embryonic axis
an elongate thickening of blastoderm tissue; the primitive differentiation of the embryo

Dictionary of ichthyology. 2009.

Look at other dictionaries:

  • embryonic axis — an imaginary line from the head end to the tail end of an embryo or, before that, the line of elongation of the primitive streak and groove …   Medical dictionary

  • embryonic anideus — a blastoderm in which no embryonic axis develops …   Medical dictionary

  • Axis — The axis is the second cervical vertebra (symbol: C2). It is called the axis because the uppermost cervical vertebra (called the atlas) rotates about the odontoid process of C2. The joint between the axis and atlas is a pivot type of joint. It… …   Medical dictionary

  • embryonic shield — a thickened arm of the germ ring representing the future longitudinal axis of the embryo …   Dictionary of ichthyology

  • anterior-posterior axis — the principal axis of the embryo. Also called rostrocaudal axis and embryonic axis …   Dictionary of ichthyology

  • egg axis — noun : an embryonic axis passing through the animal and vegetal poles of an egg …   Useful english dictionary

  • reproductive system, plant — Introduction       any of the systems, sexual or asexual, by which plants reproduce. In plants, as in animals, the end result of reproduction is the continuation of a given species, and the ability to reproduce is, therefore, rather conservative …   Universalium

  • Gastrulation — of a diploblast: The formation of germ layers from a (1) blastula to a (2) gastrula. Some of the ectoderm cells (orange) move inward forming the endoderm (red). Gastrulation is a phase early in the embryonic development of most animals, during… …   Wikipedia

  • angiosperm — /an jee euh sperrm /, n. Bot. a plant having its seeds enclosed in an ovary; a flowering plant. Cf. gymnosperm. [ANGIO + SPERM] * * * ▪ plant Introduction       any member of the more than 300,000 species of flowering plants (division Anthophyta) …   Universalium

  • primitive streak — n an elongated band of cells that forms along the axis of an embryo early in gastrulation by the movement of lateral cells toward the axis and that develops a groove along its midline through which cells move to the interior of the embryo to form …   Medical dictionary

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