Germ Layers
نویسنده
چکیده
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] reorganizes into two primary germ layers [6]: an inner layer, called endoderm [9], and an outer layer, called ectoderm [10]. Diploblastic organisms have only the two primary germ layers [6]; these organisms characteristically have multiple symmetrical body axes (radial symmetry), as is true of jellyfish, sea anemones, and the rest of the phylum Cnidaria [11]. All other animals are triploblastic, as endoderm [9] and ectoderm [10] interact to produce a third germ layer, called mesoderm [12]. Together, the three germ layers [6] will give rise to every organ in the body, from skin and hair to the digestive tract.
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] ...
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Notochord is an axial structure derived of embryonic mesoderm and in addition to structural supporting role in inducing nearby germinal layers, it has a basic role in formation of organs such as vertebral column, axial vessels, neural tube and primitive gut. This organ undergoes essential changes during the development process. First, arises from the primitive node and terms notochordal process...
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Mammalian inner cell mass cells undergo lineage-specific differentiation into germ layers of endoderm, mesoderm and ectoderm during gastrulation. It has been a long-standing challenge in developmental biology to replicate these organized germ layer patterns in culture. Here we present a method of generating organized germ layers from a single mouse embryonic stem cell cultured in a soft fibrin ...
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Next to cells, germ layers—the fundamental embryonic cell layers from which tissues and organs form—are the most long-standing units of structural organization of the embryos of multicellular animals (metazoans). First identified in chicken embryos by Pander in 1817, the history of germ layers through the nineteenth century was one of increasing appreciation of their generality and importance:
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