...He was a leading British anthropologist who was active in the field of human origin and evolution in the first half of the 20th century. Based on the anatomical characteristics of the feet, he believed that human ancestors were among the great apes that branched off before the tarsiers, and then split off into New World monkeys, Old World monkeys, and gibbons (ape theory). He claimed that at this ape level, brachiation (crossing the arms) was present, and that this led to human bipedal walking (brachiation theory). This can be considered a phylogenetic theory based on comparative anatomy rather than direct fossil research. ... From [Stimulus Conduction System]…The sinoatrial node determines the overall rhythm of the heart's contraction and relaxation, and is therefore called the pacemaker. The cells of the sinoatrial node were discovered in 1907 by Arthur Keith (1862-1956) and Martin Flack (1882-1931) in England (hence the name Keith-Flack node). They are smaller than the myocardial cells that make up the walls of the atria and ventricles. They lack myofibrils, but have all the cellular elements. … *Some of the terminology that mentions "Keith, A." is listed below. Source | Heibonsha World Encyclopedia 2nd Edition | Information |
…20世紀前半に,人類の起源・進化の研究分野で活躍したイギリスを代表する人類学者。足の解剖学的特徴から,ヒトの祖先はメガネザル以前に分岐し,次いで新世界ザル,旧世界ザル,テナガザルと分かれてきた大型類人猿のなかに含まれると考えた(類人猿説)。この類人猿レベルではブラキエーション(腕わたり)をしており,それから人類の二足歩行が導き出されたという(ブラキエーション説)。直接的な化石研究というより,比較解剖に基づく系統発生説といえよう。… 【刺激伝導系】より…このように洞房結節は心臓の収縮,弛緩のリズム全体を決定しているので,歩調とりまたはペースメーカーpacemakerといわれる。洞房結節の細胞群はイギリスのキースArthur Keith(1862‐1956)とフラックMartin Flack(1882‐1931)により1907年に発見されたもので(それでキース=フラック結節ともいう),他の心房,心室の壁を構成する心筋細胞より小さい。また筋原繊維に乏しいが細胞要素はすべて備えている。… ※「Keith,A.」について言及している用語解説の一部を掲載しています。 出典|株式会社平凡社世界大百科事典 第2版について | 情報 |
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