翻訳と辞書 Words near each other ・ Evolution of human colour vision ・ Evolution of human intelligence ・ Evolution of Infectious Disease ・ Evolution of influenza ・ Evolution of insects ・ Evolution of lemurs ・ Evolution of mammalian auditory ossicles ・ Evolution of mammals ・ Evolution of Management Systems ・ Evolution of metal ions in biological systems ・ Evolution of microeconomics ・ Evolution of molluscs ・ Evolution of morality ・ Evolution of motorway construction in European nations ・ Evolution of motorway construction in European Union member states ・ Evolution of nervous systems ・ Evolution of olfaction ・ Evolution of Pakistan Eastern Command plan ・ Evolution of photosynthesis ・ Evolution of primates ・ Evolution of Quartz C-axis Pole Figures during Dynamic Recrystallization ・ Evolution of reptiles ・ Evolution of schizophrenia ・ Evolution of sexual reproduction ・ Evolution of sirenians ・ Evolution of snake venom ・ Evolution of spiders ・ Evolution of tetrapods ・ Evolution of the brain ・ Evolution of the cochlea Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Evolution of nervous systems ： ウィキペディア英語版 Evolution of nervous systems The evolution of nervous systems dates back to the first development of nervous systems in animals (or metazoans). Neurons developed as specialized electrical signaling cells in multicellular animals, adapting the mechanism of action potentials present in motile single-celled and colonial eukaryotes. Simple nerve nets seen in animals like cnidaria evolved first, followed by nerve cords in bilateral animals - ventral nerve cords in invertebrates and dorsal nerve cords surrounded by a notochord in chordates. Bilateralization led to the evolution of brains, a process called cephalization. ==Neural precursors== Action potentials, which are necessary for neural activity, evolved in single-celled eukaryotes. These use calcium rather than sodium action potentials, but the mechanism was probably adapted into neural electrical signaling in multicellular animals. In some colonial eukaryotes such as Obelia electrical signals do propagate not only through neural nets, but also through epithelial cells in the shared digestive system of the colony. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Evolution of nervous systems」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.