Developmental Biology limb from grafted bud Fig 14.8 The size of limbs is genetically programmed in salamanders. An embryonic limb bud from a large species of salamander Ambystoma tigrinum, grafted to the embryo of a smaller species, Ambystoma punctatum grows much larger than the host limbs-to the size it would have grown in Ambystoma tigrinum Photograph from Harrison, R.G.: 1969
Developmental Biology
Developmental Biology 长骨的生长依赖生长板中细胞数量的增加 GH. IGF-1 trna seeis PH H→B trabecular 。 noed murgon PTHrP PTHrP chond 5 Fig 14.9 Growth plates and endochondral ossification in added at the growth plates, within the growth pates: cartage the long bone of a vertebrate. The long bones of vertebrate cells multiply n the proliferative zone, then mature and underg ngth by gro from cartilaginous growth plates. The growth plates are cartlaginous regons that lie hypertrophy (cell enargement). They are then replaced by bone which is had down by special cells caned osteoblasts. Secondary between he epiphysis of the future jont and the central re ol the bone, the diaphysis in the figure, bone has aiready eplaced cartilage in he diaphysis, and more bone is being
Developmental Biology GH, IGF-1 长骨的生长依赖生长板中细胞数量的增加