tro·pho·blast /ˈtrofəˌblæst/
  滋養層; 滋養母細胞
  tro·pho·blast /ˈtrofəˌblæst/ 名詞
  trophoblast
       n : the membrane that forms the wall of the blastocyst in early
           development; aids implantation in the uterine wall;
           "after implantation of the blastocyst in the uterine wall
           the trophoblast divides into two layers, the chorion and
           the placenta"