primitivism (art movement) Primitivism (art movement) Primitivism (art) Primitivism (art) primitivist

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