Definition of Primitive streak. Meaning of Primitive streak. Synonyms of Primitive streak

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Definition of Primitive streak

Primitive streak
Primitive Prim"i*tive, a. [L. primitivus, fr. primus the first: cf. F. primitif. See Prime, a.] 1. Of or pertaining to the beginning or origin, or to early times; original; primordial; primeval; first; as, primitive innocence; the primitive church. ``Our primitive great sire.' --Milton. 2. Of or pertaining to a former time; old-fashioned; characterized by simplicity; as, a primitive style of dress. 3. Original; primary; radical; not derived; as, primitive verb in grammar. Primitive axes of co["o]rdinate (Geom.), that system of axes to which the points of a magnitude are first referred, with reference to a second set or system, to which they are afterward referred. Primitive chord (Mus.), that chord, the lowest note of which is of the same literal denomination as the fundamental base of the harmony; -- opposed to derivative. --Moore (Encyc. of Music). Primitive circle (Spherical Projection), the circle cut from the sphere to be projected, by the primitive plane. Primitive colors (Paint.), primary colors. See under Color. Primitive Fathers (Eccl.), the acknowledged Christian writers who flourished before the Council of Nice, A. D. 325. --Shipley. Primitive groove (Anat.), a depression or groove in the epiblast of the primitive streak. It is not connected with the medullary groove, which appears later and in front of it. Primitive plane (Spherical Projection), the plane upon which the projections are made, generally coinciding with some principal circle of the sphere, as the equator or a meridian. Primitive rocks (Geol.), primary rocks. See under Primary. Primitive sheath. (Anat.) See Neurilemma. Primitive streak or trace (Anat.), an opaque and thickened band where the mesoblast first appears in the vertebrate blastoderm. Syn: First; original; radical; pristine; ancient; primeval; antiquated; old-fashioned.

Meaning of Primitive streak from wikipedia

- The primitive streak is a structure that forms in the early embryo in amniotes. In amphibians, the equivalent structure is the blastopore. During early...
- the embryo becomes asymmetric; (2) the primitive streak forms; (3) cells from the epiblast at the primitive streak undergo an epithelial to mesenchymal...
- differentiation of various avian body parts. Koller's sickle induces primitive streak and Hensen's node, which are major components of avian gastrulation...
- determines the cell movements that accompany the formation of the primitive streak, and helps to orient the embryo, and create bilateral symmetry. The...
- epiblast then down through the primitive streak. The first wave of epiblast cells to in****te through the primitive streak invades and displaces the hypoblast...
- towards the center form the early primitive streak. As these cells converge inward, a depression forms called the primitive groove and functions as an opening...
- way of the primitive streak which establishes bilateral symmetry. A primitive node (or primitive knot) forms in front of the primitive streak which is the...
- the primitive streak a third layer of cells, the mesoderm, extends laterally between the ectoderm and endoderm; the caudal end of the primitive streak forms...
- endomesodermal cells internalize along the frog blastopore and amniote primitive streak are surprisingly similar: the first cells that involute around the...
- the down-regulation of epithelial cadherin. Both formation of the primitive streak and mesenchymal tissue is dependent on the Wnt/β-catenin pathway. Specific...