منابع مشابه
Germ Layers
A germ layer is a group of cells in an embryo that interact with each other as the embryo develops and contribute to the formation of all organs and tissues. All animals, except perhaps sponges, form two or three germ layers [6]. The germ layers [6] develop early in embryonic life, through the process of gastrulation [7]. During gastrulation [7], a hollow cluster of cells called a blastula [8] ...
متن کاملGerm Layers
A germ layer is a group of cells in an embryo that interact with each other as the embryo develops and contribute to the formation of all organs and tissues. All animals, except perhaps sponges, form two or three germ layers [6]. The germ layers [6] develop early in embryonic life, through the process of gastrulation [7]. During gastrulation [7], a hollow cluster of cells called a blastula [8] ...
متن کاملGastrulation: making and shaping germ layers.
Gastrulation is a fundamental phase of animal embryogenesis during which germ layers are specified, rearranged, and shaped into a body plan with organ rudiments. Gastrulation involves four evolutionarily conserved morphogenetic movements, each of which results in a specific morphologic transformation. During emboly, mesodermal and endodermal cells become internalized beneath the ectoderm. Epibo...
متن کاملEvidence of male germ cell redifferentiation into female germ cells in planarian regeneration.
The source and fate of blastema cells are important and still unresolved problems in planarian regeneration. In the present investigation we have attempted to obtain new evidence of cell dedifferentiation-redifferentiation by using a polyploid biotype of Dugesia lugubris s.l. This biotype is provided with a natural karyological marker which allows the discrimination of triploid embryonic and so...
متن کاملOn the role of germ cells in planarian regeneration
Specimens from a polyploid biotype of Dugesia lugubris s.l. were used to clarify the role and fate of germ cells during planarian regeneration. These specimens provide a useful karyological marker because embryonic and somatic cells (3n = 12) can be easily distinguished from male (2n = 8) and female (6n = 24) germ cells by their chromosome number. We succeed in demonstrating how primordial germ...
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ژورنال
عنوان ژورنال: Archiv für Entwicklungsmechanik der Organismen
سال: 1904
ISSN: 0949-944X,1432-041X
DOI: 10.1007/bf02163657